Differences of tensile strength distribution between mechanically high-grade and low-grade Japanese larch lumber I: Effect of length on the strength of lumber

An experimental study was conducted to evaluate the effect of length on the parallel-to-grain tensile strength of Japanese larch (Larix kaempferi, Carriere) lumber. Six hundred pieces of mechanically graded lumber were tested at gauge lengths of 60, 100, and 180 cm. The lumber was sorted into matched groups according to the dynamic Young's modulus measured by the longitudinal vibration method before the lumber was cut to the particular length. The averages of the dynamic Young's modulus of high-grade (H) and low-grade (L) specimens were 12.8 and 7.5 GPa, respectively. Using nonparametric estimates, the estimated length effect parameters of H and L were 0.268 and 0.304 for the 50th percentile and 0.121 and 0.256 for the 5th percentile, respectively. We then concluded that the different length effect factors between H and L could be used when using the lumber for practical purposes. The parameters of L were larger than those for H, and the parameters for 5th percentiles were smaller than the parameters for 50th percentiles. When two-parameter Weibull distribution functions were fitted to the strength data, the estimated shape parameters of the Weibull distribution by the parametric method were almost identifical to the inverse of nonparametric parameters except the 5th percentiles for H. The influence of defects such as knots on the lower tail of the strength distribution in H may be different from that in L.Part of this paper was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

Differences of tensile strength distribution between mechanically high-grade and low-grade Japanese larch lumber 11: Effect of knots on tensile strength distribution

The tensile strength (TS) test results of Japanese larch (Larix kaempferi, Carriere) lumber of varying length have shown that the length effects on TS were different between high-grade (H) and low-grade (L) lumber. In this paper, we examined the effect of knots on the TS distribution by measuring the number of knots and the knot area ratio of each specimen. There were more knots in L than in H; and the knot area ratio in L distinctly increased as the length increased compared to that in H. The correlation coefficients between physical properties and TS indicated that knots were the most influencial factor for TS among several physical properties: annual ring width, distance from pith, density, dynamic Young's modulus, and knots. We attempted to estimate the length effect parameters by introducing the concept of assumed knot strength. We thought that the length effect parameters for 50th percentiles of TS could be estimated well with fitted 3P-Weibull, and that the parameters for 5th-percentiles could be estimated well with 2P-Weibull fitted to lower-tail 10% data by the likelihood method. The differences of length effect on TS between H and L should be governed by the presence of knots. The independent model based on the concept of assumed knot strength may express the TS of structural lumber of various lengths.     

The effects of one-time hoof trimming on blood biochemical composition, milk yield, and milk composition in dairy cows

Although not scientifically proven, hoof trimming has been empirically shown to increase milk yields in healthy dairy cows. In this study, we examined the effect of one-time hoof trimming on blood biochemical composition, milk yield, and milk composition in healthy dairy cows. Eleven cows in the mid to late lactation period that were clinically fit and without hoof disease were subjected to hoof trimming, and metabolic profile tests and dairy herd improving tests were performed before and three weeks after the hoof trimming. The metabolic profiles showed changes in albumin, blood urea nitrogen, ammonia, glucose, and beta-hydroxybutyric acid as a result of the hoof trimming. This was indicated by the fact that the cows began to intake more roughage after hoof trimming than prior to hoof trimming, and rumen fermentation became stable. There was no change in milk yield after trimming. However, the milk fat and milk protein compositions were significantly increased after trimming.     

Retinal neuronal cell is a toxicological target of tributyltin in developing zebrafish

Organotins are among the most common marine pollutants in the world, as they are widely used as antifouling paint on ships and fishing nets. It has been reported that organotin preferentially accumulates in the central nervous system, especially in the retinal neurons of marine organisms including fish. In this study, we investigated the effects of waterborne tributyltin (TBT) on early-stage developing zebrafish (Danio rerio). Below the lethal concentrations, TBT specifically increased the number of apoptotic cells in the retina as well as some cells near trigeminal neurons, detected by terminal transferase-mediated nick-end-labeling staining. Apoptosis peaked at 60 hpf and decreased by 72 hpf, which was associated with macrophage accumulation. Furthermore, the effect of TBT was markedly inhibited by antioxidants, ascorbic acid or trolox. These results suggest that TBT preferentially induces apoptosis in the retinal neuron of developing zebrafish. Oxidative stress may be involved in this toxicological response.     

