Effect of Heat Treatment on the Microstructure and Mechanical Properties of Rotary Friction Welded AA7075 and AA5083 Dissimilar Joint.

The present work aims to investigate the changes in the microstructural and mechanical properties of various pre- and post weld heat treatments (PWHTs) on rotary friction welded dissimilar (AA7075 and AA5083) aluminum alloys. The investigation focused on the evolution of weld macro- and microstructures, as well as the changes in hardness and tensile properties resulting from friction welding. The joint integrity was studied through various characterization techniques, and no cracks or incomplete bonding was observed. The study found that the dissimilar joints of the AA7075 and AA5083 alloys displayed higher flash formation on the AA7075 side, which has a lower melting temperature compared to the AA5083 alloy. Various zones were identified in the weld region, including the dynamic recrystallized zone (DRZ), the thermomechanically affected zone (TMAZ) consisting of TMAZ-1 (elongated grains) and TMAZ-2 (compressed/distorted grains), the heat-affected zone (HAZ), and the base metal (BM) zone. The rotary friction welded sample AA5083/AA7075-PWHT joint exhibited the highest strength (yield strength (YS): 195 ± 3 MPa, ultimate tensile strength (UTS): 387 ± 2 MPa) among all the other welded conditions, and this may be attributed to the major strengthening precipitates MgZn2 (of AA7075) formed during postweld aging. All dissimilar welds failed in the HAZ region of the AA5083 side due to the formation of coarse grains, indicating the weakest region.

Technetium-99m Thyroid Scintigraphy and Human Leukocyte Antigen - B35 in Sub-Acute Thyroiditis.

INTRODUCTION: Sub-acute thyroiditis possibly caused by a viral infection of thyroid gland is associated with a surge in thyroxine levels of the patient. Women in the younger age group are affected more than men. Markedly decreased radioactive iodine thyroid uptakes in a setting of thyrotoxicosis associated with elevated thyroxine levels and reduced thyroid stimulating hormone levels usually clinches the diagnosis. Patients mostly require symptomatic treatment with non-steroidal anti-inflammatory drugs. Sub-acute thyroiditis is a self-limiting disorder with most of the patients making a complete recovery in a span of three to six months. Being geographically and ethnically different the present studies was undertaken with an objective of understanding the clinical, laboratory and thyroid uptake profiles in patients of SAT during its natural history and also find the extent of genetic influences through its association with HLA B35. MATERIALS AND METHODS: 32 patients in the age group of 20-59 years diagnosed to have sub-acute thyroiditis were studied. 18 patients out of 32 were subjected to HLA B35 testing. Other laboratory parameters that included hormonal profile and radioactive thyroid uptakes were performed. RESULTS: Most of the patients were females and in their fourth decade of life. Thyroid stimulating hormone levels were decreased in 32 (100%). A majority of patients had normal anti TPO levels. All the patients had grossly decreased Tc-99m thyroid uptake levels at presentation. HLA B35 test done in 18 patients was reported positive in 10 (55.56%) patients. CONCLUSION: The present study is unique in having used serial Tc-99m thyroid scintigraphy in patients of SAT. A positive HLA B 35 is associated in a majority of patients conferring genetic susceptibility.

Radioactive Iodine-131 as a Definitive Treatment in Rare Association of Down Syndrome With Hyperthyroidism: A Case Report and Review of Literature.

Down syndrome characterized by trisomy of chromosome 21 is frequently associated with thyroid dysfunctions due to underlying autoimmune disorders. Hypothyroidism is the commonest thyroid dysfunction and hyperthyroidism, usually Graves' disease, is far less common. On literature review, we came across approximately 112 cases reported so far with the first such case report in 1946. The published data from India on hyperthyroidism in Down syndrome is of three case reports. We report one such patient, an adult male of 28 years who was administered Iodine-131 as a definitive treatment after 9-10 years of initial diagnosis.

Application of the basic and specific classification on patterned hair loss in indians.

CONTEXT: Several classifications for pattern hair loss (PHL) have been used over the years. The Norwood-Hamilton classification for men and Ludwig's classification for women is used commonly, but they have their limitations. AIMS: The objective of the following study is to evaluate the efficacy of the basic and specific (BASP) classification in Indian populations. SUBJECTS AND METHODS: We used the BASP classification to classify the PHL in the patients visiting our out-patient department in the period from June 2012 to May 2013. 763 patients were classified out of which 313 were females and 450 were males. RESULTS: The majority of the female patients were in the 3-5(th) decade of life and in males were in 4-6(th) decade. CONCLUSIONS: The BASP classification is, easily remembered, reproducible classification for the diagnosis and treatment for both male and female pattern alopecia.

Developmental and cell type characterization of bundle sheath and mesophyll chloroplast transcript abundance in maize.

The C4 grass Zea mays separates light and light-independent photosynthetic processes into two leaf cell types: bundle sheath (BS) and mesophyll (M). When mature, BS and M cells have anatomically and biochemically distinct chloroplasts that must cooperate to complete the process of photosynthesis. This report compares changes in transcript abundance between young and mature maize BS and M chloroplasts from specific segments of the leaf developmental gradient. Representative transcripts encoding components of Photosystem I, Photosystem II, Cytochrome b (6) f, thylakoidal NADH dehydrogenase; and the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase as well as nine nuclear-coded transcripts encoding chloroplast proteins were measured using quantitative RT-PCR. In addition, 887 nuclear genes encoding plastid-localized proteins, as well as 64 chloroplast and 34 mitochondrial genes were assayed utilizing a cDNA microarray. In 9 out of the 18 chloroplast-encoded genes and 84 genes from the 985 element microarray revealed greater than twofold transcript abundance differences between developmental stages and/or cell types. Patterns for transcripts associated with operons and gene clusters suggest differing regulatory mechanisms for particular polycistronic stretches. In summary, this report provides evidence that cell type-specific transcript abundance varies more in the young developing chloroplast, and differences plateau or subside as chloroplasts mature.

Early exposure to a nonhygienic environment alters pulmonary immunity and allergic responses.

The hygiene hypothesis suggests that early life exposure to a nonhygienic environment that contains endotoxin reduces the risk of developing allergic diseases. The mechanisms underlying the hygiene hypothesis are unclear and may involve subtle immune system interactions that occur during maturation. Experimental objectives of this study were to use a novel animal model to test the hygiene hypothesis and to characterize early life immune system responses to a nonhygienic environment. Mice were reared in corn dust, a grain-processing byproduct with a high-endotoxin content and microbial products or in a low-endotoxin environment. The influence of early or later life exposure to corn dust on a subsequent allergen stimulus (ovalbumin) was assessed by bronchoalveolar lavage (BAL) cell analysis, lung histology, serum IgE, and BAL cytokine measurements. The influence of the corn dust environment on the developing pulmonary immune system was assessed by BAL cell analysis and immunostaining of lung tissue. The corn dust environment contained significantly more endotoxin (P < 0.001), and the dust exposures attenuated the cellular inflammatory response to ovalbumin in the adult mouse (P < 0.01) but did not reduce serum IgE levels or alter baseline BAL fluid proinflammatory cytokine levels. The corn dust environment did not induce significant neutrophilia in lavage fluid but significantly increased the number of antigen-presenting cells in alveolar walls early in life by approximately 37%. In conclusion, exposure to a nonhygienic environment did not induce significant airway neutrophilia, yet altered the population of immunologically active cells in the lung and reduced subsequent allergic inflammation.