Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
1.
Artigo em Chinês | MEDLINE | ID: mdl-37805804

RESUMO

Objective: To investigate the status of knowledge, attitude, and behavior of enteral nutrition implemented by nurses in burn intensive care unit (BICU) and analyze its influencing factors. Methods: A multi-center cross-sectional survey research method was used. On May 8th, 2022, 107 BICU nurses who met the inclusion criteria were selected from the burn departments of the First Affiliated Hospital of Army Medical University (the Third Military Medical University), Guangdong Provincial People's Hospital, the First Affiliated Hospital of Guangxi Medical University, the Affiliated Hospital of Qinghai University, the Second Affiliated Hospital of Air Force Medical University, the Affiliated Hospital of Nantong University, Guiyang Steel Factory Staff Hospital, and the Second Affiliated Hospital of Kunming Medical University. The self-made nurses' enteral nutrition nursing knowledge-attitude-behavior questionnaire for severely burned patients was used to investigate the nurses' gender, age, working years, professional title, position, highest educational background, and whether they received systematic training in knowledge of enteral nutrition, the scores of each factor, and the total scores of knowledge, attitude, and behavior dimensions of enteral nutrition in nurses. The nurses were classified according to the general data, and the total scores of their knowledge, attitude, and behavior of enteral nutrition were calculated. Data were statistically analyzed with independent sample t test, one-way analysis of variance, Mann-Whitney U test, and Kruskal-Wallis H test. According to the results of univariate analysis and combined with clinical experience and significance, the generalized linear model analysis was carried out to screen the independent influencing factors of the total scores of knowledge, attitude, and behavior of enteral nutrition in BICU nurses. Results: A total of 107 nurses were surveyed, and 107 valid questionnaires were collected, with an effective recovery rate of 100%. In the BICU nurses' enteral nutrition knowledge-attitude-behavior questionnaire, the total scores of knowledge, attitude, and behavior were 44±13, 87±15, and 70±19, respectively. Most of the BICU nurses in this survey were female, aged 22-48 (31±6) years, and the number of nurses worked for 1-5, 6-10, and ≥11 years was evenly distributed. The majority of the professional titles of nurses were nurses, positions were responsible nurses, and the highest educational background was undergraduate. Forty-four nurses received systematic training in knowledge of enteral nutrition. There were statistically significant differences in the total scores of knowledge of enteral nutrition among BICU nurses with different ages, working years, professional titles, positions, highest educational background, and whether they received systematic training in knowledge of enteral nutrition (with H values of 27.36, 15.27, and 10.19, respectively, Z values of -3.33, -2.59, and -6.46, respectively, P<0.05). There were no statistically significant differences in the total scores of attitude and behavior of enteral nutrition among BICU nurses with different gender, ages, working years, professional titles, positions, highest educational background, and whether they received systematic training in knowledge of enteral nutrition (P>0.05). Age (26-30, 31-35, and ≥36 years old), highest educational background (undergraduate), and the systematic training received in enteral nutrition knowledge were the independent influencing factors for the total score of knowledge of enteral nutrition in BICU nurses (with 95% confidence intervals of 0.12-0.36, 0-0.30, 0.03-0.31, 0.01-0.32, and 0.19-0.40, respectively, standardized regression coefficients of 0.24, 0.15, 0.17, 0.17, and 0.29, respectively, P<0.05). There were no independent influencing factors for the total scores of enteral nutrition attitude and behavior of BICU nurses in different characteristics (P>0.05). Conclusions: The BICU nurses have low cognitive level in the implementation of enteral nutrition, their concept needs to be updated in time, and their behavior needs to be further standardized. Age (26-30, 31-35, and ≥36 years old), highest educational background (undergraduate), and the systematic training received in enteral nutrition knowledge were the independent influencing factors for the knowledge of enteral nutrition in BICU nurses.


