NMR spectroscopy of human post mortem cerebrospinal fluid: distinction of Alzheimer''s disease from control using pattern recognition and statistics

Mutations of ras oncogenes in 37 human stomach cancers and 13 adenomas were investigated with regard to the histological phenotypes using polymerase chain reaction (PCR), allele-specific oligonucleotide hybridization and/or direct sequencing of the PCR products. The ras mutation was found only in one case (2.7%), the histology of which was poorly differentiated adenocarcinoma. We found no mutation in stomach adenomas. The mutation consisted of a guanine-to-adenine transition in the first base of codon 13 of c-Ki-ras which replaced wild-type glycine with serine, indicating that a putative glycine-to-aspartic acid change is not necessarily the critical event for c-Ki-ras gene activation in codon 13. These results further confirm the infrequency of ras mutation in stomach tumors and also suggest that ras mutations are not specific to the differentiated type of stomach cancer.     

Internationalisation for Survival: The Case of New Ventures

The aim is to deepen our understanding about the internationalisation–survival relationship in the case of new ventures in traditional manufacturing sectors. Hypotheses were tested through Cox’s proportional hazard regressions on a sample of 3,350 firms aged 10 years or less, from the textile-clothing and footwear industry in Spain. A vast majority of new ventures that were both established and closed down over that time are purely domestic firms. That means, a firm increases its likelihood of survival when it becomes international. The highest failure risk relates to those new ventures which are territorially agglomerated and are domestically oriented. Internationalisation is an unconditional strategy for surviving in the case of new manufacturing ventures. In addition, location and efficiency in the activity both matter when operating in international markets. Statistical tests show that an interactive effect of agglomeration and internationalisation exists, while no support for the interaction between age and internationalisation is found. Future research should investigate the trade-off between growth and survival forces to determine the optimum moment to go international and to characterise the strategic choices followed by those new ventures that survive longest.     

Capacity of the linear decorrelating detector for QS-CDMA

We study the performance and capacity of a quasi-synchronous code-division multiple-access (QS-CDMA) cellular system employing the decorrelating detector. It is assumed that each of N users has a GPS generated local clock, and attempts to transmit in synchrony with the other users in its cell. The detector makes use of the small timing uncertainties to build the interference signal space and perfectly cancel the interference. Results are compared with those of an adaptive MSE receiver. It is shown that when the LMS adaptive algorithm is employed, the mean-squared-error misadjustment significantly affects the receiver performance. Finally, system capacities in terms of users/cell are evaluated     

Quality of life after transthoracic endoscopic sympathectomy for upper limb hyperhidrosis

OBJECTIVE: To assess the outcome after transthoracic endoscopic sympathectomy (TES) for upper limb hyperhidrosis. DESIGN: Prospective cohort study. SETTING: District general hospital. SUBJECTS: Consecutive patients undergoing TES for upper limb hyperhidrosis over a fifteen month period. INTERVENTIONS: One-stage bilateral TES. MAIN OUTCOME MEASURES: Change in quality of life as shown by the Short Form-36 health assessment questionnaire. RESULTS: Sixteen patients (11 women and 5 men, median age 26 years) underwent operation without complications. At median follow-up of 6.2 months, symptomatic improvement was found in 26 of 32 limbs treated (82%). Truncal compensatory hyperhidrosis was reported by 13 patients but was severe in only three. There were significant improvements in social function (p = 0.01) and mental health (p = 0.025) as assessed by the SF-36. CONCLUSION: Despite a high incidence of compensatory hyperhidrosis, TES improved both the symptoms and overall quality of life in patients with upper limb hyperhidrosis.     

Composition-dependence of photoconduction band gap in cadmium zinc phosphate glasses

Photoconduction in cadmium zinc phosphate glasses of various compositions has been measured in the spectral energy range 1.5 to 6.2 eV. With the P₂O₅ percentage remaining fixed at 60 mol %, CdO and ZnO contents have been varied between 0 and 40 mol %. Photocurrents start at about 3.85 eV and rise sharply above 4.5 eV. The optical band gap obtained by the extrapolation of the linear region of the photoresponse curve shows a slow decrease with an increase in the applied field. The optical band gap at a particular applied field decreases with increasing ZnO content. The field-dependence of the optical band gap may be explained in terms of an energy band scheme for non-crystalline solids. The composition-dependence may be due some structural changes in the glasses.     

The infrared spectra of CdO-P2O5 and CdO-ZnO-P2O5 glasses

The infrared absorption spectra of cadmium phosphate and cadmium zinc phosphate glasses were measured. The structure of cadmium phosphate glasses was found analogous to cadmium zinc phosphate glasses at 30% of ZnO but a further decrease in ZnO content causes a 30 to 40 cm^–1 change towards higher wave number of the absorption band at the stretching frequency. Annealing at different temperatures does not show a prominent change in absorption band positions.     

Blind decentralized projection receiver for asynchronous CDMA in multipath channels

An asynchronous direct sequence code division multiple access (DS-CDMA) system employing periodic spreading sequences is considered to be operating in a frequency selective channel. The cyclostationary spread signal is received at multiple sensors and/or is sampled multiple times per chip (oversampling), leading to a stationary vector-valued received signal. Hence, such a model represents a very particular multi-input multi-output (MIMO) system with plentiful side information in terms of distinct spreading waveforms for the input signals. Depending upon the finite impulse response (FIR) length of the propagation channel, and the processing gain, the channel of a certain user spans a certain number of symbol periods, thus inducing memory or intersymbol interference (ISI) in the received signal in addition to the multiple-access interference (MAI) contributed by concurrent users. The desired user’s multipath channel estimate is obtained by means of a new blind technique which exploits the spreading sequence of the user and the second-order statistics of the received signal. The blind minimum mean square error-zero forcing (MMSE-ZF) receiver or projection receiver is subsequently obtained. This receiver represents the proper generalization of the anchored MOE receiver [1] to the asynchronous case with delay spread. Classification of linear receivers obtained by various criteria is provided and the MMSE-ZF receiver is shown to be obtainable in a decentralized fashion by proper implementation of the unbiased minimum output energy (MOE) receiver, leading to the minimum variance distortionless response (MVDR) receiver for the signal of the desired user. This MVDR receiver is then adapted blindly by applying Capon’s principle. A channel impulse response is obtained as a by-product. Lower bounds on the receiver filter length are derived, giving a measure of the ISI and MAI tolerable by the receiver and ensuring its identifiability.     

AC conduction in amorphous thin films of SnO<Subscript>2</Subscript>

Alternating current (a.c.) electrical properties of thermally evaporated amorphous thin films of SnO₂ sandwiched between aluminium electrodes have been investigated for temperature during electrical measurements, film thickness, substrate temperature and post-deposition annealing. The a.c. conductivity, σ(ω), is found to vary with frequency according to the relation σ(ω) ∝ ω^s, indicating a hopping process at low temperature. The conduction is explained by single polaron hopping process as proposed by Elliott. The increase in electrical conductivity with increase in temperature during electrical measurements is ascribed to the increase in the formation and high mobility of doubly ionized oxygen vacancies. The increase in conductivity with increase in film thickness is caused by the increase in interstitial tin, oxygen vacancies and defects produced due to deviation from stoichiometry. The increase in conductivity with increase in substrate and annealing temperature may be due to the formation of singly or doubly ionized oxygen vacancies and tin species of lower oxidation state. Measurements of capacitance C as a function of frequency and temperature show a decrease in C with increasing frequency and increase in C with increasing temperature. The increase in capacitance in the high-temperature low-frequency region is probably due to space charge polarization induced by the increasing number of free carriers as a result of increasing temperature.