RESUMEN
MnFe(P,Ge) is a promising magnetocaloric material for potential refrigeration applications near room temperature. However, its relatively large hysteresis and large temperature/field range of two-phase [paramagnetic (PM) and ferromagnetic (FM)] coexistence displayed in the cyclic first order magnetic transition (FOMT) cause energy losses and reduce the energy conversion efficiency. In this work, we explore the underlying causes of phase coexistence, hysteresis and structural transformation based on determination of the Ge distribution in MnFeP1-xGex (0.10 < x < 0.50) materials. We find that all the samples crystallize in the Fe2P-type structure [P6[combining macron]2m (No. 189), Z = 3] and Ge displays a strong preference for the 2c site. First principles total energy calculations confirm this site preference of Ge, and Ge entering the 2c site changes the electronic structures and enhances the Fe and Mn 3d exchange splitting across the Fermi level as well as the FM exchange interactions, consequently leading to a linear increase in the transition temperature with increasing Ge content. Scanning electron microscopy and energy-dispersive spectroscopy reveal the inhomogeneous distribution of Ge in grains, which makes the grains with larger Ge content transform from the PM to the FM phase first when cooling and thus causes the phase coexistence. Maximum entropy method electron-densities show that weakening the coplanar Fe-P/Ge(2c) and Mn-P(1b) bonding strengths across the PM to FM phase transition can release some 3d-electrons to enhance the Fe-Mn FM exchange interaction and result in coupling between the magnetic and structural degrees of freedom. This provides first direct evidence for the dominant role of Fe-Mn exchange interaction in the ferromagnetic ordering and may provide a method to observe the exchange interaction. Diminishing the variances in covalent bonding strengths across the FOMT gives rise to an exponential decay in the heat hysteresis when increasing the Ge occupancy at the 2c site. To the best of our knowledge, this is the first time a relationship between the variances in covalent bonding strengths and hysteresis is proposed. This material thus provides an example of a FOMT and hysteresis driven by reversible weakening and strengthening of covalent bonds. Based on these, a strategy of designing better magnetocaloric materials is suggested.
RESUMEN
BACKGROUND: The increase in blaNDM-1 in Enterobacteriaceae has become a major concern worldwide. In previous study, we investigated clonal dissemination and mechanisms of resistance to carbapenem in China. METHODS: We carried out retrospective surveillance for blaNDM-1 among carbapenem-resistant enterobacter strains, which were isolated from patients at our hospital by bacterial strains selection, antimicrobial susceptibility testing, species identification, and molecular detection of resistance gene. RESULTS: We found three blaNDM-1 -positive isolates which were identified as Enterobacter aerogenes in clinical patients in China. The blaNDM-1 -positive Enterobacter aerogenes isolates were first found. CONCLUSION: It is important to mandate prudent usage of antibiotics and implement infection control measures to control the spread of these resistant blaNDM-1 -positive strains.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Enterobacter aerogenes/genética , beta-Lactamasas/genética , China , Enterobacter aerogenes/efectos de los fármacos , Enterobacter aerogenes/aislamiento & purificación , Infecciones por Enterobacteriaceae/microbiología , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
PURPOSE: To identify age risk factors of early recurrent intussusception after pneumatic enema reduction. Management opinions are proposed. METHODS: Two thousand two hundred and ninety-five intussusception patients' medical records from January 2009 to December 2011 were retrospectively reviewed and analyzed. RESULTS: Of the 2295 patients, the intussusception of 1917 of them was initially reduced by pneumatic enema, with 127 cases recurring within 72 h. The early recurrence rate is 6.62%. The early recurrence rate of patients younger than 1 year old is 2.1% (22/1032), while the rate for those older than 1 year is 11.9% (105/885). The difference is significant (P = 0.0001). There were no significant differences between age groups older than 1 year. One hundred and seventeen cases of recurrence happened within 48 h, which accounted for 92.1% of all early recurrence. Recurrence patients were treated again with pneumatic enema, with a successful reduction in 93.7%. They were followed up for 2-4 years; the long-term recurrent rate was 11.8% (14/119). No patient had poor prognosis because of delayed treatment. CONCLUSION: Intussusception patients older than 1 year tend to have greater early recurrence rate after pneumatic enema reduction; 92.1% of the early recurrent cases happened in 48 h. There is no need to hospitalize patients after pneumatic enema reduction. A repeat pneumatic enema is a good choice before surgical approach.
