Contactless Measurement of Sheet Resistance of Nanomaterial Using Waveguide Reflection Method.

Conductive nanomaterials are widely studied and used. The four-point probe method has been widely used to measure nanomaterials' sheet resistance, denoted as . However, for materials sensitive to contamination or physical damage, contactless measurement is highly recommended if not required. Feasibility of evaluation using a one-port rectangular waveguide working on the microwave band in a contact-free mode is studied. Compared with existed waveguide methods, the proposed method has three advantages: first, by introducing an air gap between the waveguide flange and the sample surface, it is truly contactless; second, within the specified range of , the substrate's effect may be neglected; third, it does not require a matched load and/or metallization at the sample backside. Both theoretical derivation and simulation showed that the magnitude of the reflection coefficient decreased monotonously with increasing . Through calibration, a quantitative correlation of and was established. Experimental results with various conductive glasses showed that, for in the range of ~10 to 400 Ohm/sq, the estimation error of sheet resistance was below ~20%. The potential effects of air gap size, sample size/location and measurement uncertainty of are discussed. The proposed method is particularly suitable for characterization of conductive glass or related nanomaterials with in the range of tens or hundreds of Ohm/sq.

Conductivity Extraction Using a 180 GHz Quasi-Optical Resonator for Conductive Thin Film Deposited on Conductive Substrate.

Measurement of electrical conductivity of conductive thin film deposited on a conductive substrate is important and challenging. An effective conductivity model was constructed for a bilayer structure to extract thin film conductivity from the measured Q-factor of a quasi-optical resonator. As a demonstration, aluminium films with thickness of 100 nm were evaporated on four silicon wafers whose conductivity ranges from ~101 to ~105 S/m (thus, the proposed method can be verified for a substrate with a wide range of conductivity). Measurement results at ~180 GHz show that average conductivities are 1.66 × 107 S/m (which agrees well with direct current measurements) with 6% standard deviation. The proposed method provides a contactless conductivity evaluation method for conductive thin film deposited on conductive substrate which cannot be achieved by the existing microwave resonant method.

Molecular differences in Alzheimer's disease between male and female patients determined by integrative network analysis.

Alzheimer's disease (AD) is a complex neurodegenerative disease and the most common cause of dementia among the elderly. There has been increasing recognition of sex differences in AD prevalence, clinical manifestation, disease course and prognosis. However, there have been few studies on the molecular mechanism underlying these differences. To address this issue, we carried out global gene expression and integrative network analyses based on expression profiles (GSE84422) across 17 cortical regions of 125 individuals with AD. There were few genes that were differentially expressed across the 17 regions between the two sexes, with only four (encoding glutamate metabotropic receptor 2, oestrogen-related receptor beta, kinesin family member 26B, and aspartoacylase) that were differentially expressed in three regions. A pan-cortical brain region co-expression network analysis identified pathways and genes (eg, glycogen synthase kinase 3ß) that were significantly associated with clinical characteristics of AD (such as neurofibrillary score) in males only. Similarity analyses between region-specific networks indicated that male patients exhibited greater variability, especially in the superior parietal lobule, dorsolateral prefrontal cortex and occipital visual cortex. A network module analysis revealed an association between clinical traits and crosstalk of sex-specific modules. An examination of temporal and spatial patterns of sex differences in AD showed that molecular networks were more conserved in females than in males in different cortical regions and at different AD stages. These findings provide insight into critical molecular pathways governing sex differences in AD pathology.

Sleep quality and health service utilization in Chinese general population: a cross-sectional study in Dongguan, China.

OBJECTIVES: The aims of this study were to explore the Pittsburgh Sleep Quality Index (PSQI) and health service utilization in Chinese general population, to investigate the association between PSQI and health service utilization and to identify the independent contributions of social demographic variables, health related factors and PSQI to health service utilization. METHODS: In a cross-sectional community-based health survey using a multi-instrument questionnaire, 4067 subjects (≥15 years old) were studied. The Chinese version of the PSQI was used to assess sleep quality. Health service utilization was measured by recent two-week physician visit and annual hospitalization rates. RESULTS: Higher PSQI scores were associated with more frequent health service utilization. Higher scores in subjective sleep quality were associated with higher rate of recent two-week physician visit (adjusted OR = 1.24 per SD increase, P = 0.015). Higher scores in habitual sleep efficiency (adjusted OR = 1.24 per SD increase, P = 0.038) and sleep disturbances (adjusted OR = 2.09 per SD increase, P < 0.001) were associated with more frequent annual hospitalization. The independent influence of PSQI on the risk of recent two-week physician visit was 0.7%, and that of annual hospitalization 31.4%. CONCLUSIONS: Poorer sleep quality predicted more frequent health service utilization. The independent contribution of PSQI on health service utilization was smaller than social demographic variables.

