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n‐Butanol has been widely used and its residue exists extensively in the environment. It could lead to conformational and functional changes of trypsin by forming a complex with it. Docking method and spectrographic technique were employed to the study of the complex of trypsin and n‐butanol. The fluorescence results indicated that n‐butanol can form a complex with trypsin and change the distance between tryptophan and fluorescence quenchers. The conformational changes of trypsin were proved by UV–visible absorption and synchronous fluorescence spectroscopy indicating that n‐butanol had little effect on the conformation of trypsin at a low concentration while denatured and coagulated the trypsin at a high concentration. The binding site was displayed by molecular modeling, which gave information about distances and binding forces between n‐butanol and trypsin. The results were in accordance with spectroscopic experiments. Besides, enzyme activity assay gave the dose‐response relationship of n‐butanol with trypsin.  相似文献   

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Hypervolume approaches are used to quantify functional diversity and quantify environmental niches for species distribution modelling. Recently, Qiao et al. ( 2016 ) criticized our geometrical kernel density estimation (KDE) method for measuring hypervolumes. They used a simulation analysis to argue that the method yields high error rates and makes biased estimates of fundamental niches. Here, we show that (a) KDE output depends in useful ways on dataset size and bias, (b) other species distribution modelling methods make equally stringent but different assumptions about dataset bias, (c) simulation results presented by Qiao et al. ( 2016 ) were incorrect, with revised analyses showing performance comparable to other methods, and (d) hypervolume methods are more general than KDE and have other benefits for niche modelling. As a result, our KDE method remains a promising tool for species distribution modelling.  相似文献   

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To determine the relationship between BMI and Medicare expenditure for adults 65‐years and older and determine whether this relationship changes after accounting for misclassification due to age‐related height loss. Using a cross sectional study design, the relationship between BMI and fee‐for‐service Medicare expenditure was examined among beneficiaries who completed the Medicare Current Beneficiary Survey (MCBS) in 2002, were not enrolled in Medicare Health Maintenance Organization, had a self‐reported height and weight, and were 65 and older (n = 7,706). Subjects were classified as underweight, normal weight, overweight, obese (obese I), and severely obese (obese II/III). To adjust BMI for the artifactual increase associated with age‐related height loss, the reported height was transformed by adding the sex‐specific age‐associated height loss to the reported height in MCBS. The main outcome variable was total Medicare expenditure. There was a significant U‐shaped pattern between unadjusted BMI and Medicare expenditure: underweight $4,581 (P < 0.0003), normal weight $3,744 (P < 0.0000), overweight $3,115 (reference), obese I $3,686 (P < 0.0039), and obese II/III $4,386 (P < 0.0000). This pattern persisted after accounting for height loss: underweight $4,640 (P < 0.0000), normal weight $3,451 (P < 0.0507), overweight $3,165 (reference), obese I $3,915 (P < 0.0010), and obese II/III $4,385 (P < 0.0004) compared to overweight. In older adults, minimal cost is not found at “normal” BMI, but rather in overweight subjects with higher spending in the obese and underweight categories. Adjusting for loss‐of‐height with aging had little affect on cost estimates.  相似文献   

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Allergic diseases have remarkably increased in recent years. Nowadays, efforts for curing and management of these disorders are an important concern worldwide. Allergen‐specific immunotherapy (ASIT) has recently gained more attention as a means for the management of allergic diseases. Adjuvants or helper agents are materials applied for better stimulating and shifting of protective responses, and these belong to an extremely diverse collection of complexes. The main function of adjuvants includes acting as depot foundations, transferring vehicles, and immunostimulators. Immunostimulatory adjuvants have gained increasing attention for ASIT. In this regard, the present study provides a review of old and new adjuvants used in allergen immunotherapy.  相似文献   

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α, ω‐Dodecanedioic acid (DC12) usually serves as a monomer of polyamides or some special nylons. During the biosynthesis, oxygenation cascaded in conversion of hydrophobic n‐dodecane to DC12, while the oxidation of n‐dodecane took place in the intracellular space. Therefore, it was important to investigate the role of oxygen supply on the cell growth and DC12 biosynthesis. It was found that stirring speed and aeration influenced the dissolved oxygen (DO) concentration which in turn affected cell growth as well as DC12 biosynthesis. However, the effect of culture redox potential (Orp) level on DC12 biosynthesis was more significant than that of DO level. For DC12 biosynthesis, the first step was to form the emulsion droplets through the interaction of n‐dodecane and the cell. When the stirring speed was enhanced, slits in the surface layer of the emulsion droplets would be increased. Thus, the substances transportation by water through the slits would be intensified, leading to an enhanced DC12 production. Compared with the batch culture at a lower stirring speed (400 rpm) without culture redox potential (Orp) control, the DC12 concentration was increased by 5 times up to 201.3 g/L with Orp controlled above 0 mV at a higher stirring speed (800 rpm).  相似文献   