Asunto(s)
Enema/métodos , Intususcepción/terapia , Aire , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Recurrencia , Factores de Riesgo , Resultado del TratamientoRESUMEN
BACKGROUND: Communicating bronchopulmonary foregut malformation (CBPFM) type IA is extremely rare and is associated with a high mortality rate. This malformation manifests with communication between the lung and the foregut, and this can lead to esophageal atresia and tracheoesophageal fistula (EA-TEF) to the distal pouch. PURPOSE: To detail radiographic findings of CBPFM type IA cases and to summarize an appropriate therapeutic strategy for the management of this disorder. METHODS: Medical data for two patients with CBPFM type IA were retrospectively reviewed with regard to radiographic characteristics, therapy, and outcome. RESULTS: Both cases were initially misdiagnosed due to the presence of EA-TEF. Unusual atelectasis of the lateral lung was observed in chest radiographs, while non-aerated hypoplastic right lung and agenesis of the right main bronchus were detected by computed tomography. A final diagnosis was made by esophagogram. Only one patient survived following surgery. CONCLUSION: CBPFM type IA is a rare condition and is extremely difficult to diagnose. However, CBPFM type IA should be suspected in patients manifesting EA and atelectasis of a unilateral lung on a chest radiograph. The decision to perform a pneumonectomy or bronchoplasty depends on the degree of exiting permitted due to pulmonary damage assessed by computed tomography.
Asunto(s)
Bronquios/anomalías , Broncografía , Atresia Esofágica/diagnóstico por imagen , Pulmón/anomalías , Pulmón/diagnóstico por imagen , Fístula Traqueoesofágica/diagnóstico por imagen , Bronquios/cirugía , Atresia Esofágica/cirugía , Resultado Fatal , Humanos , Recién Nacido , Pulmón/cirugía , Masculino , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Fístula Traqueoesofágica/cirugíaRESUMEN
RATIONALE: Tobacco-specific N-nitrosamines (TSNAs) mainly include 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosonornicotine (NNN), N-nitrosoanabasine (NAB) and N-nitrosoanatabine (NAT) that are formed from tobacco alkaloids during the curing process and contained in tobacco and tobacco smoke. They are linked with carcinogenesis. Analytical methods for quality control of products and determination of their metabolites are therefore of great importance. METHODS: The characteristic fragmentation behaviors of tobacco-specific TSNAs have been studied by electrospray ionization multistage tandem mass spectrometry. The deutero-labeled TSNA compounds have also been employed to clarify the fragmentation mechanism, which further confirms the proposed fragmentation patterns. RESULTS: Detailed analysis of the resultant fragments shows there are two different kinds of fragmentation patterns with the general fragment backbone of pyrrolidine or piperidine rings. In one route, pyrrolidine or piperidine rings undergo direct fragmentation and form some stable intermediates without affecting the parent rings. The other, however, involves ring opening and then ring closure at the pyridine-2 carbon atom to form multi-membered rings. CONCLUSIONS: This characteristic fragmentation behavior therefore provides useful information on identification of TSNAs that may be used to monitor such kinds of compound in the biological metabolism.
Asunto(s)
Deuterio/química , Nicotiana/química , Nitrosaminas/análisis , Nitrosaminas/química , Extractos Vegetales/análisis , Extractos Vegetales/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Algoritmos , Marcaje IsotópicoRESUMEN
BACKGROUND: Influenza in children is a major cause of morbidity and mortality worldwide. Nervous system diseases are a factor relating to increased mortality rate. However, reports of how these underlying diseases contribute to the death of children with influenza are rare. CASE SUMMARY: A 4-year-old-girl developed type A influenza-related encephalopathy (IAE) with seizures, acute disorder of consciousness, and intracranial hypertension (cerebrospinal fluid pressure: 250 mmH2O), and the Dandy-Walker variant was found by her first magnetic resonance imaging (MRI) when admission. Three days later, she suddenly presented anisocoria, acute pulmonary edema, and coma, and the later MRI found that she had compressed brainstem, oblongata "Z-like folding", and swelling bilateral basal ganglia. After admission, the patient were tested for routine and special biomarkers and underwent neuroimaging and neuroelectrophysiology examinations as well as Oseltamivir and intravenous immunogloblin treatments. When predicting that unstable intracranial structures detected by MRI might have disastrous consequences in the progression of IAE, she was transferred into the pediatric intensive care unit and underwent continuous assessment of clinical condition while she did not have instability of basic vital signs; at the same time, her parents were fully informed about the risk and prognosis. Although she was ultimately dead from brain stem failure, the parents expressed understanding and did not trigger a doctor-patient conflict. CONCLUSION: In case of finding an unstable intracranial structure, intensive care should be given to IAE patient and their clinical condition should be monitored continuously.
RESUMEN
In the asymmetric unit of the title compound, catena-poly[[diaqua-magnesium(II)]-µ-oxalato], [Mg(C(2)O(4))(H(2)O)(2)](n), there is one Mg atom in an octa-hedral coordination with site symmetry 222, a unique C atom of the oxalate anion lying on a twofold axis, an O atom of the anion in a general position and a water O atom at a site with imposed twofold rotation symmetry. The Mg(2+) ions are ligated by water mol-ecules and bridged by the anions to form chains that are held together by O-Hâ¯O hydrogen bonds. The structure of the title compound has already been reported in a different space group [Lagier, Pezerat & Dubernat (1969 â¶). Rev. Chim. Miner.6, 1081-1093; Levy, Perrotey & Visser (1971 â¶). Bull. Soc. Chim. Fr. pp. 757-761].
RESUMEN
The title compound, {Na(2)[Mg(2)(C(2)O(4))(3)(H(2)O)(2)]}(n), is isotypic with its Co analogue. There are two crystallographically independent oxalate groups in the asymmetric unit, one lying on an inversion center and the other on a general position. Mg(2+) ions are ligated by H(2)O mol-ecules and bridged by tri- and tetra-dentate oxalate ligands, forming ladder-like double chains that are held together via O-Hâ¯O hydrogen bonds, with Na(+) cations located between the chains to balance the charge.
RESUMEN
Two new penta-borates, tris-odium zinc cadmium penta-borate, Na3Zn0.912Cd0.088B5O10, and tris-odium zinc magnesium penta-borate, Na3Zn0.845Mg0.155B5O10, have been synthesized by high-temperature solution reactions at 1023â K. Their crystal structures were determined by single-crystal X-ray diffraction. Both solid solutions crystallize in the ortho-rhom-bic form of the parent compound Na3ZnB5O10 (space group type Pbca, Z = 8) and contain the double ring [B5O10]5- anion composed of one BO4 tetra-hedron and four BO3 triangles as the basic structural motif. The anions are bridged by tetra-hedrally coordinated and occupationally disordered M2+ (M = Zn/Cd, Zn/Mg) cations via common O atoms to form [MB5O10] n3n- layers. The intra-layer inter-secting channels and the inter-layer voids are occupied by Na+ cations to balance the charge.
RESUMEN
OBJECTIVE: To observe the effect of S100A4 gene silencing mediated by small interfering RNA (siRNA) on the proliferation of bladder cancer stem cells (CSCs) and their capacity of xenograft tumor formation. METHODS: MB49 bladder cancer stem cells (MCSCs) were isolated and identified. The differentially expressed protein S100A4 was identified in MCSCs using isobaric tags for relative and absolute quantitation technology (iTRAQ). A siRNA targeting S100A4 was constructed and transfected into MCSCs, and its inhibitory effects on S100A4 expression in MCSCs were assessed with Western blotting and qPCR. The effects of siRNA-mediated S100A4 silencing on the proliferation and xenograft tumor formation ability of MCSCs were observed. RESULTS: Among the 65 differentially expressed proteins identified by iTRAQ combined with LC/MS/MS, S100A4 protein showed the most distinct differential expression in MCSCs. Transfection of MCSCs with S100A siRNA significantly inhibited the expressions of S100A4 at both mRNA and protein levels, caused obvious suppression of the cell proliferation, and attenuated the xenograft tumor formation ability of the cells in nude mice. CONCLUSION: S100A4 in MCSCs is associated with the recurrence and metastasis of bladder cancer. S100A4 may serve as a potential therapeutic target for eliminating bladder CSCs.
RESUMEN
AIM: To investigate whether chronic bacterial prostatitis might increase oxidative stress and oxidative damage in chronic bacterial prostatitis patients (CBPP), and to explore its possible mechanism. METHODS: Enrolled in a case-control study were 70 randomly sampled CBPP and 70 randomly sampled healthy adult volunteers (HAV), on whom plasma nitric oxide (NO), vitamin C (VC), vitamin E (VE) and beta-carotene (beta-CAR) level, erythrocyte malondialdehyde (MDA) level, as well as erythrocyte superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were determined by spectrophotometry. RESULTS: Compared with the HAV group, values of plasma NO and erythrocyte MDA in the CBPP group were significantly increased (P < 0.001); those of plasma VC, VE and beta-CAR as well as erythrocyte SOD, CAT and GPX activities in the CBPP group were significantly decreased (P < 0.001). Findings from partial correlation for the 70 CBPP showed that with prolonged course of disease, values of NO and MDA were gradually increased (P < 0.001), and those of VC, VE, beta-CAR, SOD, CAT and GPX were gradually decreased (P < 0.05-0.001). The findings from stepwise regression for the 70 CBPP suggested that the model was Y = -13.2077 + 0.1894MDA + 0.0415NO - 0.1999GPX, F = 18.2047, P < 0.001, r = 0.6729, P < 0.001. CONCLUSION: The findings suggest that there exist increased oxidative stress and oxidative damage induced by chronic bacterial prostatitis in the patients, and such phenomenon was closely related to the course of disease.
