1,981 research outputs found
Population genomic analysis of base composition evolution in Drosophila melanogaster.
The relative importance of mutation, selection, and biased gene conversion to patterns of base composition variation in Drosophila melanogaster, and to a lesser extent, D. simulans, has been investigated for many years. However, genomic data from sufficiently large samples to thoroughly characterize patterns of base composition polymorphism within species have been lacking. Here, we report a genome-wide analysis of coding and noncoding polymorphism in a large sample of inbred D. melanogaster strains from Raleigh, North Carolina. Consistent with previous results, we observed that AT mutations fix more frequently than GC mutations in D. melanogaster. Contrary to predictions of previous models of codon usage in D. melanogaster, we found that synonymous sites segregating for derived AT polymorphisms were less skewed toward low frequencies compared with sites segregating a derived GC polymorphism. However, no such pattern was observed for comparable base composition polymorphisms in noncoding DNA. These results suggest that AT-ending codons could currently be favored by natural selection in the D. melanogaster lineage
BIOMECHANICS OF ACCURATE INSTEP KICK IN FUTSAL
The purpose of this study was to investigate the biomechanical parameters of instep kicking towards specific targets of the goal in Futsal. Twelve females from national soccer team in Taiwan were recruited in this study. Each subject was asked to perform instep kick of a stationary ball (size 4) toward targets in the four corners of the goal in Futsal. VICON motion analysis system and Kistler force plateform were used to collect the kinematics of the lower limb and the ground reaction forces and moments, respectively. The results showed that kicks towards the bottom targets demonstrated significantly greater ball velocity than towards the top targets (p= 0.00). In addition, the hip joint moment of supporting leg was significantly greater when kicking towards top targets of the goal (p= 0.01). The results of this study could provide training guidelines for coaches and players
Chattering-free sliding mode control with unidirectional auxiliary surfaces for miniature helicopters
Purpose – This article proposes a chattering-free sliding mode control scheme with unidirectional auxiliary surfaces (UAS-SMC) for small miniature autonomous helicopters (Trex 250).
Design/methodology/approach – The proposed UAS-SMC scheme consists of a nested sequence of rotor dynamics, angular rate, Euler angle, velocity and position loops.
Findings – It is demonstrated that the UAS-SMC strategy can eliminate the chattering phenomenon exhibiting in the convenient SMC method and achieve a better approaching speed.
Originality/value – The proposed control strategy is implemented on the helicopter and flight tests clearly demonstrate that a much better performance could be achieved, compared with convenient SMC schemes
Decreased levels of circulating sex hormones as a biomarker of lung cancer in male patients with solitary pulmonary nodules
Background: An early differentiation of malignant from benign solitary pulmonary nodules (SPNs) is essential for management and prognosis of lung cancer.Objectives: Here we investigated whether measurement of circulating sex hormones could be useful for an early detection of malignancy among patients with SPNs.Methods: We recruited 47 patients with malignant SPNs, 45 patients with benign SPNs, and 32 healthy persons. Testosterone, estradiol, and progesterone were measured. Carcinoembryonic antigen (CEA) as well as TNF-α, IL-1 and IL-6 were also measured.Results: We found that sex hormones were decreased significantly in patients with malignant SPNs, as compared to patients with benign SPNs and healthy controls (P<0.05). Sex hormones levels showed a trend to decline in patients with benign SPNs as compared to normal controls, but the difference was not statistically significant (P>0.05). CEA levels were only abnormally elevated in eight patients with lung adenocarcinoma. The inflammatory cytokines were remarkably higher in both patients than in normal controls. However, there was no statistical difference in these cytokines among patients.Conclusions: The reduced sex hormones levels seemed to be uniquely associated with lung cancer. Therefore, measurement of sex hormones may have clinical potential in the diagnosis of malignancy in patients with SPNs.Keywords: solitary pulmonary nodules (SPNs), sex hormones, lung cancer, biomarker
A coordination polymer of CdII with benzene-1,3-dicarboxylÂate and 1,4-bisÂ[1-(2-pyridylmethÂyl)benzimidazol-2-yl]butane
The title CdII coordination polymer, catena-poly[[{1,4-bisÂ[1-(2-pyridylmethÂyl)benzimidazol-2-yl]butane}cadmium(II)]-μ-benzene-1,3-dicarboxylÂato], [Cd(C8H4O4)(C30H28N6)]n, was obtained by reaction of CdCO3, benzene-1,3-dicarboxylic acid (H2btc) and 1,4-bisÂ[1-(2-pyridylmethÂyl)benzimidazol-2-yl]butane (L). The CdII cation is six-coordinated by an N2O4-donor set. L acts as a bidentate ligand and btc anions link CdII centers into a chain propagating parallel to [010]
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Dexmedetomidine post-treatment attenuates cardiac ischaemia/reperfusion injury by inhibiting apoptosis through HIF-1α signalling.
Hypoxia-inducible factor 1α (HIF-1α) plays a critical role in the apoptotic process during cardiac ischaemia/reperfusion (I/R) injury. This study aimed to investigate whether post-treatment with dexmedetomidine (DEX) could protect against I/R-induced cardiac apoptosis in vivo and in vitro via regulating HIF-1α signalling pathway. Rat myocardial I/R was induced by occluding the left anterior descending artery for 30 minutes followed by 6-hours reperfusion, and cardiomyocyte hypoxia/reoxygenation (H/R) was induced by oxygen-glucose deprivation for 6 hours followed by 3-hours reoxygenation. Dexmedetomidine administration at the beginning of reperfusion or reoxygenation attenuated I/R-induced myocardial injury or H/R-induced cell death, alleviated mitochondrial dysfunction, reduced the number of apoptotic cardiomyocytes, inhibited the activation of HIF-1α and modulated the expressions of apoptosis-related proteins including BCL-2, BAX, BNIP3, cleaved caspase-3 and cleaved PARP. Conversely, the HIF-1α prolyl hydroxylase-2 inhibitor IOX2 partly blocked DEX-mediated cardioprotection both in vivo and in vitro. Mechanistically, DEX down-regulated HIF-1α expression at the post-transcriptional level and inhibited the transcriptional activation of the target gene BNIP3. Post-treatment with DEX protects against cardiac I/R injury in vivo and H/R injury in vitro. These effects are, at least in part, mediated via the inhibition of cell apoptosis by targeting HIF-1α signalling
Factors Affecting Aluminum Dissolve from Acidified Water Purification Sludge
Recovering resources from water purification sludge (WPS) have been gradually stipulated in environmental protection laws and regulations in many nations. Hence, reusing the WPS is becoming an important topic, and recovering alum from WPS is one of the many practical alternatives. Most previous research efforts have been conducted on studying the amphoteric characteristic of aluminum hydroxide for investigating the optimum pH range to dissolve the Al(III) species from WPS, but it has been lack of reaction kinetics or mechanisms related discussion. Therefore, in this investigation, water purification sludge (WPS) solution was broken by ultrasound to make particle size of reactants smaller, specific surface area larger. According to the reaction kinetics, these phenomena let the dissolved aluminum salt quantity increased and the reaction rate go faster
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