Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 103
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Inorg Chem ; 59(10): 6763-6773, 2020 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-32343126

RESUMEN

We report high-temperature synchrotron X-ray diffraction (SXRD), magnetization, and current-voltage (I-V) characteristics for the samples of Co2.75Fe0.25O4 ferrite. The material was prepared by chemical reaction of the Fe and Co nitrate solutions at pH ∼ 11 and subsequent thermal annealing. Physical properties of the samples were measured by cycling the temperature from 300 K to high temperature (warming mode) and returning back to 300 K (cooling mode). The lattice structure showed sensitivity to high measurement temperatures. Magnetization curves showed a defect-induced ferromagnetic phase at higher temperatures and superparamagnetic blocking of the ferrimagnetic particles near to 300 K or below. Electrical conductivity exhibited a thermal hysteresis loop at higher measurement temperatures. The samples exhibited new form (not studied so far) of surface magnetism in Co rich spinel oxides and irreversibility phenomena in the lattice structure, magnetization, and conductivity on cycling the measurement temperatures.

2.
Phys Chem Chem Phys ; 22(25): 14309-14317, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32567617

RESUMEN

We have thoroughly investigated the crystal structure of ice evolved from super cooled water confined in MCM-41 cylindrical nano pores through a synchrotron-based X-ray diffraction (XRD) technique for two different levels of pore filling. A rigorous analysis of XRD data shows that the nucleation dynamics and the structure of nucleated ice highly depend on the level of pore filling. In the nearly fully hydrated pores, ice crystallites start nucleating inside the pores below 240 K and creep out of the pores to form bulk crystals having crystalline structure of a mixed phase of hexagonal and cubic forms. In the partially hydrated pores, on the other hand, ice crystals cannot creep out of the pore crossing the energy barrier. The crystalline ice particles remaining inside the cylindrical pore show a short range "cubic rich" structure. The "pure cubic" phase has not been identified at either of the pore fillings in these 2.5 nm average size pores. A large fraction of water inside the pores remains in the super cooled liquid phase even at 180 K. This observation is relevant for understanding the ice nucleation through the pore condensation and freezing mechanism, which is a major pathway for the formation of cirrus clouds in the upper atmosphere.

3.
Ann Hum Biol ; 46(1): 46-55, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30822155

RESUMEN

BACKGROUND: Menopause is the universal physiological process of women's midlife and exhibits a wide variety of symptoms. However, there is little data on the menopausal symptoms and factors associated with their severity among rural Indian women. AIM: To evaluate the prevalence of menopausal symptoms during the different transition phases of menopause among rural women of North India. SUBJECTS AND METHODS: This cross-sectional study consisted of 351 women aged 35-55 years (mean age 44.6 years) residing in rural areas of North India. A structured questionnaire was used to collect data regarding menopausal status, demographic profile and reproductive history of the participants. Frequency and severity of menopausal symptoms were evaluated using the Greene Climacteric Scale in different stages of menopause. All statistical procedures were accomplished using SPSS version 19.0. RESULTS: In the present study the mean ages of attainment of menarche and menopause were 14.3 years and 47.2 years, respectively. Mean score of total Greene Climacteric Scale was highest among perimenopausal women (16.12 ± 8.1) over post-menopausal (14.78 ± 7.3) and pre-menopausal women (11.08 ± 6.1). Logistic regression analysis revealed that advancing age, low educational attainment, low socioeconomic status, menopausal status, later age at menarche and higher BMI were all associated with more severe menopausal symptoms. CONCLUSION: The climacteric symptoms were more prevalent among women who were perimenopausal followed by post-menopausal women and were the lowest in pre-menopausal women. Age, menopausal status, socio-economic status, and reproductive factors significantly influenced the severity of menopausal symptoms.


