Mechanical Behavior of Granite Under Cyclic Compression

A better understanding of soil/rock-structure interaction is invaluable in the seismic design of concrete and masonry structures. In an effort to understand the behavior of rock under cyclic compression, both intact and faulted specimens of Westerly granite (2.5 cm. dia. x 6.25 cm. long) were subjected to uniaxial and triaxial loading at a uniform rate of one cycle per second. The fatigue strength under uniaxial loading at 106 cycles was found to be about 70% of the static compressive strength, and confining pressure improved fatigue resistance considerably. The accumulated permanent strain at the maximum stress level was found to be independent of the stress path and bounded by the complete stress-strain curve. cyclic loading produces dilatancy and the stress at the onset of dilatancy is significantly reduced by repeated cycling. In faulted specimens (saw cut at 30 degrees to the longitudinal axis), the first loading cycle produces a large amount of sliding; subsequent cycles result in a decelerating rate of increase in the amount of sliding, with a steady-state equilibrium being reached in a few cycles. Cyclic loading increases crack porosity, and progressive microcracking causes fatigue failure

Metastatic Renal Cell Carcinoma in the Sinonasal Region

Sinonasal region is an exceptional site for metastatic tumors. Renal cell carcinoma is known to metastasise to the most unusual sites, the sinonasal region being one of them. Clear cell carcinoma is its most common histologic variant. A sixty year old male presented with epistaxis and nasal obstruction. Clinical examination and CT scan revealed a vascular tumor in the right nasal cavity and maxillary sinus. The tumor was resected and sent for histopathological examination. A diagnosis of metastatic clear cell renal cell carcinoma was made and confirmed with immunohistochemistry (IHC). The pathologic diagnosis was made without prior knowledge of the primary tumor in the kidney. Very few cases of metastatic renal cell carcinoma in the sinonasal region have been reported in literature. We present this case to document its occurrence, highlight the rarity and briefly discuss the differential diagnoses of clear cell carcinoma in the sinonasal area, based on morphology and IHC

Effect of protein deficiency on absorption, transport and distribution of α-tocopherol in the rat

The absorption, transport and distribution of α-[3H]tocopherol were greatly decreased in protein deficiency. This was reflected in the subcellular distribution of α-[3H]tocopherol in livers of protein-deficient rats. The ratio, bound: free for α-[3H]tocopherol, also decreased in both serum and liver cytosol. After protein refeeding, absorption, transport and distribution patterns of α-[3H]tocopherol for the protein-deficient rats were restored to patterns similar to those of control animals

Involvement of binding lipoproteins in the absorption and transport of α-tocopherol in the rat

1. Specific lipoproteins binding α-tocopherol but not its known metabolites have been isolated and identified from cytosol of rat intestinal mucosa and from serum. 2. A timestudy of the appearance of the orally administered α-[3H]tocopherol with these lipoproteins indicates that very-low-density lipoprotein of serum acts as a carrier of the vitamin. 3. The involvement of the mucosal lipoprotein in the absorption of the vitamin from the intestine has been inferred from observations on the amounts of α-tocopherol in serum of orotic acid-fed rats where release of lipoproteins from the liver to serum is completely inhibited. A considerable decrease in the association of α-tocopherol with serum very-low-density lipoprotein under this condition is interpreted to mean that serum lipoproteins are limiting factors for the transport of the vitamin across the intestine and that this is possibly effected by exchange of α-tocopherol between serum very-low-density lipoprotein and mucosal lipoprotein

Commelina badamica (Commelinaceae), a new species from India

A new species, Commelina badamica from the sandstone plateaus of Badami, Karnataka, India is described and illustrated. C. badamica is similar to C. clavata and C. diffusa, but differs in indefinite habit; linear–narrowly lanceolate leaves; puberulous or velutinous to tomentose spathes; clawless petals; velutinous ovary; radiately tri-lobed stigma; one capsule per spathe and trapezoidal, ventrally truncate seeds

Importance of tyrosine residues of Bacillus stearothermophilus serine hydroxymethyltransferase in cofactor binding and L-allo-Thr cleavage

Serine hydroxymethyltransferase (SHMT) from Bacillus stearothermophilus (bsSHMT) is a pyridoxal 5′-phosphate-dependent enzyme that catalyses the conversion of L-serine and tetrahydrofolate to glycine and 5,10-methylene tetrahydrofolate. In addition, the enzyme catalyses the tetrahydrofolate-independent cleavage of 3-hydroxy amino acids and transamination. In this article, we have examined the mechanism of the tetrahydrofolate-independent cleavage of 3-hydroxy amino acids by SHMT. The three-dimensional structure and biochemical properties of Y51F and Y61A bsSHMTs and their complexes with substrates, especially L-allo-Thr, show that the cleavage of 3-hydroxy amino acids could proceed via Cα proton abstraction rather than hydroxyl proton removal. Both mutations result in a complete loss of tetrahydrofolate-dependent and tetrahydrofolate-independent activities. The mutation of Y51 to F strongly affects the binding of pyridoxal 5′-phosphate, possibly as a consequence of a change in the orientation of the phenyl ring in Y51F bsSHMT. The mutant enzyme could be completely reconstituted with pyridoxal 5′-phosphate. However, there was an alteration in the λmax value of the internal aldimine (396 nm), a decrease in the rate of reduction with NaCNBH3 and a loss of the intermediate in the interaction with methoxyamine (MA). The mutation of Y61 to A results in the loss of interaction with Cα and Cβ of the substrates. X-Ray structure and visible CD studies show that the mutant is capable of forming an external aldimine. However, the formation of the quinonoid intermediate is hindered. It is suggested that Y61 is involved in the abstraction of the Cα proton from 3-hydroxy amino acids. A new mechanism for the cleavage of 3-hydroxy amino acids via Cα proton abstraction by SHMT is proposed

Evaluation of Anti-Inflammatory Properties of Isoorientin Isolated from Tubers of Pueraria tuberosa

Inflammation is the major causative factor of different diseases such as cardiovascular disease, diabetes, obesity, osteoporosis, rheumatoid arthritis, inflammatory bowel disease, and cancer. Anti-inflammatory drugs are often the first step of treatment in many of these diseases. The present study is aimed at evaluating the anti-inflammatory properties of isoorientin, a selective cyclooxygenase-2 (COX-2) inhibitor isolated from the tubers of Pueraria tuberosa, in vitro on mouse macrophage cell line (RAW 264.7) and in vivo on mouse paw edema and air pouch models of inflammation. Isoorientin reduced inflammation in RAW 264.7 cell line in vitro and carrageenan induced inflammatory animal model systems in vivo. Cellular infiltration into pouch tissue was reduced in isoorientin treated mice compared to carrageenan treated mice. Isoorientin treated RAW 264.7 cells and animals showed reduced expression of inflammatory proteins like COX-2, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), 5-lipoxygenase (5-LOX), and interleukin 1-β (IL-1-β) both in vitro and in vivo. The antioxidant enzyme levels of catalase and GST were markedly increased in isoorientin treated mice compared to carrageenan treated mice. These results suggest that isoorientin, a selective inhibitor of COX-2, not only exerts anti-inflammatory effects in LPS induced RAW cells and carrageenan induced inflammatory model systems but also exhibits potent antioxidant properties