How should we interpret and distinguish subsidiary cells?

The concept of subsidiary cells is discussed in the light of the existing literature correlating ontogeny arid mature structure. The protodermal origin of each epidermal component is illustrated and explained and the status of the ontogenetic classifications of these components has been analysed and discussed. Terminology is also defined and discussed.     

Effect of Danshen on the Zero-Stress State of Rat's Abdominal Aorta

The objective of our study was to study the effect of danshen, a Chinese herbal medicine known to prevent hypertension, on the zero-stress state of rat's abdominal aorta. The zero-stress state of a blood vessel represents the release of residual stress on the vessel wall, and is the basic configuration of blood vessel affected solely by intrinsic parameters. At the in vivo state, the rat's abdominal aorta was subjected to blood pressure and flow and longitudinal stress. After dissecting from the abdominal aorta, the aortic specimens were cut into small rings at no-load state, in which the internal pressure, external pressure, and longitudinal stress in a short ring-shaped segment were all zero; by cutting radially to release the residual stress in the wall, the vessel ring opened up into a sector quickly, and the sector's configuration would not change at 20 min after cutting and was defined as the zero-stress state of a blood vessel, which was characterized by its residual strain and opening angle. Then aqueous extract of danshen prepared with methanol was added in the Krebs solution, and the changes of the aorta's zero-stress state were monitored by taking photos routinely for analysis to determine the opening angle and residual strain. Additionally, other sets of samples were tested in a Norepinephrine-Krebs solution as positive control or a Krebs solution as negative control, respectively. It was demonstrated that the zero-stress state of rat's abdominal aorta was affected by danshen extract and norepinephrine in two different patterns, while the Krebs solution did not have similar effects. The present work provides a new approach to study the anti-hypertension effect and mechanism of danshen.     

Observation of residual dipolar couplings in short peptides

Residual dipolar couplings provide information on the orientation of individual bond vectors with respect to a unique set of molecular axes. We report that short peptides from 2 to 15 amino acids in length of arbitrary sequence exhibit a modest range of residual dipolar couplings when aligned in either strained polyacrylamide gels or alkyl-PEG bicelles. The absence of significant line broadening in gels suggests peptides align predominantly through steric interactions with the polyacrylamide matrix. However, broadening of NMR lines for a subset of residues aligned in bicelles indicates some peptides bind weakly to these lipid disks, yet a weak negative correlation between the couplings measured in gels and bicelles is consistent with steric hindrance playing a role in both media. The observation of dipolar couplings for peptides of length 10-15 suggests the statistical segment lengths of polypeptide chains must often be >10-15 residues, with data from denatured proteins indicating even larger values. Presumably, local side-chain backbone interactions severely restrict chain flexibility, with the cumulative effect of many such restrictions giving rise to biases in chain direction that may persist for the entire length of a protein chain. Comparison of experimental dipolar couplings for peptides with couplings calculated for ensembles of conformations generated by molecular dynamics should permit evaluation of the accuracy of molecular mechanics potentials in reproducing sequence-specific preferences for phi and psi angles.     

Diagnostic Measures of Influence for s2

We present three intuitive diagnostic measures for judging the influence that single or multiple observations exert on the estimate s², the mean square error. The three measures are shown to be equivalent statistics. We discuss distributional properties of these measures and conclude with an example.     

