Molybdenum Phosphide Quantum Dots Encapsulated by P/N-Doped Carbon for Hydrogen Evolution Reaction in Acid and Alkaline Electrolytes.

A facile and eco-friendly strategy is presented for synthesizing novel nanocomposites, with MoP quantum dots (QDs) as cores and graphitic carbon as shells, these nanoparticles are dispersed in a nitrogen and phosphorus-doped porous carbon and carbon nanotubes (CNTs) substrates (MoP@NPC/CNT). The synthesis involves self-assembling reactions to form single-source precursors (SSPs), followed by pyrolysis at 900 °C in an inert atmosphere to obtain MoP@NPC/CNT-900. The presence of carbon layers on the MoP QDs effectively prevents particle aggregation, enhancing the utilization of active MoP species. The optimized sample, MoP@NPC/CNT-900, exhibits remarkable electrocatalytic activity and durability for the hydrogen evolution reaction (HER). It demonstrates a low overpotential of 155 mV at 10 mA cm-2 , a small Tafel slope of 76 mV dec-1 , and sustained performance over 20 hours in 0.5 M H2 SO4 . Furthermore, the catalyst shows excellent activity in 1 M KOH, with a relatively low overpotential of 131 mV and long-term durability under constant current input. The exceptional HER activity can be attributed to several factors: the superior performance of MoP QDs, the large surface area and good conductivity of the carbon substrates, and the synergistic effect between MoP and carbon species.

Admissible dissimilarity value (ADV) as a measure of subsampling reliability: case study North Sea cod (Gadus morhua).

The shape of the length frequency distribution (LFD) is an important input for stock assessments and one of the most important features in studies of fish population dynamics, providing estimates of growth parameters. In practice, oversampling may occur when sampling commercially important species. At times of more and more limited resources, the length sample size can be optimized at some stages of national or regional sampling programmes, without reducing the quality of stock assessments. The main objective of this study is to demonstrate a general distribution-free methodological approach for an optimization of sample size developed as an alternative to both analytical and bootstrap approaches. A novel framework to identify the reduced but still informative sample and to quantify the (dis) similarity between reduced and original samples is proposed. The identification procedure is based on the concept of reference subsample, which represents a theoretical minimal representative subsample that despite smaller sample size still preserves a reasonably precise LFD for certain species. The difference between the original sample and the reference subsample called admissible dissimilarity value (ADV) serves as the upper threshold and can be used to quantify the reliability of derived subsamples. Monte Carlo simulations were conducted to validate the approach under various LFD shapes. We illustrate in case studies how ADV can support to evaluate adequate sampling effort. The case studies focus on length samples from the German commercial vessels fishing for North Sea cod (Gadus morhua).

Sensitivity of multispecies maximum sustainable yields to trends in the top (marine mammals) and bottom (primary production) compartments of the southern North Sea food-web.

In marine ecosystems, maximum sustainable yield considerations are affected by any substantial changes that occur in the top and bottom compartments of the food-web. This study explores how the southern North Sea's fisheries may need to adjust their fishing efforts to maintain optimum yields of sole, plaice, cod and brown shrimps under increased marine mammal populations and a reduced primary productivity. We constructed plausible scenarios of ongoing food-web changes using the results of Bayesian age-structured population models to estimate carrying capacities of harbour porpoises (Phocoena phocoena) and grey seals (Halichoerus grypus). Losses in primary productivity were predicted by lower trophic level ecosystem models. These scenarios were implemented in a food-web model of the southern North Sea. For each scenario, we sought mixed-fleet fishing efforts that would deliver maximum yields of sole, plaice, cod and brown shrimp combined. We also did so for a baseline run with unaltered mammal and primary production, and compared the differences in optimal fishing strategies, predicted yields, and states of the stocks between the scenarios. We found stocks and yields to be far more sensitive to changes in primary productivity than to increased marine mammal predation. The latter predominantly impacted cod, and even benefitted brown shrimps compared to the baseline run. Under 30% reduced primary productivity, fishing efforts had to be reduced by 50% to still provide maximum yields, whereas the marine mammal scenario induced no need to adjust the fishing regime. This draws attention to the potential gains of incorporating bottom-up processes into long-term management considerations, while marine mammal predation may be less of a concern, in particular for flatfish fisheries in the North Sea, and may even benefit shrimp trawlers because of reduced predation on shrimp from fish predators.

