Hydrochemical analysis to evaluate the seawater ingress in a small coral island of India.

The sustainable development of the limited groundwater resources in the tropical island requires a thorough understanding of detail hydrogeological regime including the hydrochemical behavior of groundwater. Detail analysis of chemical data of groundwater helps in assessing the different groundwater zone affected by formation as well as sea water. Groundwater and saline water interaction is better understood using groundwater major ion chemistry over an island aquifer. Multivariate methods to analyze the geochemical data are used to understand geochemical evolution of groundwater. The methods are successfully used to group the data to evaluate influence of various environs in the study area. Various classification methods such as piper, correlation method, and salinity hazard measurements are also employed to critical study of geochemical characteristics of groundwater to identify vulnerable parts of the aquifer. These approaches have been used to successfully evaluate the aquifer zones of a tiny island off the west coast of India. The most part of island is found to be safe for drinking, however some parts of island are identified that are affected by sea water ingress and dissolution of formation minerals. The analysis has successfully leaded to identification of that part of aquifer on the island which needs immediate attention for restoration and avoids further deterioration.

T1-weighted fat-suppressed imaging of the pelvis with a dual-echo Dixon technique: initial clinical experience.

PURPOSE: To compare the image quality of water-only images generated from a dual-echo Dixon technique with that of standard fast spin-echo T1-weighted chemical shift fat-suppressed images obtained in patients evaluated for pelvic pain with a 1.5-T magnetic resonance (MR) system. MATERIALS AND METHODS: The ethics board granted approval for this retrospective study; patient consent was not required. Twenty-five women underwent both standard axial T1-weighted fast spin-echo chemical shift fat-suppressed imaging and dual-echo Dixon imaging of the pelvis. Two readers independently scored the acquisitions for image quality, fat suppression quality, and artifact. On the basis of signal intensity measurements, the uniformity of fat suppression, the contrast between fat-suppressed and non-fat-suppressed tissue, and the contrast between pathologic lesions and suppressed fat were calculated. Values obtained with the T1-weighted fat-suppressed and dual-echo Dixon techniques were compared by using the Wilcoxon signed rank test. RESULTS: The images generated with the dual-echo Dixon technique were of higher quality, had better fat suppression, and had less artifact (qualitative scores: 4.4, 4.6, and 4.0, respectively) compared with the standard T1-weighted fat-suppressed images (qualitative scores: 3.4, 3.3, and 3.6, respectively; P < .01). Contrast between fat-suppressed and non-fat-suppressed tissue (contrast ratio: 0.86 for dual-echo Dixon technique vs 0.42 for T1-weighted fat-suppressed technique, P < .001) and between pathologic lesions and suppressed fat (contrast ratio: 0.88 for dual-echo Dixon technique vs 0.57 for T1-weighted fat-suppressed technique, P =.012) was significantly improved with the dual-echo Dixon technique. Twelve pathologic lesions were identified with dual-echo Dixon imaging versus eight that were identified with T1-weighted fat-suppressed imaging. CONCLUSION: Compared with standard T1-weighted fat-suppressed imaging, dual-echo Dixon imaging facilitates improved image quality of fat-suppressed images of the pelvis, enabling better delineation of pathologic lesions.

Role of MRI in intracavitary brachytherapy for cervical cancer: what the radiologist needs to know.

OBJECTIVE: Intracavitary brachytherapy has an important role in treating cervical cancer. MRI is the optimal imaging technique to visualize the intracavitary brachytherapy probes and MRI-guided intracavitary brachytherapy is expected to increase significantly over the next 5 years. The purpose of this article is to review what a radiologist needs to know about imaging brachytherapy probes including the MR technique, correct positioning of the probes, and associated complications. CONCLUSION: MRI-guided intracavitary brachytherapy is an increasingly used therapy for the treatment of cervical cancer. This technique provides excellent visualization of intracavitary brachytherapy devices and allows accurate localization of residual tumor. It is important for radiologists to be familiar with the correct probe positioning as well as any potential complications.

Evaluation of Change in Surface Enamel Microhardness in Patients Undergoing Fixed Orthodontic Appliance Therapy - A Randomized Control Trial.