Assuntos
Nutrição Enteral , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Feminino , Adulto , Masculino , Estudos Transversais , Nutrição Enteral/métodos , China , Unidades de Terapia Intensiva , Inquéritos e Questionários
2.
Zhonghua Jie He He Hu Xi Za Zhi ; 45(3): 276-281, 2022 Mar 12.
Artigo em Chinês | MEDLINE | ID: mdl-35279991

RESUMO

Objective: To better understand the clinical characteristics of pulmonary nocardiosis associated with bronchiectasis. Methods: Patients diagnosed as bronchiectasis complicated with pulmonary nocardiosis in 9 tertiary general hospitals in China were enrolled from March 2016 to March 2020, with the record of general data, imaging performance and pathogen. The literature was reviewed. Results: Totally 17 patients were included. There were 12 females and 5 males. The ages ranged from 45 to 79 years, with an average of (63±9) years. There were 15 nonsmokers and 2 smokers, all of whom with chronic course. The clinical manifestations were mostly cough, expectoration, hemoptysis, fever, and dyspnea. The imaging manifestation was bronchiectasis in both lungs, with the most common involvement in the left lower lung, right middle lobe and left lingual lobe. Sputum cultures were positive in 10 cases, bronchoalveolar lavage fluid (BALF) cultures were positive in 6 cases, and next generation gene sequencings were positive in 4 cases, including 2 cases of Nocardia gelsenkii, 2 cases of Nocardia abscess, 2 cases of Nocardia stellate, 1 case of Nocardia mexicana, 1 case of Nocardia otitis caviae, and 9 cases of undetermined Nocardia. There were 3 cases of Klebsiella pneumoniae, 2 cases of Pseudomonas aeruginosa and 2 cases of Aspergillus. The symptoms and imaging of all patients were improved after anti Nocardia therapy. Conclusions: Bronchiectasis combined with nocardiosis is more common in middle-aged and elderly women without smoking, which is similar to the clinical manifestations of Lady Windermere syndrome. Bronchiectasis often involves the left lower lobe, right middle lobe and left lingual lobe. Nocardia infection might further precipitate the initiation and progression of bronchiectasis.


Assuntos
Bronquiectasia , Nocardiose , Pneumonia , Idoso , Bronquiectasia/diagnóstico , Feminino , Hemoptise/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Nocardiose/diagnóstico , Escarro
3.
Nanoscale Adv ; 3(12): 3491-3496, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-36133728

RESUMO

Scientific interest in iron-oxides and in particular magnetite has been renewed due to the broad scope of their fascinating properties, which are finding applications in electronics and biomedicine. Specifically, iron oxide nanoparticles (IONPs) are gathering attraction in biomedicine. Their cores are usually constituted by a mixture of maghemite and magnetite phases. In view of this, to fine-tune the properties of an ensemble of IONPs towards their applications, it is essential to enhance mass fabrication processes towards the production of monodisperse IONPs with controlled size, shape, and stoichiometry. We exploit the vacancy sensitivity of the Verwey transition to detect the presence of magnetite. Here we provide direct evidence for the Verwey transition in an ensemble of IONPs through neutron diffraction. This transition is observed as a variation in the Fe magnetic moment at octahedral sites and, in turn, gives rise to a change of the net magnetic moment. Finally, we show this variation as the microscopic ingredient driving the characteristic kink that hallmarks the Verwey transition in thermal variation of magnetization.