Spatially-Resolved Influence of Temperature and Salinity on Stock and Recruitment Variability of Commercially Important Fishes in the North Sea.

Understanding of the processes affecting recruitment of commercially important fish species is one of the major challenges in fisheries science. Towards this aim, we investigated the relation between North Sea hydrography (temperature and salinity) and fish stock variables (recruitment, spawning stock biomass and pre-recruitment survival index) for 9 commercially important fishes using spatially-resolved cross-correlation analysis. We used high-resolution (0.2° × 0.2°) hydrographic data fields matching the maximal temporal extent of the fish population assessments (1948-2013). Our approach allowed for the identification of regions in the North Sea where environmental variables seem to be more influential on the fish stocks, as well as the regions of a lesser or nil influence. Our results confirmed previously demonstrated negative correlations between temperature and recruitment of cod and plaice and identified regions of the strongest correlations (German Bight for plaice and north-western North Sea for cod). We also revealed a positive correlation between herring spawning stock biomass and temperature in the Orkney-Shetland area, as well as a negative correlation between sole pre-recruitment survival index and temperature in the German Bight. A strong positive correlation between sprat stock variables and salinity in the central North Sea was also found. To our knowledge the results concerning correlations between North Sea hydrography and stocks' dynamics of herring, sole and sprat are novel. The new information about spatial distribution of the correlation provides an additional help to identify mechanisms underlying these correlations. As an illustration of the utility of these results for fishery management, an example is provided that incorporates the identified environmental covariates in stock-recruitment models.

Factors predicting the postoperative outcome of lower gastrointestinal hemorrhage.

PURPOSE: To examine the treatment outcome for patients with acute bleeding from the lower gastrointestinal tract requiring transfusion and acute surgical care as a function of various risk factors MATERIALS AND METHODS: Between 1999 and 2007, we collected data on 59 patients (39 male and 20 female patients) who received surgical intervention for acute lower intestinal hemorrhage requiring transfusion at our university clinic. Treatment complications and mortality were analyzed retrospectively. RESULTS: The average age of the patients in this study is 70.0 +/- 12.2 years (range, 39 to 97 years) with an overall mortality of 15.3%. Blood transfusions >10 U (p = 0.031), postoperative need for ventilation (p = 0.004), necessary reoperations (p = 0.016), and an initial hemoglobin level <80 g/L (p = 0.043) proved to be significant risk factors for death. Blood transfusions >10 U (p = 0.028), necessary reoperations (p = 0.001), and an initial hemoglobin level <80 g/L (p = 0.033) were found to be significant risk factors for postoperative complications. All other parameters have no significant impact. CONCLUSIONS: The decisive factors for the outcome of lower gastrointestinal hemorrhage requiring surgery are the severity of bleeding, beginning of treatment (initial hemoglobin level, need for packed red blood cells), and treatment efficiency (necessary reoperation).

Surgical treatment concepts for acute lower gastrointestinal bleeding.