Asunto(s)
Menopausia/fisiología , Población Rural/estadística & datos numéricos , Adulto , Estudios Transversales , Femenino , Humanos , India , Persona de Mediana Edad
4.
Inorg Chem ; 56(6): 3335-3348, 2017 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-28263590

RESUMEN

Herein we report the high-temperature crystal chemistry of K2Ce(PO4)2 as observed from a joint in situ variable-temperature X-ray diffraction (XRD) and Raman spectroscopy as well as ab initio density functional theory (DFT) calculations. These studies revealed that the ambient-temperature monoclinic (P21/n) phase reversibly transforms to a tetragonal (I41/amd) structure at higher temperature. Also, from the experimental and theoretical calculations, a possible existence of an orthorhombic (Imma) structure with almost zero orthorhombicity is predicted which is closely related to tetragonal K2Ce(PO4)2. The high-temperature tetragonal phase reverts back to ambient monoclinic phase at much lower temperature in the cooling cycle compared to that observed at the heating cycle. XRD studies revealed the transition is accompanied by volume expansion of about 14.4%. The lower packing density of the high-temperature phase is reflected in its significantly lower thermal expansion coefficient (αV = 3.83 × 10-6 K-1) compared to that in ambient monoclinic phase (αV = 41.30 × 10-6 K-1). The coexistences of low- and high-temperature phases, large volume discontinuity in transition, and large hysteresis of transition temperature in heating and cooling cycles, as well as drastically different structural arrangement are in accordance with the first-order reconstructive nature of the transition. Temperature-dependent Raman spectra indicate significant changes around 783 K attributable to the phase transition. In situ low-temperature XRD, neutron diffraction, and Raman spectroscopic studies revealed no structural transition below ambient temperature. Raman mode frequencies, temperature coefficients, and reduced temperature coefficients for both monoclinic and tetragonal phases of K2Ce(PO4)2 have been obtained. Several lattice and external modes of rigid PO4 units are found to be strongly anharmonic. The observed phase transition and structures as well as vibrational properties of both ambient- and high-temperature phases were complimented by DFT calculations. The optical absorption studies on monoclinic phase indicated a band gap of about 2.46 eV. The electronic structure calculations on ambient-temperature monoclinic and high-temperature phases were also carried out.

5.
Phys Chem Chem Phys ; 19(8): 6030-6041, 2017 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-28184388

RESUMEN

Herein we report the evolution of the crystal structure of K3Gd5(PO4)6 in the temperature range from 20 K to 1073 K, as observed from variable temperature X-ray diffraction and Raman spectroscopic studies. K3Gd5(PO4)6 has an open tunnel containing a three dimensional structure built by [Gd5(PO4)6]3- ions which in turn are formed of PO4 tetrahedra and GdOn (n = 8 and 9) polyhedra. The empty tunnels in the structure are occupied by K+ ions and maintain charge neutrality in the lattice. Evolution of unit cell parameters with temperature shows a systematic increase with temperature. The average axial thermal expansion coefficients between 20 K and 1073 K are: αa = 10.6 × 10-6 K-1, αb = 5.5 × 10-6 K-1 and αc = 16.4 × 10-6 K-1. The evolution of distortion indices of the various coordination polyhedra with temperature indicates a gradual decrease with increasing temperature, while those of Gd2O9 and K2O8 polyhedra show opposite trends. The overall anisotropy of the lattice thermal expansion is found to be controlled largely by the effect of temperature on GdOn polyhedra and their linkages. Temperature dependent Raman spectroscopic studies indicated that the intensities and wavenumbers of most of the Raman modes decrease continuously with increasing temperature. Anharmonic analyses of Raman modes indicated that the lattice, rigid translation and librational modes have larger contributions towards thermal expansion of K3Gd5(PO4)6 compared to high frequency internal modes. The temperature and field dependent magnetic measurements indicated no long range ordering down to 2 K and the observed effective magnetic moment per Gd3+ ion and the Weiss constant are 7.91 µB and 0.38 K, respectively.

6.
Chemistry ; 22(44): 15639-15644, 2016 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-27595431

RESUMEN

A novel MnFe2 O4 -porous organic polymer (POP) nanocomposite was synthesized by a facile hydrothermal method and using the highly cross-linked N-rich benzene-benzylamine POP. The nanocomposite presented highly efficient photocatalytic performance in the hydrogen evolution reaction (HER) from pure water without addition of any sacrificial agent under one AM 1.5 G sunlight illumination. A photocatalytic activity of 6.12 mmol h-1 g-1 was achieved in the absence of any noble metal cocatalyst, which is the highest H2 production rate reported for nonprecious metal catalysts. The photocatalytic performance of MnFe2 O4 -POP could be attributed to the intrinsic synergistic effects of manganese ferrite (MnFe2 O4 ) nanoclusters interacting with the nitrogen dopant POP with a unique mesoporous nanoarchitecture and spatially confined growth of MnFe2 O4 in the interconnected POP network, leading to high visible-light absorption with fast electron transport.

