Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells.

Tandem solar cells consisting of high bandgap cadmium telluride alloys atop crystalline silicon have potential for high efficiencies exceeding the Shockley-Queisser limit. However, experimental results have fallen well below this goal significantly because of non-ideal current matching and light trapping. In this work, we simulate cadmium zinc telluride (CZT) and crystalline silicon (c-Si) tandems as an exemplary system to show the role that a hybrid light trapping and bandgap engineering approach can play in improving performance and lowering materials costs for tandem solar cells incorporating crystalline silicon. This work consists of two steps. First, we optimize absorption in the crystalline silicon layer with front pyramidal texturing and asymmetric dielectric back gratings, which results in 121% absorption enhancement from a planar structure. Then, using this pre-optimized light trapping scheme, we model the dispersion of the CdxZn1-xTe alloys, and then adjust the bandgap to realize the best current matching for a range of CZT thicknesses. Using experimental parameters, the corresponding maximum efficiency is predicted to be 16.08 % for a total tandem cell thickness of only 2.2 µm.

Age- and sex-specific association of circulating osteocalcin with dynamic measures of glucose homeostasis.

SUMMARY: Our study showed that serum osteocalcin levels are closely related to glucose metabolism in men of all ages and younger women. This association disappeared in postmenopausal women in which increases bone turnover rates. The association between serum osteocalcin levels and glucose homeostasis should be interpreted according to age and sex. INTRODUCTION: Osteocalcin, a marker of bone formation, appears to be associated with glucose homeostasis. We investigated the age- and sex-specific association of serum osteocalcin level with variables related to glucose metabolism. METHODS: This study was based on cross-sectional analysis from 719 participants aged 20-85 years after excluding patients taking antidiabetic or antiosteoporotic drugs. The subjects were divided into four groups according to age and sex as follows: men <50 years (n = 131), men ≥50 years (n = 191), women <50 years (n = 108), and women ≥50 years (n = 279). Anthropometric and biochemical variables including insulin resistance (HOMA-IR) and ß cell function (HOMA-ß) from a 75-g oral glucose tolerance test, and serum 25-OH-vitamin D and parathyroid hormone levels were measured. RESULTS: The serum osteocalcin level was significantly higher in women aged ≥50 years compared with women <50 years (20.4 ± 7.8 vs. 17.9 ± 6.8 ng/ml, p < 0.001), but there was no difference between men aged ≥50 years and men <50 years (16.4 ± 5.9 vs. 16.8 ± 6.0 ng/ml, p = 0.905). The participants diagnosed with diabetes had lower serum osteocalcin levels than normal or prediabetic participants. Multivariable regression analyses including HOMA-IR and HOMA-ß indicated that serum osteocalcin levels had a negative and independent association with HbA1c levels in men and women aged <50 years, but not in women ≥50 years. CONCLUSIONS: Low osteocalcin levels are associated with impaired glucose metabolism in men and premenopausal women. The osteocalcin levels may be determined by factors related to bone metabolism in postmenopausal women. Our data suggest that the serum levels of osteocalcin associated with glucose homeostasis should be interpreted according to age and sex.

Three-dimensional efficient dispersive alternating-direction-implicit finite-difference time-domain algorithm using a quadratic complex rational function.

Efficient unconditionally stable FDTD method is developed for the electromagnetic analysis of dispersive media. Toward this purpose, a quadratic complex rational function (QCRF) dispersion model is applied to the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method. The 3-D update equations of QCRF-ADI-FDTD are derived using Maxwell's curl equations and the constitutive relation. The periodic boundary condition of QCRF-ADI-FDTD is discussed in detail. A 3-D numerical example shows that the time-step size can be increased by the proposed QCRF-ADI-FDTD beyond the Courant-Friedrich-Levy (CFL) number, without numerical instability. It is observed that, for refined computational cells, the computational time of QCRF-ADI-FDTD is reduced to 28.08 % of QCRF-FDTD, while the L2 relative error norm of a field distribution is 6.92 %.

Time domain simulation of tandem silicon solar cells with optimal textured light trapping enabled by the quadratic complex rational function.

Amorphous silicon/crystalline silicon (a-Si/c-Si) micromorph tandem cells, with best confirmed efficiency of 12.3%, have yet to fully approach their theoretical performance limits. In this work, we consider a strategy for improving the light trapping and charge collection of a-Si/c-Si micromorph tandem cells using random texturing with adjustable short-range correlations and long-range periodicity. In order to consider the full-spectrum absorption of a-Si and c-Si, a novel dispersion model known as a quadratic complex rational function (QCRF) is applied to photovoltaic materials (e.g., a-Si, c-Si and silver). It has the advantage of accurately modeling experimental semiconductor dielectric values over the entire relevant solar bandwidth from 300-1000 nm in a single simulation. This wide-band dispersion model is then used to model a silicon tandem cell stack (ITO/a-Si:H/c-Si:H/silver), as two parameters are varied: maximum texturing height h and correlation parameter f. Even without any other light trapping methods, our front texturing method demonstrates 12.37% stabilized cell efficiency and 12.79 mA/cm² in a 2 µm-thick active layer.

Pro-inflammatory mediators and signaling proteins in the decidua of pre-eclampsia.