4.
Zhonghua Yu Fang Yi Xue Za Zhi ; 53(10): 1007-1011, 2019 Oct 06.
Artigo em Chinês | MEDLINE | ID: mdl-31607046

RESUMO

Objective: We planned to evaluate the effectiveness of moving epidemic method (MEM) in calculating influenza epidemic threshold of 7 climatic zones in China mainland. Methods: The positive rate of influenza virus was obtained from the National Influenza Surveillance Network System from 2010/2011 to 2017/2018. We divided the 31 provinces into 7 climatic zones according to previous literatures and applied MEM to calculate the influenza epidemic threshold of 2018/2019 influenza season for these climatic zones. Sensitivity, specificity, positive predictive value and negative predictive value were calculated to evaluate the effectiveness of MEM. Results: Pre-epidemic threshold (the positive rate of influenza virus) varied from 9.66% (temperate zone) to 16.36% (subtropical zone) for 2018/2019 influenza season. The gap between pre-epidemic and post-epidemic thresholds was less than 5% except for plateau zone. The sensitivity was 86.16% (95CI:66.81%-98.23%), the specificity was 94.92% (95CI: 91.13%-98.41%), the positive predictive value was 89.87% (95%CI: 84.39%-94.38%), the negative predictive value was 92.96% (95%CI: 84.46%-99.17%). Conclusion: Overall, moving epidemic Method performs well in calculating influenza epidemic threshold in China, much better than the previous study.


Assuntos
Epidemias , Influenza Humana/epidemiologia , Orthomyxoviridae , China/epidemiologia , Clima , Humanos , Sensibilidade e Especificidade
5.
Zhonghua Xue Ye Xue Za Zhi ; 40(1): 63-68, 2019 Jan 14.
Artigo em Chinês | MEDLINE | ID: mdl-30704231

RESUMO

Objective: To investigate the effects of artesunate treatment on chronic graft-versus-host disease (cGVHD). Methods: Recipient BALB/c mice received 8 × 10(6) bone marrow cells with 8×10(6) spleen cells from B10D2 mice. Artesunate solubilized in acetone was injected intraperitoneally every day at the dose of 1 mg/kg at Day 28 after BMT. The clinical scores, survival and histopathological damage were analyzed. The frequency of Th17 and Tregs in PB and spleens from the mice were evaluated by flow cytometry. In addition, CD4(+) T cells from the spleens of mice were cultured in vitro, then stimulated with artesunate, the frequency of Th17 and Tregs in these splenocytes were evaluated by flow cytometry. Results: Artesunate administration diminished clinical and histopathological damage, and improved the survival of cGVHD mice[(46.57±7.83)% vs (55.71±6.99)%, χ(2)=5.457, P=0.020]; Artesunate contributed to Tregs development [(4.45±0.04)% vs (8.40±0.23)%, t=15.679, P<0.001; (6.62±0.24)% vs (10.48±0.48)%, t=6.587, P=0.003] while decreased Th17 cells [(1.51±0.18)% vs (0.58±0.19)%, t=7.233, P<0.001; (1.48±0.38)% vs (0.71±0.18)%, t=3.653, P=0.011] expressions in both PB and spleens, and decreased the Th17/Treg ratio (0.34±0.05 vs 0.09±0.03, t=7.621, P=0.002; 0.19±0.03 vs 0.06±0.02, t=6.993, P=0.002). Moreover, artesunate suppressed the Th17 cells expressions [(0.82±0.37) % vs (3.39±1.22) %, t=4.044, P=0.007] and contributed to Tregs development [(34.63±1.29) % vs (14.28±1.69) %, t=19.119, P<0.001], and also decreased the Th17/Treg ratio (0.24±0.09 vs 0.02±0.01, t=4.780, P=0.003) in vitro. Conclusions: Artesunate suppressed the Th17 cells expressions and contributed to Tregs development, which provided new sights into the development of a novel drug for cGVHD, e.g., artemisinin.


Assuntos
Doença Enxerto-Hospedeiro , Células Th17 , Animais , Artesunato , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T Reguladores
6.
Zhonghua Liu Xing Bing Xue Za Zhi ; 39(12): 1589-1595, 2018 Dec 10.
Artigo em Chinês | MEDLINE | ID: mdl-30572383