7.
Inorg Chem ; 55(17): 8994-9005, 2016 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-27494416

RESUMEN

Variable-temperature Raman spectroscopic and synchrotron X-ray diffraction studies were performed on BaTe2O6 (orthorhombic, space group: Cmcm), a mixed-valence tellurium compound with a layered structure, to understand structural stability and anharmonicity of phonons. The structural and vibrational studies indicate no phase transition in it over a wider range of temperature (20 to 853 K). The structure shows anisotropic expansion with coefficients of thermal expansion in the order αb ≫ αa > αc, which was attributed to the anisotropy in bonding and structure of BaTe2O6. Temperature evolution of Raman modes of BaTe2O6 indicated a smooth decreasing trend in mode frequencies with increasing temperature, while the full width at half-maximum (fwhm) of all modes systematically increases due to a rise in phonon scattering processes. With the use of our earlier reported isothermal mode Grüneisen parameters, thermal properties such as thermal expansion coefficient and molar specific heat are calculated. The pure anharmonic (explicit) and quasiharmonic (implicit) contribution to the total anharmonicity is delineated and compared. The temperature dependence of phonon mode frequencies and their fwhm values are analyzed by anharmonicity models, and the dominating anharmonic phonon scattering mechanism is concluded in BaTe2O6. In addition to the lattice modes, several external modes of TeOn (n = 5, 6) are found to be strongly anharmonic. The ab initio electronic structure calculations indicated BaTe2O6 is a direct band gap semiconductor with gap energy of ∼2.1 eV. Oxygen orbitals, namely, O-2p states in the valence band maximum and the sp-hybridized states in the conduction band minimum, are mainly involved in the electronic transitions. In addition a number of electronic transitions are predicted by the electronic structure calculations. Experimental photoluminescence results are adequately explained by the ab initio calculations. Further details of the structural and vibrational properties are explained in the manuscript.

8.
Inorg Chem ; 55(22): 11791-11800, 2016 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-27934308

RESUMEN

Herein we report results of pressure- and temperature-dependent Raman scattering studies on Pr2Ti2O7. Pressure-dependent studies performed up to 23 GPa suggest a reversible phase transition above 15 GPa with subtle changes. Temperature-dependent investigations performed in the range of 77-1073 K showed anomalous temperature dependence of some of the Raman modes. Temperature-dependent X-ray diffraction data indicated no structural transition but nonlinear expansion of unit-cell parameters with increasing temperature. With increasing temperature, the structure dilates anisotropically, and volume of coordination polyhedra around all the atoms expands. Also with increasing temperature the distortions in coordination polyhedra around all the atoms decrease, and appreciable decrease is observed in Pr(1)O10 and Pr(3)O9 units. The pressure evolution of Raman-mode frequencies was analyzed for both ambient as well as high-pressure phases, and mode Grüneisen parameters for ambient pressure phase were obtained. The temperature evolution of Raman-mode frequencies was analyzed to obtain the explicit and implicit anharmonic components, and it was found that some of the modes attributable to TiO6 octahedra and PrOn polyhedra have dominating explicit anharmonic component. Comparison of the structural data with the temperature dependence of Raman modes suggests that the anomalous behavior in Raman modes is due to phonon-phonon interaction.

9.
Chemphyschem ; 15(1): 187-94, 2014 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-24307405

RESUMEN

Structurally thermostable mesoporous anatase TiO2 (m-TiO2) nanoparticles, uniquely decorated with atomically dispersed SiO2, is reported for the first time. The inorganic Si portion of the novel organosilane template, used as a mesopores-directing agent, is found to be incorporated in the pore walls of the titania aggregates, mainly as isolated sites. This is evident by transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy, combined with electron dispersive X-ray spectroscopy. This type of unique structure provides exceptional stability to this new material against thermal collapse of the mesoporous structure, which is reflected in its high surface area (the highest known for anatase titania), even after high-temperature (550 °C) calcination. Control of crystallite size, pore diameter, and surface area is achieved by varying the molar ratios of the titanium precursor and the template during synthesis. These mesoporous materials retain their porosity and high surface area after template removal and further NaOH/HCl treatment to remove silica. We investigate their performance for dye-sensitized solar cells (DSSCs) with bilayer TiO2 electrodes, which are prepared by applying a coating of m-TiO2 onto a commercial titania (P25) film. The high surface area of the upper mesoporous layer in the P25-m-TiO2 DSSC significantly increases the dye loading ability of the photoanode. The photocurrent and fill factor for the DSSC with the bilayer TiO2 electrode are greatly improved. The large increase in photocurrent current (ca. 56%) in the P25-m-TiO2 DSSC is believed to play a significant role in achieving a remarkable increase in the photovoltaic efficiency (60%) of the device, compared to DSSCs with a monolayer of P25 as the electrode.

