Development and Validation of an In-Hospital Mortality Prediction Model for Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

Purpose: Patients with chronic obstructive pulmonary disease (COPD) often face unknown risks during acute exacerbation of the disease (AECOPD), which could potentially result in mortality. This study aimed to develop and validate a nomogram model for predicting the risk of in-hospital mortality in AECOPD patients. Patients and Methods: Clinical data of patients hospitalized at The Second People's Hospital of Wuhu City for AECOPD between January 2013 and December 2022 were retrospectively collected. Variables underwent selection through LASSO regression and multivariable logistic regression to develop a nomogram model. The model's predictive performance was assessed using the concordance index, calibration curve, and decision curve analysis (DCA), with internal validation conducted using the bootstrap method. Results: A total of 1224 patients were included in this study, with 98 (8%) deaths occurring during hospitalization. LASSO regression identified 11 variables, used to construct model A. Further multivariable logistic regression was conducted to select variables with P < 0.05 to establish model B. model B was selected as the final model based on discrimination, calibration, and clinical utility, encompassing variables including acute respiratory failure, lung cancer, heart rate, hemoglobin, absolute neutrophil count, serum albumin, blood urea nitrogen, and serum chloride. The nomogram model achieved a concordance index of 0.858. Internal validation of the model was conducted using the bootstrap method with 500 repetitions, resulting in a concordance index of 0.851 (95% CI: 0.805, 0.893). The calibration curve demonstrated a good fit, with a Hosmer-Lemeshow goodness-of-fit test P-value of 0.520. Moreover, DCA findings suggested patient benefit within a threshold probability range of 0.02 to 0.73, with a maximum net benefit of 0.07. Conclusion: The model constructed in this study has good predictive performance, which helps clinical doctors identify patients at high risk of death early.

Conservation genomics analysis reveals recent population decline and possible causes in bumblebee Bombus opulentus.

Bumblebees are a genus of pollinators (Bombus) that play important roles in natural ecosystem and agricultural production. Several bumblebee species have been recorded as under population decline, and the proportion of species experiencing population decline within subgenus Thoracobombus is higher than average. Bombus opulentus is 1 species in Thoracobombus, but little is known about its recent population dynamics. Here, we employed conservation genomics methods to investigate the population dynamics of B. opulentus during the recent past and identify the likely environmental factors that may cause population decline. Firstly, we placed the scaffold-level of B. opulentus reference genome sequence onto chromosome-level using Hi-C technique. Then, based on this reference genome and whole-genome resequencing data for 51 B. opulentus samples, we reconstructed the population structure and effective population size (Ne ) trajectories of B. opulentus and identified genes that were under positive selection. Our results revealed that the collected B. opulentus samples could be divided into 2 populations, and 1 of them experienced a recent population decline; the declining population also exhibited lower genetic diversity and higher inbreeding levels. Genes related to high-temperature tolerance, immune response, and detoxication showed signals of positive selection in the declining population, suggesting that climate warming and pathogen/pesticide exposures may contribute to the decline of this B. opulentus population. Taken together, our study provided insights into the demography of B. opulentus populations and highlighted that populations of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.

Ore improver additions alter livestock manure compost ecosystem C:N:P stoichiometry.

Deciphering the pivotal components of nutrient metabolism in compost is of paramount importance. To this end, ecoenzymatic stoichiometry, enzyme vector modeling, and statistical analysis were employed to explore the impact of exogenous ore improver on nutrient changes throughout the livestock composting process. The total phosphorus increased from 12.86 to 18.72 g kg-1, accompanied by a marked neutralized pH with ore improver, resulting in the Carbon-, nitrogen-, and phosphorus-related enzyme activities decreases. However, the potential C:P and N:P acquisition activities represented by ln(ßG + CB): ln(ALP) and ln(NAG): ln(ALP), were increased with ore improver addition. Based on the ecoenzymatic stoiometry theory, these changes reflect a decreasing trend in the relative P/N limitation, with pH and total phosphorus as the decisive factors. Our study showed that the practical employment of eco stoichiometry could benefit the manure composting process. Moreover, we should also consider the ecological effects from pH for the waste material utilization in sustainable agriculture.

Core Species Derived from Multispecies Interactions Facilitate the Immobilization of Cadmium.

Microbial consortia have opened new avenues for heavy-metal remediation. However, the limited understanding of the overall effect of interspecific interactions on remediation efficacy hinders its application. Here, the effects of multispecies growth and biofilm formation on Cd immobilization were explored from direct and multiple interactions through random combinations of two or three rhizosphere bacteria. In monocultures, Cd stress resulted in an average decrease in planktonic biomass of 26%, but through cooperation, the decrease was attenuated in dual (21%) and triple cultures (13%), possibly involving an increase in surface polysaccharides. More than 65% of the co-cultures exhibited induction of biofilm formation under Cd stress, which further enhanced the role of biofilms in Cd immobilization. Notably, excellent biofilm-forming ability or extensive social induction makes Pseudomonas putida and Brevundimonas diminuta stand out in multispecies biofilm formation and Cd immobilization. These two core species significantly increase the colonization of soil microorganisms on rice roots compared to the control, resulting in a 40% decrease in Cd uptake by rice. Our study enhances the understanding of bacterial interactions under Cd stress and provides a novel strategy for adjusting beneficial soil consortia for heavy-metal remediation.