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The organic field‐effect transistor (OFET) is the basic building block of integrated circuits. The charge carrier mobility and operating frequency of OFETs have continued to increase; therefore, the power dissipation of OFETs can no longer be ignored. Many research efforts have been made to develop low‐power‐consumption OFETs and complementary circuits. Despite the switching function, OFETs can also be utilized in emerging energy‐related applications, such as near‐infrared (NIR) photodetectors and organic thermoelectric devices. Organic phototransistors show considerably higher photo responsivity than other photodetector architectures due to field‐effect charge modulation. The photoinduced gate modulating largely suppresses the dark current while simultaneously providing gain. These characteristics may favor NIR light detection and suggest that the organic phototransistor is a promising candidate for optoelectronic applications in the NIR regime. For organic thermoelectric applications, OFETs can work as a powerful tool for examining the charge and energy transport in the organic semiconductor, thus giving insight into organic thermoelectric studies. In this review, the authors highlight recent advances in OFET‐ related energy topics, including low‐power‐consumption OFETs, NIR photodetectors, and organic thermoelectric devices. The remaining challenges in the field will also be discussed.  相似文献   

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P/n‐dopable conducting polymers (CPs) are considered as the most promising choice for CP‐based supercapacitor electrode materials, as they can work at a voltage wider than 2 V and store energy several times greater than that of only positively dopable CPs. However, such electrode materials suffer severe cycling instability during a charge–discharge process. In this paper, two conducting redox polymers with different linkage modes are designed and prepared, with redox moieties embedded in the backbone or grafted as pendant groups, as p/n‐dopable electrode materials for supercapacitor. In addition to the voltage and energy advantages of p/n‐dopable electrode materials, these two conducting redox polymers show excellent cycling stability. Supercapacitors based on the polymer with backbone‐graft structure show better cycling stability, remaining 83% of initial capacitance after 2000‐cycle charge–discharge test. The relationship between the charge‐trapping (CT) effect that often occurs during the doping processes of p/n‐dopable CPs and performance degradation is investigated in detail. Results show that the CT effect occurring during the n‐doping process is probably the main cause of performance degradation. The degradation caused by the CT effect may be recovered partially or almost totally by several cyclic voltammetry scans, thereby extending the lifetime of supercapacitor devices to some degree.  相似文献   

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“The Same‐Acceptor‐Strategy” (SAS) adopts benzotriazole (BTA)‐based p‐type polymers paired with a new BTA based non‐fullerene acceptor BTA13 to minimize the trade‐off between the open‐circuit voltage (VOC) and short circuit current (JSC). The fluorination and sulfuration are introduced to lower the highest occupied molecular orbitals (HOMO) of the polymers. The fluorinated polymer of J52‐F shows the higher power conversion efficiency (PCE) of 8.36% than the analog polymer of J52, benefited from a good balance between an improved VOC of 1.18 V and a JSC of 11.55 mA cm?2. Further adding alkylthio groups on J52‐F, the resulted polymer, J52‐FS, exhibits the highest VOC of 1.24 V with a decreased energy loss of 0.48 eV, compared with 0.67 eV for J52 and 0.54 eV for J52‐F. However, J52‐FS shows an inferior PCE (3.84%) with a lower JSC of 6.74 mA cm?2, because the small ΔEHOMO between J52‐FS and BTA13 (0.02 eV) gives rise to the inefficient hole transfer and high charge recombination, as well as low carrier mobilities. The results of this study clearly demonstrate that the introduction of different atoms in p‐type polymers is effective to improve the SAS and realize the high (VOC) and PCE.  相似文献   

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Obesity is a highly heritable trait and a growing public health problem. African Americans (AAs) are a genetically diverse, yet understudied population with a high prevalence of obesity (BMI >30 kg/m2). Recent studies based upon single‐nucleotide polymorphisms (SNPs) have identified genetic markers associated with obesity. However, a large proportion of the heritability of obesity remains unexplained. Copy number variation (CNV) has been cited as a possible source of missing heritability in common diseases such as obesity. We conducted a CNV genome‐wide association study of BMI in two African‐American cohorts from Genetic Epidemiology Network of Arteriopathy (GENOA) and Hypertension Genetic Epidemiology Network (HyperGEN). We performed independent and identical association analyses in each study, then combined the results in a meta‐analysis. We identified three CNVs associated with BMI, obesity, and other obesity‐related traits after adjusting for multiple testing. These CNVs overlap the PARK2, GYPA, and SGCZ genes. Our results suggest that CNV may play a role in the etiology of obesity in AAs.  相似文献   

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