Human muscle spindles act as forward sensory models.

Modern theories of motor control incorporate forward models that combine sensory information and motor commands to predict future sensory states. Such models circumvent unavoidable neural delays associated with on-line feedback control. Here we show that signals in human muscle spindle afferents during unconstrained wrist and finger movements predict future kinematic states of their parent muscle. Specifically, we show that the discharges of type Ia afferents are best correlated with the velocity of length changes in their parent muscles approximately 100-160 ms in the future and that their discharges vary depending on motor sequences in a way that cannot be explained by the state of their parent muscle alone. We therefore conclude that muscle spindles can act as "forward sensory models": they are affected both by the current state of their parent muscle and by efferent (fusimotor) control, and their discharges represent future kinematic states. If this conjecture is correct, then sensorimotor learning implies learning how to control not only the skeletal muscles but also the fusimotor system.

Gill-damage in netted Tilapia mossambica Peters

Tilapia mossambica taken with gill-nets are often found with their gills damaged. Gill-filaments may be partly or completely lost; sometimes even the gill-arches are all missing (Plate IA). The operculum is usually undamaged but may have its posteroventral border slightly frayed (Plate IB). For comparison normal fish are shown in Plates IC and ID. Incidence of gill-damage increases rapidly with length of time the nets remain in the water; in the Parakrama Samudra a mere 2-3 hour interval between setting and lifting results in 5 to 20% of the fish being damaged.

宁蒗保种黑头山羊血液蛋白多态性研究

　采用水平板淀粉胶电泳技术对来自云南保种宁蒗黑头山羊的31 个个 体的39 个基因座位的血液同功酶进行了分析, 结果得到A KP, CES- I, ESD, GO I, M E 和N P 共6 个座位出现多态, 多态座位A KPO , CES- I2, ESDB , GO IA ,M EB 和 N PB 的基因频率较高; 多态座位百分比P = 0. 1538, 平均杂合度H = 0. 0679 ± 0. 0241。本研究首次得到了该羊的遗传多样性特征, 为该羊的保种和利用提供了基础 数据。

A bactericidal homodimeric phospholipases A(2) from Bungarus fasciatus venom

Group IIA secretory phospholipases A(2) (sPLA(2)-II) is generally known to display potent grampositive bactericidal activity, while group IA sPLA(2) (sPLA(2)-I) reportedly is not. In this work, a novel sPLA(2)-I named BFPA was identified from Bungarus fas

中国兽类一新纪录———爪哇穿山甲

记述了来自中国云南的爪哇穿山甲Manis javanica , 即中国兽类新纪录, 标本收藏在中国科学院昆明动物

Lentivirus介导神经营养因子- 3促进脊髓损伤大鼠功能恢复

　目的　探讨Lentivirus介导分泌神经营养因子- 3 (NT - 3)直接体内转基因治疗大鼠脊髓损伤作用和机制。　方法　将28只Wistar大鼠在T10水平制成半横断损伤模型,随机分为体内转基因治疗组和损伤对照组,每组14只;用携带NT - 3和绿色荧光蛋白(GFP)的Lentivirus对大鼠行直接体内转基因治疗;荧光显微镜观察体内转基因表达,后肢运动功能评分法(BBB评分) 检测大鼠后肢功能恢复情况。　结果　用荧光显微镜检测到损伤脊髓内有较多的持续表达转基因的细胞; BBB评分结果显示,从伤后第4周开始,实验组大鼠后肢功能较对照组明显恢复( P < 0. 01) ,至第10周时,实验组和对照组BBB分差增大,达3. 3分。　结论　Lentivirus是一种有效的转基因载体,由Lentivirus介导分泌NT - 3的直接体内转基因治疗能够明显促进损伤脊髓的功能恢复。

蓝氏贾第虫分离株tim 基因序列分析比较研究

　为了探讨来源于不同地理位置贾第虫分离株之间的遗传学关系, 采用tim 基因扩增、限制性酶切和 DNA 序列分析方法对来自我国(C1、C2、、CH2、CH3)、柬埔寨(CAM )、澳大利亚(A 1、A 2) 和美国(BP、CDC) 共9 株 蓝氏贾第虫的基因型进行了分析比较。结果表明,A 1、A 2 和CAM 属第1 型(WB) ; CH2 和CH3 属第2 型(JH) ; C1、 C2、BP 和CDC 属第3 型(GS)。本实验结果提示, 虫株间遗传学关系并非由地理位置的远近所决定。来源于同一地 理位置的虫株其遗传学特性可有很大的差异。相反, 来源于地理位置相隔很远的虫株其遗传学特性却可极为相近。 贾第虫分离株基因型的确定可为本虫分子系统进化和分子流行病学研究提供重要资料。

鸡胚背根神经节培养法测定神经生长因子(NGF) 活性的条件优化

目的　探索一套稳定可靠的鸡胚背根神经节测定N GF 活性的实验条件。　方法　通过观察培养 基、鸡血浆和鸡胚浸液的比例、背根神经节部位、培养时间等条件对N GF 刺激神经节生长的影响, 从而 建立一套该培养法检测N GF 活性的优化条件。　结果　以DM EM 为母液, 在含20% 鸡血浆和15% 鸡胚 浸液的培养基中, 利用伊莎褐鸡胚腰椎背根神经节, 在终浓度为30 ngöm l 的蛇毒N GF 的刺激下, 培养36h 可以得到较好的实验结果。　结论　该条件简单实用、分辨率高、重复性好。

金环蛇毒心脏毒对S180,EAC腹水癌细胞的细胞毒性作用

目的: 探讨金环蛇毒心脏毒对S180, EAC 腹水癌细胞的细胞毒作用。方法: 采用小白鼠腹腔和皮下接种S180, EAC 腹 水癌细胞造成小白鼠腹水模型后腹腔注射金环蛇毒心脏毒。结果: 腹腔注射金环蛇毒心脏毒, 能抑制肿瘤细胞的生长, 降低接 种率。但不能完全控制腹水和癌细胞的生长。体外试验表明有明显的细胞毒作用。台酚蓝染色镜检可见死细胞显著增加, 腹 水图片检查, 给药后细胞膜破裂, 纤维化坏死明显。结论: 能延长小白鼠存活时间。

尖吻蝮蛇蛇毒出血毒素的纯化与部分性质

目的　被尖吻蝮蛇(D ienag k istrod on acu tus) 咬伤会引起严重的出血, 对蛇毒出血毒素的研究有利 于治疗蛇伤出血药物筛选。方法　采用Sephadex G275, DEA E2Sephadex A 250, Sephadex G2200 和两次 PBE 聚焦层析纯化。SDS2PA GE 电泳和等电聚焦电泳测定纯化样品的纯度和等电点。氨基酸组成用自动氨 基酸分析仪测定。以小鼠背部皮下注射部位出血斑的面积来确定最小出血剂量和常规的方法测定酶活性。 结果　从尖吻蝮蛇毒中纯化到一个相对分子量为56 000 的出血毒素(DaHT23) , 经氨基酸组成测定计算, 它由487 个氨基酸残基组成。此成分在SDS2PA GE 上显示出一条均一的蛋白染色带, 其p I 为5150。该出 血成分的最小出血剂量是216Lg, 具有蛋白水解酶活力, 其活力为3168, 但没有精氨酯酶和磷脂酶A 2 活 力。当加入EDTA 螯合剂去除金属离子后, 它们的出血活力和蛋白水解酶活力均丧失。结论　这是从大 陆尖吻蝮蛇毒中获得的一个新的出血金属蛋白酶(DaHT 23)。

Dasher

Dasher is an information-efficient text-entry interface, which can be driven by natural continuous pointing gestures or by pressing buttons. Dasher is a competitive text-entry system wherever a full-size keyboard cannot be used - for example, when operating a computer one-handed, by joystick, touchscreen, trackball, or mouse; when operating a computer with zero hands (i.e., by head-mouse or by eyetracker); on a palmtop computer; on a wearable computer. The gazetracking version of Dasher allows an experienced user to write text as fast as normal handwriting - 29 words per minute; using a mouse, experienced users can write at 39 words per minute. Dasher can be used to write efficiently in any language. Dasher is free software (distributed under the GPL) and is available for many computer platforms, including linux, windows, and android.

Raman scattering efficiency of graphene

We determine the Raman scattering efficiency of the G and 2D peaks in graphene. Three substrates are used: silicon covered with 300 or 90 nm oxide, and calcium fluoride (CaF2). On Si/SiOx, the areas of the G and 2D peak show a strong dependence on the substrate due to interference effects, while on CaF2 no significant dependence is detected. Unintentional doping is reduced by placing graphene on CaF2. We determine the Raman scattering efficiency by comparison with the 322 cm -1 peak area of CaF2. At 2.41 eV, the Raman efficiency of the G peak is ∼200×10-5 m-1Sr-1, and changes with the excitation energy to the power of 4. The 2D Raman efficiency is at least one order of magnitude higher than that of the G peak, with a different excitation energy dependence. © 2013 American Physical Society.