10.
Bioinformation ; 20(1): 20-28, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38352907

RESUMEN

Forecasting consumption of blood products can reduce their order frequency by 60% and inventory level by 40%. This also prevents shortage by balancing demand and supply. The study aimed to establish a "Simple Average with Mean Annual Increment" (SAMAI) method of time series forecasting and to compare its results with those of ARIMA, ratio to trend, and simple average to forecast demand of blood products. Monthly demand data of blood component from January 2017 to December 2022 (data set I) was used for creating a forecasting model. To avoid the effect of COVID19 pandemic instead of actual data of year 2020 and 2021, average monthly values of previous three years were used (data set II). The data from January to July 2023 were used as testing data set. To assess the fitness of model MAPE (Mean Absolute Percentage Error) was used. By SAMAI method MAPE were 18.82%, 13.392%, 14.516% and 27.637% respectively for of blood donation, blood issue, RDP issue and FFP issue for data set I. By Simple Average method MAPE were 20.05%, 12.09%, 29.06% and 34.85%, respectably. By Ratio-to-Trend method MAPE were 21.08%, 21.65%, 25.62% and 39.95% respectively. By SARIMA method MAPE were 12.99%, 19.59%, 37.15% and 31.94% respectively. The average MAPE was lower in data set II by all tested method and overall MAPE was lower by SAMAI method. The SAMAI method is simple and easy to perform. It can be used in the forecasting of blood components demand in medical institution without knowledge of advanced statistics.

11.
Bioinformation ; 19(5): 582-589, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37886140

RESUMEN

Transfusion Transmissible Infections (TTIs) such as human immune-deficiency virus (HIV-I/II), hepatitis B virus (HBV), Hepatitis C virus (HCV), Malaria parasite (MP) and syphilis can spread through contaminated blood or blood products. The present study was designed to analyze the prevalence of TTIs and their association with blood group, among the blood donors of Delhi. Blood group was determined by hem-agglutination using Gel card. HIV, HBV, and HCV test was performed by ELISA, syphilis by RPR and MP rapid card method. A total Transfusion Transmissible Infections (TTIs) such as human immune-deficiency virus (HIV-I/II), hepatitis B virus (HBV), Hepatitis C virus (HCV), Malaria parasite (MP) and syphilis can spread through contaminated blood or blood products. The present study was designed to analyze the prevalence of TTIs and their association with blood group, among the blood donors of Delhi. Blood group was determined by hem-agglutination using Gel card. HIV, HBV, and HCV test was performed by ELISA, syphilis by RPR and MP rapid card method. A total of 345(2.038%) blood donors were positive for TTIs. Prevalence of HBV, HCV, HIV-I/II, syphilis and MP were 188(1.111%), 73(0.431%), 34(0.201%), 49(0.29%) and 1(0.006%) respectively. Our result shows a trend of decrease in prevalence of TTIs; 2.267%, 2.111% and 1.614% between the year 2020, 2021 and 2022 respectively. Significant association of syphilis infection (P=0.036) and HCV infection (P=0.012) with ABO blood group antigen was observed. Blood group O donors were 1.81 times more infected with syphilis compared to donor having A and B antigen. Donors having blood group antigen B were 1.80 times more infected with HCV compared to donor not having B antigen. HBV and HIV prevalence found to be not associated with ABO and Rh blood group antigens. A low prevalence of TTIs positivity was observed among blood donors. Public awareness, proper counseling, medical examination and testing can help to minimize TTIs. Our study results shows ABO blood group has an association with HCV and VDRL infection.

