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Showing content with the highest reputation on 03/25/2020 in all areas

  1. 4 points
    End of the world as we know it?
  2. 3 points
    Perhaps the last song on the Playlist should be "Stairway To Heaven".
  3. 3 points
    Shout out to @Will Meyer for his PM-120 Service Manual donation. This manual consisted of 8.5x11 sheets so I was able to scan it here at home. Text at 300dpi, Schematics/Layout at 600dpi. Added to our new database this morning. Thank you Will! I also added all of the Phase Linear manuals that we have to the new database.
  4. 3 points
    Tony, I hope its what you needed. Will
  5. 3 points
    I keep a piece of 1/2 copper pipe, an elbow actually, in my pocket. Copper ions destroys the DNA and RNA of Virus, Bacteria and Fungus. Some think I'm crazy, but I dealt with dozens of people a day, here in New Jersey, and have no symptoms. I just rub it with my fingers as much as I can. (INSERT 4TH GRADE JOKE HERE) It's less damaging to skin than hand sanitizer, too. Read THIS. Appl Environ Microbiol. 2011 Mar; 77(5): 1541–1547. Published online 2010 Dec 30. doi: 10.1128/AEM.02766-10 PMCID: PMC3067274 PMID: 21193661 Metallic Copper as an Antimicrobial Surface▿ Gregor Grass,1 Christopher Rensing,2 and Marc Solioz3,* Author information Copyright and License information Disclaimer This article has been cited by other articles in PMC. Go to: ABSTRACT Bacteria, yeasts, and viruses are rapidly killed on metallic copper surfaces, and the term “contact killing” has been coined for this process. While the phenomenon was already known in ancient times, it is currently receiving renewed attention. This is due to the potential use of copper as an antibacterial material in health care settings. Contact killing was observed to take place at a rate of at least 7 to 8 logs per hour, and no live microorganisms were generally recovered from copper surfaces after prolonged incubation. The antimicrobial activity of copper and copper alloys is now well established, and copper has recently been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. In several clinical studies, copper has been evaluated for use on touch surfaces, such as door handles, bathroom fixtures, or bed rails, in attempts to curb nosocomial infections. In connection to these new applications of copper, it is important to understand the mechanism of contact killing since it may bear on central issues, such as the possibility of the emergence and spread of resistant organisms, cleaning procedures, and questions of material and object engineering. Recent work has shed light on mechanistic aspects of contact killing. These findings will be reviewed here and juxtaposed with the toxicity mechanisms of ionic copper. The merit of copper as a hygienic material in hospitals and related settings will also be discussed. The use of copper by human civilizations dates back to between the 5th and 6th millennia B.C. It was the first metal used, presumably because it could be found in a native, metallic form which did not require smelting. Its use remained scattered throughout Europe and the Middle East, and the archeological evidence remains scarce. With the invention of smelting, the metallurgic age began and the advantage of combining copper with tin to form bronze was discovered. The earliest bronze artifacts originated from the Middle East and China and date to before 3000 B.C., but it was not until the second millennium B.C. that bronze was used throughout Europe. The ability to smelt and forge iron from about 1000 B.C. marks the end of the Bronze Age and the beginning of the Iron Age. The oldest recorded medical use of copper is mentioned in the Smith Papyrus, one of the oldest books known (8). This Egyptian medical text, written between 2600 and 2200 B.C., describes the application of copper to sterilize chest wounds and drinking water (8). Greeks, Romans, Aztecs, and others also used copper or copper compounds for the treatment of such ailments as headaches, burns, intestinal worms, and ear infections and for hygiene in general. In the 19th century, a new awareness of copper's medical potency was spawned by the observation that copper workers appeared to be immune to cholera in the 1832 and subsequent outbreaks in Paris, France (8). The use of copper in medicine became widespread in the 19th and early 20th centuries, and a variety of inorganic copper preparations were used to treat chronic adenitis, eczema, impetigo, scrofulosis, tubercular infections, lupus, syphilis, anemia, chorea, and facial neuralgia (8). The use of copper as an antimicrobial agent continued until the advent of commercially available antibiotics in 1932. The spread of antibiotic resistance through selective pressure began and today has made antibiotic-resistant bacteria ubiquitous in hospitals, nursing homes, food processing plants, and animal breeding facilities. This has raised the need for different approaches to keep pathogenic microorganisms at bay. One such alternative is the use of copper surfaces in hygiene-sensitive areas. While this approach is not novel (7), it had lost importance and acceptance in the last few decades. A 1983 report documenting the beneficial effects of using brass and bronze on doorknobs to prevent the spread of microbes in a hospitals remained largely unnoticed (18). Similarly, the idea of using copper vessels to render water drinkable has been revived only very recently as a low-cost alternative for developing countries (37). Currently, there is an intense interest in the use of copper as a self-sanitizing material, and many recent publications deal with mechanistic aspects of “contact killing” (contact-mediated killing) by copper. Go to: COPPER AS A TOXIC BUT ESSENTIAL TRACE ELEMENT Copper is an essential trace element in most living organisms, and more than 30 types of copper-containing proteins are known today. Prominent examples are lysyl oxidase, which is involved in the cross-linking of collagen, tyrosinase, required for melanin synthesis, dopamine β-hydroxylase, which functions in the catecholamine pathway, cytochrome c oxidase, the terminal electron acceptor of the respiratory chain, and superoxide dismutase, required for defense against oxidative damage. In these enzymes, copper serves as an electron