Batch Process for Microwave Sintering of Si3N4

A method for sintering silicon nitride using microwave energy at 2.45 GHz is described. Sintering takes place in air, in times of between 30 and 120 minutes and has been scaled up to give isothermal conditions over a batch size of 150 mm diameter by 200 mm in height and weighs approximately 1.0 kg. Additions of 5% alumina and 5% yttria result in a sintered product density of approximately 97% of theoretical, with a density variation better than:±0.5% throughout the batch.

It has been estimated that a load of 7.0 kg can be conventionally sintered using a 12 hour cycle and an energy consumption of 19.7 kWh/kg. In contrast with microwave energy, a batch of 540 g can be sintered in 120 minutes with an energy consumption of approximately 3.1 kWh/kg. This results in a possible energy savings of up to 78% for microwave heating.

Fabrication of Hydroxyapatite Ceramics by Microwave Processing

Various hydroxyapatite (HAp) ceramics were fabricated by microwave processing. By carefully selecting the starting material and controlling the processing conditions, regular HAp ceramics with density up to 97% of the theoretical density, porous HAp ceramics with porosity up to 76%, and fully densified transparent HAp ceramics were obtained by using a 2.45 GHz, 500W microwave oven. These ceramics were characterized for density, microstructure, strength, and phase composition, and the results were compared with the conventionally processed ceramics.

Low-Temperature (<300°C) Phosphate Ceramics from Reactive Aluminas

Reactive aluminas, including rapidly calcined gibbsites, offer exciting potential for forming ceramic materials at low temperatures. New x-ray amorphous aluminas will react with water at room temperatures to form compacts with 10–50 MPa tensile strengths, via viscous slurries. The cementious behavior of these materials has been examined. The results of TGA, x-ray diffraction, SEM, mechanical properties, and other characterization techniques, as applied to these systems, will be discussed.

Bacteria in bovine semen can increase sperm DNA fragmentation rates: a kinetic experimental approach

Cryopreserved straws of semen (n=228) from Holstein bulls (n=47) were examined for bacterial presence and sperm DNA fragmentation (SDF) dynamics. Commercial semen doses (representing six ejaculates per individual) were randomly selected from a bull stud in Spain. The dynamics of SDF were assessed after thawing (T0) and at 4, 24, 48, 72 and 96h of incubation at 37°C, using the commercial variant of the sperm chromatin dispersion test for Bovine (Halomax®). One group of bulls showed a bacterial presence in semen samples between 0 and 96h of incubation (n=23, group A) while the other did not (n=24, group B). Immediate post-thaw differences in SDF were not observed when both groups were compared. However, the rate of increase in SDF (rSDF) over time, considered as an estimate of the kinetic behaviour of sperm DNA survival, was significantly higher (P<0.05) in semen samples from group A (0.7% per hour) versus group B (0.05% per hour). Polymerase Chain Reaction (PCR) assay was used for DNA amplification using primers designed for specific regions of the bacterial gene that codifies for 16S rRNA. Different species within the phyla Bacteroidetes, Firmicutes, Proteobacteria, Cyanobacteria, Fusobacteria and Actinobacteria were identified. The results show that (1) SDF at baseline (T0) may not be affected by the presence of bacteria but the rSDF can increase due to bacterial growth during incubation, (2) the increase in the rSDF is characteristic of some bulls but not for others, and (3) certain bacterial strains are repeatedly found in separate ejaculates from the same bull.

New scalings in nuclear fragmentation

Fragment partitions of fragmenting hot nuclei produced in central and semiperipheral collisions have been compared in the excitation energy region 4-10 MeV per nucleon where radial collective expansion takes place. It is shown that, for a given total excitation energy per nucleon, the amount of radial collective energy fixes the mean fragment multiplicity. It is also shown that, at a given total excitation energy per nucleon, the different properties of fragment partitions are completely determined by the reduced fragment multiplicity (i.e., normalized to the source size). Freeze-out volumes seem to play a role in the scalings observed.

