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Matta JT, Garg U, Li W, Frauendorf S, Ayangeakaa AD, Patel D, Schlax KW, Palit R, Saha S, Sethi J, Trivedi T, Ghugre SS, Raut R, Sinha AK, Janssens RVF, Zhu S, Carpenter MP, Lauritsen T, Seweryniak D, Chiara CJ, Kondev FG, Hartley DJ, Petrache CM, Mukhopadhyay S, Lakshmi DV, Raju MK, Madhusudhana Rao PV, Tandel SK, Ray S, Dönau F. Transverse wobbling in ^{135}pr. PHYSICAL REVIEW LETTERS 2015; 114:082501. [PMID: 25768759 DOI: 10.1103/physrevlett.114.082501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Indexed: 06/04/2023]
Abstract
A pair of transverse wobbling bands is observed in the nucleus ^{135}Pr. The wobbling is characterized by ΔI=1, E2 transitions between the bands, and a decrease in the wobbling energy confirms its transverse nature. Additionally, a transition from transverse wobbling to a three-quasiparticle band comprised of strong magnetic dipole transitions is observed. These observations conform well to results from calculations with the tilted axis cranking model and the quasiparticle rotor model.
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Mitra S, Chakrabarti N, Dutta SS, Ray S, Bhattacharya P, Sinha P, Bhattacharyya A. Gender-specific brain regional variation of neurons, endogenous estrogen, neuroinflammation and glial cells during rotenone-induced mouse model of Parkinson's disease. Neuroscience 2015; 292:46-70. [PMID: 25592425 DOI: 10.1016/j.neuroscience.2014.12.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/29/2014] [Accepted: 12/30/2014] [Indexed: 12/17/2022]
Abstract
Rotenone (RT) produces reactive oxygen species (ROS) by inhibiting the mitochondrial electron transport chain; causing dopaminergic (DA) cell death in the substantia nigra (SN) and simulates other models of induced Parkinson's disease (PD). There is a sincere dearth of knowledge regarding the status of glial cells, neuroprotective estrogen and the status of neuroinflammatory TNF-α in the different brain regions in either sex during healthy, as well as during PD conditions. In the present study of RT-induced mouse model of PD, we have selected the frontal cortex (FC), hippocampus (HC) and SN from either sex of Swiss albino mice as these are the major regions involved during PD pathogenesis. During non pathogenic conditions, the ROS-scavenging enzyme activity varied among the brain regions and also in between genders. The number of DOPA decarboxylase-positive cells, astrocytes and microglia was similar in the respective regions of the brain in both the sexes. The level of proinflammatory cytokine TNF-α was same in the respective FC and HC in either sex except that of SN. The expression level of estrogen and its receptors varied among the three brain regions. During RT treatment, ROS-scavenging enzyme activities increased, DOPA decarboxylase-positive neurons and fibers in DA as well as in norepinephrinergic (NE) systems become degenerated, number of astrocytes decreased and microglial cells increased in those specific brain regions in either of the sexes except in the SN region of males where astrocyte number remained unaltered and microglial cell percentage decreased. TNF-α increased in the FC and SN but remained unaltered in the HC of both sexes. Estradiol level decreased in the HC and SN but the level unevenly varied in the FC. Similarly, the estrogen bound and nuclear-cytosolic receptor α and β also varied differentially among the brain regions of the two sexes. Therefore our present study depicts that there exists a clear variation of neuronal and astroglial cell population, estrogen and its receptor levels in different brain regions of both the sexes during control and RT-treated pathogenic condition and these variations have major implication in PD pathogenesis and progression.