donor/acceptor by alternating between the redox states Cu(I) and Cu(II) (15). Other copper proteins, such as plastocyanins or azurins, act as electron carriers. Depending on the type of coordination of the copper to the protein, the redox potential of copper can vary over the range +200 mV to +800 mV. On the other hand, the redox properties of copper can also cause cellular damage. A number or mechanisms have been suggested. Reactive hydroxyl radicals can be generated in a Fenton-type reaction: (1) The extremely reactive hydroxyl radical can participate in a number of reactions detrimental to cellular molecules, such as the oxidation of proteins and lipids (45). Copper ions can also lead to depletion of sulfhydryls, such as in cysteines or glutathione, in a cycle between reactions 2 and 3: (2) (3) The hydrogen peroxide thus generated can in turn participate in reaction 1 and lead to further generation of toxic hydroxyl radicals. It is still not clear to what extent reactions 1 to 3 cause copper toxicity. Cells try to keep H2O2 at very low levels, and reaction 1 may not be the chief toxic mechanism, although this has been frequently claimed. An alternative route of copper ion toxicity has been shown to be the displacement of iron from iron-sulfur clusters (20). Similarly, copper ions may compete with zinc or other metal ions for important binding sites on proteins. The toxic effect of copper on microbes is utilized in agriculture for the control of bacterial and fungal diseases (4), which in fact led to the first thorough investigation of bacterial resistance to copper ions (5). Bacteria evolved a range of mechanisms to protect themselves from the toxic effects of copper ions: extracellular sequestration of copper ions, relative impermeability of the outer and inner bacterial membranes to copper ions, metallothionein-like copper-scavenging proteins in the cytoplasm and periplasm, and active extrusion of copper from the cell. The latter appears to be the chief mechanism of copper tolerance in bacteria and has been extensively studied in Gram-positive and Gram-negative bacteria. In Escherichia coli, the CopA copper-transporting ATPase resides in the cytoplasmic membrane and pumps excess Cu(I) from the cytoplasm to the periplasm (32). In the periplasmic space, the multicomponent copper efflux system CusCFBA and the multicopper oxidase CueO control the copper level and redox state, respectively. In addition to these chromosomally encoded systems, E. coli strains can harbor related, plasmid-encoded systems which further increase copper tolerance (33). All the components of this copper detoxification machinery are transcriptionally upregulated by copper via two regulatory circuits. In Gram-positive bacteria, which are devoid of a periplasmic space and an outer membrane, only CopA-type copper exporters are present and a single regulatory circuit usually controls their expression (34, 36). A number of other components, like copper-binding proteins, copper reductases, etc., support these basic defense systems against copper and have been described elsewhere (2, 16, 22, 35). In contrast to copper defense, copper utilization by bacteria is much less well understood. In Synechocystis, it appears that a special copper uptake ATPase serves in supplying copper to the photosynthetic components in the thylakoid membranes (38). On the other hand, methanotrophic bacteria that require copper for particulate methane monooxygenase secrete siderophore-like substances, the methanobactins, to scavenge extracellular copper (2). In Gram-negative bacteria, like E. coli, it is believed that the metalation of cuproenzymes takes place in the periplasmic space and does not require special copper uptake systems across the cytoplasmic membrane. Finally, many novel proteins of unknown function which are regulated by copper have been identified in the Gram-positive organism Lactococcus lactis (21), and further efforts will be required for an in-depth understanding of copper handling by bacteria. Go to: CONTACT KILLING IN THE LABORATORY The study of the antimicrobial properties of metallic copper surfaces is a relatively recent development and gained momentum when the Environmental Protection Agency (EPA) registered almost 300 different copper surfaces as antimicrobial in 2008 (http://www.epa.gov/pesticides/factsheets/copper-alloy-products.htm). Prior to that, a number of studies have already dealt with the kinetics of contact killing upon exposure of bacteria to copper and copper alloy surfaces (14, 28, 29, 43, 44). Table Table11 summarizes the species tested, test procedures, and killing kinetics. In general, microbes were inactivated on copper within hours, but such parameters as the inoculation technique, incubation temperature, and copper content of the alloy used were not usually investigated in a systematic way and are difficult to compare between studies. Nevertheless, a few general principles appear clear: higher copper content of alloys (43), higher temperature (10), and higher relative humidity (25) increased the efficacy of contact killing. Treatments that lowered corrosion rates, e.g., application of corrosion inhibitors or a thick copper oxide layer, lowered the antimicrobial effectiveness of copper surfaces (9). TABLE 1. Contact killing of microbes by copper surfaces Species Application method Killing time, RTa Reference Salmonella enterica Wet, 4.5 × 106 CFUb 4 h 14 Campylobacter jejuni Wet, 4.5 × 106 CFUb 8 h 14 Escherichia coli O157 Wet, (3-4) × 107 CFUc 65 min 43 Escherichia coli O157 Wet, 2.7 × 107 CFUc 75 min 29 MRSAd (NCTC10442) Wet, (1-1.9) × 107 CFUc 45 min 28 EMRSA-1e (NCTC11939) Wet, (1-1.9) × 107 CFUc 60 min 28 EMRSA-16e (NCTC13143) Wet, (1-1.9) × 105 CFUc 90 min 28 Listeria monocytogenes Scott A Wet, 107 CFUc 60 min 44 Mycobacterium tuberculosis Wet, 2.5 × 107 CFUf 5 to 15 daysg 24 Candida albicans Wet, >105 CFUf 60 min 24 Klebsiella pneumoniae Wet, >107 CFUf 60 min 24 Pseudomonas aeruginosa Wet, >107 CFUf 180 min 24 Acinetobacter baumannii Wet, >107 CFUf 180 min 24 MRSA Wet, >107 CFUf 180 min 24 Influenza A virus (H1N1) Wet, 5 × 105 virusesh 6 h, 4-log decrease 30 C. difficile (ATCC 9689) vegetative cells and spores Wet, 2.2 × 105 CFUc 24-48 h 40 C. difficile NCTC11204/R20291 vegetative cells Wet, (1-5) × 106 CFUi 30 min 42 