[Two Kinds of HLA-mismatched Allogeneic Hematopoictic Stem Cell Transplantation for Treatment of Hematologic Malignancies].

OBJECTIVE: To investigate the safety and effectiveness of HLA-mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT) combined with related haploidentical bone marrow infusion for treatment of hematologic malignancies and to explore the mathod for reduction of aGVHD incidence and clinical significance. METHODS: A total of 30 patients with hematologic malignancies (8 cases of AML, 17 AML, 2 MDS and 3 Mix-AL) received related haploidentical and unrelated HLA-mismatched allo-HSCT combined with related haploidentical bone marrow infusion. Among them 20 cases received related haploidentical transplantation of the first donor, 10 cases received unrelated HLA-mismatched treaplantation. The new conditioning regimen for the patients underwent allo-HSCT consisted of fludarabine, busulfan, Me-CCNU and cyclophosphamide. The drugs for GVHD prophylaxis included cyclosporine A and methotrexate, while mycophenolate mofetil and rabbit anti-T-lymphocyte globulin (ATG) were used. RESULTS: All the patients achieved full engraftment. The median time for neutrophils to reach over 0.5 × 10(9)/L was 14 days (8-26 days), while the median time for platelets to reach over 20 × 10(9)/L was 11.5days (10-24 days). The incidence of I-II grade of aGVHD at 100 d was 22.28% (95% CI 9.9%-34.7%), the incidences of II-IV and III-IV grade of aGVHD were 22.7% (95% CI, 10%-35.4%) and 12.7% (95% CI 6.9%-15.5%) respectively. The incidences of I-II and III-IV cGVHD were 13.3% (95% CI, 1.4%- 26.8%) and 3.3 % (95% CI, 0%-12.2%), one case (3.3%) was in extensive cGVHD. DFS and OS of 2 years were 81.1% (95% CI, 66.0%-96.2%) and 68.2% (95% CI 51.0%-85.4%). CONCLUSION: These data suggest that the incidence of grade II-IV grade of aGVHD in recipients of 2 partially HLA-matched units was lower, co-infusion of haplo-BM and partially matched units in allogeneic transplantation is safe and effective for reducing the incidence of aGVHD and improving the survival in DFS.

[Correlations of jak2v617f mutation with clinical and laboratory findings in primary thrombocythemia patients].

To evaluate the frequency of jak2v617f mutation and analyze its correlation with clinical features of primary thrombocythemia (PT) patients, the mutation was detected by allele specific polymerase chain reaction (AS-PCR), the clinical and laboratory data in 66 PT patients with and without jak2v617f mutation were compared and clinical features of these PT patients were retrospectively analyzed. The results showed that among 66 patients, 27 patients (41%) had the mutation. The patients carrying the mutation displayed higher bone marrow erythropoiesis (26.9%+/-9.4% vs 16.3%+/-8.7%, p<0.05), higher ratio of granulopoiesis/erythropoiesis (2.9+/-1.8 vs 5.2+/-2.9, p<0.05) and higher incidence of microvascular disturbances (29.6% vs 5.1%, p<0.05). However, the age, gender, leukocyte and platelet counts, hemoglobin level, bone granulopoiesis, splenomegaly, history of thrombosis and hemorrhage had no difference between patients with and without the mutation. It is concluded that the frequency of jak2v617f mutation in primary thrombocythemia patients is 41%. The presence of the jak2v617f mutation is associated with a higher bone marrow erythropoiesis in primary thrombocythemia patients at diagnosis.

[Intraocular lens power calculation after corneal refractive surgery].

OBJECTIVES: To investigate the effective method for the calculation of intraocular lens power retrospectively from post-LASIK cases. METHODS: It was a retrospective case series. 40 eyes of 28 patients (14 male and 14 Female) had the Phacoemulsification post-LASIK in HongKong Sanitorium & Hospital; the age ranged from 41.00 to 69.00 years ages, (50.68 +/- 6.56) years. LASIK was done from January, 1997 to April, 2005. Phacoemulsification was done from October, 2000 to September, 2005. RESULTS: Average axial length was (28.06 +/- 1.98) mm (rang from 24.28 to 31.96 mm). The initial refraction power (Spherical Equivalent, SE) before LASIK was from -3.13 to -18.00 D, (-10.44 +/- 3.93) D. K value pre-LASIK was 41.40 to 46.90 D, (43.57 +/- 1.47) D. The best corrected visual acuity (BCVA) preLASIK was 20/20 in 19 eyes, 20/25 in 10 eyes, 20/30 in 7 eyes and 20/40 in 4 eyes. The refraction power of 6 months post-LASIK (SE) was -2.83 to +1.25 D, (-0.32 +/- 0.95) D. The refraction power pre-phaco (SE) was -5.75 to +1.13 D, (-2.35 +/- 2.16) D. The calculated K1 (KpreLASIK-RpostLASIK + RpreLASIK) was 27.60 to 40.70 D, (34.62 +/- 3.56) D. The K from the IOLmaster (K2) was 32.39 to 43.53 D, (38.04 +/- 2.45) D. The target refraction of K1 was -3.69 to 0.61 D, (-1.32 +/- 1.00) D, the target refraction of K2 was -3.67 approximately 3.95 D, (-0.60 +/- 1.84) D. There was significant difference between these two target refraction, (t = -2.40, P = 0.02). The refraction power of post-phaco (> 3 months) was -4.50 to +1.75 D, (-1.10 +/- 1.51) D. The BCVA post-Phaco was 20/20 in 20 eyes, 20/25 in 9 eyes, 20/30 in 5 eyes and 20/40 in 6 eyes. CONCLUSIONS: The formula used in the study for the calculation of intraocular lens power is accurate and effective.