12.
Bioinformation ; 19(5): 576-581, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37886143

RESUMEN

Blood groups had associations with many diseases that affect blood transfusion services by increasing or decreasing the blood demand of particular blood group. The present study was designed to compare the frequency of ABO and Rh blood groups among blood donors and blood component recipients. The ABO and Rh(D) blood groups of donors and recipients were determined using Gel card method. The frequency of blood donors and blood component recipients from January 1, 2020, to December 31, 2023, at regional blood transfusion centre of Delhi, were compared using χ² test. The ABO blood group frequencies of blood donors (n=23025) were: A(23.1%), B(37.53%), AB(10.09%), and O(29.29%). The blood issue (n=20255) was significantly (p=0.0000) higher in A(24.96%), B(39.92%), and lower in AB(9.76%) and O(25.37%). The RDP issue (n=7239) was significantly (p=0.0000) higher in A(24.71%), B(39.34%), and AB(11.53%) and lower in O(24.41%). The FFP issue (n=4164) was significantly (p=0.00024) higher in AB (12.3%) and lower in A (22.05%), B(37.32%), and O(28.14%). The difference between the blood donor frequencies of Rh(D)+Ve(95.19%) and Rh(D)-Ve(4.81%) and the blood issued by Rh(D)+Ve(95.06%) and Rh(D)-Ve(4.94%) was statistically not significant(P=0.52).Blood issues were higher in blood group A and B than in O, platelet issues were higher in A, B and AB than in O, and FFP issues were higher in the AB. Non-O blood groups may have a higher frequency of blood transfusions, while O blood groups may have a protective influence against diseases due to their innate immune response.

13.
Blood Sci ; 5(3): 209-217, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37546709

RESUMEN

The unforeseen and uncertain life-threatening situation of the COVID-19 pandemic dramatically affected all areas of the human daily work schedule. This study was designed to assess the impact of the COVID-19 pandemic on blood transfusion services and discuss the adopted confrontation measures for uninterrupted blood supply during the pandemic situation. The data on blood donation, blood component preparation, and issue from January 2019 to December 2022 were collected from the inventory registers of the RBTC, Delhi, India. Compared to the non-pandemic year 2019, during the year 2020, all variables decreased gradually. The observed maximum decrease in variables such as blood collection (-79.16%) in the month of October, blood issue (-71.61%) in the month of August, random donor platelets (RDP) preparation (-98.09%) in the month of October, RDP issue (-86.08%) in the month of September, fresh frozen plasma (FFP) preparation (-100%) in the month of October, and FFP issue (-96.08%) in the month of July with an annual decrease of -45.52%, -42.87%, -33.00%, -59.79%, -40.98%, and -54.48%, respectively, as compared to year 2019. Compared to year 2020, in year 2021, the annual increase in blood collection, blood issue, FFP preparation, FFP issue, RDP preparation, and RDP issue was +50.20%, +21.68%, +65.31%, +78.52%, +116.23%, and +213.30%, respectively. Our study results show that the COVID-19 pandemic has significantly affected blood transfusion services at our blood bank. The adopted coping strategies to maintain the safe and uninterrupted blood transfusion chain at our blood bank gave us lessons for future preparedness if faced with a similar situation.

14.
Bioinformation ; 19(4): 385-391, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37822811

RESUMEN

The ABO and Rh blood group phenotypes, alleles, and genotype frequencies have many biological and medical implications. The frequency differs broadly according to races, geographical borders and ethnicity, even within the same region. This study was designed to determine the frequency of ABO and Rh blood groups among blood donors attending the regional blood transfusion centre in Delhi. The gel card method was used to determine the ABO and Rh(D) blood groups of donors who donated blood between January 1, 2020, and June 30, 2022. The assumption of Hardy-Weinberg equilibrium was used to determine allele and genotype frequencies of blood donors. A total of 16,925 blood units were donated during the study period. Donors phenotype frequencies of ABO were as follows: 'A' (23.88%), 'B' (37.38%), 'AB' (9.97%) and 'O '(29.27%). Rh(D)+Ve (D) were (94.9%) and Rh(D)-Ve (d) were (5.01%), which follow an order of B > O > A > AB and Rh-D > d for Rh. Donors ABO and Rh (D) allele frequencies were IA-0.183, IB-0.277, IO-0.541 and ID-0.776, Id-0.224 respectively. Allele frequencies follow an order of IO > IB > IA and Rh- ID > Id. Donors ABO genotype frequencies were AA-0.0333, AO-0.198, BB-0.0768, BO-0.30, AB-0.101, OO-0.293 and Rh(D) genotype frequencies were DD-0.602, Dd-0.347, dd-0.0501. Genotype frequencies follow an order of BO > OO > AO > AB > BB > AA and DD > Dd > dd. Among our donors, which were mostly from northern India, the ABO and Rh(D) blood groups have the highest proportion of ABO-B and Rh(D)+Ve and the lowest proportion of ABO-AB and Rh(D)-Ve, with a stable order of B > O > A > AB and D > d for phenotype, IO > IB > IA and ID > Id for allele and BO > OO > AO > AB > BB > AA and DD > Dd > dd for genotype.

