Magnetsko-optička svojstva legure In1−xGaxP

The room-temperature dependence on composition of the energy gap is measured for the ternary alloy system In1−xGaxP semiconductors. The cross-over point from the direct to indirect optical transition energy gap is found at x = 0.718. An empirical relation for the alloy system energy-gap dependence is found for both direct and indirect transition regions. From the empirical relations belonging to the direct region transition, the values of the expected indirect energy transition at Γc1 are calculated. The difference between these values and the corresponding indirect energy (Γc1−Xc1) are also calculated. The change of Eg due to the effects of magnetic field up to 1.6 T (Tesla) was also measured. The magnetic coefficient is found to be between 3.33×10−7 and 3.87×10−7 eV/T for x = 0.31 to x = 1. A clear deviation of the magnetic coefficient occurred for the change from the direct-region to that of the indirect-region transition.Mjerili smo ovisnost energijskog procijepa u trojnom sustavu poluvodičke legure In1−xGaxP na sobnoj temperaturi. Našli smo prijelaznu točku od izravnih k neizravnim optičkim prijelazima za x = 0.718. Izveli smo iskustvenu ovisnost energijske ovisnosti energijskog procijepa tog sustava za izravne i neizravne prijelaze. Na osnovi iskustvene ovisnosti za područje izravnih prijelaza izračunali smo energiju neizravnih prijelaza za Γc1. Izračunali smo također razlike tih vrijednosti koje odgovaraju energiji neizravnih prijelaza (Γc1−Xc1). Promjene Eg zbog učinaka magnetskog polja mjerili smo do 1.6 T. Našli smo magnetski koeficijent između 3.33 × 10−7 i 3.87 × 10−7 eV/T za x = 0.31 do x = 1. Opaža se jasan otklon magnetskog koeficijenta pri prijelazu od izravnih k neizravnim prijelazima

Magnetsko-optička svojstva legure In1−xGaxP

The room-temperature dependence on composition of the energy gap is measured for the ternary alloy system In1−xGaxP semiconductors. The cross-over point from the direct to indirect optical transition energy gap is found at x = 0.718. An empirical relation for the alloy system energy-gap dependence is found for both direct and indirect transition regions. From the empirical relations belonging to the direct region transition, the values of the expected indirect energy transition at Γc1 are calculated. The difference between these values and the corresponding indirect energy (Γc1−Xc1) are also calculated. The change of Eg due to the effects of magnetic field up to 1.6 T (Tesla) was also measured. The magnetic coefficient is found to be between 3.33×10−7 and 3.87×10−7 eV/T for x = 0.31 to x = 1. A clear deviation of the magnetic coefficient occurred for the change from the direct-region to that of the indirect-region transition.Mjerili smo ovisnost energijskog procijepa u trojnom sustavu poluvodičke legure In1−xGaxP na sobnoj temperaturi. Našli smo prijelaznu točku od izravnih k neizravnim optičkim prijelazima za x = 0.718. Izveli smo iskustvenu ovisnost energijske ovisnosti energijskog procijepa tog sustava za izravne i neizravne prijelaze. Na osnovi iskustvene ovisnosti za područje izravnih prijelaza izračunali smo energiju neizravnih prijelaza za Γc1. Izračunali smo također razlike tih vrijednosti koje odgovaraju energiji neizravnih prijelaza (Γc1−Xc1). Promjene Eg zbog učinaka magnetskog polja mjerili smo do 1.6 T. Našli smo magnetski koeficijent između 3.33 × 10−7 i 3.87 × 10−7 eV/T za x = 0.31 do x = 1. Opaža se jasan otklon magnetskog koeficijenta pri prijelazu od izravnih k neizravnim prijelazima

Prognostic Significance of Vascular Endothelial Growth Factor (VEGF) and Her-2 Protein in the Genesis of Cervical Carcinoma

