A certified 25.2% efficiency of metal halide perovskite solar cells (PSCs) has been rapidly reached in 2019 within just a decade which is unprecedented in the field of photovoltaics. Excellent ...optoelectronic properties such as high absorption coefficient, tunable direct bandgap, long diffusion length, and high carrier mobility promise a further improvement of device performance. However, as a result of the solution precursor compositions and rapid processing conditions, tremendous amounts of defects with various types are formed within perovskite absorbers or on the surfaces, which serve as the nonradiative recombination centers to impede the rapid development of PSCs. Therefore, learned from the field of mature Silicon-based solar cell, passivation of such defects in the bulk and/or at the surface, as well as influence the interface tuning of structure and energetics has to be urgently conducted by choosing appropriate chemical molecules, which have the potential of tailoring crystallization and growth of perovskite absorbers. Here, recent advances in passivation engineering for perovskite film formation or interface optimization are summarized and discussed according to the following typical categories: Lewis acid (e.g., metal cations, organic cations, zwitterion, fullerene derivatives), Lewis base based on the donor type (e.g., anions, S-donor, N-donor, O-donor, graphene derivatives, and n-π conjugated materials), passivators with multifunctional groups. Finally, a perspective is predicted on future research trends concerning passivation engineering in advancing the development of PSCs, especially in efficiency, stability, and commercialization.
Display omitted
•Defects in the surface and GB of PSCs seriously limit efficiency enhancement.•The diversity of defects require passivators with different passivation capacities.•Different functional groups of passivators determine the effect of passivation.•The mechanisms of passivators with different functional groups are reviewed.
Brain-inspired electronics require artificial synapses that have ultra-low energy consumption, high operating speed, and stable flexibility. Here, we demonstrate a flexible artificial synapse that ...uses a rapidly crystallized perovskite layer at room temperature. The device achieves a series of synaptic functions, including logical operations, temporal and spatial rules, and associative learning. Passivation using phenethyl-ammonium iodide eliminated defects and charge traps to reduce the energy consumption to 13.5 aJ per synaptic event, which is the world record for two-terminal artificial synapses. At this ultralow energy consumption, the device achieves ultrafast response frequency of up to 4.17 MHz; which is orders of magnitude magnitudes higher than previous perovskite artificial synapses. A multi-stimulus accumulative artificial neuromuscular system was then fabricated using the perovskite synapse as a key processing unit to control electrochemical artificial muscles, and realized muscular-fatigue warning. This artificial synapse will have applications in future bio-inspired electronics and neurorobots.
Studies have examined the characteristics of individuals who use e-cigarettes, including sociodemographic and smoking characteristics, and the relationship of e-cigarette use to tobacco control ...policies. While most studies consider a subset of these characteristics with weak measures of regular e-cigarette use, this study uses a large, recent U.S. survey to simultaneously consider the association of each of these factors with different use measures. Data from the May 2014 Tobacco Use Supplement-Current Population Survey is supplemented with information on tobacco control policies. The prevalence of ever, current (at least 1 of the last 30 days), and regular (at least 20 of the last 30 days) e-cigarette use were 7.7%, 2.1% and 0.9%, implying that 27.0% of ever users were current users of which 45.3% were regular users. E-cigarette use varied by socio-demographic characteristics and by smoking status, and depended on the measure of use adopted. However, regardless of measures, e-cigarette use was higher among those smokers who smoked more cigarettes. The association with policies was generally weak, but we found more regular use by smokers in low tax and low tobacco control spending states. The results indicate that the user characteristics differ depending on the e-cigarette use measure. The measure of use should be carefully considered in analyzing how e-cigarette use affects cigarette use.
•The conditions of hydrogen production by Chlorella vulgaris were optimized.•Simplified the procedure of hydrogen production by Chlorella.•Reduced the cost of hydrogen production by ...Chlorella.•Chlorella solution has great potential for biological hydrogen production.
In the paper, Use Chlorella as raw material, HAU-M1 Photosynthetic bacteria (PSB) as hydrogen-producing bacteria, the influence of initial pH on bio-hydrogen by photosynthetic organisms from Chlorella vulgaris with diverse enzyme addition was studied. The results showed that when using cellulase as hydrolase, the optimum initial pH was 7.0 and highest bio-hydrogen was 25.99 mL/g dry cell weight. Using neutral protease as hydrolase, the optimum initial pH was 8.0 and highest bio-hydrogen was 16.47 mL/g dry cell weight. Using mixed enzyme of cellulase and protease as hydrolase, the optimal initial pH was 7.0 and highest bio-hydrogen was 27.43 mL/g dry cell weight. The bio-hydrogen from Chlorella after mixed enzymatic hydrolysis is better than that of single enzymatic hydrolysis, we think the mixed enzymatic hydrolysis of cellulase and protease was superior to the single enzymatic hydrolysis of the two enzymes, which provides a scientific reference and low-cost bio-hydrogen technology by microalgae.