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Chaterjee S, Ghosh S, Ray S, Rudra A. Pain Management After Spinal Surgery. INDIAN JOURNAL OF PAIN 2015. [DOI: 10.4103/0970-5333.145916] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Verma V, Ray S, Bajaj R, Kumar A. Effect of prolonged exercise on blood glucose levels of under-trainee divers : A pilot study. JOURNAL OF MARINE MEDICAL SOCIETY 2015. [DOI: 10.4103/0975-3605.203392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Popescu BA, Stefanidis A, Nihoyannopoulos P, Fox KF, Ray S, Cardim N, Rigo F, Badano LP, Fraser AG, Pinto F, Zamorano JL, Habib G, Maurer G, Lancellotti P. Updated standards and processes for accreditation of echocardiographic laboratories from The European Association of Cardiovascular Imaging: an executive summary. Eur Heart J Cardiovasc Imaging 2014; 15:1188-93. [DOI: 10.1093/ehjci/jeu057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Arianmehr I, Ting DK, Ray S. Effect of a transverse groove on cooling of a surrogate photovoltaic panel. ACTA ACUST UNITED AC 2014. [DOI: 10.1080/00207233.2014.967016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Sarathi Patra P, Das K, Bhattacharyya A, Ray S, Hembram J, Sanyal S, Dhali GK. Natural resolution or intervention for fluid collections in acute severe pancreatitis. Br J Surg 2014; 101:1721-8. [PMID: 25329330 DOI: 10.1002/bjs.9666] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/23/2014] [Accepted: 09/05/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Revisions in terminology of fluid collections in acute pancreatitis have necessitated reanalysis of their evolution and outcome. The course of fluid collections in patients with acute pancreatitis was evaluated prospectively. METHODS Consecutive adults with acute pancreatitis, who had contrast-enhanced CT (CECT) within 5-7 days of symptom onset, were enrolled in a prospective cohort study in a tertiary-care centre. Patients were treated according to standard guidelines. Follow-up transabdominal ultrasonography was done at 4-week intervals for at least 6 months. CECT was repeated at 6-10 weeks, or at any time if there were new or persistent symptoms. Asymptomatic collections were followed until spontaneous resolution. Risk factors for pancreatic pseudocysts or walled-off necrosis (WON) were assessed in multivariable analyses. RESULTS Of 122 patients with acute pancreatitis, 109 were analysed. Some 91 patients (83·5 per cent) had fluid collections at baseline. Eleven of 29 with interstitial oedematous pancreatitis had acute peripancreatic fluid collections, none of which evolved into pseudocysts. All 80 patients with acute necrotizing pancreatitis had at least one acute necrotizing collection (ANC); of these, five patients died (2 after drainage), three underwent successful drainage within 5 weeks, and collections resolved spontaneously in 33 and evolved into WON in 39. By 6 months' follow-up, WON had required drainage in eight patients, resolved spontaneously in 23 and was persistent but asymptomatic in seven. Factors associated with increased risk of WON were blood urea nitrogen 20 mg/dl or more (odds ratio (OR) 10·96, 95 per cent c.i. 2·57 to 46·73; P = 0·001) and baseline ANC diameter greater than 6 cm (OR 14·57, 1·60 to 132·35; P = 0·017). Baseline ANC diameter over 6 cm was the only independent predictor of either the need for drainage or persistence of such collections beyond 6 months (hazard ratio 6·61, 1·77 to 24·59; P = 0·005). CONCLUSION Pancreatic pseudocysts develop infrequently in oedematous acute pancreatitis. Only one-quarter of ANCs either require intervention or persist beyond 6 months, whereas more than one-half of WONs resolve without any intervention within 6 months of onset. Baseline diameter of ANC(s) is an important predictor of outcome.
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Narendra H, Thomas J, Ray S, Fernandes DJ. An analysis of response to neo-adjuvant chemotherapy in patients with locally advanced breast cancer with emphasis on pathological complete response. Indian J Cancer 2014; 51:587-92. [PMID: 26842205 DOI: 10.4103/0019-509x.175316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
CONTEXT In India, most breast cancer women present at a locally advanced stage. Routine practice in majority of the cancer centers is to administer neo-adjuvant chemotherapy (NACT) followed by loco-regional treatment. Surgery is scheduled after 3 or 4 cycles. The patients who achieve pathological complete response (pCR) are expected do well. AIMS The present study was conducted to analyze our results with NACT, to know pCR rate, to compare pCR rates among various subgroups and to determine the factors which predict pCR. SETTINGS AND DESIGN The study was conducted in a tertiary care university affiliated cancer hospital in South India. SUBJECTS AND METHODS All patients with non-metastatic locally advanced breast cancer and agreed by the hospital tumor board to receive NACT were included. At each visit, response was assessed according to RECIST criteria. Re-staging work up and mammography was done prior to surgery. STATISTICAL ANALYSIS USED Chi square test was used to analyze categorical variables and uni and multivariate analysis were performed to determine the factors predicting pCR rates. RESULTS A total of 84 patients received NACT. Median age was 46 years (ranged from 28 to 66), 46 patients were premenopausal. Totally 72 patients completed the full course before surgery. Clinical response was complete in 26, partial in 52 and 3 had local progression, one stable and two patient developed distant metastasis. Forty-eight patients underwent modified radical mastectomy and breast could be conserved in 34 patients, pCR rate was 36%. CONCLUSIONS Compared with historical controls particularly from India, we could achieve higher pCR rates.