BACKGROUND: Angiogenesis plays a pivotal role in the progression of tumours through the formation of new blood vessels. Vascular endothelial growth factor (VEGF) is a chief factor responsible for inducing and regulating angiogenesis. Additionally, the human epidermal growth factor receptor family of receptors also plays an important role in the pathogenesis of tumours.AIM: This study aimed to examine the association between VEGF and Her-2 protein expression and its correlation with clinic-pathological characteristics; in particular, prognosis.METHODS: A total of 65 cases of cervical carcinoma and 10 samples of inflammatory lesions were evaluated for VEGF and Her-2 protein expression.RESULTS: Expression of VEGF and Her-2 was detected in 63.07% and 43.07% in cervical carcinoma cases respectively whereas control cases did not show any expression. The difference in the expression pattern of both markers comparing cancer and control cases was statistically significant (p < 0.05). However, no significant difference in the expression pattern of VEGF protein was observed among the different grades and stages of tumours (p > 0.05). Comparing different grades of a tumour, expression of Her-2 was detected in 31.8% of well-differentiated tumours, 36.0 % in moderately differentiated tumours and 66.66 % in poorly differentiated cancers. The expression of Her-2 was increased in high-grade tumours, and the difference of expression level between tumour grades was statistically significant (p < 0.05). The expression level of Her-2 protein was not correlated with the stage of a tumour (p > 0.05).CONCLUSION: The present study supports earlier findings that over-expression / up-regulation of VEGF and Her - 2 is linked with poor prognosis and may play a vital role in the development and progression of cervical cancer

Clinicopathological Significance of Vimentin and Cytokeratin Protein in the Genesis of Squamous Cell Carcinoma of Cervix

Cervical cancer is one of the commonest types of cancers worldwide especially in developing countries. Intermediate filaments protein family has shown a role in the diagnosis of various cancers, but a few studies are available about the vimentin and cytokeratin roles in the cervical cancer. This case control study aimed to interpret the expression of vimentin and cytokeratin proteins in the development and progression of cervical cancer and its correlation with clinicopathological features. The cytoplasmic expression of vimentin was observed in 40% of cases, but not in inflammatory lesions of cervix. It was noticed that vimentin expression was increasing significantly with high grade of the tumour. Cytokeratin expression was observed in 48.33% and it was noticed that the expression was 62.5% in well differentiated (G1), 45% in moderately differentiated (G2), and 41.66% in poorly differentiated carcinoma, yet statistically insignificant. The expression of vimentin and cytokeratin proteins was not significantly associated with age groups. The current findings concluded a possible role of vimentin in the development and progression of cervical cancer and vimentin marker will be useful in the diagnosis and grading of cervical cancer

A Network Model of Local Field Potential Activity in Essential Tremor and the Impact of Deep Brain Stimulation

Essential tremor (ET), a movement disorder characterised by an uncontrollable shaking of the affected body part, is often professed to be the most common movement disorder, affecting up to one percent of adults over 40 years of age. The precise cause of ET is unknown, however pathological oscillations of a network of a number of brain regions are implicated in leading to the disorder. Deep brain stimulation (DBS) is a clinical therapy used to alleviate the symptoms of a number of movement disorders. DBS involves the surgical implantation of electrodes into specific nuclei in the brain. For ET the targeted region is the ventralis intermedius (Vim) nucleus of the thalamus. Though DBS is effective for treating ET, the mechanism through which the therapeutic effect is obtained is not understood. To elucidate the mechanism underlying the pathological network activity and the effect of DBS on such activity, we take a computational modelling approach combined with electrophysiological data. The pathological brain activity was recorded intra-operatively via implanted DBS electrodes, whilst simultaneously recording muscle activity of the affected limbs. We modelled the network hypothesised to underlie ET using the Wilson-Cowan approach. The modelled network exhibited oscillatory behaviour within the tremor frequency range, as did our electrophysiological data. By applying a DBS-like input we suppressed these oscillations. This study shows that the dynamics of the ET network support oscillations at the tremor frequency and the application of a DBS-like input disrupts this activity, which could be one mechanism underlying the therapeutic benefit

