Successful operation of 4H-silicon carbide (SiC) MOSFET and integrated electronic circuit based on 4H-SiC MOSFET is reported at temperature up to <inline-formula> <tex-math ...notation="LaTeX">500~^{\circ }\text{C} </tex-math></inline-formula> in air. The high-temperature operation of the integrated circuit (IC) based on 4H-SiC MOSFET strongly depends on the reliability of metal/SiC contact. Based on the transfer length method (TLM), the Ni/Nb/n-type 4H-SiC junction exhibits ohmic behavior with specific contact resistance of <inline-formula> <tex-math notation="LaTeX">1.86\times 10^{-{4}}\,\, \Omega \cdot </tex-math></inline-formula>cm 2 when operating at <inline-formula> <tex-math notation="LaTeX">500~^{\circ }\text{C} </tex-math></inline-formula>. In contrast, the voltage gain of the amplifier is strongly governed by the variation of carrier mobility of the 4H-SiC MOSFET when temperature varies from room temperature to <inline-formula> <tex-math notation="LaTeX">500~^{\circ }\text{C} </tex-math></inline-formula>. The experimental results show that, when the temperature is increased from <inline-formula> <tex-math notation="LaTeX">20~^{\circ }\text{C} </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">300~^{\circ }\text{C} </tex-math></inline-formula>, the amplifier gain of the IC increased from 23.8 to 153.0. Though the voltage gain decreases when the temperature increases above <inline-formula> <tex-math notation="LaTeX">300~^{\circ }\text{C} </tex-math></inline-formula>, it is still higher than 50 at <inline-formula> <tex-math notation="LaTeX">500~^{\circ }\text{C} </tex-math></inline-formula>. These results indicate that integrated electronic circuits based on this 4H-SiC MOSFET technology could be potentially used for harsh environment applications.
Staphylococcus epidermidis infections Vuong, Cuong; Otto, Michael
Microbes and Infection,
04/2002, Letnik:
4, Številka:
4
Book Review, Journal Article
Recenzirano
The opportunistic human pathogen
Staphylococcus epidermidis has become the most important cause of nosocomial infections in recent years. Its pathogenicity is mainly due to the ability to form ...biofilms on indwelling medical devices. In a biofilm,
S. epidermidis is protected against attacks from the immune system and against antibiotic treatment, making
S. epidermidis infections difficult to eradicate.
A heterojunction of p-Si(100)/n-ZnO nanorods was fabricated by a simple hydrothermal method. The photocatalytic activity of this heterojunction was examined by degradation of Rhodamine B (RhB) under ...UV light irradiation. The results indicated that the p-Si(100)/n-ZnO nanorods heterojunction exhibits higher photocatalytic activity compared to that of a glass/n-ZnO nanorods. The inner electric field created by the space charge region of heterojunction will oppose the recombination of photogenerated electrons and holes. Furthermore, this heterojunction serves as a convenient recyclable and effective photocatalyst. The photodecomposition rate of RhB after 5 cycles is negligible change in an experiment using this heterojunction.
•A heterojunction of p-Si/n-ZnO NRs was fabricated by a simple hydrothermal method.•An improvement in photocatalytic activity of the heterojunction was demonstrated.•The enhancement is attributed to the inner electric field and effective surface area.•This heterojunction serves as a convenient recyclable and effective photocatalyst.
Staphylococcus aureus remains one of the leading causes of morbidity and mortality worldwide. This is to a large extent due to antibiotic-resistant strains, in particular methicillin-resistant S. ...aureus (MRSA). While the toll of invasive MRSA infections appears to decrease in U.S. hospitals, the rate of community-associated MRSA infections remains constant and there is a surge of MRSA in many other countries, a situation that calls for continuing if not increased efforts to find novel strategies to combat MRSA infections.
This review provides an overview of current investigational drugs and therapeutic antibodies against S. aureus in early clinical development (up to phase II clinical development). It includes a short description of the mechanism of action and a presentation of microbiological and clinical data.
Increased recent antibiotic development efforts and results from pathogenesis research have led to several new antibiotics and therapies, such as anti-virulence drugs, as well as a more informed selection of targets for vaccination efforts against MRSA. This developing portfolio of novel anti-staphylococcal drugs will hopefully provide us with additional and more efficient ways to combat MRSA infections in the near future and prevent us from running out of treatment options, even if new resistances arise.