C. difficile dormant spores Wet, 8 × 106 CFUi Unaffected in 3 h 42 C. difficile germinating spores Wet, 8 × 106 CFUi 3 h, 3-log decrease 42 Pseudomonas aeruginosa PAO1 Wet, 2.2 × 107 CFUj 120 min 10 MRSA NCTC 10442 Wet, 2 × 107 CFU 75 min, 7 log decrease 25 Escherichia coli W3110 Dry, 109 CFUi 1 min 12 Acinetobacter johnsonii DSM6963 Dry, 109 CFUk A few minutes 12 Pantoea stewartii DSM30176 Dry, 109 CFUi 1 min 12 Pseudomonas oleovorans DSM 1045 Dry, 109 CFUk 1 min 12 Staphylococcus warnerii DSM20316 Dry, 109 CFUk A few minutes 12 Brachybacterium conglomeratum DSM 10241 Dry, 109 CFUk A few minutes 12 Aspergillus flavus Wet, (2-300) × 105 sporesc 120 h 41 Aspergillus fumigatus Wet, (2-300) × 105 sporesc >120 h 41 Aspergillus niger Wet, (2-300) × 105 sporesc > 576 h 41 Fusarium culmonium Wet, (2-300) × 105 sporesc 24 h 41 Fusarium oxysporum Wet, (2-300) × 105 sporesc 24 h 41 Fusarium solani Wet, (2-300) × 105 sporesc 24 h 41 Penicillium crysogenum Wet, (2-300) × 105 sporesc 24 h 41 Candida albicans Wet, (2-300) × 105 sporesc 24 h 41 Enterococcus hirae ATCC 9790 Wet, 107 CFUc 90 min 27 Different Enterococcus spp. Wet, 106 CFUf 60 min 39 Candida albicans Dry, 106 CFUk 5 min 31 Saccharomyces cerevisiae Dry, 106 CFUk 30 s 31 Open in a separate window aRT, room temperature; only the values for the most efficient alloy are reported. bInoculation with 1.5 ml of culture (4.5 × 106 CFU), kept under humid conditions. cInoculation with a 20-μl drop of culture. dMethicillin-resistant Staphylococcus aureus. eEpidemic methicillin-resistant Staphylococcus aureus. fTwenty microliters of culture spread on coupons. gTime before strain became culture positive in Bactec 12B growth medium after exposure to copper. hInoculation with 20 μl of virion suspension. iOne hundred microliters of dilute culture. jTwenty-five microliters of culture spread on coupons with a glass spreader. kThin film applied with a cotton swab. In most studies on contact killing, a “wet” inoculation technique was used by applying typically 20 μl of cell suspensions to coupons. While this is a valid approach for laboratory testing, it might not mimic well the dry copper surfaces encountered in health care environments. In an alternative “dry” method, a small volume of liquid is applied to coupons with a cotton swab. The thin film of liquid evaporates within seconds and allows direct contact of all cells with the metal surface. Under these conditions, E. coli and other bacteria were inactivated within a few minutes of exposure (11-13). This suggests that dry metallic copper surfaces are even more antimicrobial than moist ones, which raises interesting questions about the mechanism of contact killing. Certain Gram-positive bacteria, such as members of the Bacilli and Clostridia, form endospores which can resist heat, radiation, desiccation, denaturing chemicals, etc. Thus, endospores pose a real challenge to aseptic procedures. Clostridium difficile is an important pathogen of the group of spore-forming bacteria and leads to diseases like diarrhea and colitis. Excretion of endospores by infected persons might contaminate surfaces and generate a long-term reservoir for transmission. In spite of the robustness of these spores, killing by metallic copper has been reported in some cases. In one study, viable spores were found to be diminished by 99.8% in 3 h on solid copper (42), while complete inactivation of spores in 24 to 48 h was reported in a second study (40). Clearly, endospores are more resilient to contact killing by copper than vegetative cells, but killing may still occur and thus warrant the strategic use of copper to curb spreading of C. difficile. What is the mechanism of contact killing? This question cannot yet be answered clearly, but a number of factors contributing to contact killing have been identified. In wet inoculation of copper surfaces with bacteria, the copper homeostatic systems of the cell appear to play a role. Pseudomonas aeruginosa PAO1 deleted in the cinR gene, encoding a copper-responsive regulator, or the cinA gene, encoding an azurin-like protein involved in copper resistance, was more rapidly killed on copper surfaces than the wild type (10). Similarly, an Enterococcus hirae mutant deleted in the gene for the copper export pump, copB, was killed after 75 min, while complete inactivation of the wild type took 90 min. In E. coli, finally, deletion of three systems, cueO (encoding periplasmic copper oxidase), cus (encoding a periplasmic copper efflux system), and copA (encoding a cytoplasmic copper extrusion pump), led to faster killing kinetics than for the wild type, preincubated with copper to express the copper-homeostatic genes (10, 13). Preincubation with copper also increased the killing time of E. coli carrying the plasmid-borne pco copper resistance system (13). Clearly, bacterial copper resistance systems do not offer protection from contact killing, but they do prolong survival. This suggests the involvement of dissolved copper ions in the killing process (Fig. (Fig.1).1). This is further supported by the effect of medium composition on contact killing. Application of the cells to copper surfaces in Tris buffer dramatically enhanced contact killing, and much more copper was dissolved by Tris buffer than by water or phosphate buffer (27). Although spent medium dissolved as much copper as Tris buffer, this copper was probably tightly bound to media components and not bioavailable and thus did not accelerate contact killing. For E. coli, it was shown that copper chelators protected cells from contact killing (13). All these observations support a role of surface-released free copper ions in contact killing, but they are clearly not the sole determinant of the process. FIG. 1. Cartoon of the tentative events in contact killing. (A) Copper dissolves from the copper surface and causes cell damage. (B) The cell membrane ruptures because of copper and other stress phenomena, leading to loss of membrane potential and cytoplasmic content. (C) Copper ions induce the generation of reactive oxygen species, which cause further cell damage. (D) Genomic and plasmid DNA becomes degraded. Recent studies showed that large amounts of copper ions were taken up by E. coli over 90 min, when cells were applied to copper coupons in a standing drop. When cells