RESUMO

Objective: To analyze the epidemiological characteristics of notifiable infectious diseases among Chinese students from 2011 to 2016 and to provide reference for the effective prevention and control programs on infectious disease among students. Methods: Both morbidity and mortality of notifiable infectious diseases among Chinese students aged 6-22 years from 2011 to 2016 were analyzed, with main characteristics of the disease described. Results: During 2011 to 2016, morbidities of Categories A, B and C infectious diseases among the Chinese students aged 6-22 years showed a decreasing trend, from 248.24/100 000 in 2012 to 158.57/100 000 in 2016. Mortality rates of Category A, B and C infectious diseases had also decreased from 0.12/100 000 in 2011 to 0.07/100 000 in 2016. The average morbidity of the top four diseases from Category A and B infectious diseases appeared as: tuberculosis (16.24/100 000), scarlet fever (9.39/100 000), hepatitis B (7.69/100 000) and bacillary and amebic dysentery (7.15/100 000). The average rates of mortality on the top four diseases appeared as: rabies (0.044 8/100 000), HIV/AIDS (0.027 7/100 000), tuberculosis (0.008 0/100 000) and Japanese encephalitis (0.005 9/100 000). The average rates of morbidity on the top four diseases appeared as: mumps (75.81/100 000), hand-foot-mouth disease (28.55/100 000), other infectious diarrhea (22.41/100 000) and influenza (15.67/100 000) in the Category C. Reported death cases were from hand-foot-mouth disease (11 cases), influenza (9 cases), mumps (1 case) and rubella (1 case). The prevalence rates varied among different student populations, with higher HIV/AIDS, hepatitis B and tuberculosis rates among college and senior high school students, while higher mumps, influenza and hand-foot-mouth disease rates among primary school and junior high school students. Conclusions: Both morbidity and mortality of notifiable infectious diseases among Chinese students aged 6-22 years had decreased significantly in 2011-2016. However, the major infectious diseases had become new challenges among students. HIV/AIDS had become a key infectious disease among college students and the relatively high prevalence of tuberculosis was seen in college and high school students.


Assuntos
Doenças Transmissíveis/epidemiologia , Notificação de Doenças/estatística & dados numéricos , Vigilância da População/métodos , Estudantes/estatística & dados numéricos , Adolescente , Criança , China/epidemiologia , Humanos , Prevalência , Adulto Jovem
7.
Zhonghua Xue Ye Xue Za Zhi ; 39(11): 927-931, 2018 Nov 14.
Artigo em Chinês | MEDLINE | ID: mdl-30486590

RESUMO

Objective: To explore the expression of SLAMF6 on CD8(+) T cells in patients with severe aplastic anemia (SAA) and its correlation with disease immune status. Methods: By flow cytometry (FCM), SLAMF6 expression level in peripheral blood CD8(+) T cells was detected in 21 patients with SAA and 15 normal controls respectively from February 2017 to April 2018. The correlation between SLAMF6 expression level and hematopoietic functions, including HGB, PLT, the neutrophil granulocyte and reticulocyte absolute value in peripheral blood, hyperplasia degree (percentage of granulocytes, erythrocytes, lymphocytes and megakaryocytes in bone marrow) and perforin, granzyme B, IFN-γ expression level in CD8(+) T cells were evaluated. To further confirm the effect of SLAMF6 on CD8(+) T cells, anti-SLAMF6 Ab was used to block SLAMF6 pathway (IgG as control), and FCM was used to detect the perforin, granzyme B, and IFN-γ production of CD8(+) T cells. Results: The expression of SLAMF6 on CD8(+) T cells in untreated SAA patients[(56.29±12.97)%]was significantly lower than that of normal controls[(80.96±7.36)%](t=-7.672, P<0.001). The expression of SLAMF6 on CD8(+) T cells in SAA patients were positively correlated with the HGB, PLT, the neutrophil granulocyte and reticulocyte absolute value in peripheral blood, percentage of granulocytes, erythrocytes in bone marrow (all P<0.05), but they were negatively correlated with the percentage of lymphocytes in bone marrow, and the expression of perforin, granzyme B, and IFN-γ of CD8(+) T cells (all P<0.05). After blocking SLAMF6 pathway by anti-SLAMF6 Ab, the expression levels of perforin, granzyme B and IFN-γ in SAA patients were significantly higher than those in the untreated group, and the differences were statistically significant (all P<0.05). Conclusions: SLAMF6 is significantly down-regulated on CD8(+) T cells in SAA patients, which may act as a negative immunoregulatory molecule participating in the mechanism of SAA by affecting the functional molecules secretion on CD8(+) T cells.


