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The effects of the thermal cyclic aging treatment on the microstructure and mechanical properties of 2060 Al–Li alloy laser beam welded joints were investigated. Aging treatments were conducted at different temperatures and for different cycles. Test results showed that the tensile strength of the weld joints increased and the elongation slightly decreased after the thermal cycling treatment. It was also found that the heat affected zone (HAZ) of the welds exhibited a significant increase in microhardness, whilst the microhardness variation of the nondendrite equiaxed zone (EQZ) can be neglected. The strengthening effect of the thermal cycling became more obvious as the temperature and cycles increased. The highest strength of around 513 MPa (96% of the base metal) was obtained at the temperature of 180 °C. Reprecipitation of strengthening phases such as T1 in the HAZ at 180 °C was observed by TEM, which can be considered as the main reason for the strengthening effect of the aging treatment.
As high-entropy alloys (HEAs) are being actively explored for next-generation structural materials, gaining a comprehensive understanding of their creep, fatigue, and fracture behaviors is indispensable. These three aspects of mechanical properties are particularly important because (i) creep resistance dictates an alloy’s high-temperature applications; (ii) fatigue failure is the most frequently encountered failure mode in the service life of a material; (iii) fracture is the very last step that a material loses its load-carrying capability. In consideration of their importance in designing HEAs toward applicable structural materials, this article offers a comprehensive review on what has been accomplished so far in these three topics. The sub-topics covered include a comparison of different creep testing methods, creep-parameter extraction, creep mechanism, high-cycle fatigue S–N relation, fatigue-crack-growth behavior, fracture toughness, fracture under different loading conditions, and fractography. Directions for future efforts are suggested in the end.
Mastery of strengthening strategies to achieve high-capacity anodes for lithium-ion batteries can shed light on understanding the nature of diffusion-induced stress and offer an approach to use submicro-sized materials with an ultrahigh capacity for large-scale batteries. Here, we report solute strengthening in a series of silicon (Si)–germanium (Ge) alloys. When the larger solute atom (Ge) is added to the solvent atoms (Si), a compressive stress is generated in the vicinity of Ge atoms. This local stress field interacts with resident dislocations and subsequently impedes their motion to increase the yield stress in the alloys. The addition of Ge into Si substantially improves the capacity retention, particularly in Si0.50Ge0.50, aligning with literature reports that the Si/Ge alloy showed a maximum yield stress in Si0.50Ge0.50. In situ X-ray diffraction studies on the Si0.50Ge0.50 electrode show that the phase change undergoes three subsequent steps during the lithiation process: removal of surface oxide layer, formation of cluster-size Lix(Si,Ge), and formation of crystalline Li15(Si,Ge)4. Furthermore, the lithiation process starts from higher index facets, i.e., (220) and (311), then through the low index facet (111), suggesting the orientation-dependence of the lithiation process in the Si0.50Ge0.50 electrode.
Mammalian neonates undergo rapid transitions from a sterile uterine environment with a continuous intravenous supply of nutrients to a microbe-rich environment with intermittent ingesting of colostrum/milk via the gut. Currently, little is known about the colostrum-induced alterations of intestinal mucosal proteins in piglets with intra-uterine growth restriction (IUGR). In this study, we sought to investigate the innate differences and effects of colostrum on alterations in small-intestinal proteomes of IUGR piglets. Two IUGR (approximately 0·9 kg) and two normal-birth weight (NBW; approximately 1·3 kg) piglets were obtained from each of six sows at birth. One half (n 12; 6 IUGR v. 6 NBW) of the selected newborn piglets were killed to obtain jejunum samples, and the other half (n 12; 6 IUGR v. 6 NBW) of the newborn piglets were allowed to suckle colostrum from their own mothers for 24 h before jejunum sample collection. On the basis of proteomic analysis, we identified thirty-one differentially expressed proteins in the jejunal mucosa between IUGR and normal neonates before or after colostrum consumption. The intestinal proteins altered by colostrum feeding play important roles in the following: (1) increasing intestinal integrity, transport of nutrients, energy metabolism, protein synthesis, immune response and, therefore, cell proliferation; and (2) decreasing oxidative stress, and therefore cell apoptosis, in IUGR neonates. However, colostrum only partially ameliorated the inferior status of the jejunal mucosa in IUGR neonates. These findings provide the first evidence in intestinal protein alterations of IUGR neonates in response to colostrum ingestion, and thus render new insights into the mechanisms responsible for impaired growth in IUGR neonates and into new nutritional intervention strategies.
The pathophysiology of cognitive impairment in patients with the major depressive disorder (MDD) may involve neuroinflammation mediated by cytokines.
