Initiation of cationic polymerization with alcohol/Lewis acid systems

Alcohols in conjunction with BCl₃ have been found to be efficient initiating systems for the polymerization of isobutylene in CH₂Cl₂ solvent. The following alcohols exhibited high initiating activity: tert.-butanol, 1,1-diphenyl ethanol, 2-phenyl-2-propanol, benzhydrol. The organic moiety of the alcohol becomes the head-group of the polyisobutylene formed. The tailgroup of the polymer is a tertiary chlorine most likely because termination is by chlorination by the BCl₃OH^Θ counter anion.     

Substrate issues for the growth of mercury cadmium telluride

Close lattice matching and lattice compatibility with mercury cadmium telluride (MCT) make CdTe and related alloys ideal substrate materials for growth of MCT layers for the purpose of making high-performance second-generation infrared detectors. However, the limitations in the properties of CdTe and the difficulties in its bulk growth have prompted extensive research in the area of alternative substrates. Some basic relevant characteristics of substrates such as sapphire, GaAs, and silicon are compared and the possibilities and problems associated with each material are analyzed in the light of the most recent results in the field.     

Pyogenic bacterial pneumonia in human immunodeficiency virus-infected inpatients: a clinical, radiological, microbiological, and epidemiological study

We prospectively studied features of pyogenic bacterial pneumonia in 263 consecutive human immunodeficiency virus-infected inpatients over a 6-month study period. Risk factors for bacterial pneumonia were examined by a case-control study that included 33 cases who presented with at least one episode of bacterial pneumonia and 80 controls without bacterial pneumonia. The estimated cumulative incidence of bacterial pneumonia per year was 12.5 cases per 100 inpatients (95% confidence interval [CI], 8.8-17.2). The 38 episodes of bacterial pneumonia that occurred in the 33 inpatients were mainly unilateral, but 32 episodes were patchy lobar or diffuse infiltrates. Microbiological etiologies were obtained in 33 of the 38 episodes of bacterial pneumonia. Thirty-seven pathogens were identified, including Streptococcus pneumoniae (16, of which 12 had a decreased susceptibility to penicillin), Haemophilus influenzae (6), and Pseudomonas aeruginosa (6). The risk factors for bacterial pneumonia that were identified after logistic regression included prior sinusitis within 1 month before admission (odds ratio [OR], 3.2; 95% CI, 1.1-9.1) and prior bacterial infection of the lower respiratory tract within 6 months before admission (OR, 3.1; 95% CI, 1.1-8.3).     

Compaction Studies on Beads: Compression and Consolidation Parameters

The purpose of this work was to evaluate compaction of the beads containing microcrystalline cellulose (MCC). Although MCC in its powder form is universally recognized as a very compressible material, studies in these laboratories demonstrated that MCC beads prepared by extrusion/spheronization were not. In fact, MCC beads are very hard and not easily deformable or broken. Therefore, the objectives of this work were to modify the bead composition by incorporating materials which might change the bead compactibility and to describe the effects. The dissolution properties of the compacted forms were also evaluated.

To study the compaction behavior of the MCC beads it was necessary to modify the Athy-Heckel equation to describe compression and to combine that analysis with the Leuenberger equation to describe consolidation.     

The cognitive consequences of secrecy.

Four research paradigms explored links from secrecy to the suppression and intrusive recurrence of secret thoughts. In Study 1, keeping a word secret enhanced cognitive accessibility of the word on a Stroop color-naming task. Study 2 revealed that secret memory topics were recalled earlier than topics about which a lie or the truth was told. Study 3 showed that when participants were keeping secrets, their ratings of suppression and intrusive thinking of the secret became positively correlated. Study 4 participants rated 50 everyday topics for intrusiveness, suppression, and secrecy. Across topics, positive mean within-subject correlations were found among these variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A 128 K×8 70-MHz multiport video RAM with auto registerreload and 8×4 block WRITE feature

An 80-ns 1-Mb multiport video random-access memory (VRAM) can be organized as 128 K×8 or 256 K×4. Uninterrupted serial data streams of 70 MHz are achieved by combining pipelining and interleaving techniques with an internally triggered automatic memory-to-register transfer mechanism. DRAM bandwidth is enhanced by a block WRITE feature which can write as many as four column address locations in every CAS cycle. The write-per-bit feature has been expanded by including an on-chip write-per-bit latch and an extended mode of operation to simplify its use in a wider range of systems. The VRAM is fabricated in a 1 μm CMOS technology using double-level poly/polycide, single level metal, and trench DRAM storage capacitors for high noise immunity     

Prediction of heats of mixing of liquid mixtures containing aliphatic hydrocarbons and ketones by a group solution model

A group solution model for heats of mixing of liquid mixtures has been tested and found satisfactory for mixtures containing ketones and alkanes. No provision was made for a skeletal contribution Group contribution functions were generated from experimental data on acetone/n-hexane mixtures at 25°C and are presented. These functions allow the prediction of heats of mixing of binary or multicomponent mixtures containing alkanes and/or ketones at 25°C. No experimental data are required