AIM: This study aims at determining the amount of enamel decalcification in terms of microhardness. MATERIALS AND METHODS: Twenty patients requiring treatment by extraction method for Class I malocclusion with bimaxillary protrusion were selected for the study. Twenty patients were randomly divided into control group and experimental group. In the control group (n = 40), extraction of permanent first premolars was done on day 1 of bonding to assess the Vickers hardness number (VHN) of enamel surface, and in the experimental group (n = 40), extraction of the contralateral premolars was done on the 28th day after bonding to assess the VHN of enamel surface. The values are tabulated and analyzed by SPSS software. RESULTS: There is significant surface enamel dissolution of enamel crystals in the experimental group compared to the control group, and a statistically significant difference in VHN is evident between the control and experimental groups. The surface enamel dissolution (VHN) is not significant difference noted between mandibular and maxillary premolars of the control and experimental groups. CONCLUSION: The present study has demonstrated a higher level of surface enamel dissolution in the experimental group. There is a marked difference in the VHN between the control and experimental groups, which is statistically significant. The scanning electron microscopy study also confirms the presence of surface enamel demineralization following orthodontic bonding.

Age-related morphology and function of human arterial endothelial cells.

Endothelialization of cardiovascular implants is regarded as a promising strategy for long-term compatibility. While umbilical vein endothelial cells are typically applied in research, human arterial endothelial cells (HAEC) from elderly donors would be the obvious source for autologous cellularization strategies.In our approach, HAEC from 16 donors of varying age (16-63 years) were divided into two groups (<30 years and >30 years) and analyzed regarding morphology, viability, proliferation, function and senescence status.No age-related differences were found regarding morphology, viability, density, prostacyclin and nitrite secretion or collagen and laminin production. However, the metabolic activity was slightly decreased (p = 0.0374) and the membrane integrity marginally impaired (p = 0.0404) in cells from older donors. Two out of three senescence assays detected more senescence markers in cells from older donors.According to the assays applied here, HAEC from young and elderly donors up to the age of 63 years could be judged equally suitable for autologous cellularization strategies. However, this finding should be regarded with caution due to the extremely large variability between individual donors. Further studies comprising a larger sample size are necessary to investigate this issue more thoroughly.

Effects of acrolein in comparison to its prodrug cyclophosphamide on human primary endothelial cells in vitro.

Cyclophosphamide (CPA) is one of the most successful anticancer prodrugs that becomes effective after biotransformation in the liver resulting in the toxic metabolite acrolein. Cancer is often accompanied by thromboembolic events, which might be a result of dysfunctional endothelial cells due to CPA treatment. Here, the effect of 1 mM CPA or acrolein (10/50/100/500 µM) on human umbilical vein endothelial cells (HUVECs) was analyzed after two days of treatment. The addition of CPA or 10 µM acrolein did not affect HUVECs. However, concentrations of 100 µM and 500 µM acrolein significantly reduced the number of adherent cells by 86 ±â€¯13% and 99 ±â€¯1% and cell viability by 51 ±â€¯29% and 93 ±â€¯8% compared to the control. Moreover, pronounced stress fibers as well as multiple nuclei were observed and von Willebrand factor (vWF) was completely released. Lactate dehydrogenase was 8.5 ±â€¯7.0-fold and 252.9 ±â€¯42.9-fold increased showing a loss of cell membrane integrity. The prostacyclin and thromboxane secretion was significantly increased by the addition of 500 µM acrolein (43.1 ±â€¯17.6-fold and 246.4 ±â€¯106.3-fold) indicating cell activation/pertubation. High doses of acrolein led to HUVEC death and loss of vWF production. This effect might be associated with the increased incidence of thromboembolic events in cancer patients treated with high doses of CPA.

Barriers affecting adherence to radiation treatment and strategies to overcome those barriers.

BACKGROUND: The WHO defines adherence as the extent to which a patient's behavior coincides with recommendations from a health-care provider. Nonadherence to cancer treatment has a major impact on the therapeutic outcome. AIM OF THE STUDY: To assess the prevalence of nonadherence to radiation regimen and to analyze the factors that affect adherence to cancer treatment. MATERIALS AND METHODS: Patients receiving radiation treatment in our hospital were screened for adherence to appointment keeping and to the prescribed radiation regimen and patients who had unplanned treatment breaks during treatment were interviewed. Between January and July 2013, we identified 61 patients who had unplanned breaks during treatment. We analyzed the social, emotional, educational, economic, and therapeutic barriers that led to nonadherence. RESULTS: Of the 61 patients who had unplanned breaks during treatment, 54% were males and 46% were females. Fifty-seven percent of patients had head and neck cancers and 25% had gynecological cancers. Seventy-one percent of patients were planned for concurrent chemoradiation. The number of days of unplanned treatment breaks ranged from 3 to 27 days. Social and therapeutic barriers were found to be the most common factor that led to nonadherence in these patients. CONCLUSION: Identification of barriers that lead to nonadherence, designing strategies to overcome such barriers and effective communication becomes imperative to ensure uninterrupted treatment. Based on the above analysis, we have designed several strategies to improve adherence to treatment among our patients.

