Measurement and comparison of head scatter factor for 7 MV unflattened (FFF) and 6 MV flattened photon beam using indigenously designed columnar mini phantom

Aim

To measure and compare the head scatter factor for 7 MV unflattened and 6 MV flattened photon beam using a home-made designed mini phantom.

Background

The head scatter factor (Sc) is one of the important parameters for MU calculation. There are multiple factors that influence the Sc values, like accelerator head, flattening filter, primary and secondary collimators.

Materials and methods

A columnar mini phantom was designed as recommended by AAPM Task Group 74 with high and low atomic number material for measurement of head scatter factors at 10 cm and d_max dose water equivalent thickness.

Results

The Sc values measured with high-Z are higher than the low-Z mini phantoms observed for both 6MV-FB and 7MV-UFB photon energies. Sc values of 7MV-UFB photon beams were smaller than those of the 6MV-FB photon beams (0.6–2.2% (Primus), 0.2–1.4% (Artiste) and 0.6–3.7% (Clinac iX (2300CD))) for field sizes ranging from 10 cm × 10 cm to 40 cm × 40 cm. The SSD had no influence on head scatter for both flattened and unflattened beams. The presence of wedge filters influences the Sc values. The collimator exchange effects showed that the opening of the upper jaw increases Sc irrespective of FF and FFF.

Conclusions

There were significant differences in Sc values measured for 6MV-FB and unflattened 7MV-UFB photon beams over the range of field sizes from 10 cm × 10 cm to 40 cm × 04 cm. Different results were obtained for measurements performed with low-Z and high-Z mini phantoms.     

Protective effect of curcumin against intracerebral streptozotocin induced impairment in memory and cerebral blood flow

AimsThe aim of the present study is to investigate the effect of curcumin on cerebral blood flow (CBF), memory impairment, oxidative stress and cholinergic dysfunction in intracerebral (IC) streptozotocin (STZ) induced memory impairment in mice.Main methodsMemory impairment was induced by STZ (0.5 mg/kg, IC) administered twice with an interval of 48 h in mice. Memory function was assessed by Morris water maze and passive avoidance test. CBF was measured by Laser Doppler Flowmetry (LDF). To study the preventive effect, curcumin (10, 20 and 50 mg/kg, PO) was administered for 21 days starting from the first dose of STZ. In another set of experiment, curcumin was administered for 7 days from 19th day after confirming STZ induced dementia to observe its therapeutic effect. Biochemical parameters of oxidative stress and cholinergic function were estimated in brain on day 21.Key findingsThe major finding of this study is that STZ (IC) caused a significant reduction in CBF along with memory impairment, cholinergic dysfunction and enhanced oxidative stress. Curcumin dose dependently improved CBF in STZ treated mice together with amelioration of memory impairment both in preventive and therapeutic manner.SignificanceThe present study clearly demonstrates the beneficial effects of curcumin, the dietary staple of India, on CBF, memory and oxidative stress which can be exploited for dementia associated with age related vascular and neurodegenerative disorders.     

Genomewide linkage scan for split-hand/foot malformation with long-bone deficiency in a large Arab family identifies two novel susceptibility loci on chromosomes 1q42.2-q43 and 6q14.1

Split-hand/foot malformation with long-bone deficiency (SHFLD) is a rare, severe limb deformity characterized by tibia aplasia with or without split-hand/split-foot deformity. Identification of genetic susceptibility loci for SHFLD has been unsuccessful because of its rare incidence, variable phenotypic expression and associated anomalies, and uncertain inheritance pattern. SHFLD is usually inherited as an autosomal dominant trait with reduced penetrance, although recessive inheritance has also been postulated. We conducted a genomewide linkage analysis, using a 10K SNP array in a large consanguineous family (UR078) from the United Arab Emirates (UAE) who had disease transmission consistent with an autosomal dominant inheritance pattern. The study identified two novel SHFLD susceptibility loci at 1q42.2-q43 (nonparametric linkage [NPL] 9.8, P=.000065) and 6q14.1 (NPL 7.12, P=.000897). These results were also supported by multipoint parametric linkage analysis. Maximum multipoint LOD scores of 3.20 and 3.78 were detected for genomic locations 1q42.2-43 and 6q14.1, respectively, with the use of an autosomal dominant mode of inheritance with reduced penetrance. Haplotype analysis with informative crossovers enabled mapping of the SHFLD loci to a region of approximately 18.38 cM (8.4 Mb) between single-nucleotide polymorphisms rs1124110 and rs535043 on 1q42.2-q43 and to a region of approximately 1.96 cM (4.1 Mb) between rs623155 and rs1547251 on 6q14.1. The study identified two novel loci for the SHFLD phenotype in this UAE family.     

Role of TLR2, TLR4, and MyD88 in murine ozone-induced airway hyperresponsiveness and neutrophilia.