15.
Bioinformation ; 19(4): 362-368, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37822830

RESUMEN

Regular blood transfusion is a lifesaving treatment for thalassemia patients; however, it exposes them to multiple alloantigens. The present study was designed to assess the frequency of alloantibodies in thalassemia patients receiving multiple blood transfusions. Blood samples were tested by Gel card method for ABO, Rh, Direct Antiglobulin Test (DAT), Indirect Antiglobulin Test (IAT), Auto Control (AC) and presence of alloantibody. Alloantibody screening and identification were performed using commercial 3-cell and 11-cell identification panels. Of a total of 66 thalassemia patients, 37 were male and 29 were female, with a mean age of 15.63±5.93 years and a range of 4.0 to 29.0 years. The ABO profiles of thalassemia patients were B-33, A-19, O-11, and AB-3, with 63 Rh-D positives and 3 Rh-D negatives. An average of 533.39±284.95 units were transfused an average of 304±119.65 times. Positive cases for DAT were 29(43.93%), AC was 26(39.39%) and IAT was 4(6.06%). Nine (13.636%) patients had developed alloantibodies, in which anti-K was seen in 5(27.77%), anti-Kpa in 4(22.22%), anti-C in 3(16.66%), anti-Cw in 3(16.66%), anti-D in 1(5.55%), anti-Lea in 1(5.55%), anti-Lua in 1 (5.55%). Alloantibodies were single in 4(44.44%) and multiple in 5(55.55%) patients. The rate of alloimmunization and positivity of DAT, AC, ICT, and splenectomy were significantly associated with higher age, the number of units transfused, and also the number of times of transfusion. Every new thalassemia patient needs extended blood group typing prior to the start of a blood transfusion and antigen-matched blood. For patients with alloantibodies, corresponding antigen-negative blood must be selected for cross-matching.

16.
Catheter Cardiovasc Interv ; 80(5): 735-43, 2012 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-22121113

RESUMEN

BACKGROUND: Management of elderly patients with acute coronary syndromes (ACS) is not standardized and physicians discretion for invasive versus conservative strategies lacks sufficient evidence. The purpose of this analysis was, therefore, to evaluate treatment strategies and outcomes of elderly patients with ACS and to highlight reasons for the treatment decision in a consecutive series of elderly patients. METHODS: This is a retrospective analysis of 1,001 elderly patients (>75 years) presenting with ACS. Patients were identified on the basis of their final discharge diagnosis. Baseline data, past medical history, cardiac and noncardiac concomitant diseases, treatment strategy, and adverse outcomes were evaluated, using patient's charts. Various co-variates were used to determine the association or predictive value of these co-variates to the invasive versus conservative management of the subjects. Thirty-day mortality and long-term survival were assessed either directly or in discharged patients via telephone interview with the patients, the patients' relatives or the primary care physicians. RESULTS: A total of 776 (77.5%) patients were treated invasively and 225 (22.5%) conservatively. Logistic regression analysis revealed that patients with advanced age, Killip class > II, pre-existing coronary artery disease, prior stroke, pre-existing renal failure, obesity, non-ST-elevation myocardial infarction, prior ACS, and the presence of supraventricular arrhythmias were significantly more likely to undergo conservative treatment. In-hospital mortality was significantly higher in conservatively treated patients (P < 0.001). CONCLUSION: In this retrospective analysis, we identified age as the main predictor for a conservative treatment strategy in elderly patients, albeit an invasive strategy was associated with a significantly better outcome.