Dpp and Hedgehog mediate neuron-glia interactions in Drosophila eye development by promoting the proliferation and motility of subretinal glia.

Neuron-glia interactions are crucial for the establishment of normal connectivity in the nervous system during development, but the molecular signals involved in these interactions are largely unknown. Here we show that differentiating photoreceptors in the developing Drosophila eye influence the proliferative and migratory behavior of the subretinal glia through the diffusible factors Decapentaplegic (Dpp) and Hedgehog (Hh). We demonstrate that proliferation and migration of the glia are separable processes, and that Dpp promotes both the proliferation and motility of the glia, whereas Hh appears to promote only their motility; neither specifies the direction of migration. We present evidence that Dpp and Hh act on the glia in parallel and through the regulation of transcription. Finally, we show that ectopic migration of subretinal glia can result in the ectopic projection of photoreceptor axons. Our study suggests a novel function for Hh in regulating migratory behavior and provides further evidence for a complex mutual dependence between glial and neuronal cells during development.

Molecular cloning and developmental expression of a zebrafish axonal glycoprotein similar to TAG-1.

TAG-1 is a mammalian cell adhesion molecule of the immunoglobulin superfamily that is expressed transiently by a subset of neurons and serves as a fertile substrate for neurite outgrowth in vitro (Furley, A.H., Morton, S.B., Manalo, D., Karagogeos, S., Dodd, H., Jessell, T.M., 1990 The axonal glycoprotein TAG-1 is an immunoglobulin superfamily member with neurite outgrowth promoting activity. Cell 61, 157-170). In order to examine the in vivo function of this molecule, we have cloned a zebrafish tag1-like cDNA and analyzed its expression patterns. tag1 Is expressed transiently by specific subsets of neurons when they are projecting their axons or when they are migrating. The specific and dynamic pattern of expression of zebrafish tag1 is consistent with its proposed role in axon guidance and cell migration.

Preparation of organic-inorganic composite anion-exchange membranes via aqueous dispersion polymerization and their characterization.

Organic-inorganic composite membranes based on poly(vinyl alcohol)/SiO(2) were prepared via an aqueous dispersion polymerization route and anion-exchange groups were introduced in the membrane matrix by the chemical grafting of 4-vinylpyridine with the desired content. These membranes were extensively characterized for their surface morphology, thermal stability, water content, and surface-charge properties using SEM, TEM, FTIR, TGA, water uptake, and ion-exchange capacity measurements. Counterion transport numbers across these membranes were estimated from membrane potential data. Membrane conductance measurements were also performed and these data were used for the estimation of values of counterion diffusion coefficients in the membrane phase. Physicochemical and electrochemical properties of these membranes and equivalent pore radius (estimated from electroosmotic flux measurements) were found to be highly dependent on the 4-vinylpyridine (4-VP) content in the membrane phase. It was also observed that for better selectivity and membrane conductivity of anion-exchange membranes complete optimization of the loading of 4-VP in the membrane phase is necessary. Furthermore, among these, membrane with 25% loading with 4-VP exhibited very good selectivity, water content, and ion-exchange capacity along with moderate membrane conductivity, which may be used for their application in electro-driven separation at elevated temperatures or for other electrochemical processes.

Lymphocyte-induced macrophage cytotoxicity. III. Induction of specific macrophage cytotoxicity is independent of lipopolysaccharide.

The induction of specific macrophage cytotoxicity by allo-sensitized T cells in vitro is shown to be independent of the presence of lipopolysaccharide (LPS). This contrasts with the induction of macrophage cytotoxicity by Macrophage Activating Factor (MAF). The specific macrophage cytotoxicity could be induced in LPS-free medium (less than l ng/ml). Addition of LPS to the macrophages did not increase the cytotoxicity. Addition of LPS-binding polymyxin B to the macrophages before and during the induction of cytotoxicity did not reduce the specific macrophage cytotoxicity. Macrophages obtained from the LPS-unresponsive mouse strain C3H/HeJ were rendered cytotoxic by the allo-sensitized lymphocytes to the same extent as the macrophages from LPS-responsive C3HeB/Fe and C57BL mice. This indicates that the induction of macrophage cytotoxicity by MAF is different from the induction of specific macrophage cytotoxicity by Specific Macrophage Arming Factor (SMAF).

