l-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) selectively destroys dopaminergic neurons in the pars compacta of the substantia nigra (A8 and A9 cells). MPTP or its metabolite enters nerve cells at the level of their terminals in the caudate nucleus and putamen leading to a disturbance in axoplasmic flow and retrograde degeneration. The species-dependent neurotoxicity of MPTP (primate vs. rodent) suggests that a biochemical property of the cell related to neuromelanin may be important in the mechanism of cell injury.

Residual stress in MEMS is of inherent importance in various respects. This study proposes a specific method using ANSYS including the birth and death method and combined with the optimal method (SCGM) to reduce the residual stresses during the CMOS fabrication process. The suitable cooling temperature for decreasing the residual stress is proposed and available. It demonstrates that the suitable parameter on the fabrication can reduce the residual stress in MEMS devices without any extra manufacturing process or external apparatus. The proposed method can expand to simulate the realistic MEMS model effectively.

In clinical practice, cam-out failure at the recess-screwdriver interfaces may occur when tightening or removing a bone screw. For titanium-based periarticular fixation, the literature reports have revealed that cold welding at the plate-screw interfaces makes the screw recess especially prone to cam-out failure during screw removal. In this study, the effects of the four recess shapes (cross, hexagon, star, and crest), three torque value (0.8, 1.0, and 1.2N-m), and the three interfacial misfits (0.00, 0.05, and 0.10mm) on the cam-out failure were numerically evaluated. The free-rotation angle, torque-recess angle, slippage-resisting length, and interfacial stress distribution were defined and chosen as comparison indices for the twelve recess-misfit variations. The results revealed that the interfacial slippage, torque transfer, and stress distribution are highly related to both recess shape and interfacial misfit. The stresses of all recesses and screwdrivers consistently initiate at the contact sites. However, the recess profile significantly affects the stress propagation. The stress patterns of the recess and screwdriver are quite different between the cross-star and hexagon-crest groups. The cross-star group is superior to the hexagon-crest group in terms of the torque-recess angle and slippage-resisting length over. This makes the recess of the cross-star group less stressed than its counterpart. However, the volumes of the cross and the star screwdriver are more highly stressed than the hexagon due to the irregular shape and the thinner flange, respectively. The greater torque and misfit increase the performance difference between the four recess designs. In conclusion, the geometry of the cross and star groups provide the better performance of the screw recess in terms of torque-transferring efficiency and slippage-resisting ability. If the screwdriver material is properly strengthened and the stress-concentrating corners are modified, the cross and star groups would be the optimal designs that protects and extends the lifetime of both recess and reused screwdriver.

Transient phenomena that impact the speed of electron devices fabricated from organic semiconductor materials are of critical importance for the development of this new technology. Here we investigate theoretically and experimentally the effects of traps on the establishment and the depletion of the conducting channel in organic semiconductor field effect transistors (OFETs). The device structures explored resemble typical organic thin-film transistors with one of the channel contacts removed. The channel length is varied, and generally is longer than in typical OFETs, in order to vary the carrier transit time. By measuring the displacement current associated with charging and discharging of the channel in these capacitors, transient effects on the carrier transport in organic semiconductors may be studied. When carriers are injected into the device, a conducting channel is established with traps that are initially empty. Gradual filling of the traps then modifies the transport characteristics of the injected charge carriers. In contrast, DC experiments as they are typically performed to characterize the transport properties of organic semiconductor channels investigate a steady state with traps partially filled. Numerical and approximate analytical models of the formation of the conducting channel and the resulting displacement currents are presented. Two simple scenarios are considered first: the spatially-averaged carrier density model neglects carrier dynamics but shows the salient trapping/detrapping effects. Second: a simple geometric model neglects traps but elucidates the effect of carrier dynamics and is used to define an effective mobility that can be extracted from experiments. Finally, numerical simulations are used to study the dynamical and trap effects together. Comparing the average trapping time with the time scale of the current transient sheds light on the influence of traps on the effective mobility. If the average trapping time is very long the effect of traps is negligible and the mobility is largely unaffected by traps on the timescale of the experiment. If the average trapping time is short the effective mobility is reduced but it is time-independent. However, the effective mobility changes with time if the average trapping time is comparable to the current transient interval, eventually reaching a constant value once the trapping and detrapping events balance. Furthermore, the temperature dependence of the effective mobility arising from the temperature dependence of the trap emission rate is explored. Experimental data for pentacene based devices of different channel length and obtained over in the temperature range 120K < T < 300K support the concepts of the physical model.

A retrospective study of clinical characteristics, outcome and prognostic factors of patients with cryptococcosis was undertaken in intensive care units (ICUs) of a medical centre for the period 2000–2005. Twenty-six patients with Cryptococcus neoformans var. grubii infection were identified (16 males, median age 58 years). The most frequent underlying diseases were liver cirrhosis (38·5%), diabetes mellitus (26·9%) and HIV infection (19·2%). The most frequently identified sites of infection were blood (61·5%), cerebrospinal fluid (38·5%) and airways (34·6%). The mean Acute Physiologic and Chronic Health Evaluation II score at ICU admission was 22·46. The ICU mortality rate in these patients was 73·1% (19/26) and there were a further two mortalities recorded after discharge from ICU, reaching a total mortality rate of 80·8% (21/26). Patients with ICU survival >2 weeks had lower rates of HIV infection (P=0·004), less use of inotropic agents during ICU stay (P<0·001) and lower white blood cell counts (P=0·01). After adjusting for clinical variables in the multivariate Cox regression model, diabetes and cryptococcal infection after ICU admission were independent predictors of good long-term prognosis (P=0·015) and HIV infectious status was associated with poor outcome (P=0·012).

