21 research outputs found

    ZnSe Nanorods as Visible-Light Absorbers for Photocatalytic and Photoelectrochemical H2 Evolution in Water

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    A precious-metal- and Cd-free photocatalyst system for efficient H2 evolution from aqueous protons with a performance comparable to Cd-based quantum dots is presented. Rod-shaped ZnSe nanocrystals (nanorods, NRs) with a Ni(BF4 )2 co-catalyst suspended in aqueous ascorbic acid evolve H2 with an activity up to 54±2 mmol H 2  gZnSe -1  h-1 and a quantum yield of 50±4 % (λ=400 nm) under visible light illumination (AM 1.5G, 100 mW cm-2 , λ>400 nm). Under simulated full-spectrum solar irradiation (AM 1.5G, 100 mW cm-2 ), up to 149±22 mmol H 2  gZnSe -1  h-1 is generated. Significant photocorrosion was not noticeable within 40 h and activity was even observed without an added co-catalyst. The ZnSe NRs can also be used to construct an inexpensive delafossite CuCrO2 photocathode, which does not rely on a sacrificial electron donor. Immobilized ZnSe NRs on CuCrO2 generate photocurrents of around -10 μA cm-2 in an aqueous electrolyte solution (pH 5.5) with a photocurrent onset potential of approximately +0.75 V vs. RHE. This work establishes ZnSe as a state-of-the-art light absorber for photocatalytic and photoelectrochemical H2 generation.Christian Doppler Research Association (Austrian Federal Ministry of Science, Research and Economy and the National Foundation for Research, Technology and Development), the OMV Group, the EPSRC NanoDTC, EPSRC Underpinning Multi-User Equipment Grant (EP/P030467/1), the Erasmus+ program (D.W.), the Erasmus program (A.S.) and the World Premier International Research Center Initiative, MEXT, Japa

    Analysis of Epstein-Barr virus reservoirs in paired blood and breast cancer primary biopsy specimens by real time PCR

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    INTRODUCTION: Epstein-Barr virus (EBV) is present in over 90% of the world's population. This infection is considered benign, even though in limited cases EBV is associated with infectious and neoplastic conditions. Over the past decade, the EBV association with breast cancer has been constantly debated. Adding to this clinical and biological uncertainty, different techniques gave contradictory results for the presence of EBV in breast carcinoma specimens. In this study, minor groove binding (MGB)-TaqMan real time PCR was used to detect the presence of EBV DNA in both peripheral blood and tumor samples of selected patients. METHODS: Peripheral blood and breast carcinoma specimens from 24 patients were collected. DNA was extracted and then amplified by MGB-TaqMan real time PCR. RESULTS: Of 24 breast tumor specimens, 11 (46%) were positive for EBV DNA. Of these 11 breast tumor specimens, 7 (64%) were also positive for EBV DNA in the peripheral blood, while 4 (36%) were positive for EBV DNA in the tumor, but negative in the blood. CONCLUSION: EBV was found at extremely low levels, with a mean of 0.00004 EBV genomes per cell (range 0.00014 to 0.00001 EBV genomes per cell). Furthermore, our finding of the presence of EBV in the tumor specimens coupled to the absence of detection of EBV genomic DNA in the peripheral blood is consistent with the epithelial nature of the virus. Because of the low levels of viral DNA in tumor tissue, further studies are needed to assess the biological input of EBV in breast cancer

    Major pancreatic resections for suspected cancer in a community-based teaching hospital: lessons learned.

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    BACKGROUND: The literature reports 4-10% mortality rate, 30-60% morbidity rate, and 9-29% anastomotic leak rate after pancreaticoduodenectomy (PD) performed for periampullary tumors. These data demonstrate a linear relationship between surgical volume and outcome. METHODS: The objective of this study was to evaluate the experience of a high-volume hospital with low-volume pancreatoduodenectomy for suspected cancer. The study was designed as a retrospective review of medical records of all patients who underwent pancreatoduodenal resection or total pancreatectomy for a suspected periampullary carcinoma between January 1994 and December 2003. The setting of the study was a community-based teaching hospital with a general surgery residency training program. RESULTS: A total of 63 patients underwent pancreatoduodenal resection or total pancreatectomy. All procedures were performed by a total of 15 different surgeons; however, 27 operations were performed by one surgeon. Pre-operative diagnosis in most cases was either a known malignancy-27 cases (43%) or a tumor of the head of the pancreas, suspicious for malignancy-36 cases (57%). One patient underwent a total pancreatectomy. In 62 patients a pancreatoduodenal resection (Whipple procedure) was performed. Post-operative 30-day mortality was 4.7% (three patients). Overall in-hospital mortality was 9.5% (six patients). Ten (16.1%) had a leak of the pancreato-jejunal anastomosis, six of which resolved with non-operative management. Of the remaining four patients, three died from peritonitis or consequences of erosive hemorrhage. CONCLUSIONS: Post-operative leak of the pancreatic anastomosis represents a technical challenge. Although most of the leaks can be treated non-operatively, those that lead to peritonitis or erosive hemorrhage warrant operative intervention. Major pancreatic resections can be performed safely with low rates of morbidity and operative mortality with careful selection of patients at a low-volume community-based teaching hospital

    Hepatic resection at a major community-based teaching hospital can result in good outcome.