Asunto(s)
Síndrome Coronario Agudo/terapia , Fármacos Cardiovasculares/uso terapéutico , Técnicas de Apoyo para la Decisión , Síndrome Coronario Agudo/mortalidad , Factores de Edad , Anciano , Anciano de 80 o más Años , Distribución de Chi-Cuadrado , Comorbilidad , Femenino , Mortalidad Hospitalaria , Hospitales Comunitarios , Humanos , Estimación de Kaplan-Meier , Modelos Logísticos , Masculino , Selección de Paciente , Intervención Coronaria Percutánea/efectos adversos , Intervención Coronaria Percutánea/instrumentación , Intervención Coronaria Percutánea/mortalidad , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Stents , Factores de Tiempo , Resultado del Tratamiento
17.
J Biomol Struct Dyn ; 40(1): 565-571, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-32835626

RESUMEN

Garlic, as well as several natural food ingredients such as basil, ginger, turmeric, cinnamon, clove, pepper etc., has long been traditionally used as routine anti-viral and anti-bacterial remedy. Allyl methyl sulfide (AMS) is reportedly a persistent main active metabolite component of allicin after garlic ingestion accounting for at least 90% of the allicin consumed. Several studies have reported the presence of AMS in organs such as lung, kidney etc. and body fluids such as mucous, and blood-plasma. Glycoproteins of enveloped viruses are actively involved in viral pathogenesis. N-acetylneuraminic acid (sialic acid) and N-Acetylglucosamine, are some of the vital amino acids involved in several viral infections using glycoproteins via glycosylation. Simulations studies based on First-principles density functional theory show that these amino acids attach with AMS, and the reactions are thermodynamically spontaneous (ΔG and ΔS negative are at 310.15 K as well as lower and higher temperatures). Further, phospholipid phosphatidylethanolamine (a component of some viral envelops) also attaches readily with AMS and the reaction is spontaneous. AMS molecules attachment with viral phospholipids and amino-acids involved in viral infection would denature the virus and prevent its attachment to the host cell.Communicated by Ramaswamy H. Sarma.


Asunto(s)
Ajo , Virosis , Compuestos Alílicos , Aminoácidos , Disulfuros , Humanos , Fosfolípidos , Sulfuros , Virosis/tratamiento farmacológico
18.
Europace ; 13(4): 492-8, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21278151

RESUMEN

AIMS: Image integration of three-dimensional (3D) reconstructions of left atrial (LA) and pulmonary vein (PV) anatomy into electroanatomical mapping (EAM) plays a major role in atrial fibrillation (AF) ablation. Point-by-point EAM is commonly used for registration of imported LA and PV anatomy. We aimed to assess the accuracy of intraprocedural rotational angiography-based LA imaging registered by spatial reconstruction of intracardiac echocardiography (ICE) in patients undergoing AF ablation. METHODS AND RESULTS: Twenty-two patients (11 males, 66 ± 12 years) were studied. Reconstructions of LA and PVs based on rotational angiography were registered by a second 3D reconstruction based on ICE. In a second step, EAM points were added to ICE 3D reconstructions. A 3D image of the LA and PVs was reconstructed in all patients by both imaging modalities. Rotational angiography and ICE-based LA 3D reconstructions took 11.5 ± 5.2 and 20.4 ± 11.2 min, respectively. A total of 17 ± 6 two-dimensional ICE fans were used for spatial reconstruction of ICE. The deviation between the two 3D shells was 2.6 ± 0.5 mm. Integration of 78 ± 58 EAM points into ICE 3D reconstruction did not significantly reduce the deviation to rotational angiography-based reconstructions (2.7 ± 0.6 mm). All PVs were isolated successfully. CONCLUSIONS: Intraprocedural 3D reconstruction of LA and PVs for ablation of AF is feasible based on both rotational angiography and ICE. LA reconstructions based on rotational angiography can accurately be registered using 3D ICE shells. Additional EAM does not enhance accuracy. Therefore, registration of rotational angiography-based 3D reconstructions by 3D reconstructions from ICE seems to be an alternative technique to support AF ablation.