Durability associated efficacy of long-lasting insecticidal nets after five years of household use

<p>Abstract</p> <p>Background</p> <p>Long-lasting insecticidal nets (LLINs) have been strongly advocated for use to prevent malaria in sub-Saharan Africa and have significantly reduced human-vector contact. PermaNet^®2.0 is among the five LLINs brands which have been given full approval by the WHO Pesticide Evaluation Scheme (WHOPES). The LLINs are expected to protect the malaria endemic communities, but a number of factors within the community can affect their durability and efficacy. This study evaluated the durability, efficacy and retention of PermaNet^®2.0 after five years of use in a Tanzanian community.</p> <p>Method</p> <p>Two to three day- old non blood-fed female mosquitoes from an insectary susceptible colony (<it>An. gambiae </it>s.s, this colony was established at TPRI from Kisumu, Kenya in 1992) and wild mosquito populations (<it>An. arabiensis </it>and <it>Culex quinquefasciatus</it>) were used in cone bioassay tests to assess the efficacy of mosquito nets.</p> <p>Findings</p> <p>The knockdown effect was recorded after three minutes of exposure, and mortality was recorded after 24 hours post-exposure. Mortality of <it>An. gambiae </it>s.s from insectary colony was 100% while <it>An. arabiensis </it>and <it>Cx.quinquefasciatus </it>wild populations had reduced mortality. Insecticide content of the new (the bed net of the same brand but never used before) and used PermaNet^®2.0 was determined using High Performance Liquid Chromatography (HPLC).</p> <p>Conclusion</p> <p>The results of this study suggest that, in order to achieve maximum protection against malaria, public health education focusing on bed net use and maintenance should be incorporated into the mass distribution of nets in communities.</p

Killing Hypoxic Cell Populations in a 3D Tumor Model with EtNBS-PDT

An outstanding problem in cancer therapy is the battle against treatment-resistant disease. This is especially true for ovarian cancer, where the majority of patients eventually succumb to treatment-resistant metastatic carcinomatosis. Limited perfusion and diffusion, acidosis, and hypoxia play major roles in the development of resistance to the majority of front-line therapeutic regimens. To overcome these limitations and eliminate otherwise spared cancer cells, we utilized the cationic photosensitizer EtNBS to treat hypoxic regions deep inside in vitro 3D models of metastatic ovarian cancer. Unlike standard regimens that fail to penetrate beyond ∼150 µm, EtNBS was found to not only penetrate throughout the entirety of large (>200 µm) avascular nodules, but also concentrate into the nodules' acidic and hypoxic cores. Photodynamic therapy with EtNBS was observed to be highly effective against these hypoxic regions even at low therapeutic doses, and was capable of destroying both normoxic and hypoxic regions at higher treatment levels. Imaging studies utilizing multiphoton and confocal microscopies, as well as time-lapse optical coherence tomography (TL-OCT), revealed an inside-out pattern of cell death, with apoptosis being the primary mechanism of cell killing. Critically, EtNBS-based photodynamic therapy was found to be effective against the model tumor nodules even under severe hypoxia. The inherent ability of EtNBS photodynamic therapy to impart cytotoxicity across a wide range of tumoral oxygenation levels indicates its potential to eliminate treatment-resistant cell populations

Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging

The desire to study biology in situ has been aided by many imaging techniques. Among these, X-ray fluorescence (XRF) mapping permits observation of elemental distributions in a multichannel manner. However, XRF imaging is underused, in part, because of the difficulty in interpreting maps without an underlying cellular ‘blueprint’; this could be supplied using contrast agents. Carbon nanotubes (CNTs) can be filled with a wide range of inorganic materials, and thus can be used as ‘contrast agents’ if biologically absent elements are encapsulated. Here we show that sealed single-walled CNTs filled with lead, barium and even krypton can be produced, and externally decorated with peptides to provide affinity for sub-cellular targets. The agents are able to highlight specific organelles in multiplexed XRF mapping, and are, in principle, a general and versatile tool for this, and other modes of biological imaging