Assuntos
Anemia Aplástica , Medula Óssea , Linfócitos T CD8-Positivos , Citometria de Fluxo , Humanos , Perforina , Família de Moléculas de Sinalização da Ativação Linfocitária
8.
Zhonghua Yi Xue Za Zhi ; 98(31): 2476-2480, 2018 Aug 21.
Artigo em Chinês | MEDLINE | ID: mdl-30138998

RESUMO

Objective: To explore whether cephalic artery peak velocity variation during passive leg raising (ΔVpeak(CA)-PLR) could effectively predict fluid responsiveness in mechanically ventilated severe sepsis patients with spontaneous breathing. Methods: Total of 38 patients on mechanical ventilation with spontaneous breathing admitted to the Fourth Departments of Intensive Care Unit (ICU) of Fujian Provincial Hospital from January to December in 2017 were enrolled.The patients were diagnosed with severe sepsis or sepsis shock.The peak velocity in cephalic artery (Vpeak(CA)) during PLR was measured by bedside portable ultrasonic, and then ΔVpeak(CA)-PLR was calculated.All patients received volume expansion (VE) test and the changes of stroke volume during VE test (ΔSV-VE) were measured.Patients were classified as responsive group or non-responsive group according to the ΔSV-VE increased ≥15% or not after VE test.Furthermore, the sensitivity and specificity of ΔVpeak(CA)-PLR for predicting fluid responsiveness were evaluated by receiver operating characteristic (ROC) curve.The comparisons between groups were performed with Student's unpaired two-tailed t test, and Pearson's test was used for the correlation analysis. Results: Among the patients, 22 cases responded to VE test and the rest 16 cases did not.There were no significantly differences in age, gender, body mass index, infection site, sepsis-related organ failure assessment score, acute physiology and chronic health evaluation Ⅱ score, ventilator parameters and dose of vasoactive agent between the two groups.The ΔVpeak(CA)-PLR in responsive group was markedly higher than that in non-responsive group (15.7%±4.2% vs 6.9%±4.3%, t=6.240, P<0.05), and the ΔVpeak(CA)-PLR in the responsive group was positively related to the ΔSV-VE (r=0.723, P<0.05). Furthermore, the area of ΔVpeak(CA)-PLR under ROC curve was 0.912.The sensitivity and specificity of ΔVpeak(CA)-PLR≥12.2% to predict fluid responsiveness in the patients with sepsis were 81.8% and 87.5%, respectively. Conclusion: ΔVpeak(CA)-PLR measured by bedside portable ultrasonic can predict the fluid responsiveness in mechanically ventilated severe sepsis patients with spontaneous breathing, and it can be used to guide further fluid resuscitation.


Assuntos
Sepse , Artérias , Hidratação , Hemodinâmica , Humanos , Unidades de Terapia Intensiva , Curva ROC , Respiração Artificial , Volume Sistólico
9.
Nanotechnology ; 29(42): 425705, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30052525

RESUMO

Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpinTMR), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpinTMXS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 105 rad s-1, the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FS-L, XL, XXL) excel in magnetic hyperthermia experiments.