Hospital readmissions following severe infections are a major economic burden on the health care system and have a negative influence on patients' quality of life. Understanding the risk factors for ...readmission, particularly the extent to which they could be prevented, is of a great importance. In this study we evaluated potentially preventable risk factors for 60-day readmission in patients surviving hospitalization for complicated urinary tract infection (cUTI). This was a multinational, multicentre retrospective cohort study conducted in Europe and the Middle East. Our cohort included survivors of hospitalization due to cUTI during the years 2013-2014. The primary outcome was 60-day readmission following index hospitalization. Patient characteristics that could have influenced readmission: demographics, infection presentation and management, microbiological and clinical data; were collected via computerized medical records from infection onset up to 60 days after hospital discharge. Overall, 742 patients were included. The cohort median age was 68 years (interquartile range, (IQR) 55-80) and 43.3% (321/742) of patients were males. The all-cause 60-day readmission rate was 20.1% (149/742) and more than half were readmitted for infection 57.1%, (80/140). Recurrent cUTI was the most frequent cause for readmission 46.4% (65/140). Statistically significant risk factors associated with 60-day readmission in multivariable analysis were: older age (odds ratio (OR) 1.02 for an one-year increment, confidence interval (CI) 1.005-1.03), diabetes mellitus (OR 1.63, 95% CI 1.04-2.55), cancer (OR 1.7, 95% CI 1.05-2.77), previous urinary tract infection (UTI) in the last year (OR 1.8, 95% CI: 1.14-2.83), insertion of an indwelling bladder catheter (OR 1.62, 95% CI 1.07-2.45) and insertion of percutaneous nephrostomy (OR 3.68, 95% CI 1.67-8.13). In conclusion, patients surviving hospitalization for cUTI are frequently re-hospitalized, mostly for recurrent urinary infections associated with a medical condition that necessitated urinary interventions. Interventions to avoid re-admissions should target these patients.
In patients with complicated urinary tract infections, we found no benefit of early appropriate empirical treatment on survival rates or other outcomes. Physicians might consider supportive treatment ...and watchful waiting in stable patients until the cause of sepsis is clear and pathogen is defined.
Abstract
Background
Complicated urinary tract infections (cUTIs) are responsible for a major share of all antibiotic consumption in hospitals. We aim to describe risk factors for treatment failure and mortality among patients with cUTIs.
Methods
A multinational, multicentre retrospective cohort study, conducted in 20 countries in Europe and the Middle East. Data were collected from patients' files on hospitalised patients with a diagnosis of cUTI during 2013-2014. Primary outcome was treatment failure, secondary outcomes included 30 days all-cause mortality,among other outcomes. Multivariable analysis using a logistic model and the hospital as a random variable was performed to identify independent predictors for these outcomes.
Results
A total of 981 patients with cUTI were included. Treatment failure was observed in 26.6% (261/981), all cause 30-day mortality rate was 8.7% (85/976), most of these in patients with catheter related UTI (CaUTI). Risk factors for treatment failure in multivariable analysis were ICU admission (OR 5.07, 95% CI 3.18-8.07), septic shock (OR 1.92, 95% CI 0.93-3.98), corticosteroid treatment (OR 1.92, 95% CI 1.12-3.54), bedridden (OR 2.11, 95%CI 1.4-3.18), older age (OR 1.02, 95% CI 1.0071.03-), metastatic cancer (OR 2.89, 95% CI 1.46-5.73) and CaUTI (OR 1.48, 95% CI 1.04-2.11). Management variables, such as inappropriate empirical antibiotic treatment or days to starting antibiotics were not associated with treatment failure or 30-day mortality. More patients with pyelonephritis were given appropriate empirical antibiotic therapy than other CaUTI 110/171; 64.3% vs. 116/270; 43%, p <0.005, nevertheless, this afforded no advantage in treatment failure rates nor mortality in these patients.
Conclusions
In patients with cUTI we found no benefit of early appropriate empirical treatment on survival rates or other outcomes. Physicians might consider supportive treatment and watchful waiting in stable patients until the causative pathogen is defined.
This paper studies the investment decision by a monopolistic internet service provider (ISP) in different regulatory environments. We consider that the ISP can technically provide separate quality ...upgrades to two vertically differentiated content providers (CPs). Our results show that if unregulated, the ISP could optimally provide asymmetric quality upgrades to both CPs, in favor of the high-quality CP. This subsequently increases the degree of content differentiation, softening competition between the CPs. Imposing a nondiscrimination regulation that forces the ISP to provide an equal quality upgrade to both CPs, however, reduce the ISP’s investment incentive and social welfare. Furthermore, the social planner provides preferential treatment to the high-quality CP if the degree of substitutability is sufficiently low. In contrast, it is socially optimal to prioritize the low-quality CP if the contents are sufficient substitutes, or provide exclusivity if vertical differentiation is high.
Two hetero-tri-organometallic compounds with potent activity against Gram-positive bacteria including multi-resistant Staphylococcus aureus (MRSA) were identified. The compounds consist of a peptide ...nucleic acid backbone with an alkyne side chain, substituted with a cymantrene, a (dipicolyl)Re(CO)3 moiety, and either a ferrocene (FcPNA) or a ruthenocene (RcPNA). Comparative proteomic analysis indicates the bacterial membrane as antibiotic target structure. FcPNA accumulation in the membrane was confirmed by manganese tracing with atomic absorption spectroscopy. Both organometallics disturbed several essential cellular processes taking place at the membrane such as respiration and cell wall biosynthesis, suggesting that the compounds affect membrane architecture. Correlating with enhanced antibacterial activity, oxidative stress was induced only by the ferrocene-substituted compound. The organometallics described here target the cytoplasmic membrane, a clinically proven antibacterial target structure, feature a bactericidal but non-bacteriolytic mode of action and limited cytotoxicity within the limits of solubility. Thus, FcPNA represents a promising lead structure for the development of a new synthetic class of antibiotics.
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