were plated on copper by the dry method, the accumulation of copper ions by cells was even more dramatic, reaching a low molar concentration, or 27-fold the level observed by wet plating, in a fraction of the time. The copper ion level of cells remained high throughout the killing phase, suggesting that cells become overwhelmed by their intracellular copper (11). Another factor that influences cell survival on metallic copper is oxidative stress. Generation of reactive oxygen species (ROS) is probably mediated by redox cycling between the different copper species, Cu(0), Cu(I), and Cu(II). The absence of oxygen did not inhibit contact killing of E. coli but doubled the time required for complete killing of 109 cells from 1 to 2 min in the dry plating method (13). This indicates that stress caused by reactive oxygen species is another factor contributing to contact killing. The fate of DNA during contact killing by copper has also been investigated. According to one study, DNA is a major target of copper toxicity, leading to rapid DNA fragmentation and cell death (39). This contrasts with recent findings by Espirito Santo et al., which suggest that the primary damage to cells in contact killing is membrane damage (11). It is likely that DNA damage ensues only as a secondary event following cell death. It could be shown that membrane damage by copper was not accompanied by an increase in the mutation rate or DNA fragmentation. Deinococcus radiodurans is a bacterium that is exceptionally resistant to ionizing radiation because of its ability to repair even highly fragmented DNA. Remarkably, D. radiodurans was as sensitive as E. coli to contact killing by copper (11). At the current state of knowledge, it appears that contact killing proceeds by successive membrane damage, copper influx into the cells, oxidative damage, cell death, and DNA degradation (cf. Fig. Fig.1).1). Clearly, this sequence of events is still tentative, and further work on contact killing is required to offer more-detailed molecular insight into the process. How soiling, cleaning, exposure to chemicals, and tarnishing affect the antimicrobial properties of copper has not yet been studied in detail. In a study where copper surfaces were inoculated with bacteria in 1% solutions of albumin, dried, and subsequently cleaned with 70% ethanol or 1% sodium hypochlorite, there was a build-up of residues and a concomitant decrease in killing efficiency (1). On the other hand, it was reported that copper surfaces remained active when soiled (42). Also, it was found that there was no reduction in killing efficiency over 30 cycles of bacterial inoculation, followed by cleaning with a 1% nonionic detergent solution (M. Solioz and C. Molteni, unpublished observations). From what is known about the mechanism of contact killing, it appears clear that a clean copper surface, free of oxide, wax, or other coating agents, will always be active in contact killing. A future task will be to establish reproducible protocols for cleaning copper surfaces such that they maintain maximal efficacy in contact killing. Go to: CONTACT KILLING IN HEALTH CARE SETTINGS Touch surfaces commonly found in hospitals, such as door handles, touch plates, bed rails, call buttons, toilet seats, etc., can be highly contaminated with microbes. It was shown that germs such as Staphylococcus aureus and Acinetobacter spp. can persist on such surfaces for months (17). Frequent and efficient cleaning, combined with proper hand hygiene, diminishes transmission of infections, but complete elimination appears impossible (6). With the worldwide spread of such antibiotic-resistant organisms as methicillin-resistant S. aureus (MRSA) or more recently New Delhi metallo-beta-lactamase (NDM)-harboring strains, dangerous nosocomial infections have become a primary concern for hospitals. It can be approximated that in 2006 there were about 720,000 hospital-acquired infections in the United States, causing $125 billion in extra hospital charges and more than 74,000 fatalities (database on hospital-acquired infections in Pennsylvania [http://www.phc4.org/]). These numbers emphasize the need for new approaches to hospital hygiene, and antimicrobial copper promises to provide one such approach to supplement the current hygiene measures. Stainless steel is the metal predominantly used in health care environments because of its “clean” appearance and corrosion resistance. However, there is no inherent antimicrobial advantage to using this metal (19). Copper surfaces, with their self-sanitizing properties, could be envisioned as making an important contribution to infection control. Thus, the use of antimicrobial metallic copper surfaces is likely to provide protection from infectious microbes by reducing surface contamination, as was recently shown in successful hospital trials. Hospital trials are now ongoing worldwide, and the first results have been reported (3, 23, 26). The 10-week Selly Oak Hospital trial in Birmingham, United Kingdom, was carried out with both copper and control surfaces in the same ward. This approach was chosen to decrease potential bias in the microbial challenge to copper and control surfaces (3). In addition, after 5 weeks, the copper-containing and non-copper-containing surfaces and items were interchanged to further diminish bias. Bacterial contamination of a copper-coated (70% Cu) composite toilet seat, brass tap handles (60% Cu), and a brass door push plate (70% Cu) was compared against that of equivalent items with plastic, chrome-plated, or aluminum surfaces. Median numbers of bacteria recovered from surfaces of copper-containing items were between 90% and 100% lower than those from control surfaces. While MRSA and C. difficile were not isolated in this study, methicillin-sensitive S. aureus (MSSA), vancomycin-resistant Enterococcus (VRE), and E. coli were found only on control surfaces but not on copper surfaces. It is noteworthy that in contrast to laboratory studies, in which unused copper surfaces are usually tested, this hospital trial employed “aged” surfaces. The items to be tested were installed at least 6 months prior to commencement of the study. This also allowed domestic staff and health care workers to become accustomed to the copper-containing fixtures. In addition, it