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Ray S, Basak S, Chatterjee P. Malignant Leiomyoblastoma: An Incidental Diagnosis. NEPAL JOURNAL OF OBSTETRICS AND GYNAECOLOGY 2014. [DOI: 10.3126/njog.v7i2.11147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DOI: http://www.dx.doi.org/10.3126/njog.v7i2.11147 Nepal Journal of Obstetrics and Gynaecology / Vol 7 / No. 2 / Issue 14 / July-Dec, 2012 / 55-56
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Ray S, Miglio C, Eden T, Del Rio D. Assessment of vascular and endothelial dysfunction in nutritional studies. Nutr Metab Cardiovasc Dis 2014; 24:940-946. [PMID: 24925123 DOI: 10.1016/j.numecd.2014.03.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 02/05/2023]
Abstract
Vascular and endothelial dysfunction (VED) is emerging as a potential set of early markers of cardiovascular disease risk and tests for its measurement have been widely used in clinical research. The aim of this viewpoint is to describe and discuss the current usage of these measures in well-designed nutritional trials, using the potential relationship between fruit juice intake and VED as example. A search was conducted using the NHS evidence portal including studies published in English between January 1980 and October 2013. Only 10 suitable studies were selected, which investigated the effect of fruit juice intake on VED, among which 4 interventions used flow-mediated dilatation, 2 arterial stiffness, 2 a combination of arterial stiffness and flow-mediated dilatation, 2 carotid intimal media thickness and 1 iontophoresis with laser Doppler. Despite minimal effects reported on classical CVD markers, such as lipids, 8 out of the 10 identified studies reported an effect on endothelial function following juice consumption, indicating that VED tests can be effectively used in human dietary interventions to identify relationships between bioactive compounds from fruit and CVD risk. However, paucity of available data, scarcity of compound bioavailability and metabolism information, strong heterogeneity among experimental methodologies and a number of limitations to study designs, still limit the interpretation of the results obtained through these measures. Future, well-designed studies with greater attention to consider use of VED measures are needed to strengthen the utility of VED tests in nutrition research such as those investigating the impact of polyphenol-rich juices and CVD risk.
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Cheng Y, Ray S, Chang M, Menon S. Statistical Monitoring of Clinical Trials With Multiple Co-Primary Endpoints Using Multivariate B-value. Stat Biopharm Res 2014. [DOI: 10.1080/19466315.2014.923324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Lips KS, Kauschke V, Hartmann S, Thormann U, Ray S, Schumacher M, Gelinsky M, Heinemann S, Hanke T, Kautz AR, Schnabelrauch M, Szalay G, Heiss C, Schnettler R, Alt V, Kilian O. Cholinergic nerve fibers in bone defects of a rat osteoporosis model and their regulation by implantation of bone substitution materials. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2014; 14:173-188. [PMID: 24879021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVES Bone is innervated by autonomic nervous system that consists of sympathetic and parasympathetic nerves that were recently identified in bone. Thus we asked whether parasympathetic nerves occur in bone defects and at the interface of substitution materials that were implanted for stabilization and improvement of healing in an osteoporosis animal model. METHODS Osteoporosis was induced in rats by ovariectomy and deficiency diet. A wedge-shaped osteotomy was performed in the metaphyseal area of femur. Eight different implants were inserted that were based on calcium phosphate cement, iron, silica-mineralized collagen, and modifications with strontium. Nerves were identified by immunohistochemistry with antibodies against vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH) and protein gene product 9.5 (PGP 9.5) as neuronal marker. RESULTS Cholinergic nerves identified with VAChT immunostaining were detected in defects filled with granulation tissue and in surrounding mast cells. No immunolabeling of cholinergic nerves was found after implantation. The general presence of nerves was reduced after implantation as shown by PGP 9.5. Sympathetic nerves identified by TH immunolabeling were increased in strontium functionalized materials. CONCLUSION Since cholinergic innervation was diminished after implantation a further increase in the compatibility of substitution materials to nerves could improve defect healing especially in osteoporotic bone.
