黑龙江省不同地点蒙古栎林生态特点研究

通过对黑龙江省６个地点的天然蒙古栎林的结构和更新特点的分析,蒙古栎林可划分为不同特点的蒙古栎群落,即纯蒙古栎群落、蒙古栎桦树群落、蒙古栎槭树群落、蒙古栎红松群落和蒙古栎松混交林群落,其演替趋势如下：红蒙古栎群落、蒙古栎桦树群落至蒙古栎槭树落、蒙古栎红松群落,再至蒙古栎红松混交林群落,蒙古栎群落类型的多样性主要反应群落不同的演替阶段,造成蒙古栎群落多样的原因是人类活动和自然因素作用的结果,随着群落的演替,蒙古栎的优势地位逐渐被消弱,乔木种类丰富度增多,草本种类丰富度增多;蒙栎的相对密度下降,林内环境由于干燥逐渐变中性至较湿润,蒙古栎幼苗和幼树在总幼苗和幼树中所占的比例下降,耐荫物中色木槭等的幼苗和幼树所占比例上升;在演替过程中,蒙古栎分布格局－聚集分布的聚集程度逐渐降低,并向随机分布的方向发展。     

东灵山地区辽东栎叶的生长及其光合作用

测定辽东栎叶在不同发育时期的长度,面积和干重,应用红外ＣＯ２技术测定叶的净光合速率和暗呼吸速率的季节变化和日变化,并根据叶的平均生长速率和净光合速率推算叶生长过程中碳的输入和输出的变化趋势。结果表明：⑴辽东栎叶的长度、面积和干重的增加有共同趋势,即在叶生长早期增加很快,其后渐渐降低。叶长度、面积约在６月初达极大值;叶干重稍后达极大值。⑵净光合速率在整个生长季里随叶的生长发育是先上升,至７月中旬达极     

长汀水土流失区侵蚀劣地马尾松种群动态

先锋树种马尾松种群的生存状态是南方红壤侵蚀退化区开展水土流失治理措施的关键前提。通过对长汀水土流失区侵蚀劣地"小老头松林"的样地调查,基于种群统计的方法,建立年龄结构图和静态生命表、绘制存活曲线和生存分析函数、应用时间序列模型,对侵蚀退化生境马尾松种群动态变化过程开展研究。结果表明:马尾松种群年龄结构呈基部极宽、顶部狭窄的金字塔型,幼龄个体数量丰富但续存率低,成年个体很少,种群增长性低;死亡在各个生活史阶段均有出现,个体存活曲线属于Deevey-Ⅱ型,种群处于动态稳定状态;种群在幼龄期和壮龄期的生存状况不稳定,新生苗和壮龄期个体死亡密度大;种群时间动态预测显示,未来成年个体数量将增多,种群呈增长趋势。今后的森林生态管理中,可针对幼龄个体和壮龄成年个体采取抚育措施,提高小老头松林的生态效益。     

Similar Impacts of the Interaural Delay and Interaural Correlation on Binaural Gap Detection

The subjective representation of the sounds delivered to the two ears of a human listener is closely associated with the interaural delay and correlation of these two-ear sounds. When the two-ear sounds, e.g., arbitrary noises, arrive simultaneously, the single auditory image of the binaurally identical noises becomes increasingly diffuse, and eventually separates into two auditory images as the interaural correlation decreases. When the interaural delay increases from zero to several milliseconds, the auditory image of the binaurally identical noises also changes from a single image to two distinct images. However, measuring the effect of these two factors on an identical group of participants has not been investigated. This study examined the impacts of interaural correlation and delay on detecting a binaurally uncorrelated fragment (interaural correlation = 0) embedded in the binaurally correlated noises (i.e., binaural gap or break in interaural correlation). We found that the minimum duration of the binaural gap for its detection (i.e., duration threshold) increased exponentially as the interaural delay between the binaurally identical noises increased linearly from 0 to 8 ms. When no interaural delay was introduced, the duration threshold also increased exponentially as the interaural correlation of the binaurally correlated noises decreased linearly from 1 to 0.4. A linear relationship between the effect of interaural delay and that of interaural correlation was described for listeners participating in this study: a 1 ms increase in interaural delay appeared to correspond to a 0.07 decrease in interaural correlation specific to raising the duration threshold. Our results imply that a tradeoff may exist between the impacts of interaural correlation and interaural delay on the subjective representation of sounds delivered to two human ears.     

Discovery of new quinazoline derivatives as irreversible dual EGFR/HER2 inhibitors and their anticancer activities – Part 1

Overexpression of EGFR and HER2 are observed in many breast, ovarian, colon and prostate cancers. The second and third generation irreversible EGFR/HER2 dual kinase inhibitors became popular after the approval of Afatinib by FDA to overcome the mutation related problem. To find efficacious drug candidates, a series of novel quinazoline derivatives were designed, synthesized and evaluated as dual EGFR/HER2 tyrosine kinase (TK) inhibitors. Selected twenty four compounds were reported here with significant inhibitory activities against EGFR/HER2 tyrosine kinases. Several compounds showed nanomolar IC₅₀ values. In vitro studies of quinazoline derivatives were done on NCI-H1975, HCC827, A431, MDA MB-453 cell lines. The compounds 1a, 1d and 1v were found more potent compared to standard drug afatinib. In vivo efficacy study of 1d on nude mice NCI-H1975 tumour xenograft model was discussed.     