10.
Zhonghua Liu Xing Bing Xue Za Zhi ; 38(11): 1480-1483, 2017 Nov 10.
Artigo em Chinês | MEDLINE | ID: mdl-29141333

RESUMO

Objective: To evaluate the accuracy of human brucellosis diagnosis and reporting in medical institutions in Shanxi province, and understand the performance of clinical doctors to diagnose human brucellosis according to diagnostic criteria. Methods: Field investigation was conducted in 6 medical institutions in the key areas of human brucellosis in Shanxi province. The diagnosis data of the reported brucellosis cases in 2015 were collected and reviewed retrospectively for the evaluation of the diagnosis accuracy with systematic sampling method. The database was established with Excel 2010 and the descriptive analysis and statistical test were conducted with software R 3.3.2. Results: The diagnosis consistent rate of the 377 brucellosis cases reviewed was 70.8% (267/377), the diagnosis consistent rates in medical institutions at city-level and country-level were 77.0% (127/165) and 66.0% (140/212) respectively, the differences had significance (χ(2)=5.4, P=0.02). Among the reviewed cases, the diagnosis consistent rate of laboratory diagnosis and clinical diagnosis were 87.1% (256/294) and 13.3% (11/83) respectively, and the differences had significance (χ(2)=170.7, P<0.001). Among the 21 investigated clinical doctors, the numbers of the doctors who correctly diagnosed the suspected cases, probable cases and lab-confirmed cases were only 3, 0 and 8 respectively. All of the clinical doctors knew that it is necessary to report the brucellosis cases within 24 hours after diagnosis. Conclusion: The accuracy of human brucellosis diagnosis in key areas of human brucellosis in Shanxi was low, and the performance of the clinical doctors to diagnose human brucellosis according to diagnostic and case classification criteria was unsatisfied.


Assuntos
Brucelose/diagnóstico , Competência Clínica , Notificação de Doenças , Médicos , Bases de Dados Factuais , Notificação de Doenças/métodos , Notificação de Doenças/normas , Meio Ambiente , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Estudos Retrospectivos , Software
11.
Sci Rep ; 7: 45990, 2017 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-28397851

RESUMO

The structural and magnetic properties of magnetic multi-core particles were determined by numerical inversion of small angle scattering and isothermal magnetisation data. The investigated particles consist of iron oxide nanoparticle cores (9 nm) embedded in poly(styrene) spheres (160 nm). A thorough physical characterisation of the particles included transmission electron microscopy, X-ray diffraction and asymmetrical flow field-flow fractionation. Their structure was ultimately disclosed by an indirect Fourier transform of static light scattering, small angle X-ray scattering and small angle neutron scattering data of the colloidal dispersion. The extracted pair distance distribution functions clearly indicated that the cores were mostly accumulated in the outer surface layers of the poly(styrene) spheres. To investigate the magnetic properties, the isothermal magnetisation curves of the multi-core particles (immobilised and dispersed in water) were analysed. The study stands out by applying the same numerical approach to extract the apparent moment distributions of the particles as for the indirect Fourier transform. It could be shown that the main peak of the apparent moment distributions correlated to the expected intrinsic moment distribution of the cores. Additional peaks were observed which signaled deviations of the isothermal magnetisation behavior from the non-interacting case, indicating weak dipolar interactions.

13.
Curr Oncol ; 22(1): e11-9, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25684992

RESUMO

BACKGROUND: We aimed to characterize the localization and prognostic significance of tumour-associated macrophages (tams) in pancreatic ductal adenocarcinoma (pdac). METHODS: Tumour specimens from 70 patients with pdac and inflammatory specimens from 13 patients with chronic pancreatitis were collected and analyzed for tam and M2 macrophage counts by immunohistochemistry. Correlations between tam distributions and clinicopathologic features were determined. RESULTS: Immunohistochemical analysis showed that tam and M2 macrophage counts were higher in tissues from pdac than from chronic pancreatitis. The tams and M2 macrophages both infiltrated more into peritumour. Both macrophage types were positively associated with lymph node metastasis (p = 0.041 for tams in peritumour, p = 0.013 for M2 macrophages in introtumour, p = 0.006 for M2 macrophage in peritumour). In addition, abdominal pain was significantly more frequent in pdac patients with a greater tams count. The survival rate was much lower in patients having high infiltration by M2 macrophages than in those having low infiltration. CONCLUSIONS: The tam count might be associated with neural invasion in pdac, and M2 macrophages might play an important role in lymph node metastasis. Higher counts of either macrophage type were associated with increased risk of lymph node metastasis, and the M2 macrophage count could potentially be a marker for evaluating prognosis.