In vivo nitric oxide sensor using non-conducting polymer-modified carbon fiber.

Nitric oxide (NO) is emerging as a very important and ubiquitous gaseous messenger in the body. The response characteristics of NO sensors made of non-conducting polymer modified carbon fiber electrodes are investigated to determine their selectivity, sensitivity, and stability for in vivo use. A composite polymer, comprising Nafion, m-phenylenediamine, and resorcinol, showed the best selectivity and stability to amperometric NO detection. The non-conducting, self-limiting polymer film protects the electrode from interference and fouling by other biochemicals. Although the relative sensitivity to NO of the modified sensor is lower than that of the unmodified carbon fiber electrodes (less than 6%), the composite polymer electrode showed high selectivity against ascorbic acid (> 2000:1), nitrite (> 600:1), and dopamine (> 200:1). The stability of the NO sensor was maintained for at least 1 week. The NO sensitivity after in vivo experiments (n = 8) is 88.1 +/- 5.6% of initial sensitivity data obtained before in vivo experiments. Preliminary in vivo experiments done with this electrode are shown to capture elevated NO levels in brain following an ischemic injury.

Somatosensory stimulus entrains spindle oscillations in the thalamic VPL nucleus in barbiturate anesthetized rats.

This study reports the effect of external stimuli on spindle oscillations in the somatosensory thalamus of barbiturate anesthetized rats. Multi-unit responses to somatosensory stimuli were measured from the contralateral thalamic ventral posterior lateral (VPL) nucleus at different stimulus strengths and periods. Spindle oscillations could be entrained by the somatosensory stimuli at periods between 2 and 5 s. A resonance phenomenon described as a quiescent pre-stimulus period followed by entrained post-stimulus oscillations, was observed for somatosensory stimuli above the threshold for eliciting cortical evoked potentials and a stimulus period between 2 and 5 s. This study demonstrates an ascending pathway for localized modulation of spindle oscillations.

Chloride channel block phase advances the single-unit activity rhythm in the SCN.

The mammalian suprachiasmatic nuclei (SCN) contain a circadian pacemaker that exhibits a 24 h rhythm in single-unit activity in vivo and in vitro. Chloride channel block by a saturating concentration of picrotoxin at either CT6 or CT15 produces large phase advances in the SCN single-unit activity rhythm in vitro. These phase advances are not affected by simultaneous blockade of voltage-sensitive sodium and calcium channels by TTX and magnesium. Thus, the effects of picrotoxin appear to be mediated by direct blockade of the chloride channel, rather than subsequent membrane depolarization. GABA-A receptor-mediated chloride flux may be part of the mechanism of circadian timekeeping.

Studies on the electrochemical and permeation characteristics of asymmetric charged porous membranes.

Asymmetric charged porous membranes were prepared by imbedding 10% (W/W) ion-exchange resin in cellulose acetate binder. Membrane potential and conductance measurements have been carried out in sodium chloride solutions at different concentrations to investigate the relationship between concentration of fixed charges and electrochemical properties of developed nonselective cation- and anion-exchange membranes. Counterion transport number and permselectivity of these membranes were found to vary due to the presence of ion-exchange resin. The hydrodynamic and electroosmotic permeability of sodium chloride solutions has been studied in order to compute equivalent pore radius. For cation- and anion-exchange membranes good agreement was observed between pore radius values estimated from hydrodynamic and electroosmotic permeability coefficient separately, while for nonselective membranes no correlation was found. Membrane conductance data, along with values of concentration of fixed charges, were used for the estimation of the tortuosity factor, salt permeability coefficient, and frictional coefficient between solute and membrane matrix employing an interpretation by nonequilibrium thermodynamic principles based on frictional forces. Moreover, surface morphological studies of these membranes also have been carried out and the membranes were found to be reasonably homogeneous.

Studies of the effect of variation of blend ratio on permselectivity and heterogeneity of ion-exchange membranes.

Heterogeneous ion-exchange membranes (both cationic and anionic types) have been synthesized by solution casting techniques using polyvinyl chloride (PVC) as binder and ion-exchange resin (-300+400 mesh). The binder:resin ratio varied from 60:40 to 30:70. The transport behavior of the membranes has been evaluated chronopotentiometrically in sodium chloride (NaCl) solutions of different concentrations. The different parameters E(0) (potential drop across the membrane at the instant of application of current I), E(max) (maximum potential drop across the membrane after the application of current I), DeltaE (magnitude of the potential jump across the membrane at transition time tau), Itau(1/2), tau, etc., have been evaluated. The isoconductance points were determined and based on the microheterogeneous model proposed by Zabolotsky and Nikonenko (J. Membrane Sci. 79 (1993) 181) the distribution factors beta has been evaluated for both types of ion exchange membranes. The electroconductivity of the joint gel (kappa ) and pure gel phases (kappa ' ) has been determined. At any particular solution concentration the transport number as well as the permselectivity of membranes increases with increased resin content of the membrane. The microheterogeneity factor beta exhibits synchronization among the each set of four different membranes for both the cationic and anionic type.

