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11.
Two new nonfullerene small molecule acceptors (NF‐SMAs) AT‐NC and AT‐4Cl based on heptacyclic anthracene(cyclopentadithiophene) (AT) core and different electron‐withdrawing end groups are designed and synthesized. Although the two new acceptor molecules use two different end groups, naphthyl‐fused indanone (NINCN) and chlorinated INCN (INCN‐2Cl) demonstrate similar light absorption. AT‐4Cl with chlorinated INCN as end groups are shifted significantly due to the strong electron‐withdrawing ability of chlorine atoms. Thus, desirable Voc and photovoltaic performance are expected to be achieved when polymer PBDB‐T is used as the electron donor with AT‐NC as the acceptor, and fluorinated analog PBDB‐TF with down‐shifted energy levels is selected to blend with AT‐4Cl. Consequently, the device based on PBDB‐TF:AT‐4Cl yields a high power conversion efficiency of 13.27% with a slightly lower Voc of 0.901 V, significantly enhanced Jsc of 19.52 mA cm?2 and fill factor of 75.5% relative to the values based on PBDB‐T:AT‐NC. These results demonstrate that the use of a new electron‐rich AT core, together with energy levels modulations by end‐group optimizations enabling the match with polymer donors, is a successful strategy to construct high‐performance NF‐SMAs.  相似文献   
12.

Loading in cartilage is supported primarily by fibrillar collagen, and damage will impair the function of the tissue, leading to pathologies such as osteoarthritis. Damage is initiated by two types of matrix metalloproteinases, collagenase and gelatinase, that cleave and denature the collagen fibrils in the tissue. Experimental and modeling studies have revealed insights into the individual contributions of these two types of MMPs, as well as the mechanical response of intact fibrils and fibrils that have experienced random surface degradation. However, no research has comprehensively examined the combined influences of collagenases and gelatinases on collagen degradation nor studied the mechanical consequences of biological degradation of collagen fibrils. Such preclinical examinations are required to gain insights into understanding, treating, and preventing degradation-related cartilage pathology. To develop these insights, we use sequential Monte Carlo and molecular dynamics simulations to probe the effect of enzymatic degradation on the structure and mechanics of a single collagen fibril. We find that the mechanical response depends on the ratio of collagenase to gelatinase—not just the amount of lost fibril mass—and we provide a possible mechanism underlying this phenomenon. Overall, by characterizing the combined influences of collagenases and gelatinases on fibril degradation and mechanics at the preclinical research stage, we gain insights that may facilitate the development of targeted interventions to prevent the damage and loss of mechanical integrity that can lead to cartilage pathology.

  相似文献   
13.
This study demonstrates for the first time the presence of marine‐associated mites in the Andaman Sea and Strait of Malacca and reveals a relatively high diversity of these taxa with six species from two different families: Selenoribatidae and Fortuyniidae. Indopacifica, a new genus of Selenoribatidae, is described from Thailand and Malaysia, with two new species, Indopacifica pantai n. sp. and Indopacifica parva n. sp. The genus is characterized by the unique combination of following characters: lacking lamellar ridges, incomplete dorsosejugal suture, fourteen pairs of notogastral setae, and presence of epimeral foveae. A phylogenetic reconstruction based on 18S ribosomal RNA sequences clearly confirms the distinctness of the new genus Indopacifica and places it close to the genus Rhizophobates. The lack of molecular genetic data of possible relatives impedes a clear assessment, and hence, we emphasize the need for further combined approaches using morphological and molecular genetic sequence data. All species show wide distribution areas within this geographic region suggesting that these taxa are good dispersers despite their minute size and wingless body. Molecular genetic data demonstrate recent gene flow between far distant populations of I. pantai n. sp. from the coasts of Thailand and two islands of Malaysia and hence confirm this assumption. The seasonally changing surface currents within this geographic area may favor hydrochorous dispersal and hence genetic exchange. Nevertheless, morphometric data show a slight trend to morphological divergence among the studied populations, whereas this variation is suggested to be a result of genetic drift but also of habitat differences in one population of Alismobates pseudoreticulatus.  相似文献   
14.