Assessment of heterogeneity of residual variances using changepoint techniques

Several studies using test-day models show clear heterogeneity of residual variance along lactation. A changepoint technique to account for this heterogeneity is proposed. The data set included 100 744 test-day records of 10 869 Holstein-Friesian cows from northern Spain. A three-stage hierarchical model using the Wood lactation function was employed. Two unknown changepoints at times T₁ and T₂, (0 <T₁ <T₂ <t_max), with continuity of residual variance at these points, were assumed. Also, a nonlinear relationship between residual variance and the number of days of milking t was postulated. The residual variance at a time t() in the lactation phase i was modeled as: for (i = 1, 2, 3), where λ_ι is a phase-specific parameter. A Bayesian analysis using Gibbs sampling and the Metropolis-Hastings algorithm for marginalization was implemented. After a burn-in of 20 000 iterations, 40 000 samples were drawn to estimate posterior features. The posterior modes of T₁, T₂, λ₁, λ₂, λ₃, , , were 53.2 and 248.2 days; 0.575, -0.406, 0.797 and 0.702, 34.63 and 0.0455 kg², respectively. The residual variance predicted using these point estimates were 2.64, 6.88, 3.59 and 4.35 kg² at days of milking 10, 53, 248 and 305, respectively. This technique requires less restrictive assumptions and the model has fewer parameters than other methods proposed to account for the heterogeneity of residual variance during lactation.     

具有空间自相关残差的回归模型及其应用

提出了具有空间自相关残差的多变量回归问题,这种残差包括单点、局部和区域化三种尺度.文中提出了两种处理空间自相关的方法:把自相关加入残差协方差作参数的改进估计──相邻相关方法和把残差作区域化最优自相关估计──一般空间自相关方法.用森林对舞毒蛾危害敏感性概率的大范围估计为例,比较了传统回归方法和本文方法间的差异,交叉检验结果表明本文的方法明显优于直接回归方法,这说明加入空间自相关对空间回归问题是必要的.     

残膜密度及面积对土壤水分累积入渗量的影响

随着地膜使用量和年限的不断增加,残膜在农田土壤中不断累积并趋于破碎化,影响土壤水分的入渗过程。本研究采用室内土壤水分一维垂直入渗试验,通过设置5个残膜面积水平(0.25、0.5、1、2、8 cm²)和5个残膜密度水平(0、60、180、300、420 kg·hm^-2)共21组试验处理,分析了不同残膜密度及面积对土壤水分累积入渗量的影响。结果表明: 在容重1.53 g·cm^-3的黏壤土中掺入一定量的残膜,加快了土壤水分入渗速率,增加了累积入渗水量;不同残膜面积处理的总入渗水量总是在单片残膜面积为1 cm²时出现突变或转折;残膜面积和残膜密度较大和较小时都会对累积入渗量产生显著影响,且以0.5 cm²残膜面积与200 kg·hm^-2残膜密度组合处理为明显分界,单片残膜面积为0.25 cm²时,累积入渗量最大;土壤中均匀混入单片面积≤0.25 cm²的残膜后,土壤水分累积入渗量曲线的斜率变化显著不同于其他残膜处理,形成了“新构”土壤,具有独特的水分入渗特征。     

Behavior of a Viscous LNAPL Under Variable Water Table Conditions

An intermediate-scale experiment in a 1.02-m-long, 0.75-m-high, and 0.05-m-wide flow cell was conducted to investigate the behavior of a viscous LNAPL under variable water table conditions. Two viscous LNAPL volumes (0.4 L) were released, one week apart, from a small source zone on top of the flow cell into a partly saturated, homogenously packed porous medium. Following a redistribution period of 30 days after the second release, the water table was increased 0.5 m in 50 minutes. After the water table rise, viscous LNAPL behavior was monitored for an additional 45 days. Fluid saturation scans were obtained periodically with a fully automated dual-energy gamma radiation system. Results show that both spills follow similar paths downwards. Within two hours after the first LNAPL arrival, the capillary fringe was reduced across the cell by approximately 0.04 m (22%). This reduction is directly related to the decrease in the air-water surface tension from 0.072 to 0.057 N/m.