Identifying determinants of smoking cessation is critical for developing optimal cessation treatments and interventions. Machine learning (ML) is becoming more prevalent for smoking cessation success ...prediction in treatment programs. However, only individuals with an intention to quit smoking cigarettes participate in such programs, which limits the generalizability of the results. This study applies data from the Population Assessment of Tobacco and Health (PATH), a United States longitudinal nationally representative survey, to select primary determinants of smoking cessation and to train ML classification models for predicting smoking cessation among the general population. An analytical sample of 9,281 adult current established smokers from the PATH survey wave 1 was used to develop classification models to predict smoking cessation by wave 2. Random forest and gradient boosting machines were applied for variable selection, and the SHapley Additive explanation method was used to show the effect direction of the top-ranked variables. The final model predicted wave 2 smoking cessation for current established smokers in wave 1 with an accuracy of 72% in the test dataset. The validation results showed that a similar model could predict wave 3 smoking cessation of wave 2 smokers with an accuracy of 70%. Our analysis indicated that more past 30 days e-cigarette use at the time of quitting, fewer past 30 days cigarette use before quitting, ages older than 18 at smoking initiation, fewer years of smoking, poly tobacco past 30-days use before quitting, and higher BMI resulted in higher chances of cigarette cessation for adult smokers in the US.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Two-component systems (TCSs) assume a pivotal function in Mycobacterium tuberculosis (M.tuberculosis) growth. However, the exact regulatory mechanism of this system needs to be elucidated, and only a ...few studies have investigated the effect of gene mutations within TCSs on M.tuberculosis transmission. This research explored the relationship between TCSs gene mutation and the global transmission of (M.tuberculosis).
A total of 13531 M.tuberculosis strains were enrolled in the study. Most of the M.tuberculosis strains belonged to lineage4 (n=6497,48.0%), followed by lineage2 (n=5136,38.0%). Our results showed that a total of 36 single nucleotide polymorphisms (SNPs) were positively correlated with clustering of lineage2, such as Rv0758 (phoR, C820G), Rv1747(T1102C), and Rv1057(C1168T). A total of 30 SNPs showed positive correlation with clustering of lineage4, such as phoR(C182A, C1184G, C662T, T758G), Rv3764c (tcrY, G1151T), and Rv1747 C20T. A total of 19 SNPs were positively correlated with cross-country transmission of lineage2, such as phoR A575C, Rv1028c (kdpD, G383T, G1246C), and Rv1057 G817T. A total of 41 SNPs were positively correlated with cross-country transmission of lineage4, such as phoR(T758G, T327G, C284G), kdpD(G1755A, G625C), Rv1057 C980T, and Rv1747 T373G.
Our study identified that SNPs in genes of two-component systems were related to the transmission of M. tuberculosis. This finding adds another layer of complexity to M. tuberculosis virulence and provides insight into future research that will help to elucidate a novel mechanism of M. tuberculosis pathogenicity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Feature selection plays a key role in target recognition especially for multiple combined sensors’ applications. This study presents an improved relief feature selection (Relief‐F) model to rank ...features for multi‐target recognition. Besides, the evaluation of the effectiveness of the method is conducted based on the following three measuring indices: feature redundancy, class separability and overall accuracy. The simulated data acquired by radar infrared combined sensors are used to verify the metrics of the proposed method. The experimental results demonstrate that the Relief‐F method reveals the best results compared to other feature selection methods, including principal component analysis and Fisher linear discriminant analysis. It indicates that Relief‐F can be an effective option for feature selection with high‐class separability and a low feature redundancy rate. Furthermore, high overall accuracy can be obtained using a relatively small amount of features selected by the Relief‐F method.
Maternal exposure to antibiotics existing in the environment is a predisposing factor for developmental malformation with metabolic disorders in offspring. In this study, female zebrafish (3 months) ...were exposed to 0.05 mg/L and 0.5 mg/L florfenicol (FF) for 28 days. After pairing and spawning with healthy male fish, F1 embryos were collected and developed to 5 d post-fertilization (dpf) in clear water. And the adverse effects on the F1 generation were examined thoroughly. The fecundity of F0 female fish and the hatchability, mortality, and body length of F1 larvae significantly decreased in the treatment group. Meanwhile, multi-malformation types were found in the exposure group, including delayed yolk sac absorption, lack of swim bladder, and spinal curvature. Metabolomic and transcriptomic results revealed alterations in metabolism with dysregulation in tricarboxylase acid cycle, amino acid metabolism, and disordered lipid metabolism with elevated levels of glycerophospholipid and sphingolipid. Accompanying these metabolic derangements, decreased levels of ATP and disordered oxidative-redox state were observed. These results were consistent with the damaged mitochondrial membrane potential and respiratory chain function, suggesting that the developmental toxicity and perturbed metabolic signaling in the F1 generation were related to the mitochondrial injury after exposing F0 female zebrafish to FF. Our findings highlighted the potential toxicity of FF to offspring generations even though they were not directly exposed to environmental contaminants.
•The adverse effect of maternal exposure to florfenicol on F1 larvae was studied.•Decreased hatchability and increased malformation rate were observed.•The level of metabolites, lipids, and related gene expression were changed.•Impaired mitochondrial and disordered cellular oxidative state were observed.
A 2-fold interpenetrated microporous MOF Ni2(C2O4)(L)2 n ·6nH2O (HL = 4,2′:4″,2′-terpyridine-4′-carboxylic acid) (1) was synthesized and structurally characterized. 1 has obvious 1D channels along ...the crystallographic a and c axes with a pore size of 5.7 to 6.9 Å. Topological analysis shows that the framework of 1 can be interpreted as a (3,4)-connected net with point symbol (63)(65·8). 1 exhibits high water and thermal stability, which is demonstrated by TGA, PXRD, and VT-PXRD. Additionally, the high temperature structure of 1′ (433 K) undoubtedly demonstrates the stability of the framework. More importantly, 1 shows high selectivities for CO2 over N2, H2, and CH4 at low pressure and 273 K.
PDF