Two hundred and four Salmonella enterica serotype Typhi (S. Typhi) isolates were collected from seven Asian countries during 2002–2004. Multidrug-resistant S. Typhi (resistant to ⩾3 antibiotics) was detected in 84 (41·2%) isolates and 142 (69·6%) showed reduced susceptibility to ciprofloxacin (minimum inhibitory concentration=0·125–1·0 mg/l). This study highlights the worsening situation of antimicrobial resistance of S. Typhi in Asia.

A series solution is presented for a spherical inclusion embedded in an infinite matrix under a remotely applied uniform intensity. Particularly, the interface between the inclusion and the matrix is considered to be inhomegeneously bonded. We examine the axisymmetric case in which the interface parameter varies with the cone angle θ. Two kinds of imperfect interfaces are considered: an imperfect interface which models a thin interphase of low conductivity and an imperfect interface which models a thin interphase of high conductivity. We show that, by expanding the solutions of terms of Legendre polynomials, the field solution is governed by a linear set of algebraic equations with an infinite number of unknowns. The key step of the formulation relies on algebraic identities between coefficients of products of Legendre series. Some numerical illustrations are presented to show the correctness of the presented procedures. Further, solutions of the boundary-value problem are employed to estimate the effective conductivity tensor of a composite consisting of dispersions of spherical inclusions with equal size. The effective conductivity solely depends on one particular constant among an infinite number of unknowns.

The aim of the study was to elucidate the epidemiological features of Hepatitis C virus (HCV) infection among teenagers in an endemic area by conducting a mass screening study. We also investigated the clinical outcome of the anti-HCV-positive subjects by conducting subsequent short-term and long-term follow-up studies. All 2837 students of two junior middle schools in Tzukuan, aged 13–16 years, were invited to be screened for anti-HCV, HBsAg, AST and ALT in October 1995. A total of 2726 (96%) students responded. Anti-HCV, HCV RNA and aminotransferase levels were evaluated among anti-HCV-positive students 1 month and 30 months later, respectively. A total of 38 (1·4%; M/F = 22/16) participants were anti-HCV-positive. The anti-HCV-positive students had higher rates of exposures to transfusion, anti-HCV-positive families and surgery. The prevalence (2·8%) of the 7 maritime villages was markedly higher than that (0·7%) of the other 8 villages (P < 0·001). Subsequent follow-up studies demonstrated that there might be 5 cases of acute or recent HCV infection, and 6 cases who had recovered from chronic HCV infection.

A monolithic quantum well infrared photodetector (QWIP) structure has been presented that is suitable for dual bands in the two atmospheric transmission windows of 3 – 5.3 μm and 7.5 – 14μm, respectively. The proposed structure employs dual stacked, strain InGaAs/AlGaAs and latticematched GaAs/AlGaAs quantum well infrared photodetector for mid wavelength and long wavelength detection. The response peak of the strain InGaAs/AlGaAs quantum well is at 4.9 μm and the lattice-matched GaAs/AlGaAs is at 10.5μm; their peak sensitivities are in the spectral regions of 3 – 5.3mu;m and 7.5 – 14μm. The peak responsivity when the dual-band QWIP is biased at 5 Volts is ∼0.065A/W at 4.9μm and ∼0.006A/W at 10.5μm; at this voltage the dual-band QWIP is more sensitive at the shorter wavelengths due to its larger impedance thus exhibiting wavelength tunability characteristics with bias. Additionally, single colored 4.9 and 10.5μm QWIPs were fabricated from the dual-band QWIP structure to study the bias-dependent behavior and also to understand the effects of growing the strain layer InGaAs/AlGaAs QWIP on top of the lattice-matched GaAs/AlGaAs QWIP. In summary, two stack dual-band QWIPs using GaAs/AlGaAs and strained InGaAs/AlGaAs multiquantum wells have been demonstrated with peak spectral sensitivities in the spectral region of 3 – 5.3μm and 7.5 – 14μm. Also, the voltage tunable dual-band detection have been realized for this kind of QWIP structure.

The development of cracks in a PZT thin film prepared by pulsed laser deposition on an unheated Pt-coated silicon substrate, and subsequently crystallized by post-deposition annealing, was investigated as a function of film thickness. As deposited, the film was amorphous. The film was heated at 600°C to produce predominantly ferroelectric crystalline PZT. Spacing, width and morphology of cracks in the film followed a regular progression in which crack area decreased with decreasing film thickness. Data on area shrinkage, as deduced from crack area, were fit equally well as either a linear or a parabolic function of film thickness. It is suggested that crystallization-induced stresses rather than thermal-gradient related stresses, were dominant in the formation of the cracks, and that these stresses were modified by interaction with the substrate.