LNAPL drainage from the unsaturated zone was relatively slow and a considerable residual LNAPL saturation was observed after 30 days of drainage. Most of the mobile LNAPL moved into the capillary fringe during this period. After a rapid 0.5 m water table rise, the LNAPL moved up in a delayed fashion. The LNAPL used the same path upwards as it used coming down during the infiltration phase. After 45 days, the LNAPL had moved up only approximately 0.2 m. Since the LNAPL had only moved up a limited amount, nonwetting fluid entrapment was limited. The experiment was simulated using the STOMP multifluid flow simulator, which includes entrapped and residual LNAPL saturation formation. A comparison indicates that the simulator is able to predict the observed phenomena well, including residual saturation formation in the vadose zone, and limited upward LNAPL movement after the water table rise. The results of this experiment show that viscous mobile LNAPL, subject to variable water table conditions, does not necessarily float on the water table and may not appear in an observation well.     

Accurate measurement of residual dipolar couplings in anisotropic phase

The determination of residual dipolar couplings (RDCs) by quantitative J spectroscopy methods such as Heteronuclear Single Quantum Correlation with Phase Encoded Coupling (HSQC-PEC) is prone to systematic errors that may be caused by differential attenuation during the conversion of orthogonal density operator components into observable terms. The attenuation may be caused by miscalibration of radio-frequency pulses and by relaxation effects. A simple method is presented that allows one to remove most of these systematic errors without losses in sensitivity or resolution.     

Amyloid formation in denatured single-mutant lysozymes where residual structures are modulated

Reduced hen lysozyme has a residual structure involving long-range interaction. It has been demonstrated that a single mutation (A9G, W62G, W111G, or W123G) in the residual structure differently modulates the long-range interactions of reduced lysozyme. To examine whether such variations in the residual structure affect amyloid formation, reduced and alkylated mutant lysozymes were incubated under the amyloid-fibrillation condition. From the analyses of CD spectra and thioflavine T fluorescences, it was suggested that variation in residual structure led to different amyloid formation. Interestingly, the extent of amyloid formation did not always correlate with the extent to which the residual structure was maintained, resulting in the involvement of a hydrophobic cluster normally contained in W111 in the reduced lysozyme.     

A new approach for applying residual dipolar couplings as restraints in structure elucidation

Residual dipolar couplings are useful global structural restraints. The dipolar couplings define the orientation of a vector with respect to the alignment tensor. Although the size of the alignment tensor can be derived from the distribution of the experimental dipolar couplings, its orientation with respect to the coordinate system of the molecule is unknown at the beginning of structure determination. This causes convergence problems in the simulated annealing process. We therefore propose a protocol that translates dipolar couplings into intervector projection angles, which are independent of the orientation of the alignment tensor with respect to the molecule. These restraints can be used during the whole simulated annealing protocol.     

重组白细胞介素2制品外源残余DNA的检测

采用ＤＮＡ杂交技术,用３２Ｐ标记的探针检测重组白细胞介素２制品的外源ＤＮＡ残余量。设三个水平：２５个剂量、１５个剂量、５个剂量。结果提示该方法是一种敏感有效的检测方法,其最小用样量为５个剂量单位。这为新制品检测方法的建立提供依据。     

Nanoindentation as a Probe of Nanoscale Residual Stresses: Atomistic Simulation Results

Abstract

Results from two sets of molecular dynamics simulations are reported. In the first set of simulations a nanoscale tip was used to indent single-crystal gold lattices subjected to external strains. These were carried out to explore possible relationships between nanoindentation curves and elastic properties of uniformly strained films. The changes in the slope of the loading curves reflect the stress state of the sample. In the second set of simulations the use of shallow nanoindentation for mapping nonuniform residual surface stress near a dislocation intersecting a surface was tested. Correlation between the maximum force on the tip and the initial local stresses at the point of indentation were observed. Preliminary atomistic simulations indicate that atomic-force microscopy can be used as a nondestructive, nanoscale probe of the surface stress distributions.     