Molecular serotype identification of Streptococcus agalactiae of bovine origin by multiplex PCR-based reverse line blot (mPCR/RLB) hybridization assay

We used a multiplex PCR-based reverse line blot (mPCR/RLB) hybridization assay and sequencing of a variable region of the cps cluster to identify serotypes of 140 Streptococcus agalactiae (group B Streptococcus; GBS) isolates from cattle. Only 71 (51%) isolates were typeable using antisera, but molecular serotypes (MS) were assigned to 133 (95%) and 139 (99%) isolates by partial cpsE-cpsF-cpsG sequencing and mPCR/RLB, respectively. Ninety-four isolates (67%) belonged to MS III and most belonged to a molecular serosubtype (msst) III-3, which is uncommon among GBS isolates from humans. Our results demonstrate that cps clusters of bovine GBS differ significantly from those of GBS isolates from humans.     

Primitive Auditory Memory Is Correlated with Spatial Unmasking That Is Based on Direct-Reflection Integration

In reverberant rooms with multiple-people talking, spatial separation between speech sources improves recognition of attended speech, even though both the head-shadowing and interaural-interaction unmasking cues are limited by numerous reflections. It is the perceptual integration between the direct wave and its reflections that bridges the direct-reflection temporal gaps and results in the spatial unmasking under reverberant conditions. This study further investigated (1) the temporal dynamic of the direct-reflection-integration-based spatial unmasking as a function of the reflection delay, and (2) whether this temporal dynamic is correlated with the listeners’ auditory ability to temporally retain raw acoustic signals (i.e., the fast decaying primitive auditory memory, PAM). The results showed that recognition of the target speech against the speech-masker background is a descending exponential function of the delay of the simulated target reflection. In addition, the temporal extent of PAM is frequency dependent and markedly longer than that for perceptual fusion. More importantly, the temporal dynamic of the speech-recognition function is significantly correlated with the temporal extent of the PAM of low-frequency raw signals. Thus, we propose that a chain process, which links the earlier-stage PAM with the later-stage correlation computation, perceptual integration, and attention facilitation, plays a role in spatially unmasking target speech under reverberant conditions.     

Effects of Length of Abstinence on Decision-Making and Craving in Methamphetamine Abusers

Rationale

The majority of drug abusers are incapable of sustaining abstinence over any length of time. Accumulating evidence has linked intense and involuntary craving, Impulsive decision-making and mood disturbances to risk for relapse. However, little is known about temporal changes of these neuropsychological functions in methamphetamine (METH)-dependent individuals.

Objectives

To investigate the effect of length of abstinence on decision-making, craving (baseline and cue-induced), and emotional state in METH-addicted individuals.

Methods

In this cross-sectional study, 183 adult METH-dependent patients at an addiction rehabilitation center who were abstinent for 6 days (n = 37), 14 days (n = 33), 1 month (n = 31), 3 months (n = 30), 6 months (n = 26), or 1 year (n = 30) and 39 healthy subjects were administered the Iowa Gambling Task (IGT) to assess decision-making performance. Depression, anxiety, and impulsivity were also examined. One hundred thirty-nine METH abusers who were abstinent for the aforementioned times then underwent a cue session, and subjective and physiological measures were assessed.

Results

METH dependent individuals who were abstinent for longer periods of time exhibited better decision-making than those who were abstinent for shorter periods of time. And self-reported emotional symptoms improved with abstinence. METH abusers’ ratings of craving decreased with the duration of abstinence, while cue-induced craving increased until 3 months of abstinence and decreased at 6 months and 1 year of abstinence.

Conclusions

We present time-dependent alterations in decision-making, emotional state, and the incubation of cue-induced craving in METH-dependent individuals, which might have significant clinical implications for the prevention of relapse.     

Daphnane-type diterpenes with inhibitory activities against human cancer cell lines from Daphne genkwa

Four new daphnane-type diterpenes, genkwadanes A–D (1–4), together with 19 known ones, were isolated from ethanol extract of the flower buds of Daphne genkwa. Their structures were determined on the basis of extensive spectroscopic data. Among them, daphnane-type diterpene with a 1,10-double bond (1) was isolated from this plant for the first time. The cytotoxicity of all compounds 1–23 against the 10 selected human cancer cell lines was assayed. A number of compounds exhibited significant activities against the 10 cancer cell lines (IC₅₀ < 9.56 μM). and most interestingly, all the compounds revealed preferred cytotoxicities on the HT-1080 cell line and displayed much stronger inhibitory activities (IC₅₀ < 29.94 μM) compared with positive control 5-fluorouracil (IC₅₀ = 35.62 μM), particularly, compounds 9–11, 13, 16 and 19 exhibited the strongest cytotoxicity activities against the HT-1080 cell line (IC₅₀ < 0.1 μM).