Thermo-optic observations on a main-chain thermotropic liquid-crystal polymer

Summary The morphological transitions of a main-chain liquid crystalline chromophoric polymer in which all of the electric dipole moments were arranged head-to-tail were investigated using the techniques of small-angle light scattering, x-ray scattering, differential scanning calorimetry and polarised optical microscopy. Above 96°C the material developed a birefringent nematic texture followed, at temperatures higher than 141°C, by a monotropic structure which was retained until the onset of thermal degradation. Under certain heating/cooling regimes non-centrosymmetric solid polymer films with low scattering characteristics could be prepared.     

Enantiospecific synthesis fromd-fructose of (2S,5R)- and (2R,5R)-2-methyl-1,6-dioxaspiro[4.5]decane [the odor bouquet minor components ofParavespula vulgaris (L.)]

The synthesis of (2S,5R)-(1) and (2R,5R)-2-methyl-1,6-dioxaspiro [4.5]decane (2) from (2RS,5R,8R,9R,10S)-8,9,10-trihydroxy-2-methyl-1, 6-dioxaspiro[4.5]decane (8), obtained in five steps fromd-fructose using Wittig's methodology, reduction, and spiroketalation, has been accomplished by a Corey dideoxygenation at C-8,9, followed by a Barton deoxygenation at C-10, of the appropriately protected derivatives.Enantiospecific synthesis of spirocetals. Part V. For Part IV, see Izquierdo et al. (1992).     

Location of Aluminum in Substituted Calcium Silicate Hydrate (C-S-H) Gels as Determined by 29Si and 27Al NMR and EELS

Solid-state ²⁷Al and ²⁹Si magic angle spinning NMR spectroscopy has been combined with electron energy loss spectroscopy carried out in the transmission electron microscope to determine the location of Al substituting in a semicrystalline C-S-H gel present in a hydrated synthetic slag glass. The gel is found to contain mainly pentameric silicate chains in which the central silicon is substituted by aluminum.     

Effect of red blood cells on platelet aggregation

This study briefly reviews the model that describes platelet behavior resulting in aggregation and thrombus formation. This is followed by an overview of the basics of the dissipative particle dynamics (DPD), the simulation method adopted here.Details of the numerical simulations is then described and results of these simulations are presented.     

Adsorption of Positively-Charged β-Lactoglobulin Derivatives to Casein Micelles

Positively-charged β-lactoglobulin derivatives prepared by amidation or esterification of available carboxyl groups of the native protein were bound strongly by casein micelles. Increasing amounts of these additives progressively decreased rennet coagulation time of casein micelles. Higher concentrations of positively-charged proteins coagulated casein micelles without addition of rennet extract. Of the modified proteins tested, approximately 1.0 g amidated β-lactoglobulin, 2.0 g ethyl-esterified β-lactoglobulin, or 1.0 g methyl-esterified β-lactoglobulin would be required to coagulate 100 ml of casein micelles at concentrations in milk.     

Langmiur–Blodgett studies of silicon(IV) phthalocyanine bis(trihexylsilyoxide) and its optical properties

Although much solution-based research has been carried out on silicon phthalacyanines, little work has been done on Si Pc LB films. In order to attempt studies on thin films, ultrathin Langmuir–Blodgett films of silicon(IV) phthalocyanine bis(trihexylsilyoxide), C₆₈H₉₄N₈O₂Si₃ have been studied and characterised. Whilst silicon(IV) phthalocyanine bis(trihexylsilyoxide) is not a traditional LB film forming material, it can be made conducive to deposition by mixing with ideal film forming materials such as calixarenes. Surface pressure–area isotherms revealed an area per molecule of around 7.5 Å² which indicates that the silicon(IV) phthalocyanine bis(trihexylsilyoxide) forms multi-lamella stacks. Thermal optical polarised spectroscopy revealed the formation of brightly coloured mesophases in films. DSC showed the presence of an irreversible A phase and a reversible T phase.     

Campylobacter and Salmonella in raw red meats in the United Kingdom: prevalence, characterization and antimicrobial resistance pattern, 2003-2005

The prevalence of Campylobacter and Salmonella was assessed in 3959 raw red meats in the UK during 2003-2005. Meats were more frequently contaminated with Campylobacter (7.2%) than with Salmonella (2.4%). Lamb and other meats (e.g. mutton, rabbit) exhibited the highest contamination from Campylobacter (12.6% and 19.8%, respectively), compared with pork (6.3%) and beef (4.9%). Pork however had the highest contamination from Salmonella (3.9%), followed by lamb (2.0%), other meats (2.0%) and beef (1.3%). Offal samples (36.6%) were more frequently contaminated with Campylobacter or Salmonella than muscle tissue (7.0%). C. jejuni predominated in all meat types. C. coli isolates were more likely to exhibit antimicrobial drug resistance, including quinolones, than C. jejuni. Salmonella typhimurium was the most frequent Salmonella serotype isolated from meats; S. typhimurium DT104/104b isolates exhibited higher rates of multiple drug resistance than other serotypes. The findings reinforce the importance of adequate cooking of meat and good hygiene to avoid cross-contamination.     

The TDS: a new device for comparing active and passive-guided touch.

A problem when comparing active and passive tactile perception of two-dimensional (2-D) stimuli is matching the active and passive tasks on all variables except the one of interest--active versus passive touch. A new computer-controlled device--the tactile display system (TDS)--has been developed to deal with this problem. The TDS tracks an "active" subject's fingertip movements during exploration of a raised line drawing and digitally records this spatio-temporal information. It then guides a passive participant's fingertip over the same path, matching for location and speed. Any difference in performance can thus be attributed to the different conditions (active versus passive) because other variables are held constant.     

The ability of non-ergonomists in the health care setting to make manual handling risk assessments and implement changes

The health care setting presents particular risks from manual handling and it is known that training in manual handling techniques is ineffective in reducing these risks when used as a stand-alone measure. The 'Manual Handling Operations Regulations 1992' requires employers to consider hazardous manual handling, advising the use of an ergonomics approach. However, it is not known how well-equipped non-ergonomists in the health care setting are to deal with this approach. Therefore, the ability of non-ergonomists to make manual handling risk assessments, with or without additional training, and to implement changes to the work environment was investigated. Twenty-five pairs of subjects from a broad cross section of departments in a busy teaching hospital were studied; training and a guide book were provided for one of each pair and the guide book only for the other. Subjects then independently prioritised three tasks in their department and undertook a full assessment of a specified task. All work was repeated by an ergonomist and the subjects' assessments were scored in comparison with the ergonomist. Each department was followed up after six months to assess progress with implementing recommendations. Trends in the data indicated that both groups appeared able to identify hazards though not necessarily to prioritise the tasks. The trained group tended to score better in assessments although wide variation existed within both groups and inter-group differences were not significant at the 5% level. Approximately half of staff assessments were considered 'adequate' to 'very good', in comparison with the ergonomist. Implementation of assessment recommendations ranged from nil to almost full compliance. Incomplete implementation seemed to be related to an apparent confusion in some departments over who was responsible for making changes, a lack of finances for changes and overstretched managers having other priorities.