Long-term and residual melanotropin-stimulated tyrosinase activity in S91 melanoma cells is density dependent

Summary Cell density is a factor that affects the capacity of Cloudman S91 melanoma cells to respond to melanotropins in monolayer culture. Continuous exposure of melanoma cells to α-melanotropin or its potent analog [Nle⁴,D-Phe⁷]-α-MSH, resulted in maximal stimulation of tyrosinase after 2 d of treatment, but the magnitude of stimulation decreased thereafter despite the continued presence of the melanotropins. However, when melanoma cells continually exposed to melanotropins were subcultured to an initial low cell density and maintained in contact with α-MSH or [Nle⁴,D-Phe⁷]-α-MSH (long-term culture), tyrosinase activity was rapidly restored and greatly enhanced. Also, when cells were seeded at initial densities ranging from 0.2 to 3.2×10⁶ cells/flask, and exposed for 24 h to 10⁻⁷ M α-MSH, only the cultures seeded at low densities (0.2 and 0.4×10⁶ cells/flask) exhibited maximal tyrosinase activity during the 24 h exposure to the melanotropins. Therefore, tyrosinase activity was primarily affected by cell density rather than by the duration of time the cells were in culture or by continuous exposure to melanotropin. Other flasks of various cell densities were treated with 10⁻⁷ M α-MSH or [Nle⁴,D-Phe⁷]-α-MSH for 24 h, followed byremoval of the melanotropins from the culture medium. The magnitude and duration of theresidual stimulation of melanoma tyrosinase activity by melanotropins were also found to be dependent on the initial cell density. These results reveal that there is a limited range of optimal cell densities at which melanoma cells can respond to melanotropins and express increased tyrosinase activity.     

Design and validation of a new method to detect and quantify residual host cell DNA in human recombinant erythropoietin (rEPO)

During the purification of human recombinant erythropoietin (rEPO) from host cells, residual DNA may remain in final products. This contamination is a risk factor for patients and may result in the inactivation of some tumor suppressor genes or activation of oncogenes if its concentration is more than the standard defined by WHO. Based on WHO’s criteria, acceptable level of residual DNA in biopharmaceuticals is less than 10–100?pg/dose. In this study, we have designed a sensitive and specific quantitative real-time polymerase chain reaction (PCR) assay for the detection of residual DNA in human rEPO products. All reported sequences of CHO’s GAPDH gene were retrieved from GenBank, and a multiple alignment was performed using Mega 6 software to find conserved regions of the gene. Primers and probe were designed by AlleleID7 software for the highly conserved region. Quantitative real-time PCR showed an R² value more than 0.99 and the efficiency equal to 101% indicating a highly accurate and efficiency of the reaction, respectively. Based on the standard curve, the limit of detection of the assay was determined to be 10?copies/µL (0.00967?fg/µL). In addition, the inter- and intra-assay of the test were determined to be 1.14% and 0.65%, respectively, which are in acceptable range according to the WHO’s guidelines.     

Impact of lactation upon fertility in the New World primate capuchin monkey (Cebus apella)

In the present paper, we have studied the impact of lactation upon fertility in the capuchin monkey, Cebus apella, under laboratory conditions. Nursing females (ten females, 12 postpartum periods) presented lactational amenorrhea (first menses at 159.2 +/- 9.0 vs 42.6 +/- 5.8 days postpartum in five non-nursing females, seven postpartum periods). Plasma estradiol and progesterone concentrations during lactational amenorrhea were lower than those during the follicular phase of the menstrual cycle. Prolactin was higher than in non-nursing females at 31-60 days postpartum. Interbirth interval, studied in three non-nursing (four intervals) and six nursing females (eight intervals) lasted for 349.5 +/- 11.8 and 613.4 +/- 30.8 days, respectively. In non-nursing females, early recovery of the menstrual cycle was followed by a residual infertility (mating but no pregnancy) lasting 152.8 +/- 7.9 days. In nursing females, recovery of the menstrual cycle was followed by an extended residual infertility of 301.5 +/- 22.7 days. Thus, in the capuchin monkey, nursing prolongs the interbirth interval by inducing lactational amenorrhea and extending the residual infertility period.