Asunto(s)
Infecciones Bacterianas/fisiopatología , Estrés Oxidativo/fisiología , Prostatitis/microbiología , Adulto , Ácido Ascórbico/sangre , Infecciones Bacterianas/sangre , Estudios de Casos y Controles , Catalasa/sangre , Eritrocitos/metabolismo , Glutatión Peroxidasa/sangre , Humanos , Masculino , Malondialdehído/sangre , Óxido Nítrico/sangre , Prostatitis/sangre , Prostatitis/fisiopatología , Valores de Referencia , Superóxido Dismutasa/sangre , Vitamina E/sangre , beta Caroteno/sangreRESUMEN
OBJECTIVE: To investigate whether chronic bacterial prostatitis (CBP) increases oxidative stress and damage in patients with CBP, and to explore its possible mechanism. METHODS: Eighty patients with CBP and 80 healthy adults as controls were enrolled in a case-control study, in which levels of nitric oxide (NO), vitamin C (VC), and vitamin E (VE) in plasma, as well as malondialdehyde (MDA), activities of superoxide dismutase (SOD), and catalase (CAT) in erythrocytes were determined by spectrophotometry. RESULTS: Compared with the average values of NO, VC, VE, MDA, SOD, and CAT in the healthy control group, those of plasma NO and erythrocyte MDA in the CBP group were significantly increased (P < 0.001), and those of plasma VC and VE as well as erythrocyte SOD and CAT in the CBP group were significantly decreased (P < 0.001). Findings from partial correlation analysis for course of the disease and NO, VC, VE, MDA, SOD, and CAT in 80 patients with CBP, adjusted for age, suggested that with prolonged course of the disease, values of NO and MDA were gradually increased (P < 0.001), and those of VC, VE, SOD, and CAT were gradually decreased (P < 0.05-0.001). The findings from stepwise regression analysis for course of the disease and NO, VC, VE, MDA, SOD, and CAT in CBP group suggested that the model of stepwise regression was Y = -19.1160 + 0.3112MDA + 0.0337NO, F = 22.1734, P < 0.001, r = 0.6045, P < 0.001. The findings from the reliability analysis for VC, VE, SOD, CAT, NO, and MDA in the CBP group showed that the reliability coefficients' alpha (6 items) was 0.7195, P < 0.0001, and the standardized item alpha was 0.9307, P < 0.0001. CONCLUSION: There exist increased oxidative stress and damage induced by chronic bacterial prostatitis in patients, and such a phenomenon is closely related to the course of disease.
Asunto(s)
Estrés Oxidativo , Prostatitis/sangre , Adulto , Ácido Ascórbico/sangre , Estudios de Casos y Controles , Catalasa/metabolismo , Eritrocitos/enzimología , Humanos , Masculino , Malondialdehído/metabolismo , Óxido Nítrico/sangre , Prostatitis/diagnóstico , Espectrofotometría , Superóxido Dismutasa/metabolismo , Vitamina E/sangreRESUMEN
OBJECTIVE: To investigate whether overweight and obesity might cause oxidative stress and potential oxidative damage in overweight and obese children, and to explore its possible mechanism. METHODS: Eighty-five overweight and obese children (OOC), and eighty-five age-matched healthy children (HC) were recruited in this case-control study. The present study analyzed spectrophotometrically vitamin C (VC), vitamin E (VE), and 3-carotene (P-CAR) in plasma, as well as the activities of superoxide dismutase (SOD), catalase (CAT), and the level of malondialdehyde (MDA) in erythrocytes. RESULTS: Compared with those of VC, VE, P-CAR, SOD, CAT and MDA in the HC group, the average values of VC, VE, 3-CAR, SOD, and CAT in the OOC group were significantly decreased (P<0.001), while the average value of MDA in the OOC group was significantly increased (P<0.001). The regression analysis demonstrated that VC, VE, P-CAR, SOD, and CAT were negatively correlated (P<0.05-0.01), and MDA was positively correlated with BMI (P<0.05). Fitting to the model of multiple stepwise regression of BMI on VC, VE, P-CAR, SOD, CAT, and MDA in 85 OOC was Y= 27.0041 + 0.2541MDA - 2.1448beta-CAR - 0.0090CAT, where F= 43.8088, P<0.001, r = 0.7866, r(2)= 0.6187, adjusted r(2)= 0.6046. The findings from the reliability analysis for VC, VE, P-CAR, SOD, CAT, and MDA used to reflect increased oxidative stress and potential oxidative damage in the OOC showed that the reliability coefficients (alpha, 6 items) = 0.7231, P<0.0001, and that the standardized item alpha = 0.9207, P<0.0001. CONCLUSION: The present study suggests that there exists an increased oxidative stress in overweight and obese children.