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Paul A, Gunewardena S, Stecklein SR, Saha B, Parelkar N, Danley M, Rajendran G, Home P, Ray S, Jokar I, Vielhauer GA, Jensen RA, Tawfik O, Paul S. PKCλ/ι signaling promotes triple-negative breast cancer growth and metastasis. Cell Death Differ 2014; 21:1469-81. [PMID: 24786829 DOI: 10.1038/cdd.2014.62] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 12/29/2022] Open
Abstract
Triple-negative breast cancer (TNBC) is a distinct breast cancer subtype defined by the absence of estrogen receptor (ER), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2/neu), and the patients with TNBC are often diagnosed with higher rates of recurrence and metastasis. Because of the absence of ER, PR and HER2/neu expressions, TNBC patients are insensitive to HER2-directed and endocrine therapies available for breast cancer treatment. Here, we report that expression of atypical protein kinase C isoform, PKCλ/ι, significantly increased and activated in all invasive breast cancer (invasive ductal carcinoma or IDC) subtypes including the TNBC subtype. Because of the lack of targeted therapies for TNBC, we choose to study PKCλ/ι signaling as a potential therapeutic target for TNBC. Our observations indicated that PKCλ/ι signaling is highly active during breast cancer invasive progression, and metastatic breast cancers, the advanced stages of breast cancer disease that developed more frequently in TNBC patients, are also characterized with high levels of PKCλ/ι expression and activation. Functional analysis in experimental mouse models revealed that depletion of PKCλ/ι significantly reduces TNBC growth as well as lung metastatic colonization. Furthermore, we have identified a PKCλ/ι-regulated gene signature consisting of 110 genes, which are significantly associated with indolent to invasive progression of human breast cancer and poor prognosis. Mechanistically, cytokines such as TGFβ and IL1β could activate PKCλ/ι signaling in TNBC cells and depletion of PKCλ/ι impairs NF-κB p65 (RelA) nuclear localization. We observed that cytokine-PKCλ/ι-RelA signaling axis, at least in part, involved in modulating gene expression to regulate invasion of TNBC cells. Overall, our results indicate that induction and activation of PKCλ/ι promote TNBC growth, invasion and metastasis. Thus, targeting PKCλ/ι signaling could be a therapeutic option for breast cancer, including the TNBC subtype.
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Lindsay BG, Markatou M, Ray S. Kernels, Degrees of Freedom, and Power Properties of Quadratic Distance Goodness-of-Fit Tests. J Am Stat Assoc 2014; 109:395-410. [PMID: 24764609 PMCID: PMC3979448 DOI: 10.1080/01621459.2013.836972] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this article, we study the power properties of quadratic-distance-based goodness-of-fit tests. First, we introduce the concept of a root kernel and discuss the considerations that enter the selection of this kernel. We derive an easy to use normal approximation to the power of quadratic distance goodness-of-fit tests and base the construction of a noncentrality index, an analogue of the traditional noncentrality parameter, on it. This leads to a method akin to the Neyman-Pearson lemma for constructing optimal kernels for specific alternatives. We then introduce a midpower analysis as a device for choosing optimal degrees of freedom for a family of alternatives of interest. Finally, we introduce a new diffusion kernel, called the Pearson-normal kernel, and study the extent to which the normal approximation to the power of tests based on this kernel is valid. Supplementary materials for this article are available online.