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    BACKGROUND: The relationship between volume and outcome has been established in the literature for several complex surgical procedures. Improved outcome has been suggested at high-volume hospitals or with high-volume surgeons. METHODS: The objective of this study was to evaluate the experience of a low-volume hospital with major liver resections. The setting of the study was a community-based teaching hospital with a surgical residency training program. RESULTS: A total of 46 major liver resections were performed between January 1992 and December 2002. Procedures performed were hepatic lobectomies (n = 15; right, n = 11; left, n = 4), trisegmentectomies (n = 5; right, n = 3; left, n = 2), segmentectomies (n = 16; left lateral, n = 12; right posterior, n = 4), and wedge resections (n = 10). Operations were performed by 14 different surgeons; however, 23 operations were performed by 1 surgeon. Sixteen patients (34%) developed 23 complications. The average length of hospital stay was 9.7 days. There were no 30-day postoperative mortalities. Out of 46 patients who underwent major liver resection over the last 10 years, 13 patients are still alive. Overall survival ranged from 3 to 84 months, with a median survival of 30.6 months. The actual 5-year survival was 36% (8 of 22) for all patients operated on \u3e5 years ago, and the actual 2-year survival was 61% (20 of 33). CONCLUSIONS: Major liver resection can be performed safely with low rates of morbidity and operative mortality with careful selection of patients at a low-volume community-based teaching hospital

    ZnSe quantum dots modified with a Ni(cyclam) catalyst for efficient visible-light driven CO2 reduction in water.

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    A precious metal and Cd-free photocatalyst system for efficient CO2 reduction in water is reported. The hybrid assembly consists of ligand-free ZnSe quantum dots (QDs) as a visible-light photosensitiser combined with a phosphonic acid-functionalised Ni(cyclam) catalyst, NiCycP. This precious metal-free photocatalyst system shows a high activity for aqueous CO2 reduction to CO (Ni-based TONCO > 120), whereas an anchor-free catalyst, Ni(cyclam)Cl2, produced three times less CO. Additional ZnSe surface modification with 2-(dimethylamino)ethanethiol (MEDA) partially suppresses H2 generation and enhances the CO production allowing for a Ni-based TONCO of > 280 and more than 33% selectivity for CO2 reduction over H2 evolution, after 20 h visible light irradiation (λ > 400 nm, AM 1.5G, 1 sun). The external quantum efficiency of 3.4 ± 0.3% at 400 nm is comparable to state-of-the-art precious metal photocatalysts. Transient absorption spectroscopy showed that band-gap excitation of ZnSe QDs is followed by rapid hole scavenging and very fast electron trapping in ZnSe. The trapped electrons transfer to NiCycP on the ps timescale, explaining the high performance for photocatalytic CO2 reduction. With this work we introduce ZnSe QDs as an inexpensive and efficient visible light-absorber for solar fuel generation

    Activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa from patients in the Middle East and Africa – Study for Monitoring Antimicrobial Resistance Trends (SMART) 2017-2020

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    Objectives: We evaluated the activity of ceftolozane/tazobactam (C/T), and comparators against clinical Pseudomonas aeruginosa isolates collected for the global Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance program in ten countries in the Middle East and Africa to augment scarce standardized surveillance data in this region. Methods: Minimum inhibitory concentrations (MICs) were determined using Clinical and Laboratory Standards Institute broth microdilution and interpreted with European Committee on Antimicrobial Susceptibility Testing breakpoints. P. aeruginosa isolates testing with C/T MIC >4 mg/l or imipenem MIC >2 mg/l were screened for β-lactamase genes. Results: C/T was active against 91.4% and 87.0% of P. aeruginosa isolates from the Middle East and Africa, respectively (14-21 and 7-16 percentage points higher than most β-lactam comparators, respectively). Considerable variation in susceptibility was seen across countries, which largely correlated with the observed prevalence of carbapenemases and/or extended-spectrum β-lactamases. Differences across countries were smaller for C/T than for the β-lactam comparators, ranging from 81% C/T-susceptible among isolates from Jordan to 95% for Qatar. Among subsets resistant to meropenem, ceftazidime, or piperacillin/tazobactam, C/T maintained activity against 51-73% of isolates from the Middle East and against 27-54% from Africa (where metallo-β-lactamase and GES carbapenemase rates were higher). Conclusion: Given the desirability of β-lactam use among clinicians, C/T represents an important option in the treatment of infections caused by P. aeruginosa
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