The aim of this study was to examine the serum interleukin-6 (IL-6) levels, sustained attention, and their association in patients with MDD.
Thirty patients with MDD and 30 healthy controls were enrolled in this case-control study. Sustained attention was measured using the Rapid Visual Information Processing (RVP) task in the Cambridge Neuropsychological Tests Automated Battery. The serum IL-6 levels of all subjects were assessed by sandwich enzyme-linked immunosorbent assays.
There were significant differences in the log10RVP total hits, log10RVP total misses, and log10RVP mean latency between patients with MDD and healthy controls (F = 6.04, p = 0.017; F = 19.77, p < 0.0001; F = 14.42, p < 0.0001, respectively). The serum levels of Log10IL-6 were significantly higher in patients with MDD than in healthy controls (F = 192.27, p < 0.0001). The log10IL-6 levels were also positively correlated with the log10RVP mean latency in patients with MDD (r = 0.45, p = 0.013). A further stepwise multivariate regression analysis indicated that the log10IL-6 levels were significantly associated with the log10RVP mean latency in patients with MDD (β = 0.31, t = 2.41, p = 0.025).
Our data suggested that increased IL-6 levels were associated with the psychopathology of MDD, and that abnormal IL-6 levels were implicated in the impairment of sustained attention in patients with MDD.
We have observed a young stellar object, IRAS 18360-0537, with a far-infrared luminosity of 1.2 × 105 L⊙. It is perhaps the most promising candidate of a high-mass protostar associated with a Keplerian disk and a jet/outflow system in the regime of L > 105L⊙. We are conducting the SMA, VLA, and VLBA studies to provide a comprehensive understanding of this interesting high mass star formation scenario.
In the past few years, we have performed a 22 GHz H2O maser survey towards hundreds of BGPS sources using the 25-meter Nanshan Radio Telescope (NSRT) of the Xinjiang Astronomical Observatory, and detected more than one hundred masers. Our aim is to study star formation activities associated with these sources, as well as search for any correlations that may exist between 22 GHz H2O masers and the evolutionary stage of high-mass star formation regions. The NSRT has been upgraded and have now an effective diameter of 26 meter. Besides, cryogenically cooled dual-beam receiver systems covering seven millimeter-wave observing bands have been installed on the NSRT. For the next step of maser observation, we will continue to do H2O and SiO masers survey of massive dust clumps and monitor some maser sources.
Interleukin (IL)-13-associated signal pathway plays an important role in schistosomiasis hepatic fibrosis. In this study we tried to investigate the effects of corilagin to ameliorate schistosomiasis hepatic fibrosis through regulating IL-13-associated signal pathway in vitro and in vivo. Cellular model was set up with hepatic stellate cells-T6 cells stimulated by rIL-13 and male Balb/c mice were infected with Schistosoma japonicum cercariaeas as animal model. Liver histological changes were observed with haematoxylin and eosin staining. Masson staining was employed to observe the change of egg granulomas. Expression of Col (collagen) and Col III were examined with Immunohistochemistry. Western bolt was employed to detect the JAK-1 and IL13Rα1 proteins. The mRNA expression of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were tested by quantitative polymerase chain reaction. As a result, less inflammatory changes were found in all corilagin groups compared with model group and praziquantel group. The mRNA levels of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were significantly decreased after corilagin intervention (P < 0·01). JAK-1 and IL-13Rα1 protein levels were also greatly decreased in the corilagin groups (P < 0·01). In conclusion, corilagin could ameliorate schistosomiasis hepatic fibrosis by down-regulating the expression of IL-13 and signal molecules in IL-13 pathway.
Accumulating evidence suggests that altered immunity contributes to the
development of major depressive disorder (MDD).
To examine whether complement factor H (CFH), a regulator of activation
of the alternative pathway of the complement cascade, confers
susceptibility to MDD.
Expression analyses were tested in 53 unmedicated people with MDD and 55
healthy controls. A two-stage genetic association analysis was performed
in 3323 Han Chinese with or without MDD. Potential associations between
CFH single nucleotide polymorphisms and age at MDD
onset were evaluated.
CFH levels were significantly lower in the MDD group at
both protein and mRNA levels (P = 0.009 and
P = 0.014 respectively). A regulatory variant in the
CFH gene, rs1061170, showed statistically significant
genotypic and allelic differences between the MDD and control groups
(genotypic P = 0.0005, allelic P =
0.0001). Kaplan–Meier survival analysis showed that age at onset of MDD
was significantly associated with the C allele of
rs1061170 (log rank statistic χ2 = 6.82, P =
0.009). The C-allele carriers had a younger age at onset
of MDD (22.2 years, s.d. = 4.0) than those without the C
allele (23.6 years, s.d. = 4.3).