Asunto(s)
Angiografía/métodos , Fibrilación Atrial/cirugía , Técnicas de Imagen Cardíaca/métodos , Ablación por Catéter , Ecocardiografía/métodos , Atrios Cardíacos/diagnóstico por imagen , Anciano , Estudios de Factibilidad , Femenino , Humanos , Imagenología Tridimensional/métodos , Masculino , Persona de Mediana Edad , Monitoreo Intraoperatorio/métodos , Venas Pulmonares/diagnóstico por imagen , Venas Pulmonares/cirugía
19.
Europace ; 13(5): 675-82, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21310732

RESUMEN

AIMS: Rotational angiography (RA) of the coronary sinus (CS) provides more anatomical insights compared with static angiographies. We evaluated intraprocedural three-dimensional (3D) CS reconstruction (RC) based on RA, using syngo(®) DynaCT Cardiac to guide CS lead implantation. METHODS AND RESULTS: In 24 patients with indication for cardiac resynchronization therapy, intraprocedural RA and 3D RC of the CS was performed. Lead placement was guided by 3D image integration into real-time fluoroscopy. Rotational angiography and 3D RCs were evaluated regarding visibility of the CS and tributaries, CS-to-target vein angles, and vessel diameters. The target vein for CS lead implantation, identified by RA, was successfully displayed by 3D RC in 20 (91%) of 22 patients with adequate RA. All lead implantations were guided successfully by 3D image integration into real-time fluoroscopy. Cranial or caudal angulations were used in 95% of the procedures without further angiographies. Rotational angiography displayed a mean of 2.9 ± 1.0 second-order side branches compared with 1.8 ± 1.1 in 3D RCs (P< 0.05). The CS-to-target vein angle estimated from static projections (right anterior oblique 20°, left anterior oblique 40°, and even optimal RA view) differed substantially from 3D RCs. Main vessel diameters did not differ significantly between both techniques. CONCLUSION: Intraprocedural 3D RC of the CS and 3D image integration-guided lead placement is feasible. Coronary sinus-to-target vein angles seemed to be misestimated even by RA views compared with 3D RC. Thus RA and 3D CS RC should be applied routinely for CS lead implantation.


Asunto(s)
Terapia de Resincronización Cardíaca/métodos , Angiografía Coronaria/métodos , Seno Coronario/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/terapia , Anciano , Electrodos Implantados , Estudios de Factibilidad , Femenino , Fluoroscopía/métodos , Humanos , Imagenología Tridimensional/métodos , Masculino , Persona de Mediana Edad , Venas
20.
Europace ; 13(12): 1688-94, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21784744

RESUMEN

AIMS: In pacemaker patients with preserved atrio-ventricular (AV) conduction, atrial fibrillation (AF) can lead to symptomatic ventricular rate irregularity and loss of ventricular stimulation. We tested if dynamic ventricular overdrive (DVO) as a potentially pacemaker-integrated algorithm could improve both aspects. METHODS AND RESULTS: Different settings of DVO and ventricular-ventricular-inhibited-pacing (VVI) with different base rates were tested in two consecutive phases during electrophysiological studies for standard indications. Mean heart rate (HR), HR irregularity and percentage of ventricular pacing were evaluated. A fusion index (FI) indicative of the proportion of fusion beats was calculated for each stimulation protocol. Dynamic ventricular overdrive from the right ventricular apex was acutely applied in 38 patients (11 females, mean age 62.1 ± 11.5 years) with sustained AF and preserved AV conduction. Dynamic ventricular overdrive at LOW/MEDIUM setting increased the amount of ventricular pacing compared with VVI pacing at 60, 70, and 80 beats per minute (bpm; to 81/85% from 11, 25, and 47%, respectively; P < 0.05). It also resulted in a maximum decrease in interval differences (to 48 ± 18 ms from 149 ± 28, 117 ± 38, and 95 ± 46 ms, respectively; P < 0.05) and fusion (to 0.13 from 0.41, 0.42, and 0.36, respectively; P < 0.05) compared with VVI pacing at 60, 70, and 80 bpm. However, the application of DVO resulted in a significant increase in HR compared with intrinsic rhythm and VVI pacing at 80 bpm (to 97 bpm from 89 and 94 bpm, respectively; P < 0.05). CONCLUSION: Dynamic ventricular overdrive decreases HR irregularity and increases ventricular pacing rate compared with VVI pacing at fixed elevated base rates and spontaneous rhythm. Fusion index might help to refine information on pacing percentages provided by device counters.


Asunto(s)
Algoritmos , Fibrilación Atrial/fisiopatología , Terapia de Resincronización Cardíaca/métodos , Sistema de Conducción Cardíaco/fisiopatología , Frecuencia Cardíaca/fisiología , Ventrículos Cardíacos/fisiopatología , Anciano , Fibrilación Atrial/terapia , Nodo Atrioventricular/fisiopatología , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Marcapaso Artificial/clasificación , Posición Supina
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA