Projection patterns of individual X- and Y-cell axons from the lateral geniculate nucleus to cortical area 17 in the cat

Horseradish peroxidase was injected intracellularly into single, physiologically-identified X- and Y-cell geniculocortical axons projecting to area 17 of the cat. This injection anterogradely labeled the axon terminal fields in cortex and retrogradely labeled the somata of these same axons in laminae A and A1 of the lateral geniculate nucleus (LGN). The laminar projections of 21 X- and 15 Y-cell axons were analyzed. For these, the laminar terminations of ten X- and seven Y-cell axons were also related to their cells' positions in the A-laminae. The terminal fields of X- and Y-cell axons overlapped substantially in layers IV and VI of area 17. Some X-cells terminated mainly in IVb, others mainly in IVa, and still others throughout IVa and IVb. The latter two groups also projected up to 100 micron into lower layer III. Y-cells terminated primarily in layer IVa and projected up to 200 microns into lower layer III. Some also arborized throughout the depth of layer IVb. Both X- and Y-cell axons terminated throughout the depth of layer VI, although more so in the upper half. We found no relationship between the diameter of the parent axon and its sublaminar projection within layer IV. Within layer IV, X-cell axons generally terminated within a single, continuous clump and had surface areas of 0.6 to 0.9 mm2. Axons of Y-cells often terminated in two to three separate clumps, separated by terminal free gaps 400 to 600 micron wide. Their total surface areas, including gaps, were 1.0 to 1.8 mm2, roughly 1.6 times the surface areas of X-cell axons. Despite considerable overlap, Y-cell arbors contained significantly more boutons than did X-cell arbors. The sublaminar projections of the X- and Y-cell axons within layer IV reflected the locations of the cells' somata within the depth of the A-laminae. X-cells located in the dorsal or ventral thirds of the depths of the laminae projected mainly to layer IVa or throughout layer IV in cortex. Those located in the central thirds projected mainly to layer IVb. Y-cells showed a similar positional relationship, but they appeared to follow different rules. Y-cells in the outer thirds of the A-laminae projected mainly to layer IVa; those in the central thirds, in addition, expanded their projections to include layer IVb. In general, larger sized somata in the LGN gave rise to more widely spreading terminal arbors and greater numbers of boutons in cortex than did smaller somata.(ABSTRACT TRUNCATED AT 400 WORDS)     

An integrated approach to reduced-order control theory

Linear-Quadratic-Gaussian (LQG) theory generally requires the use of a full-order dynamic observer whose dimension is often prohibitive in applications so that reduced-order controller design techniques are needed. A general formalism is presented here for the optimal design of controllers of arbitrary prescribed order with the usual quadratic cost functionals. The gradients of the cost functional are obtained in explicit form and involves Liapunov equations. A fundamental aspect of this paper is a unifying formalism; direct output feedback and reduced-order controllers, stochastic and deterministic systems, infinite-time and finite-time problems and time-invariant and time-varying problems are considered. Optimization of sensor and actuator locations and parameter-variation-insensitive controller design are also considered within this framework. Examples are treated.     

超声引导下及传统解剖定位下行深静脉穿刺置管术在血液净化中的比较

目的探讨B超定位下与传统解剖定位下行深静脉穿刺置管术在血液净化治疗中的优劣。方法选择100例行血液净化深静脉穿刺置管患者,随机分为两组,A组(50例)在B超定位下行颈内静脉穿刺置管术;B组(50例)在传统解剖定位下行颈内静脉穿刺置管术。观察:1穿刺及钢丝置入一次性成功率。2不良事件发生率。结果 A组患者穿刺及钢丝置入一次性成功率均高于B组;损伤动脉发生率、维持性血液净化治疗过程中深静脉管路血流量不足发生率、深静脉管路感染及堵塞并发症的发生率均低于B组(P<0.05)。结论在超声引导下行深静脉穿刺置管术是一种快速准确、安全有效的方法,适用于需行血液净化治疗的患者。     

Protein found to promote DNA repair, prevent cancer

Background It is uncertain whether genotypes of Candida albicans （C. albicans） are associated with colonizing body locations or variant conditions of infection. The aim of this study was to investigate whether there are significant associations between strain genotypes and body sites of infection and to determine the potential pathogenesis of cutaneous candidiasis at multiple locations. Methods A total of 151 strains of C. albicans were isolated from 74 infant patients with cutaneous candidiasis and 61 female patients with vaginal candidiasis. Patients were grouped according to the body sites and underlying conditions of infection. Genotypes were identified by polymerase chain reaction （PCR） of the 25S rDNA and PCR-restriction fragment length polymorphism （RFLP） of ALT repeats digested with EcoRI and Clal. Results Ten genotypes were detected. There were significant differences in genotype frequencies between the two groups. However, we found no clear association between genotypes and the sites of cutaneous infection or the underlying conditions of vaginal candidiasis （VVC）. In addition, strains of C. albicans from multiple cutaneous locations of the same patient had identical genotypes. Conclusions Populations of C. albicans from patients with cutaneous and vaginal candidiasis were genetically different. However, the lack of genetic difference between strains from different body sites with cutaneous infections or from different underlying conditions for VVC suggests no evidence of genotype selection for different skin surfaces or patients with different underlying conditions for VVC.     

Does work-related and commuting physical activity predict changes in physical activity and sedentary behavior during the transition to retirement? GPS and accelerometer study

We examined how GPS and accelerometer measured work-related and commuting physical activity contribute to changes in physical activity and sedentary behavior during the retirement transition in the Finnish Retirement and Aging study (n = 118). Lower work-related activity was associated with a decrease in sedentary time and an increase in light physical activity during retirement. Conversely, higher work-related activity was associated with an increase in sedentary time and a decrease in light physical activity, except among those active workers who also were active commuters. Thus, both work-related and commuting physical activity predict changes in physical activity and sedentary behavior when retiring.