Relationship between trace elements status in mane hair and atrial fibrillation in horse

To investigate the relationships between trace elements concentrations in hair and atrial fibrillation (AF) in horses, concentrations of nineteen trace elements were detected in hair using the particle induced X-ray emission (PIXE) method. The horses were assigned to either control (n=22, no abnormalities) or AF groups (n=5) based on electrocardiograph findings. The mean concentrations of Ca and Zn in the hair of the AF group were significantly higher than those in the control group. The Zn/Cu ratio of the hair in the AF group (29.8 +/- 5.5) was significantly higher than that in the control group (23.4 +/- 2.2, P<0.05). The results of the present study suggest that there is a relationship between elevated concentrations of Ca and Zn in hair and AF.     

Establishing conditions for the storage and elution of rabies virus RNA using FTA? cards

The Flinders Technology Associates filter paper cards (FTA^® cards) can be used to store nucleic acid from various samples and are easily portable. However, RNA is physicochemically unstable compared with DNA, and appropriate methods have not been established for storage and extraction of RNA from FTA^® cards. The present study investigated the optimum conditions for storage and elution of viral RNA (vRNA) using rabies virus (RABV) applied to FTA^® cards. When TE buffer was used, the elution rates of vRNA increased with the length of the elution time. When the cards were stored at −80°C or −20°C, vRNA was stable over 3 months. Degradation of vRNAs occurred following storage at 4°C and room temperature, suggesting that RNA should be extracted from cards as soon as possible if no freezer is available. When we tried to amplify vRNA from RABV-infected animal brains applied to FTA^® cards and stored at −80°C for 6 months, we did not detect any amplified products with the primer set for 964 bp of RABV N gene. However, we were able to detect amplified products by increasing the elution time of vRNA from FTA^® cards from 30 min to 24 hr or by changing the primer sets to amplify 290 bp of N gene. Thus, we recommend extending the elution time for damaged or low concentration samples in FTA^® cards.     

盐分再分配条件下河套灌区冲洗水量的数值模拟

该文旨在探讨干旱缺水地区长期灌溉条件下,合理解决节水灌溉与冲洗灌溉间矛盾的途径,为在该地区实施节水灌溉战略提供理论依据。采用修正的对流扩散模型(SOTR)及特征有限元方法对中国内蒙古河套灌区冲洗—蒸发条件下的冲洗定额进行数值模拟研究。并用γ射线测定土柱土壤水盐运移结果标定了数值模拟结果。重点分析了基于土壤水动力学与溶质动力学原理,再灌溉冲洗与再分配条件下,均质垂直剖面上溶质运移过程;长期灌溉条件下,干旱地区土壤盐分布与冲洗定额、初始土壤盐分含量、地下水位埋深及地下水矿化度间的内在联系;在此基础上,确定节水灌溉条件下河套灌区最优的冲洗定额。该成果对于促进该地区农业可持续发展具有一定的指导意义     

Inhibitory actions of several natural products on proliferation of rat vascular smooth muscle cells induced by Hsp60 from Chlamydia pneumoniae J138

Atherosclerosis is a vascular disorder involving inflammation, a narrowed vascular lumen in the entire tunica intima, and reduced elasticity of the arterial wall. It has been found that Hsp60 from Chlamydia pneumoniae, an obligate bacterial pathogen associated with atheroma lesions, mimics human Hsp60, thereby causing attacks by immune cells on stressed endothelial cells expressing endogenous Hsp60 on their surface. Furthermore, Hsp60 from C. pneumoniae has been shown to promote the growth of vascular smooth muscle cells (VSMCs). To explore probes that can be used for studying signal transduction elicited by the chlamydial Hsp60, we have tested several natural products for their inhibitory actions on the Hsp60-induced proliferation of rat arterial smooth muscle cells. Sesamol, vanillyl alcohol, and trans-ferulic acid exhibited moderate inhibitory actions on the Hsp60-induced cell proliferation; zerumbone, humulene, and caryophylene effectively inhibited it at low concentrations with IC(50) values of 529, 122, and 110 nM, respectively. The results indicated that the 11-membered alicyclic ring is favorable for interactions with receptors involved in the Hsp60-induced VSMC proliferation.     

Probing asthenospheric density, temperature, and elastic moduli below the western United States

Periodic ocean tides continually provide a cyclic load on Earth's surface, the response to which can be exploited to provide new insights into Earth's interior structure. We used geodetic observations of surface displacements induced by ocean tidal loads to constrain a depth-dependent model for the crust and uppermost mantle that provides independent estimates of density and elastic moduli below the western United States and nearby offshore regions. Our observations require strong gradients in both density and elastic shear moduli at the top and bottom of the asthenosphere but no discrete structural discontinuity at a depth of 220 kilometers. The model indicates that the asthenosphere has a low-density anomaly of ~50 kilograms per cubic meter; a temperature anomaly of ~300°C can simultaneously explain this density anomaly and inferred colocated minima in elastic moduli.