provides support for the notion that copper surfaces will not lose their antimicrobial activity over time. Nevertheless, long-term studies are still required to evaluate the sustainability of the antimicrobial properties of copper surfaces over the course of several years. A second hospital trial was contracted at a walk-in primary health care clinic in Grabouw, a rural region of the Western Cape, South Africa (23). Here, a consulting room rather than a medical ward was refitted with copper surfaces. In this room, items in frequent contact with patients and staff, such as desks, trolleys, the top of a cupboard, and windowsills, were covered with copper sheets. During 6 months, surfaces were sampled every 6 weeks for a 4.5-day period, with multiple samplings per day. An overall 71% reduction in the bacterial load of the copper surfaces was observed compared to that of the control surfaces, with significantly lower mean total colony counts during working days and overnight (23). Interestingly, comparable numbers of bacteria were counted when surfaces remained untouched over the weekends (71 h), but this phenomenon was not investigated further. Finally, in the German trial at the Asklepios Hospital, Hamburg, touch surfaces in patient bed rooms, rest rooms, and staff rooms in an oncological/pneumological and a geriatric ward were refitted with brass (a copper/zinc alloy). Control rooms retained aluminum door handles and push plates and plastic light switches (26). The total duration of this trial was 32 weeks, equally divided into summer and winter months. The number of aerobic, heterotrophic bacteria on these surfaces was determined once or twice per week. The presence of ciprofloxacin-resistant Staphylococcus (CRS) as an indicator organism for multiple-drug-resistant nosocomial pathogens was determined. Following sampling each morning, all surfaces were cleaned with a disinfectant. Additional samples were taken immediately after cleaning and 3, 6, and 9 h later. Over both halves of the trial, there was an average 63% reduction in the bacterial load on copper surfaces compared to controls. Results were significant for door handles, which had the highest overall microbial load. Bacterial numbers recovered from copper and plastic light switches were similar. No significant differences in the survival of CRS on copper and noncopper surfaces were observed, but on average cell numbers from copper were lower. Interestingly, the repopulation of surfaces by microbes occurred at different rates. For copper surfaces, the average rate of repopulation was less than half of that for the control surfaces, documenting the antibacterial properties of copper surfaces. Results are still awaited from trials at the Memorial Sloan-Kettering Cancer Center in New York City, NY, the Medical University of South Carolina in Charleston, SC, the Ralph H. Johnson VA Medical Center in Charleston, the Hospital del Cobre de Calama in Chile, and the Kitasato University Hospital in Japan. In the hospitals trials described so far, only heterotrophic, aerobic bacteria were assessed. It would be interesting to conduct similar trials in which anaerobic bacteria, including endospore formers and eukaryotic microbes, are also evaluated, since these microbes pose their own unique challenges. Go to: CONCLUSIONS AND FUTURE DIRECTIONS The antimicrobial properties of copper surfaces have now been firmly established. Hospital trials have shown a reduction in bacterial counts, indicating that copper surfaces are a promising additional tool alongside other hygienic measures to curb the number and severity of hospital-acquired infections. At this point, additional studies would be helpful in determining the most cost-effective way to give maximal protection in hospitals. For example, should only highly frequented sites be made of copper, e.g., doorknobs, faucets, and bed rails, or should the majority of accessible surfaces be made of copper? In addition, different copper alloys should be tested not only for their effectiveness but also for their esthetic appeal. Finally, the antimicrobial properties of copper surfaces must be integrated with other methods of disinfection and the overall hygiene concept of a health care facility. Additional measures, such as the addition of spore germinants to cleaning solutions to improve killing of spores, also deserve further investigation. Bacterial resistance is a major concern in infection control. Are there bacteria which are naturally refractory to contact killing by copper? It is known that live bacteria can be isolated from copper-containing surfaces, and in a recent study, 294 isolates from European 50-cent coins were investigated in regard to copper resistance. Some of the isolates indeed exhibited prolonged (1 to 3 days) survival on dry but not on moist copper surfaces, but none of the strains was exceptionally copper resistant in culture (12). Survival on copper-containing coins appeared to be the consequence of either endospore formation, survival on patches of dirt, or a special ability to endure a dry metallic copper surface. While the latter, rare property is not yet understood, widespread appearance of bacterial resistant to contact killing appears unlikely for the following reasons: (i) plasmid DNA is completely degraded after cell death by contact killing, preventing the transfer of resistance determinants between organisms (39), (ii) contact killing is very rapid, and cells are not dividing on copper surfaces, precluding the acquisition of resistance, and (iii) copper and copper alloys have been used by humans for thousands of years, yet no bacteria fully resistant to contact killing have been discovered. Go to: ACKNOWLEDGMENTS Financial support from the Swiss National Foundation (grant 3100A0_122551 to M.S.), pilot NIH grant P20 RR-017675 from the National Center for Research Resources (to G.G.), National Institutes of Health grant GM079192 (to C.R.), grants from the International Copper Association to G.G., C.R., and M.S., and a grant from the Swiss State Secretary for Education & Research (to M.S.) are greatly appreciated. Equipment in the lab of G.G. was purchased with Nebraska Tobacco Settlement Biomedical Research Development Funds. The contents of this work are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.
  6. 2 points
    This play list was put out by the Arizona AV Club today. We aren't under quarantine yet, but a lot of the old farts in Scottsdale are staying home listening to tunes.
  7. 2 points
    I take a zinc supplement daily. I can't say for sure if it works and on what. But, it's been in my daily routine for many years.
  8. 2 points
    It will work as parts or a whole amp. Only time will tell. Tony
  9. 2 points
    The Mars Reconnaissance Orbiter (MRO) delivers once again... https://www.universetoday.com/145441/another-incredible-picture-of-mars-this-time-from-a-region-just-outside-valles-marineris/
  10. 2 points
  11. 2 points
    Get the M-0.5t! Hashy believes they can be modded for more power and I believe it.
  12. 2 points
    I have seen one definite benefit from this COVID-19 nonsense: People are working from home. This will help change the business mindset for a lot of "old school" managers. At my previous job the VP I reported to was always making comments about how people needed to be in the office so they could focus on work. He would always add "I know you are different" because I worked from home. (Some of you remember that I was in limbo for 24 months because I packed my house to move to Birmingham for this VP. Luckily I landed another job and I never had to move.) I was in his office one day and I said "Let's take a walk." We walked around the large office, a mixture of private offices on the perimeter of the building and massive cubicle farms on the interior, with two large break rooms, a mail room and a "common area". As we walked around I asked him to note how many people were gathered in all of these areas. There were two or more people in most of the offices and people gathered about in all other areas. As we walked the floor plenty of folks saw us coming and broke away from their gathering, hurrying to their desk. I asked him "Do you think ALL of these conversations are business related?" He said it's easy to see that isn't the case. I asked him how many of these people were married or in a relationship? He said most of the folks were, except for a batch of young, single guys fresh out of college. I asked him how many of the folks that were married or in relationships had spouses who were not employed? He conceded that most spouses / significant others were likely employed. I asked him if he decided to work from home if his wife sat in his home office and bothered him all day? He laughed and said she knew better. I asked him - so if all of these people worked from home and were alone for the most of the day, how many would be gathered in the break rooms, around each others desks, etc. socializing instead of working? He said I see your point but they could be watching TV, playing X-Box, etc. I asked him if he trusted his management team? He said of course - you guys run the business. I asked him if he thought that I did a good job with staffing levels, work load completion, etc. He said of course - if you didn't I'd get rid of you and get someone who would. I asked him how any of my team could possibly be watching X-Box or TV if I was giving them assignments and they were getting them completed on time and within budget? Wasn't it my responsibility to ensure that the team's productivity was maintained and if I noticed someone slipping I would investigate and resolve it? Even with that lengthy description of events, he still clung to the "you need to be in the office" mindset. I left that job of 34 years on July 23, 2018. In my new role I manage a team of 11 design engineers - ALL of them work from their homes, as do I. We use various technologies to stay in contact and collaborate and I speak to every team member at least twice a week, even if only to BS for a few minutes. We are more productive than the team I managed in the previous role. As a rule we seem to be a happier bunch as well. Fast forward to the COVID-19 madness... I have maintained contact with my former VP. We were friends for many years as we both grew our careers. I spoke to him last week and he related that they had outfitted their employees with headsets, dual monitors and docking stations for use at their homes. He was concerned that everyone was going to be at home instead of the office where "we could keep an eye on them." I asked if their work was getting done? He responded with a hesitant "Yeah, but I'm still not sure how this is going to work long-term." I asked him how much the 5th floor he leased in the fancy office building cost per month, including utilities. He said it was over $50,000. I asked him if he thought employees just might be happier and more productive without having to drive to and from the office each day? He said he was sure they were happier because of the traffic everyone endured getting to the office, especially with Interstate construction that had been going on for several years. I personally believe we are seeing the tip of the iceberg related to the spread of this virus, which will likely lead to things being shut down or restricted for longer than the next two or three weeks. I plan on calling him again as this unfolds and see if his 1960's mentality regarding home workers is starting to change?
  13. 1 point
  14. 1 point
    I have relied on zinc lozenges to shorten the duration of a sore throat for years. And i wear a copper wrist bracelet.