Outcomes of respiratory diphtheria in a tertiary referral infectious disease hospital

BACKGROUND

Diphtheria is a fatal disease and may cause serious complications if not recognized early and treated properly.

OBJECTIVES

To study the epidemiology, clinical features, complications, and outcomes in respiratory diphtheria.

MATERIALS AND METHODS

Diphtheria cases admitted in the infectious disease hospital, Beliaghata, Kolkata, India between January 2009 to January 2011 were evaluated in respect to demographic profile, immunization status, clinical features, complications, and outcomes.

RESULTS

200 diphtheria cases were studied. 150 (75%) patients had history of an adequate immunization, and 100 (50%) patients were from lower socio-economic groups. Common clinical features observed were throat pain in 148 (74%) cases and fever in 112 (56%) cases. Complications observed were myocarditis in 136 (68%) cases, neuropathy in 30 (15%) cases, and respiratory compromise in 14 (7%) cases. Death occurred in 5 (2.5%) patients.

CONCLUSIONS

diphtheria is still a public health problem in many developing countries. Strict public health measures like an increased immunization coverage, improvement of socio-economic status, easy availability of anti-diphtheritic serum (ADS), early recognition and effective treatment-all may reduce the incidence and mortality.

Ceramics by the solution-sol-gel route

The use of solution mixing followed by gelation to make ultrahomogeneous glasses and ceramics of various oxide compositions for laboratory experimentation, with first organic and later principally colloidal inorganic, precursors was developed over 30 years ago. Major technologies that use the solution-sol-gel route have been developed to make nuclear fuel pellets, ceramic fibers, thin coatings, and abrasive grain. This article reviews the early history and summarizes present research in this field, particularly new processes aimed at achieving xerogel precursors of maximum heterogeneity with respect either to composition or to structure. Such nanocomposites provide major advantages in lowering sintering temperatures, refining microstructure, and controlling morphology and final phase composition.

Characterization of casein gene complex and genetic diversity analysis in Indian goats

Milk protein polymorphism plays an important role in genetic diversity analysis, phylogenetic studies, establishing geographical diversity, conservation decision, and improving breeding goals. Milk protein polymorphism in Indian goat breeds has not been well studied; therefore, an investigation was carried out to analyze the genetic structure of the casein gene and milk protein diversity at six milk protein loci in nine Indian goat breeds/genetic groups from varied agro-climatic zones. Milk protein genotyping was carried out in 1098 individual milk samples by SDS-PAGE at alphaS1-CN (CSN1S1), beta-CN (CSN2), alphaS2-CN (CSN1S2), kappa-CN (CSN3), beta-LG, and alpha-LA loci. Indian goats exhibited alphaS1-casein A allele in higher frequency in the majority of breeds except Ganjam and local goats. The alphaS1-casein A allele frequencies varied from 0.45 to 0.77. A total of 16 casein haplotypes were observed in seven breeds and breed specific haplotypes were observed with respect to geographic region. The average number of alleles was lowest in Ganjam (1.66 +/- 0.81) and highest in Sirohi goats (2.50 +/- 1.05). Expected heterozygosity at six different loci demonstrated genetic diversity and breed fragmentation. Neighbor-Joining tree was built basing on Nei's distance. There was about 16.95% variability due to differences between breeds, indicating a strong subdivision. Principal component analysis was carried out to highlight the relationship among breeds. The variability among goat breeds was contributed by alphaS2-CN, beta-LG and alphaS1-CN. The Indian goats exhibited alphaS1-CN (CSN1S1) A allele in higher frequency in all the breeds indicating the higher casein yield in their milk.

Vessels in femoral triangle in a rare relationship

The femoral region of the thigh is utilised for various clinical procedures, both open and closed, particularly in respect to arterial and venous cannulations. A rare vascular pattern was observed during the dissection of the femoral region on both sides of the intact formaldehyde-preserved cadaver of a 42-year-old Indian man from West Bengal. The relationships and patterns found were contrary to the belief that the femoral vein is always medial to the artery, just below the inguinal ligament and the common femoral artery. The femoral artery crossed the vein just deep to the inguinal ligament so that the femoral vein was lying deep to the artery at the base of the femoral triangle. Just deep to the inguinal ligament, the profunda femoris artery (deep femoral artery) arose from the femoral artery, and the long saphenous vein drained into the femoral vein. The embryological and clinical correlations are discussed.

Bimodal behavior of the heaviest fragment distribution in projectile fragmentation

The charge distribution of the heaviest fragment detected in the decay of quasiprojectiles produced in intermediate energy heavy-ion collisions has been observed to be bimodal. This feature is expected as a generic signal of phase transition in nonextensive systems. In this Letter, we present new analyses of experimental data from Au on Au collisions at 60, 80, and 100 MeV/nucleon showing that bimodality is largely independent of the data selection procedure and of entrance channel effects. An estimate of the latent heat of the transition is extracted.

Characterization of exon 2 and intron 2 of leptin gene in Indian goats

Leptin, the hormonal product of the leptin (obese) gene (LEP), has multiple physiological effects and plays a pivotal role in the control of body growth, immune function, and reproduction. LEP gene polymorphism has been analyzed in cattle, buffalo, and pigs, and the polymorphic pattern has been associated with energy balance, milk production, and live weight and fertility trait in different livestock species. The present study has been designed to analyze polymorphism in exon 2 and intron 2 region of leptin gene in Indian goats. Genotyping was carried out in 111 kids including 70 samples from Barbari and 41 samples from Jamunapari breeds. The amplified product of exon 2 and intron 2 region of leptin gene was 152 bp and 400 bp, respectively, in both breeds. Sequencing of the exon 2 and intron 2 region of leptin gene and restriction analysis were carried out to analyze the polymorphism in goats. Five major haplotypes were observed in exon 2 region and six major haplotypes observed in intron 2 region in both breeds. Restriction fragment analysis and sequence analysis confirmed the mutation at 60 bp position of exon 2 and 100 bp position in intron 2 in all the analyzed samples. Sequences of exon 2 region of goats were unique as compared to other livestock species in BLAST analysis.

Influence of palliative surgical resection on overall survival in patients with advanced colorectal cancer: a retrospective single institutional study

BACKGROUND

The role of palliative surgical resection in patients presenting with locally advanced or metastatic colorectal cancer (CRC) is unclear. Resection is often limited to symptomatic management of bleeding, obstruction, perforation or for relief of pain, in patients with an adequate performance status and an expected life span of over several weeks. An exploratory analysis to evaluate the influence of a palliative surgical resection on survival outcome in patients with advanced CRC is reported.

METHOD

A retrospective review of medical records of all patients diagnosed with advanced CRC at our institution between the years 1998 and 2003 was undertaken. Tumour registry data were reviewed to identify age, gender, modalities of therapy [i.e. surgery (S), chemotherapy (C), radiation] and overall survival. IRB approval was obtained for this study.

RESULTS

One hundred and eighty-five patients were identified. Median age was 67 years (range 30-99). M:F ratio was 1:1. Sixty-two per cent of patients (115/185) underwent a palliative surgical intervention. Median survival of patients who underwent S and those that did not undergo S was 22 and 3 months respectively (P < 0.0001). Forty-eight per cent of patients (79/184) underwent systemic C. Median survival of patients who received C + S, and patients who received C alone was 30 and 15 months respectively (P < 0.0004). Fifty-one per cent of patients who underwent S, received C; 30% of patients who did not undergo S, received C. Chemotherapy data were available on 46 of 79 patients. Patients treated with S + C, and C without S, received a median of 9 and 6 months of therapy respectively. The median number of regimens used were similar in both.

CONCLUSION

These exploratory data suggest a positive influence of a palliative resection performed during the disease course of patients with advanced CRC. The increased frequency of utilization and the more prolonged duration of C in the surgically treated patients may in part contribute to this improved survival. This may also be reflective of performance status at the time of diagnosis. Future trials enrolling patients with advanced CRC should prospectively stratify for surgical intervention to further clarify the influence of this modality on the outcome of systemic therapy in this disease.