Xie J B  Liu T  Wei P  Jia Y M  Luo C 《农业工程》2007,27(7):2704-2714
Ecological experiments are usually conducted on small scales, but the ecological and environmental issues are usually on large scales. Hence, there is a clear need of scaling. Namely, when we deal with patterns and processes on larger scales, a special connection needs to be established on the small scales that we are familiar with. Here we presented a wavelet analysis method that could build relationships between spatial distribution patterns on different scales. With this method, we also studied how spatial heterogeneity and distribution patterns changed with the scale. We investigated the distribution and the habitat of C. ewersmanniana in two plots (200 m × 200 m; the distance between these two plots is 15 km) at Mosuowan desert. The results demonstrated that spatial heterogeneity and distribution patterns were incorporated into larger scales when the wavelet scale varied from one (5 m) to four (20 m). However, if the wavelet scale was above five (25 m), the spatial distribution patterns varied placidly, the oscillation frequency of landforms stabilized at 110 m, and the dynamic quantity period of C. ewersmanniana stabilized at 115–125 m. We also identified signal mutation points with wavelet analysis and verified the heterogeneity degree of local space with position variance. We found that position variance decomposed the distribution patterns on large scales into small sampling plots, and the position with the largest variance also had the strongest heterogeneity. In a word, the wavelet analysis method could scale-up spatial distribution patterns and habitat heterogeneity. With this method and other methods derived from this one, such as wavelet scale, wavelet variance, position variance and extremely direct-viewing graphs, wavelet analysis could be widely applied in solving the scaling problem in ecological and environmental studies.  相似文献   
15.
Long noncoding RNA CPS1-IT1 is recently recognized as a tumor suppressor in several cancers. Here, we investigate the role of CPS1-IT1 in human melanoma. Presently, our study reveals the low expression of CPS1-IT1 in human melanoma tissues and cell lines, which is significantly associated with metastasis and tumor stage. Besides, the potential of CPS1-IT1 as a prognosis-predictor is strongly indicated. Functionally, CPS1-IT1 overexpression inhibits cell migration, invasion, epithelial–mesenchymal transition, and angiogenesis in melanoma cells. CYR61, an angiogenic factor that participates in tumor metastasis as well as a recognized oncogene in melanoma, is shown to be confined under CPS1-IT1 overexpression in melanoma cells. Furthermore, enforced expression of Cyr61 in CPS1-IT1-silenced melanoma cells dramatically normalized the protein level of Cyr61 and that of its downstream targets vascular endothelial growth factor and matrix metalloproteinase-9, as well as the repressive effect of CPS1-IT1 overexpression on melanoma cell metastasis. BRG1, a core component of SWI/SNF complex, is implied to interact with both CPS1-IT1 and Cyr61 in melanoma cells. Moreover, CPS1-IT1 negatively regulates Cyr61 expression by blocking the binding of BRG1 to Cyr61 promoter. Jointly, CPS1-IT1 controls melanoma metastasis through impairing Cyr61 expression via competitively binding with BRG1, uncovering a novel potential therapeutic and prognostic biomarker for patients with melanoma.  相似文献   
16.
Expression of the E3 ligase TRIM21 is increased in a broad spectrum of cancers; however, the functionally relevant molecular pathway targeted by TRIM21 overexpression remains largely unknown. Here, we show that TRIM21 directly interacts with and ubiquitinates CLASPIN, a mediator for ATR-dependent CHK1 activation. TRIM21-mediated K63-linked ubiquitination of CLASPIN counteracts the K6-linked ubiquitination of CLASPIN which is essential for its interaction with TIPIN and subsequent chromatin loading. We further show that overexpression of TRIM21, but not a TRIM21 catalytically inactive mutant, compromises CHK1 activation, leading to replication fork instability and tumorigenesis. Our findings demonstrate that TRIM21 suppresses CHK1 activation by preferentially targeting CLASPIN for K63-linked ubiquitination, providing a potential target for cancer therapy.  相似文献   
17.