CFH is likely to play an important role in the
development of MDD. rs1061170 has an important effect on age at onset of
MDD in Han Chinese and may therefore be related to early pathogenesis of
MDD, although further study is needed.
Most idiopathic right ventricular tachycardias originate from the outflow tract. We present a case series of idiopathic incessant ventricular tachycardia arising from unusual sites of the right ventricle in children, which were well resolved by catheter ablation.
A retrospective review was performed of all three patients who underwent ablation of idiopathic ventricular tachycardia below the level of the right ventricular outflow tract using three-dimensional mapping in our institute.
All three patients presented with tachycardia-induced cardiomyopathy due to incessant ventricular tachycardia on first admission. The sites of successful ablation were at the proximal right bundle branch, distal right bundle branch, and apex of the right ventricle, respectively. No complications occurred, and there has been no recurrence of ventricular tachycardia after the final ablation at an average follow-up period of 9 months. All three patients have achieved normalisation of left ventricular size and systolic function.
Incessant idiopathic ventricular tachycardia originating from unusual sites of the right ventricle in children, resulting in significant symptoms and impaired ventricular function, can be successfully treated with catheter ablation.
Postnatal rapid growth by excess intake of nutrients has been associated with an increased susceptibility to diseases in neonates with intra-uterine growth restricted (IUGR). The aim of the present study was to determine whether postnatal nutritional restriction could improve intestinal development and immune function of neonates with IUGR using piglets as model. A total of twelve pairs of normal-birth weight (NBW) and IUGR piglets (7 d old) were randomly assigned to receive adequate nutrient intake or restricted nutrient intake (RNI) by artificially liquid feeding for a period of 21 d. Blood samples and intestinal tissues were collected at necropsy and were analysed for morphology, digestive enzyme activities, immune cells and expression of innate immunity-related genes. The results indicated that both IUGR and postnatal nutritional restriction delayed the growth rate during the sucking period. Irrespective of nutrient intake, piglets with IUGR had a significantly lower villous height and crypt depth in the ileum than the NBW piglets. Moreover, IUGR decreased alkaline phosphatase activity while enhanced lactase activity in the jejunum and mRNA expressions of Toll-like receptor 9 (TLR-9) and DNA methyltransferase 1 (DNMT1) in the ileum of piglets. Irrespective of body weight, RNI significantly decreased the number and/or percentage of peripheral leucocytes, lymphocytes and monocytes of piglets, whereas the percentage of neutrophils and the ratio of CD4+ to CD8+ were increased. Furthermore, RNI markedly enhanced the mRNA expression of TLR-9 and DNMT1, but decreased the expression of NOD2 and TRAF-6 in the ileum of piglets. In summary, postnatal nutritional restriction led to abnormal cellular and innate immune response, as well as delayed the growth and intestinal development of IUGR piglets.
The shift-and-invert Arnoldi method is a most effective approach to compute a few eigenpairs of a large non-Hermitian Toeplitz matrix pencil, where the Gohberg-Semencul formula can be used to obtain the Toeplitz inverse. However, two large non-Hermitian Toeplitz systems must be solved in the first step of this method, and the cost becomes prohibitive if the desired accuracy for this step is high — especially for some ill-conditioned problems. To overcome this difficulty, we establish a relationship between the errors in solving these systems and the residual of the Toeplitz eigenproblem. We consequently present a practical stopping criterion for their numerical solution, and propose an inexact shift-and-invert Arnoldi algorithm for the generalised Toeplitz eigenproblem. Numerical experiments illustrate our theoretical results and demonstrate the efficiency of the new algorithm.
The aim of the present study was to determine whether increased consumption of methionine as dl-methionine (DLM) or its hydroxy analogue dl-2-hydroxy-4-methylthiobutanoic acid (HMTBA) could benefit milk synthesis and neonatal growth. For this purpose, eighteen cross-bred (Landrace × Yorkshire) primiparous sows were fed a control (CON), DLM or HMTBA diet (n 6 per diet) from 0 to 14 d post-partum. At postnatal day 14, piglets in the HMTBA group had higher body weight (P= 0·02) than those in the CON group, tended (P= 0·07) to be higher than those in the DLM group, and had higher (P< 0·05) mRNA abundance of jejunal fatty acid-binding protein 2, intestinal than those in the CON and DLM groups. Compared with the CON diet-fed sows, milk protein, non-fat solid, and lysine, histidine and ornithine concentrations decreased in the DLM diet-fed sows (P< 0·05), and milk fat, lactose, and cysteine and taurine concentrations increased in the HMTBA diet-fed sows (P< 0·05). Plasma homocysteine and urea N concentrations that averaged across time were increased (P< 0·05) in sows fed the DLM diet compared with those fed the CON diet. Metabolomic results based on 1H NMR spectroscopy revealed that consumption of the HMTBA and DLM diets increased (P< 0·05) both sow plasma methionine and valine levels; however, consumption of the DLM diet led to lower (P< 0·05) plasma levels of lysine, tyrosine, glucose and acetate and higher (P< 0·05) plasma levels of citrate, lactate, formate, glycerol, myo-inositol and N-acetyl glycoprotein in sows. Collectively, neonatal growth and milk synthesis were regulated by dietary methionine levels and sources, which resulted in marked alterations in amino acid, lipid and glycogen metabolism.