14.
J Phys Condens Matter ; 21(21): 215606, 2009 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-21825555

RESUMO

Structural properties and hole distribution in the spin-ladder compound Sr(14-x)Ca(x)Cu(24)O(41) have been extensively investigated by transmission electron microscopy (TEM). The complex electron diffraction patterns and high-resolution TEM observations reveal a clear incommensurate structural modulation along the c-axis direction attributable to two mismatched sublattices; this modulation strongly depends on hole distribution in the compounds. The fine structures of the O K and Cu L(2,3) ionization edges for the Sr(14-x)Ca(x)Cu(24)O(41) compounds recorded under different conditions indicate that more doped holes reside in the chains than the ladders, and that substituting Ca for Sr atoms results in a charge redistribution between the chains and ladders. Based on the experimental findings, the theoretical results, including the partial density of states and optical conductivity spectra calculated by the density functional theory, are also discussed.

15.
J Phys Condens Matter ; 21(4): 045601, 2009 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-21715815

RESUMO

The charge/orbital ordering (COO) of the layered mixed-valence manganites (La,Sr)(n+1)Mn(n)O(3n+1) (n = 1 and 2) is examined by first-principles calculations and discussed in comparison with the La(0.5)Ca(0.5)MnO(3) perovskite phase ([Formula: see text]). The results demonstrated that the layered structural features could yield not only visibly weak coupling between Mn-O layers but also various features in the orbital ordering associated with different types of local structural distortions. In both La(0.5)Sr(1.5)MnO(4) (n = 1) and LaSr(2)Mn(2)O(7) (n = 2) phases, the orbital ordering can be chiefly assigned to the d(x(2)-y(2)) orbital, in contrast with the zigzag-type d(z(2)) orbital ordering in the [Formula: see text] perovskite phase. Our theoretical analysis shows that a variety of essential factors, including the local structural distortions of the MnO(6) octahedra, the on-site Coulomb interaction, and magnetic interaction, have to be properly considered in order to achieve acceptable COO ground states for the layered variants in (La,Sr)(n+1)Mn(n)O(3n+1).

16.
J Phys Condens Matter ; 20(27): 275230, 2008 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-21694391

RESUMO

The structural properties associated with the orbitally induced Peierls transition in MgTi(2)O(4) are characterized by in situ cooling TEM observations. A distinctive structural modulation with the wavevector of q(1) = 1/4 (0, 0, 4) has been well demonstrated below a critical temperature of about 260 K for MgTi(2)O(4). Systematic analysis demonstrates that this structural modulation can be well explained by an orbital order existing in the low-temperature insulating phase. It is also noted that the nonstoichiometric feature commonly appearing in the present system could yield visible changes in both physical and structural properties. A low-temperature study of the microstructure of Mg[Ti(1.9)Mg(0.1)]O(4) reveals that a little substitution of Mg(2+) for Ti(3+) ions on the octahedral sites can disrupt the long-range order of the t(2g) orbitals, resulting in complex tweed structures in the superstructure phase.