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Som N, Roy P, Ray S. Menopause-specific quality of life of a group of urban women, West Bengal, India. Climacteric 2014; 17:713-9. [PMID: 24742367 DOI: 10.3109/13697137.2014.913283] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To find out the association of menopause-specific quality of life of women with menopausal status. METHODS In this cross-sectional study, we involved 250 Bengali-speaking women of Hindu ethnic group (118 perimenopausal and 132 postmenopausal), aged 40-65 years from urban areas of North 24 Paraganas, a district of West Bengal, India. The Menopause-Specific Quality of Life questionnaire (MENQOL) consisting of 29 menopausal symptoms, grouped under four menopausal domains (vasomotor, psychosocial, physical and sexual), was used to assess menopause-specific quality of life. Scores of four menopausal domains generated a composite score of 'Quality of Life'. Additionally, participants were also interviewed for their sociodemographic characteristics. RESULTS Bivariate analyses showed significant difference in all the domains of menopause-specific quality of life (barring vasomotor domain) when compared for menopausal status. Results of ANCOVA showed that menopausal status was significantly associated only with the physical domain after removing the effects of sociodemographic characteristics. CONCLUSION Menopausal status had a significant association with the physical domain of menopause-specific quality of life of women.
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Anand D, Ray S, Bhargava S, Das S, Garg A, Taneja S, Dhar D, Srivastava LM. Proinflammatory versus anti-inflammatory response in sepsis patients: looking at the cytokines. Crit Care 2014. [PMCID: PMC4273725 DOI: 10.1186/cc14016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Bresciani L, Calani L, Bocchi L, Delucchi F, Savi M, Ray S, Brighenti F, Stilli D, Del Rio D. Bioaccumulation of resveratrol metabolites in myocardial tissue is dose-time dependent and related to cardiac hemodynamics in diabetic rats. Nutr Metab Cardiovasc Dis 2014; 24:408-415. [PMID: 24462050 DOI: 10.1016/j.numecd.2013.09.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/05/2013] [Accepted: 09/23/2013] [Indexed: 01/23/2023]
Abstract
BACKGROUND AND AIMS Trans-resveratrol (RSV) is a natural compound occurring in different foods and plants, which in vivo is rapidly conjugated with glucuronic acid and sulfate. Despite its demonstrated cardioprotective activity, the bioaccumulation of RSV or its metabolites in cardiac tissue is still unknown. METHODS AND RESULTS Diabetic rats were randomized to 1, 3 or 6 weeks of RSV treatment at two different doses (1 or 5 mg/kg/day). A dose and time-dependent accumulation was observed, with no detectable levels of RSV metabolites found in heart tissues after 1 week and significant concentrations of RSV-3-sulfate and RSV-3-glucuronide after 6 weeks of treatment (0.05 nmol/g of tissue and 0.01 nmol/g of tissue, respectively). Tissue accumulation of RSV metabolites was accompanied by an improvement of cardiac function in long-term diabetes, when myocardial morpho-functional damage is more evident, with an almost complete recovery of all hemodynamic parameters, at the highest RSV dose. CONCLUSION Even if a higher concentration of RSV in tissues cannot be ruled out after constant oral administration, an accumulation coherent with what is usually evaluated in cell based mechanistic studies is largely unattainable and the RSV unconjugated form would not be present in this paradigm. The current investigation provides data on myocardial tissue concentrations of RSV metabolites, after short/medium term RSV treatment. This knowledge constitutes a basic requirement for future studies aimed at reliably defining the molecular pathways underlying RSV-mediated cardioprotective effects and opens up new perspectives for research focused on testing phenolic compounds as adjuvants in degenerative heart diseases.
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Popescu BA, Stefanidis A, Nihoyannopoulos P, Fox KF, Ray S, Cardim N, Rigo F, Badano LP, Fraser AG, Pinto F, Zamorano JL, Habib G, Maurer G, Lancellotti P. Updated standards and processes for accreditation of echocardiographic laboratories from The European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging 2014; 15:717-27. [DOI: 10.1093/ehjci/jeu039] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Deeken C, Ray S, Ward K, Barrett C, Pichert M, Eliason B, MacEwan M, Frisella M, Matthews B. Biomechanical Evaluation of Novel Electrospun Scaffold in a Porcine Model of Ventral Hernia Repair. J Surg Res 2014. [DOI: 10.1016/j.jss.2013.11.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bollen KA, Harden JJ, Ray S, Zavisca J. BIC and Alternative Bayesian Information Criteria in the Selection of Structural Equation Models. STRUCTURAL EQUATION MODELING : A MULTIDISCIPLINARY JOURNAL 2014; 21:1-19. [PMID: 31360054 PMCID: PMC6663110 DOI: 10.1080/10705511.2014.856691] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Selecting between competing Structural Equation Models (SEMs) is a common problem. Often selection is based on the chi square test statistic or other fit indices. In other areas of statistical research Bayesian information criteria are commonly used, but they are less frequently used with SEMs compared to other fit indices. This article examines several new and old Information Criteria (IC) that approximate Bayes Factors. We compare these IC measures to common fit indices in a simulation that includes the true and false models. In moderate to large samples, the IC measures outperform the fit indices. In a second simulation we only consider the IC measures and do not include the true model. In moderate to large samples the IC measures favor approximate models that only differ from the true model by having extra parameters. Overall, SPBIC, a new IC measure, performs well relative to the other IC measures.