AIMS: DNA fingerprinting of Salmonella enterica serotype Paratyphi B isolated in Malaysia during 1982-83, 1992 and 1996-2002 was carried out by pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility tests and D-tartrate utilization tests to assess the extent of genetic diversity of these isolates in Malaysia. METHODS AND RESULTS: Eighty-six human isolates and one food isolate of Salm. Paratyphi B were analysed by PFGE, antimicrobial susceptibility tests and D-tartrate utilization tests. Sixty-five strains were D-tartrate-negative (dT-) while 22 strains were D-tartrate-positive (dT+). Thirty-seven per cent of the Salm. Paratyphi B strains were resistant to one or more antimicrobial agents. PFGE analysis clearly distinguished the dT- and dT+ strains into two clusters based on the unweighted pair group average method (UPGMA). Twenty-two XbaI-pulsotypes were observed among the 65 dT- strains while 17 XbaI-pulsotypes were observed among the 22 isolates of Salm. Paratyphi B dT+. CONCLUSIONS: The present study showed that PFGE was very discriminative with 33.7% of the strains yielding distinct fingerprints. Paratyphoid fever in Malaysia is probably caused by one predominant, endemic clone of Salm. Paratyphi B dT- with various subtypes. There was no association between the pulsotypes and the severity of the disease indicating that the severity of the disease is probably multifactorial. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of the present study verify the usefulness of PFGE in characterizing strains of Salm. Paratyphi B. This is the first report on the application of PFGE on a large collection of Salm. Paratyphi B in Malaysia.  相似文献   
18.
An experiment was conducted to determine the effect of water stress on nutritional changes in tolerant (DS-4 and Chakwal-86) and susceptible (DS-17 and Pavon) genotypes in lysimeters. The stress was imposed at different growth stages (pre-anthesis, post-anthesis, terminal drought). The biomass (dry weight) and Ca, Mg and P concentration decreased with water stress in all the wheat genotypes. However, the tolerant genotypes had less reduction than susceptible at all the treatments. Potassium increased in all wheat genotypes due to water stress and was higher in tolerant than susceptible genotypes. Sodium content was not affected by water stress.  相似文献   
19.
Chrysin (5, 7- dihydroxyflavone) is a flavonoid with several pharmacological properties that include antioxidant, anti-inflammatory and antiapoptotic activities. in this work, we investigated some effects of three graded oral doses of chrysin (10, 50 and 250 mg/kg) on kidney structure and function in rats with experimental chronic renal disease (CKD) induced by adenine (0.25% w/w in feed for 35 days), which is known to involve inflammation and oxidative stress. Using several indices in plasma, urine and kidney homogenates, adenine was found to impair kidney function as it lowered creatinine clearance and increased plasma concentrations of creatinine, urea, neutrophil gelatinase-associated lipocalin and N-Acetyl-beta-D-glucosaminidase activity. Furthermore, it raised plasma concentrations of the uremic toxin indoxyl sulfate, some inflammatory cytokines and urinary albumin concentration. Renal morphology was severely damaged and histopathological markers of inflammation and fibrosis were especially increased. In renal homogenates, antioxidant indices, including superoxide dismutase and catalase activities, total antioxidant capacity and reduced glutathione were all adversely affected. Most of these adenine – induced actions were moderately and dose -dependently mitigated by chrysin, especially at the highest dose. Chrysin did not cause any overt adverse effect on the treated rats. The results suggest that different doses of chrysin produce variable salutary effects against adenine-induced CKD in rats, and that, pending further pharmacological and toxicological studies, its usability as a possible ameliorative agent in human CKD should be considered.  相似文献   
20.
As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.  相似文献   
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