17.
Br J Biomed Sci ; 62(1): 5-8, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15816204

RESUMO

Progressive deterioration of beta-cell function is proposed as a disease-related factor of sulphonylurea (SU) failure in type 2 diabetes. If it gradually worsens over time then disease duration may mirror the progressive beta-cell deterioration. The aim of the present study is to assess whether or not disease duration is influential in remodelling the secretion pattern of insulin-like molecules and in glucose control of SU-treated type 2 diabetes. A research model is used to investigate proinsulin secreting capacity over time, using two groups of patients: i) disease duration <5 years (n=62), comprising SU responders (SUr; n=48) and SU failures (SUf; n=14); and ii) disease duration > or = 5 years (n= 37), comprising an SUr group (n=17) and an SUf group (n=20). Blood samples are taken at 0 h, 0.5 h 1 h, 2 h and 3 h during a standard oral glucose tolerance test and measured for glucose, total proinsulin (TPI), intact proinsulin (IPI) and specific insulin (SI) concentrations. Pairwise comparison of estimated marginal means of blood glucose, SI, IPI and TPI levels at each time point are carried out between groups and subgroups. (SUr vs. SUf). Homa insulin resistance index (IR index) is applied to analyse IR between the groups. It was found that patients with shorter disease duration had higher proinsulin (TPI and IPI) levels at all time points (P<0.05), together with a lower glucose level at 2 h and 3 h (P<0.05). Homa insulin index analysis showed no difference between the two groups (P=0.26). Results also showed that the SUr group had a significantly lower glucose level at Oh and 3h (P<0.05), although no significant difference in insulin and proinsulin levels was found between the SUr and SUf groups. In conclusion, proinsulin may play an important role in glucose control in SU-treated type 2 diabetes, but the effect is reduced in SUf patients.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Hipoglicemiantes/uso terapêutico , Proinsulina/sangue , Compostos de Sulfonilureia/uso terapêutico , Adulto , Idoso , Glicemia/análise , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
18.
Br J Biomed Sci ; 60(1): 9-13, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12680624

RESUMO

Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Proinsulina/sangue , Compostos de Sulfonilureia/uso terapêutico , Adulto , Idoso , Área Sob a Curva , Glicemia/análise , Diabetes Mellitus Tipo 2/sangue , Feminino , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Falha de Tratamento
19.
Ann Clin Biochem ; 37 ( Pt 4): 447-51, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10902859

RESUMO

Cardiac troponin I (cTnI) was measured by chemiluminescent immunoassay following burn injury. Thirty patients [total body surface area (TBSA) of burn 15-98%] were included in this study and each had four to six blood samples collected at 2-day intervals between the 5th and 14th days post-burn. All patients were found to have increased cTnI on two or more occasions. The mean cTnI concentration was significantly higher in patients with TBSA of burn > 30% (0.34 microg/L compared with 0.09 microg/L, P<0.001) and in those with obvious burn wound exudation (0.32 microg/L compared with 0.12 microg/L, P<0.01). cTnI concentrations peaked at the time when there was obvious burn wound exudation or spontaneous separation of eschar, then decreased after surgical excision. Two patients with persistently high cTnI concentrations developed tachycardia. We conclude that burned patients have varying degrees of non-ischaemic cardiac injury, manifesting as leakage of cTnI from myocytes into the circulation.


Assuntos
Biomarcadores , Queimaduras , Miocárdio/metabolismo , Troponina I/sangue , Adolescente , Adulto , Idoso , Doenças Cardiovasculares/etiologia , Criança , Pré-Escolar , Feminino , Humanos , Imunoensaio , Medições Luminescentes , Masculino , Pessoa de Meia-Idade , Taquicardia , Fatores de Tempo
20.
Zhongguo Zhong Yao Za Zhi ; 25(3): 184-8, 2000 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-12212106

RESUMO

OBJECTIVE: To study the taxonomy of Caprifoliaceae. METHOD: Using chemotaxonomical methods to discuss the distribution characteristics of chemical constituents in Caprifoliaceae family. RESULTS: Iridoids and flavonoids were confirmed as the characteristic constituents of Caprifoliaceae family. CONCLUSION: Though there are great deviations among the genera of Caprifoliaceae family, it is not recommended to separate genus Sambucus and genus Viburnum from Caprifoliaceae family.


Assuntos
Caprifoliaceae/química , Caprifoliaceae/classificação , Flavonoides/análise , Iridoides/análise , Iridoides/química , Estrutura Molecular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...