Development of urethane acrylate composite ion-exchange membranes and their electrochemical characterization.

With the objective of introducing antifouling characteristics into interpolymer types of cation and anion exchange membranes, the surface of these membranes was coated with a 12-microm-thick urethane acrylate layer and was cured by UV radiation of wavelengths 308 and 172 nm under a complete inert atmosphere. Different urethane acrylate composite ion exchange membranes developed were characterized in NaCl solution by measuring their ion-exchange capacity, volume fraction of water, contact angle with water, membrane conductance, and membrane potential. It was found that the electrochemical transport properties of urethane acrylate composite cation-exchange membranes were increased due to resonance stabilization of the urethane group, which acts as a weak acid and dissociates as a negatively charged urethane ion and a positively charged proton. This contributes toward the net charge density of the membrane matrix responsible for enhanced selectivity and conductivity, while for urethane acrylate composite anion-exchange membranes reduction in net charge density was responsible for reduction in electrochemical transport properties. Counterion transport number, permselectivity, and counterion diffusion coefficient values for these membranes were also estimated. Experiments were also carried out in higher homologs of sodium carboxylate solutions in order to observe the fouling tendencies of these membranes. It was concluded that it is possible to obtain antifouling characteristics of ion-exchange membranes by coating and curing thin hydrophilic layers of urethane acrylate on their surfaces without sacrificing their electrochemical transport properties.

Preparation and electrochemical characterization of cation- and anion-exchange/polyaniline composite membranes.

Composite membranes were prepared by chemical polymerization of a thin layer of polyaniline (PANI) in the presence of a high oxidant concentration on a single face of a sulfonated cation-exchange membrane (CEM) and quaternary aminated anion-exchange membrane (AEM). IR and SEM studies for both types of membranes confirmed PANI loading on the ion-exchange membranes. PANI composite ion-exchange membranes were characterized as a function of the polymerization time by ion-exchange capacity, coating density, and membrane conductance measurements. Membrane potential measurements were performed in various electrolyte solutions in order to observe the selectivity of these membranes for different types of counterions. Membrane potential data in conjunction with membrane conductance data was interpreted on the basis of frictional considerations between membrane matrix and solute. Electrodialysis experiments, using PANI composite ion-exchange membranes with 4 h polymerization time, were performed in single and mixed electrolyte solutions for observing electromigration of solute across PANI composite ion-exchange membranes. Relative dialytic rates of Na(2)SO(4), CaCl(2), and CuCl(2) were estimated with reference to NaCl on the basis of electrodialysis experiments and it was concluded that it is possible to separate different electrolytes using PANI composite ion-exchange membranes.

Studies on exchange equilibria of cations between cation-exchange membranes and electrolytic solutions.

The variations of the selectivity coefficient K(A)(B) between Na(+)-H(+), Na(+)-K(+), and Na(+)-Cu(2+) systems and the separation factor alpha(A)(B) between Na(+)-Cu(2+) and K(+)-Cu(2+) systems in cation-exchange membranes as functions of loading and particle size of resin have been measured. The exchange affinities of all the membranes increase as H(+)

Ultrafiltration membranes for the separation of catalyst and products in homogeneous catalysis systems.

Results of preliminary studies on concentration by ultrafiltration and reuse of a Ru(III)EDTA complex in homogeneous catalysis are reported. A method of preparation and selection of conditions of making cellulose acetate membranes for concentrating Ru(III)EDTA is described. At an operating pressure of 75 psig (517 kPa), the above catalyst can be concentrated to seven to eight times its initial concentration. The membrane used exhibits a separation of about 97.5% for the complex with a permeate flow rate of about 3-6 gallons per sq. ft per day. The catalyst activities were determined for two reactions, viz. hydroformylation of 1-hexene and carbonylation of ammonia for five cycles of concentration followed by reuse. The experimental data indicated that the catalyst concentration by ultrafiltration for subsequent reuse is simple and attractive and can provide potentially energy saving alternative to the cumbersome conventional separation processes associated with the recovery of catalysts in homogeneous catalysis.