  15. 1 point
    From the CDC: Key Points Nationally, the percent of specimens testing positive for influenza at clinical laboratories continued to decrease while ILI activity increased for the second week in a row after declining for three weeks. Due to the ongoing COVID-19 pandemic, more people may be seeking care for respiratory illness than usual at this time. Nationally, influenza A(H1N1)pdm09 viruses are now the most commonly reported influenza viruses this season. Previously, influenza B/Victoria viruses predominated nationally. Laboratory confirmed influenza-associated hospitalization rates for the U.S. population overall remain moderate compared to recent seasons, but rates for children 0-4 years and adults 18-49 years are now the highest CDC has on record for these age groups, surpassing rates reported during the 2009 H1N1 pandemic. Hospitalization rates for school-aged children (5-17 years) are higher than any recent regular season but remain lower than rates experienced by this age group during the pandemic. Pneumonia and influenza mortality levels have been low, but 149 influenza-associated deaths in children have been reported so far this season. This number is higher than recorded at the same time in every season since reporting began in 2004-05, except for the 2009 pandemic. CDC estimates that so far this season there have been at least 38 million flu illnesses, 390,000 hospitalizations and 23,000 deaths from flu. Antiviral medications are an important adjunct to flu vaccine in the control of influenza. Almost all (>99%) of the influenza viruses tested this season are susceptible to the four FDA-approved influenza antiviral medications recommended for use in the U.S. this season. Hospitalizations per 100,000 is 65.1 (all ages), with a 7.1% mortality rate (flu and pneumonia). Which makes covid-19 seem like a vacation at this point. According to the math, it's safer to get covid-19 than the flu. The numbers we see for the coronavirus is number of confirmed tested vs hospitalizations. It's still a skewed picture of data. However, what's undeniable is that it causes substantial hospitalizations in some areas. If Wuhan and Italy never made the news, what would we be thinking about all this right now? So far, only two outbreaks in the entire world have caused stress on local healthcare facilities - Wuhan and Italy. I don't think these outbreaks have been explained properly. What the hell is going on? It seems that the total number of infected is substantially higher than implied. But why some areas are overrun by severe illness is a bit boggling to me if we consider what happens with the flu and pneumonia every year. A better question, since the flu is still in widespread circulation right now... How many covid-19 cases also have the flu and/or bacterial pneumonia? Pneumonia happens to be the 5th leading cause of death without covid-19. I'm not writing this to oppose the shutdowns. I'm trying to understand what is going on with the hospitalizations because the virus doesn't seem to be as dangerous as expected. Yes, it definitely spreads rapidly but part of that reason is because so many people don't get sick from it! Are we looking at a feather that causes the house of cards to fall over?
  16. 1 point
    Today was a good day to spend at the scanner and working on the files. I replaced an extremely poor C-16 Owner's Manual with a fresh much improved scan.
  17. 1 point
    Yes, from a communal standpoint, I can see that citizen M watching netflix all day is impeding citizen P's medical conferencing. From the commerce standpoint, citizen P is paying for 200/20 and should get it irrespective of citizen M's usage
  18. 1 point
    Looking forward to his new album Blue Moon releasing on 3/27. Heard a couple tracks on a local jazz station and they sounded great! Here's the first release from that album.......
  19. 1 point
  20. 1 point
    Call the Doctor.....J.J. Cale (Naturally)
  21. 1 point
  22. 1 point
    For better or for worse, luck can sweep in from nowhere and alter our lives... https://aeon.co/ideas/if-all-our-actions-are-shaped-by-luck-are-we-still-agents
  23. 1 point
    Just a couple of links to live cams with animals. Naked Mole Rats https://nationalzoo.si.edu/webcams/naked-mole-rat-cam Lots to choose from but tend to watch the eagles. Before bandwidth sharing concerns, my wife would have one on during stressful times at a old job. https://explore.org/livecams https://www.wdwinfo.com/news-stories/disneys-animal-kingdom-shows-off-baby-porcupine/
  24. 1 point
  25. 1 point
    Mindi Abair & The Boneshakers Featuring Joe Bonamassa 'Pretty Good For A Girl'
  26. 1 point
    Human memory is complex... https://brainworldmagazine.com/memory-versus-media-creating-false-memory-virtual-reality/
  27. 1 point
    Wise Data Recovery is part of Wise Care 365 and can recover deleted photos, documents, videos, emails and more from any of your drives... https://www.majorgeeks.com/files/details/wise_data_recovery.html
  28. 1 point
  29. 1 point
  30. 1 point
    The Who The Seeker (LIVE)
  31. 1 point
    Hi Sk1bum, Thank you for sharing! Funny thing is, I live in the Austin area. There's so much music here, you cant possibly take it all in. If any of you make your way here (after the Covid-apocalypse, of course!) Be sure to check out Parker Jazz Club and The elephant Room. 🙂
  32. 1 point
    It made it here in one piece. Thanks Will! Tony
  33. 1 point
    Maybe not a bright spot, but a revelation perhaps. My wife and several peers are having trouble with choppy video on their tele-health appointments with patients. We WERE getting 175mbps throughput with our ISP (COX); that's down to 2.75 on a good day. About 5 is minimum for smooth video at lower resolution. Cox is waving their hand and blaming demand. I understand everyone's at home, but a drop from 175 to 2.75? that implies to me that I've been overpaying considerably for the service, and that their backbone is woefully inadequate. Cox has been in this for a long time, if their backbone is THIS inadequate, wjhy hasn't it been upgraded with the money I'm overpaying them?
  34. 1 point
    You may really like your MXR when it’s finished. But who am I to stop more Carver collecting?
  35. 1 point
    I had an M0.5t for a while. I thought it was a real nice amp, but sold it to get a more powerful amp. If I remember correctly it cannot be bridged. It is rated at 140 watts @ 8 ohms, and 220 watts @ 4 ohms.
  36. 1 point
    I have an MXR 150 that greg is working on and I am pushing V15E Pro Cerwin Vegas. They are rated at 350w. I am interested in the DPL-33 and the C-1 and if any of the power amps can have more power than the MX then I might go with them. Can the M0.5t be bridged? I think if I can get some equipment for a good price then I would like to start collecting some pieces. Also, I would like a Carver CD player. Thanks for the feedback so far guys. I appreciate it!