The aim of the present study was to determine whether early weaning-induced growth retardation could be attenuated by increased consumption of methionine as dl-methionine (DLM) or dl-2-hydroxy-4-methylthiobutyrate (HMTBA) in both lactating sows and weaned piglets. Therefore, diets containing DLM and HMTBA at 25 % of the total sulphur-containing amino acids (AA) present in the control (CON) diet were fed to lactating sows and weaned piglets and their responses were evaluated. Compared with the CON diet-fed sows, the HMTBA diet-fed sows exhibited a tendency (P< 0·10) towards higher plasma taurine concentrations and the DLM diet-fed sows had higher (P< 0·05) plasma taurine concentrations, but lower (P< 0·05) isoleucine concentrations. Suckling piglets in the HMTBA treatment group had higher (P< 0·05) intestinal reduced glutathione (GSH) content, lower (P< 0·05) oxidised glutathione (GSSG):GSH ratio, and higher (P< 0·05) plasma cysteine and glutathione peroxidase (GPx) activity than those in the CON and DLM treatment groups. The feed intake (P< 0·05) and body weight of piglets averaged across post-weaning (PW) days were higher (P< 0·05) in the HMTBA treatment group than in the DLM treatment group and were higher (P< 0·05) and tended (P< 0·10) to be higher, respectively, in the HMTBA treatment group than in the CON treatment group. Increased (P< 0·05) GSSG content and GSSG:GSH ratio and down-regulated (P< 0·05) expression of nutrient transport genes were observed in the jejunum of piglets on PW day 7 than on PW day 0. On PW day 14, the HMTBA diet-fed piglets had higher (P< 0·05) intestinal GSH content than the CON diet-fed piglets and higher (P< 0·05) plasma GPx activity, villus height and goblet cell numbers than the CON diet- and DLM diet-fed piglets. In conclusion, early weaning-induced growth retardation appears to be attenuated through changes in plasma AA profiles and elevation of growth performance and intestinal antioxidant capacity in piglets following increased consumption of methionine as HMTBA.
The high repetition rate 10 J/10 ns Yb:YAG laser system and its key techniques are reported. The amplifiers in this system have a multi-pass V-shape structure and the heat in the amplifiers is removed by means of laminar water flow. In the main amplifier, the laser is four-pass, and an approximately 8.5 J/1 Hz/10 ns output is achieved in the primary test. The far-field of the output beam is approximately 10 times the diffraction limit. Because of the higher levels of amplified spontaneous emission (ASE) in the main amplifier, the output energy is lower than expected. At the end we discuss some measures that can improve the properties of the laser system.
This study mainly focused on the key technologies, the photon dose calculation based on the Monte Carlo Finite-Size Pencil Beam (MCFSPB) model in the Accurate Radiotherapy System (ARTS). In the MCFSPB model, the acquisition of pencil beam kernel is one of the most important technologies. In this study, by analyzing the demerits of the clinical pencil beam dose calculation methods, a new pencil beam kernel model was developed based on the Monte Carlo (MC) simulation and the technology of medical accelerator energy spectrum reconstruction. which greatly improved the accuracy of calculated result. According to the axial symmetry principle, only part of simulation results was used for the data of pencil beam kernel, which greatly reduced the data quantity of the pencil beam and reduced calculated time. Based on the above studies, the MCFSPB method was designed and implemented by the Visual C++ development tool. With several tests including the comparisons among the American Association of Physicists in Medicine (AAPM) No. 55 Report sample and the ion chamber measurement of lung-simulating inhomogeneous phantom in clinical treatment plan, the results showed that the maximum error of most calculated point was less than 0.5% in the homogeneous phantom and less than 3% in the heterogeneous phantom. This method met the clinical criteria, and would be expected to be used as a fast and accurate dose engine for clinic TPS.