Effective immobilization of heavy metals via reactive barrier by rhizosphere bacteria and their biofilms.

As the portal of plants, rhizosphere microorganisms play an essential role in controlling the species, transformation, and bioavailability of heavy metals, yet the potential passivation mechanism is still unclear. In this study, two heavy metal resistant and growth-promoting rhizosphere bacteria were screened, and their mechanisms in dealing with external stress and immobilizing heavy metal were explored. The results showed that heavy metals inhibited the ability of Pseudomonas sp. H13 and Brevundomonas sp. H16 to promote plant growth, but stimulated the production of extracellular polysaccharides and inorganic labile sulfide, and enhanced biofilm formation, thereby significantly improved the removal efficiency of Cu2+, Zn2+, Cd2+, and Pb2+. Compared with H16, the biofilm of H13 disintegrated rapidly in the later stage, so more metal ions were adsorbed on the planktonic cells. The C-OH and PO groups related to polysaccharides play a crucial role in heavy metal adsorption, and the immobilization mechanism of the planktonic cell is mainly ion exchange and group complex, but for H16, intracellular enrichment cannot be ignored. Functional group complexes played a dominant role in biofilm, and the immobilized heavy metals were more difficult to release into the environment. This study highlighted the potential application prospects of biofilm bacteria in heavy metal remediation and explained the reactive barrier of rhizosphere bacteria to heavy metals.

Influence of Quantum-Well Width on the Electroluminescence Properties of AlGaN Deep Ultraviolet Light-Emitting Diodes at Different Temperatures.

The influence of quantum-well (QW) width on electroluminescence properties of AlGaN deep ultraviolet light-emitting diodes (DUV LEDs) was studied at different temperatures. The maximum external quantum efficiency (EQE) ratios of LED with 3.5 nm QW to that with 2 nm increased from 6.8 at room temperature (RT) to 8.2 at 5 K. However, the ratios for LED with 3.5 nm QW to that with 5 nm QW decreased from 4.8 at RT to 1.6 at 5 K. The different changes of EQE ratios were attributed to the decrease of non-radiative recombination and the increase of volume of the active region. From theoretical analysis, the LED with 2-nm wells had a shallowest barrier for electron overflow due to the quantum-confined effect, whereas the LED with 5-nm wells showed the least overlap of electron and hole due to the large internal field. Therefore, the LED with 3.5 nm QW had the highest maximum EQE at the same temperature. As temperature decreased, the current for maximum EQE decreased for all the LEDs, which was believed to be due to the increase of electron which overflowed out of QWs and the decrease of hole concentration. The results were helpful for understanding the combination of polarization effect and electron overflow in DUV LEDs.

Nanoporous photocathode and photoanode made by multilayer assembly of quantum dots.

We perform in this paper a kinetic study of the photoelectrochemical responses of nanoporous thin photoactive films. The films were fabricated by by a layer-by-layer assembly of positively charged polyelectrolytes (poly-l-Lysine, pLys) and negatively charged semiconductor nanoparticles (NPs) on a carboxylic acid terminated alkanethiol-modified gold electrode. Two types of NPs were used to build uniform films: cadmium selenide (CdSe) and cadmium selenide/cadmium sulfide core/shell (CdSe@CdS). Large photocathodic and photoanodic currents were recorded for CdSe and CdSe@CdS sensitized films, respectively. A theoretical model of the photocurrent responses was developed to analyze the kinetics of photoinduced processes and coupled reactions, showing that the multilayer films behave as homogeneous nanoporous semiconducting photoelectrodes.

Novel carboxylated oligothiophenes as sensitizers in photoelectric conversion systems.

Novel carboxylated oligothiophenes with different thiophene units were designed and synthesized as photosensitizers in dye-sensitized solar cells (DSSCs) for efficient opto-electric materials. The introduction of -COOH into thiophene molecules can lead to a red shift of UV-visible absorption, increase light-harvesting efficiency, and enhance photoinduced charge transport by forming efficient covalent bonds to the substrate surface. A red shift of the absorption spectrum of oligothiophene is also achieved by the increase in the number of thiophene units. The DSSCs based on the oligomers have excellent photovoltaic performances. Under 100 mW cm(-2) irradiation a short-circuit current of 10.57 mA cm(-2) and an overall energy conversion efficiency of 3.36 % is achieved when pentathiophene dicarboxylated acid was used as a sensitizer. The incident photo-to-current conversion efficiency (IPCE) has a maximum as high as 80 %. In addition, photovoltage and photocurrent transients show that slow charge recombination in DSSCs is important for efficient charge separation and excellent photoelectric conversion properties of the oligomers. These initial and promising results suggest that carboxylated oligothiophenes are efficient photosensitizers.

Property influence of polyanilines on photovoltaic behaviors of dye-sensitized solar cells.

The influence of polyanilines (PANIs) as hole conductors on the photovoltaic behaviors of dye-sensitized solar cells is studied. The current-voltage (I-V) characteristics and the incident photon to current conversion efficiency (IPCE) curves of the devices are determined as the function of different conductivities and morphologies of PANIs. The results show that the conductivity of PANIs affects the performance of the devices greatly, and PANI with the intermediate conductivity value (3.5 S/cm) is optimum. In addition, the effects of both the film formation property and the cluster size of polyanilines on the photovoltaic behaviors of the devices are also discussed.