Asunto(s)
Obesidad/metabolismo , Estrés Oxidativo/fisiología , Adolescente , Niño , Preescolar , Femenino , Humanos , MasculinoRESUMEN
OBJECTIVE: To investigate whether pregnancy-induced hypertension (PIH) may increase oxidative stress in women with PIH, and to explore the mechanisms by which PIH may increase oxidative stress and potential free radical damage. METHODS: Seventy women with PIH and seventy women with uncomplicated normotensive pregnancy (UNP) whose age, nutritional conditions, levels of hemoglobin and albumin were all matched, were enrolled in a randomized controlled trial. Their plasma concentrations of nitric oxide (NO), vitamin C (VC), vitamin E (VE), and beta-carotene (beta-CAR) as well as their erythrocyte malondialdehyde (MDA), and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were determined by spectrophotometry. RESULTS: Compared with average values of the above experimental parameters in the women with UNP, the average value of erythrocyte MDA in the women with PIH significantly increased (P<0.0001), while the average values of plasma NO, VC, VE, and beta-CAR as well as those of erythrocyte SOD, CAT, and GPX in the women with PIH significantly decreased (P<0.0005-0.0001). The findings from partial correlation analysis (controlling for age) for 70 women with PIH showed that with elevated systolic blood pressure (SBP) and diastolic blood pressure (DBP), MDA value gradually increased (P<0.001), and NO, VC, VE, beta-CAR, SOD, CAT, and GPX values gradually decreased (P<0.02-0.001). The findings from reliability analysis for NO, VC, VE, beta-CAR, SOD, CAT, GPX, and MDA values used to reflect increased oxidative stress and potential free radical damage in women with PIH showed that the reliability coefficients (alpha, 8 items) = 0.7062, P<0.0001, and the standardized item alpha = 0.9116, P<0.0001. CONCLUSION: The findings in the present research suggest that pregnancy-induced hypertension can increase oxidative stress and potential free radical damage in women with pregnancy-induced hypertension.
Asunto(s)
Hipertensión/metabolismo , Estrés Oxidativo , Complicaciones Cardiovasculares del Embarazo/metabolismo , Adulto , Estudios de Casos y Controles , Femenino , Radicales Libres/metabolismo , Humanos , EmbarazoRESUMEN
The title compound represents a new structure type, in which distorted VO6 octahedra are bridged by iodate groups to form infinite two-dimensional [VO2(IO3)2]- layers that are separated by octahedrally coordinated Li+ cations.
RESUMEN
Ga(IO(3))(3) crystallizes in the space group P6(3), with the Ga atom at a site with imposed threefold symmetry. The crystal structure consists of slightly distorted GaO(6) octahedra that are bridged by I atoms of IO(3)(-) groups, giving rise to a three-dimensional polar network. The framework contains unoccupied hexagonal channels running parallel to the hexagonal [001] direction. The iodate groups have their stereochemically active non-bonded electron pairs pointing in the same direction along [001], which creates the polarity in the structure. The I-O bond distances and O-I-O angles are normal, being in the ranges 1.783 (3)-1.847 (2) A and 94.68 (11)-99.61 (12) degrees , respectively.
RESUMEN
The crystal structure of Ce(IO3)3 consists of one-dimensional chains of edge-sharing CeO9 polyhedra which are crosslinked into two-dimensional layers through bridging IO3- groups. The layers are held together via long I...O contacts, resulting in an extended three-dimensional network. The I-O bond distances and O-I-O angles are normal, lying in the ranges 1.806 (4)-1.846 (4) A and 89.9 (2)-100.9 (2) degrees, respectively. The three crystallographically independent iodate groups all show different coordination modes.