BACKGROUND AND PURPOSE: To this day, the diagnostic and therapeutic strategy for acute lower gastrointestinal hemorrhage requiring transfusion varies among different hospitals. The purpose of this paper was to evaluate our own data on the group of patients presented and to outline our diagnostic and therapeutic regime taking into account the literature of the past 30 years. METHODS: Following prospective data collection on 63 patients of a university hospital (40 male, 23 female patients) who received surgical intervention for acute lower intestinal hemorrhage requiring transfusion, we retrospectively analyzed the data. After a medical history had been taken, all patients underwent clinical examination, including digital palpation; 62 patients underwent procto-rectoscopy, 38 gastroscopy and colonoscopy, 52 patients colonoscopy only, and 45 patients gastroscopy only. Angiography was applied in 14 cases and scintigraphy in 20 cases. RESULTS: Diagnostic procedures to localize hemorrhage were successful in 61 cases, 41 of which through endoscopy, 12 through angiography, and eight through scintigraphy. Of our group of patients, 32 suffered from a bleeding colonic diverticulum, eight from angiodysplasia, and five from bleeding small bowel diverticula. Five patients had inflammatory bowel disease and three neoplasia. Among the surgical interventions, segmental resections were performed most frequently (15 sigmoidectomies, 11 small bowel segmental resections, 11 left hemicolectomies, seven right hemicolectomies, one proctectomy). Subtotal colectomies were carried out in ten cases. The complication rate for this group of critically ill, negatively selected patients was 60.3% and the mortality rate was 15.9%. CONCLUSIONS: Examination and stabilization of the patient is directly followed by diagnostic localization. Today, we primarily rely on nonsurgical control of hemorrhage by endoscopy or angiography; the indication for surgery is mainly limited to peracute, uncontrollable, and recurrent forms. In the case of surgery, intestinal segmental resection is recommended after identification of the lesion; if the localization of colonic hemorrhage is uncertain, subtotal resection is the method of choice. For stable patients with unverifiable small-bowel hemorrhage we recommend regular re-evaluation.

Fecal leukocyte proteins in inflammatory bowel disease and irritable bowel syndrome.

UNLABELLED: The aim of this prospective study was to compare five different leukocyte proteins in feces of patients with chronic inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and healthy persons who underwent prophylactic colonoscopy. METHODS: The leukocyte proteins calprotectin, lactoferrin, lysozyme, myeloperoxidase, and PMN-elastase were determined with immunoassays in fecal samples of three consecutive feces (e.g. three days) in 40 healthy persons, 39 patients with chronic IBD (of these 21 with Crohn's disease and 18 with ulcerative colitis), and 40 patients with IBS. RESULTS: ROC curves calculated for healthy persons and patients with IBD yielded the following areas under the curves (AUCs): PMN-elastase 0.916, calprotectin 0.872, myeloperoxidase 0.750, lysozyme 0.726, and lactoferrin 0.693. The AUCs of PMN-elastase and calprotectin were not significantly different (p = 0.327), whereas PMN-elastase or calprotectin vs. the other proteins were significantly different (p < 0.001). PMN-elastase and calprotectin correlated with the endoscopically classified severity of inflammation. All fecal leukocyte markers in IBS were found in the range of the healthy persons. Data on storage stability of leukocyte proteins in fecal supernatants are given. CONCLUSION: Fecal PMN-elastase and calprotectin support the differentiation of chronic IBD from IBS and correlate with the severity of inflammation.

Comparison of different salivary and fecal antibodies for the diagnosis of celiac disease.

To investigate the detectability and expressiveness of salivary and fecal anti-gliadin (AGA), anti-endomysium (EMA) and anti-tissue-transglutaminase (ATA) antibodies, 127 salivary and 160 fecal samples of healthy volunteers and salivary and fecal samples of 17 patients with histologically proven and 9 patients with suggested celiac disease were investigated in this study. With all salivary parameters and fecal IgA AGA, IgM AGA, IgA EMA and IgG EMA, healthy volunteers and patients showed partially overlapping results. The most promising results in our study with higher concentrations in patients with celiac disease were obtained by fecal scIgA AGA and a combined determination of fecal IgA AGA, IgG AGA and IgM AGA. Further investigations should be performed with fecal IgA EMA and scIgA ATA based on human recombinant tissue-transglutaminase. One patient with histologically proven celiac disease had normal serological but high fecal scIgA AGA and scIgA ATA values. This patient emphasizes the importance of fecal antibody determination for the diagnosis of celiac disease, at least in patients with suggested celiac disease and negative serum antibodies.