Exposure to air pollutants such as ozone (O(3)) induces airway hyperresponsiveness (AHR) and airway inflammation. Toll-like receptors (TLR) are first-line effector molecules in innate immunity to infections and signal via adapter proteins, including myeloid differentiation factor-88 (MyD88). We investigated the sensing of ozone by TLR2, TLR4, and MyD88. Ozone induced AHR in wild-type (WT) C57BL/6 mice, but AHR was absent in TLR2(-/-), TLR4(-/-), and MyD88(-/-) mice. Bronchoalveolar lavage neutrophilia induced by ozone was inhibited at 3 h but not at 24 h in TLR2(-/-) and TLR4(-/-) mice, while in MyD88(-/-) mice, this was inhibited at 24 h. We investigated the expression of inflammatory cytokines and TLR2, TLR4, and MyD88 in these mice. Ozone induced time-dependent increases in inflammatory gene expression of keratinocyte chemoattractant (KC) and IL-6 and of TLR2, TLR4, and MyD88 in WT mice. IL-6 and KC expression induced by ozone was inhibited in TLR2(-/-), TLR4(-/-), and MyD88(-/-) mice. Expression of MyD88 was increased in TLR2(-/-) and TLR4(-/-) mice, while induction of TLR2 or TLR4 was reduced in TLR2(-/-) and TLR4(-/-) mice, respectively. TLR2 and TLR4 mediate AHR induced by oxidative stress such as ozone, while the adapter protein MyD88, but not TLR2 or TLR4, is important in mediating ozone-induced neutrophilia. TLR2 and TLR4 may also be important in regulating the speed of neutrophilic response. Therefore, ozone may induce murine AHR and neutrophilic inflammation through the activation of the Toll-like receptor pathway that may sense noninfectious stimuli such as oxidative stress.     

Arecanut: India’s popular masticatory —history,chemistry and utilization

Economic Botany - To the Indians, Malayans, or the Indonesians, betel-nut chewing is as familiar as chewing gum to the Americans. In India the use of arecanut and its cultivation constitute a...     

NADPH production from NADP+ with a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans

Summary A convenient and efficient method of NADPH production from NADP⁺ has been established using a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans IFO 3172. Using airdried cells of the bacterium, the optimum conditions for NADPH production were examined, including the cell and glucose concentrations, NADP⁺ concentration, pH, buffer and reaction temperature. Under suitable conditions, the conversion ratio and the amount of NADPH accumulated reached about 100% and 73 mg/ml of the reaction mixture, respectively, after 1-h reaction. Intact cells of the bacterium also showed high NADPH production even in the reaction mixture without a surfactant. The addition of Triton X-100 to the reaction mixture and freeze-thawing treatment of intact cells enhanced the production. The NADPH production method was further improved by using cells of the bacterium immobilized by entrapment in a -carrageenan gel lattice. The immobilized cells had almost the same enzymatic properties as the air-dried cells. The conditions for the continuous production of NADPH with an immobilized cell column were also investigated. NADPH was produced in a good yield (about 95%) with this continuous process.     

Ripening of fleshy fruit: Molecular insight and the role of ethylene

Development and ripening in fruit is a unique phase in the life cycle of higher plants which encompasses several stages progressively such as fruit development, its maturation, ripening and finally senescence. During ripening phase, several physiological and biochemical changes take place through differential expression of various genes that are developmentally regulated. Expression and/or suppression of these genes contribute to various changes in the fruit that make it visually attractive and edible. However, in fleshy fruit massive losses accrue during post harvest handling of the fruit which may run into billions of dollars worldwide. This encouraged scientists to look for various ways to save these losses. Genetic engineering appears to be the most promising and cost effective means to prevent these losses. Most fleshy fruit ripen in the presence of ethylene and once ripening has been initiated proceeds uncontrollably. Ethylene evokes several responses during ripening through a signaling cascade and thousands of genes participate which not only sets in ripening but also responsible for its spoilage. Slowing down post ripening process in fleshy fruit has been the major focus of ripening-related research. In this review article, various developments that have taken place in the last decade with respect to identifying and altering the function of ripening-related genes have been described. Role of ethylene and ethylene-responsive genes in ripening of fleshy fruit is also included. Taking clues from the studies in tomato as a model fruit, few case studies are reviewed.     

Antidiabetic vanadium compound and membrane interfaces: interface-facilitated metal complex hydrolysis

The interactions of metabolites of the antidiabetic vanadium-containing drug bis(maltolato)oxovanadium(IV) (BMOV) with lipid interface model systems were investigated and the results were used to describe a potentially novel mechanism by which these compounds initiate membrane-receptor-mediated signal transduction. Specifically, spectroscopic studies probed the BMOV oxidation and hydrolysis product interaction with interfaces created from cetyltrimethylammonium bromide (CTAB) which mimics the positively charged head group on phosphatidylcholine. ¹H and ⁵¹V NMR spectroscopies were used to determine the location of the dioxobis(maltolato)oxovanadate(V) and the maltol ligand in micelles and reverse micelles by measuring changes in the chemical shift, signal linewidth, and species distribution. Both micelles and reverse micelles interacted similarly with the complex and the ligand, suggesting that interaction is strong as anticipated by Coulombic attraction between the positively charged lipid head group and the negatively charged complex and deprotonated ligand. The nature of the model system was confirmed using dynamic light scattering studies and conductivity measurements. Interactions of the complex/ligand above and below the critical micelle concentration of micelle formation were different, with much stronger interactions when CTAB was in the form of a micelle. Both the complex and the ligand penetrated the lipid interface and were located near the charged head group. These studies demonstrate that a lipid-like interface affects the stability of the complex and raise the possibility that ligand exchange at the interface may be important for the mode of action for these systems. Combined, these studies support recently reported in vivo observations of BMOV penetration into 3T3-L1 adipocyte membranes and increased translocation of a glucose transporter to the plasma membrane.     

Involvement of gibberellins in breaking bud dormancy in euphorbia crinkle mosaic virus-infected stem cuttings ofEuphorbia pulcherrima willd.

Euphorbia pulcherrima, an ornamental plant, exhibits severe systemic viral infection. It grows vegetatively during summer and is dormant in winter. During the dormant period the buds on healthy stem cuttings remained dormant or rarely formed cyathia while the buds on virus-infected stem cuttings grew into leafy shoots and never became dormant. Quantitative estimation has revealed that breaking of bud dormancy in virus-infected stem cuttings may be regulated by markedly higher GA-like activity in them throughout the period than in their corresponding healthy stem cuttings.