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Ray S, O'Dell W, Barmpoutis A. Perpendicular fibre tracking for neural fibre bundle analysis using diffusion MRI. INTERNATIONAL JOURNAL OF BIOINFORMATICS RESEARCH AND APPLICATIONS 2014; 10:75-92. [PMID: 24449694 DOI: 10.1504/ijbra.2014.058779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Information on the directionality and structure of axonal fibres in neural tissue can be obtained by analysing diffusion-weighted MRI data sets. Several fibre tracking algorithms have been presented in the literature that trace the underlying field of principal orientations of water diffusion, which correspond to the local primary eigenvectors of the diffusion tensor field. However, the majority of the existing techniques ignore the secondary and tertiary orientations of diffusion, which contain significant information on the local patterns of diffusion. In this paper, we introduce the idea of perpendicular fibre tracking and present a novel dynamic programming method that traces surfaces, which are locally perpendicular to the axonal fibres. This is achieved by using a cost function, with geometric and fibre orientation constraints, that is evaluated dynamically for every voxel in the image domain starting from a given seed point. The proposed method is tested using synthetic and real DW-MRI data sets. The results conclusively demonstrate the accuracy and effectiveness of our method.
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Collins-Hooper H, Sartori R, Macharia R, Visanuvimol K, Foster K, Matsakas A, Flasskamp H, Ray S, Dash PR, Sandri M, Patel K. Propeptide-Mediated Inhibition of Myostatin Increases Muscle Mass Through Inhibiting Proteolytic Pathways in Aged Mice. J Gerontol A Biol Sci Med Sci 2014; 69:1049-59. [DOI: 10.1093/gerona/glt170] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Rahman A, Gupta RK, Bhattacharya SN, Ray S, Costa F. Simulation Study of Thermotropic LCPs and Prediction of Normal Stress Difference at High Shear Rate. INT POLYM PROC 2013. [DOI: 10.3139/217.2756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The shear viscosity and normal stress difference of two filled and two unfilled thermotropic liquid crystal polymer (TLCPs) were studied. The rigid and rod like molecules of TLCPs orientate differently at different shear rates. Under low shear rate, the molecules tend to align in the direction of the flow but also tumble and wagging on their own axis. The abnormal orientation of the molecules also depends upon temperature, fillers contents, aspect ratio and elastic nature of LCP molecules. These behaviors lead to unusual rheological properties of LCPs, such as negative first normal stress difference for filled LCPs at low shear rates. But with the increase of shear rate, the molecules are oriented in the direction of flow, which lead to isotropic flow at high shear rates. The complicated rheological properties and characteristic anisotropic properties of LCPs are modelled by recently developed Leonov's viscoselastic constitutive equations. Simulation has been carried out using Mathematica software and the characteristic anisotropic properties of LCPs have been identified. The experimentally measured viscosities at high shear rate have been compared with model predictions. Moreover, the normal stress differences using at high shear rates have been estimated using Leonov's model, which is experimentally not accessible.
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Minners J, Jander N, Gerdts E, Pedersen TR, Ray S, Chambers JB, Wachtell K, Holme I, Neumann FJ, Gohlke-Baerwolf C. Outcome in 1763 asymptomatic patients with mild or moderate calcific aortic stenosis followed prospectively with annual echocardiography. Eur Heart J 2013. [DOI: 10.1093/eurheartj/eht308.1815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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