[The investigation of JAK2 V617F point mutation in myeloproliferative disorders by allele-specific polymerase chain reaction in combination with sequence analysis].

OBJECTIVE: To study the JAK2 V617F point mutation in myeloproliferative disorders (MPD) and explore the clinical significance. METHODS: We used Allele-specific polymerase chain reaction (AS-PCR) in combination with sequence analysis to detect the mutation in genomic DNA of peripheral blood mononuclear cells from 20 chronic myelogenous leukemia (CML) patients, 23 polycythaemia vera (PV), 40 essential thrombocythaemia (ET), 8 idiopathic myelofibrosis (IMF), 3 hypereosinophilic syndrome (HES). RESULTS: JAK2 V617F was found in 38 (51.4%) of 74 BCR/ABL-negative MPD including 16 PV, 18 ET, 3 IMF and 1 HES patients. All positive samples and 10 negative samples identified by AS-PCR were confirmed by sequence analysis. Mutation-positive patients with ET had significantly increased hemoglobin, hematocrit, and neutrophil proportion than those without the mutation. CONCLUSION: JAK2 V617F mutation is the key molecular genetics feature of BCR/ABL-negative MPD. Detection of JAK2 V617F mutation will bring about a major impact to the diagnosis, classification and treatment of MPD.

[JAK2V617F mutation in patients with idiopathic myelofibrosis].

To investigate JAK2V617F mutation and its clinical significance in patients with idiopathic myelofibrosis (IMF), genomic DNA was extracted from peripheral blood cell samples of 12 IMF cases. Allele-specific PCR (AS-PCR) was performed to identify JAK2V617F mutation, and the results were confirmed by sequence analysis. A retrospective study was performed to explore the correlation between JAK2V617F mutation and the clinical, hematologic features. The results showed that in follow-up for 2 to 15 months, the occurrence of the positive point mutation in 12 patients with IMF was 50%, and the half of these positive patients had thrombosis. Patients with JAK2V617F point mutation had a higher counts of platelets and megakaryocytes in bone marrow than those in patients without JAK2V617F point mutation. Out of other 6 IMF patients without JAK2V617F point mutation only 1 patient had thrombosis, and lower counts of platelets in peripheral blood and megakaryocytes in bone marrow. It is concluded that majority of IMF patients with positive JAK2V617F point mutation have typical clinical and hematologic features, higher incidence of thrombosis, and higher counts of platelets in peripheral blood and megakaryocytes in bone marrow.

Protective effect of O6-methylguanine-DNA-methyltransferase on mammalian cells.

BACKGROUND: O(6)-methylguanine-DNA-methyltransferase (MGMT) is a specific DNA revising enzyme transferring alkylated groups from DNA to its cysteine residue to avoid the abnormal twisting of DNA. Therefore, it is one of the drug resistant genes targeted in the treatment of cancer. This study explored the protective effect of MGMT gene transferred into mammalian cells. METHODS: Mammalian expression vector containing the MGMT gene cloned from human hepatocytes by RT-PCR was constructed and transferred into K562 cells and human peripheral blood mononuclear cells (PBMCs) via liposome, then assayed for gene expression at RNA and protein levels. MTT assay was used to check the drug resistance of cells transfected with MGMT gene. RESULTS: MGMT gene was successfully cloned. Real-time PCR showed that the mRNA expression in gene transfected groups in K562 cell line and PBMC were 13.4 and 4.0 times that of the empty vector transfected groups respectively. RESULTS: of Western blotting showed distinct higher expression of MGMT in gene transfected group than in other two groups. The IC(50) values increased to 7 and 2 times that of the original values respectively in stable transfected K562 cells and transient transfected PBMC. CONCLUSION: The alkylating resistance of eukaryotic cells is enhanced after being transfected with MGMT gene which protein product performs the protective function, and may provide the reference for the protective model of peripheral blood cells in cancer chemotherapy.