  37. 1 point
    Apple is offering users in the U.S. (and hopefully elsewhere soon) a selection of free books and audiobooks to help while away the hours while in self-isolation... https://www.cultofmac.com/695039/apple-books-offering-free-novels-and-audiobooks-to-get-you-through-self-isolation
  38. 1 point
    Shout out to @4RUNNER for his TD-1700 Owners Manual Donation. Added today. I also found a Receiver 6200 Service Manual in my stash. Scanned and added today. I also started adding in the Phase Linear manuals this morning. I will be working on getting these posted this week. @Will Meyer Thanks for your donations. I received another one today. I like to take the large sheets to Staples were I can do full sheet scans. So it might be a few days/weeks before I can get there. Wife has me sequestered.
  39. 1 point
    I learned that the 'common' col/flu infectious rate is only 1:1.3 (one sick person infects on average 1.3 others) I thought it was higher than that, and have often in my life 'blamed' others for 'giving us all a cold' when in fact we probably just got it ourselves
  40. 1 point
    I really hope that many of the protocols recently instituted become permanent. Shouldn't public transportation be cleaned and disinfected regularly? Shouldn't store owners wipe down the door handles to their places of business regularly? Our school district has successfully implemented "online" classrooms. My son did raise one concern... will this eliminate "snow days?" ...
  41. 1 point
    Pretty much any heavy metal is toxic to pathogens, especially silver.
  42. 1 point
    I agree with the above statements regarding trust and management. I have been working from a home office for 5 or 6 years now. There are a LOT fewer distractions in my home office than I had with an office at the hospital. My wife has been with her current employer nearly a year and has been working from home for around 5 months now. Her office is upstairs, mine is in the basement aka my Subterranean Lair. Her employer is very happy with her performance numbers, my manager has known me for a long long time and knows I take care of business. My productivity numbers I’m sure reflect this as well. Leadership - real leadership - will know who’s up to the task and will let the team do what they do best. I share the hope that this will serve as a wake up call to businesses everywhere. What we do in an office ACN be done in any office. It doesn’t matter where the office is. With this, the COVID-19 scare really hasn’t affected us at all.
  43. 1 point
    I agree with you. And more benefits to mention: The macro-economic benefits, strain/wear on infrastructure, burning of hydrocarbons for commuting, effect on the environment, and so on. And microeconomic benefits that no longer commuting will bump everyone's total comp reducing cost of fuel..., and more. And quality of life for workers, being home with family more, seeing kids events, participating in local life, and so on. There are some hurdles. The challenge some organizations may have is how to prevent/stop the knee-jerk fear that drives micro-management. Managers need some training both in the art of managing this way, as well as working through the transition in culture, as your experience points out. I'm with you on your observation..., but my recent experience as I get older, and work for younger managers is that there continues to be a deficit in remote management skills among many (not all) to be able to lead this way. Interesting recent observation from "webinarists" (a new species of internet "teacher" [comment omitted]). Many of the business/management/leadership webinars (that I get invites in my inbox to in the last few weeks) have shifted to topics on "60 Minutes to Master Managing Remote Teams. Register Now $100." I'm not sure that this culture shift can be taught to old-school managers in 60 minutes for $100. Quick look at the "webinarist" shows weak or no management experience or other credential. Irony or?
  44. 1 point
    The Carversite is primarily a community. We want a safe and pleasurable site for all that want to participate here. We do allow buying, selling, and trading in the Trading Post area. Listed below are some common sense guidelines for use of the Trading Post. To use this area, you must have reached Novice status. Inbounds can read but not post to this category. The Carversite Administrators, Moderators, and Staff are not responsible for your private transactions. The Carversite is not responsible for the outcome of any transaction of any kind. Caveat emptor! If you list something for sale, please post pictures and describe the condition in as much detail as possible. If you list something for sale, be honorable and stand behind it. If you sell something to another novice or member, make sure that it's packed properly to minimize the chances of shipping damage. If in doubt, ask questions. It is your responsibility as a seller to do everything in your power to ensure the package is delivered safely. Pictures of the packaging process will help get the item reimbursed if there is shipping damage. Don't be afraid to take too many pictures. If you buy something from another novice or member, be reasonable. If there's a problem, contact the other party privately, and give them a chance to make it right. Again, be reasonable, and do not expect perfect pieces for throw away prices. Do not bash each other in the forums. This will result in sandboxing of both parties. Novices can buy, sell, and trade here: https://thecarversite.com/forum/50-novices-gear-fswtb/ Members can buy, sell, and trade from the Novices area and here https://thecarversite.com/forum/17-members-gear-fswtb/ Any evidence of wrongdoing submitted to the Staff will result in Sandboxing, and then a permanent ban if necessary.
  45. 1 point
    I will report back what I end up doing. Tony
  46. 1 point
    I just dropped it off at FedEx. I hope this works out for you. You've definitely got a higher use for it than I had planned.
  47. 1 point
    Hello all and thanks for a wonderful Carver resource. I've been wanting a Carver system for many years and recently had the opportunity to purchase a very nice suite of equipment. My local repair shop and second hand dealer had this set. A friend of mine went in to pick up some things that he had had repaired and mentioned that there was a complete Carver set. I called the next day and picked it up the day after that. I am now the proud owner of a TX-11 tuner, C-4000t preamp and M-1.5t amplifier. I'm using them to drive a set of Polk SDA 2 speakers, and how wonderful does it all perform! First audition was yesterday afternoon. More to follow.
  48. 1 point
    Just working out the details. Tony
  49. 1 point
    Brian Culbertson 'Colors of Love' from the same-titled album
  50. 0 points
    Slade - Mama Weer All Crazee Now
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