OBJECTIVE: To evaluate the role of CD68+ macrophages and inflammatory/signaling proteins in the decidua of singleton pregnancies with late-onset pre-eclampsia. PATIENTS AND METHODS: This study was designed as a prospective case-control study. Decidual tissue samples were obtained from twenty healthy pregnant women as a control group and twenty pregnant women with late-onset pre-eclampsia showing severe symptoms as the study group. We examined the abundance of CD68+ macrophages in both groups using flow cytometry. Protein and mRNA expression levels of inflammatory/signaling proteins, including inducible nitric oxide synthase, nuclear factor-κB inhibitor α, cyclooxygenase-2, and phosphorylated c-Jun N-terminal kinase, in the decidua of both groups were measured using Western blotting and Reverse Transcription-Polymerase Chain Reaction, respectively. Student's t-tests were performed for statistical analysis. RESULTS: The numbers of CD68+ macrophages were similar in the study and control groups (p=0.47). However, the levels of inducible nitric oxide synthase, nuclear factor-κB, cyclooxygenase-2, and phosphorylated c-Jun N-terminal kinase were significantly increased in the study group. Therefore, pro-inflammatory mediators and signaling proteins in the decidua during pre-eclampsia may be related to the pathogenesis of pre-eclampsia. CONCLUSIONS: Pre-eclampsia-induced alterations in the expression of inflammatory/signaling proteins in the decidua during singleton pregnancies may play a critical role in the pathogenesis of pre-eclampsia.

Chip- and board-level optical interconnections using rigid flexible optical electrical printed circuit boards.

A new optical interconnection scheme based on a rigid flexible optical electrical printed circuit board (RFOE-PCB) is suggested. The easily installed RFOE-PCB can be universally applied for both chip- and board-level optical interconnections. This letter describes the detailed fabrication process, optical properties, and heat-resisting property of the RFOE-PCB. The fabricated RFOE-PCB was also successfully demonstrated with a 2.5-Gb/s data transmission through a 45 degrees-ended optical waveguide embedded in the RFOE-PCB.

Analysis of efficacy and safety of core-needle biopsy versus fine-needle aspiration cytology in patients with cervical lymphadenopathy and salivary gland tumour.

In this study, we compared the diagnostic accuracy and safety of fine-needle aspiration cytology and core-needle biopsy in patients with cervical lymphadenopathy or salivary gland tumour, and provided a basis for selecting the appropriate diagnostic method in clinical situations. A total of 278 patients were included in this study. The sensitivities of fine-needle aspiration cytology and core-needle biopsy were 66.7% and 100%, respectively, and negative predictive values were 92.6% and 100%, respectively, for diagnosing malignancy. In diagnosing lymphoma, fine-needle aspiration cytology gave false-negative results in all patients. In diagnosing tuberculous lymphadenopathy, the sensitivities of fine-needle aspiration cytology and core-needle biopsy were 33.3% and 91.15%, respectively, and the negative predictive values were 90.0% and 95.1%, respectively. The sensitivities of fine-needle aspiration cytology and core-needle biopsy were 42.9% and 100% in diagnosing malignant salivary gland tumours, and the negative predictive values were 91% and 100%, respectively. The results of this study showed that core-needle biopsy was superior in diagnosing and distinguishing critical diseases such as malignant lymphadenopathy and tuberculosis in patients with cervical lymphadenopathy and salivary gland tumour.

Identification of new minimally lost regions on 18q in head and neck squamous cell carcinoma.

Loss of heterozygosity (LOH) on 18q predicts poor survival in head and neck squamous cell carcinomas (HNSCCs). Several putative tumor suppressor genes, such as DCC, DPC4/Smad4, and MADR2/Smad2, are mapped to 18q, but thus far, the important gene locus in HNSCC is not known. To identify possible gene loci on 18q, we performed LOH studies using tumor DNA from 57 HNSCC primary tumor cell lines and DNA isolated from fibroblasts or lymphoblastoid cells from the same patients. Forty-two highly polymorphic microsatellite markers spaced not more than 5 cM apart (mean distance, 1.82 cM) spanning the region from D18S44 in 18q11.1 to D18S1141 in 18q23 were used. D18S71 in 18p11.21 on 18p was also used to determine whether the short arm was retained. Forty-three of 57 (75%) HNSCC lines showed LOH or isolated allelic imbalance (AI) for at least one locus on 18q. Although many of the cell lines had large distal 18q deletions with a breakpoint between 18q11.1 and 18q12.2 to qter, three loci were identified that were lost in 70% or more of the cases. The minimally lost regions (MLRs) range in size from 1.5-15.79 cM. The most proximal is centered on D18S39 (1.56 cM) in band 18q21.1, with LOH or isolated AI in 28 of 38 (74%) of informative cases. The largest (15.8 cM) begins at D18S61 (28 of 40; 70%) in band 18q22.2 and extends through D18S50 in 18q23. The third is centered on D18S70 (30 of 40; 75%) in band 18q23 (3.67 cM). Of these MLRs, only the one centered on D18S39 has been implicated previously in HNSCC. D18S70, the most frequently lost marker, was the only marker consistently lost in three tumor cell lines with very minimal losses, UM-SCC-19, UM-SCC-67, and UM-SCC-73A. In addition, UM-SCC-91 exhibited AI only at this locus, and UT-SCC-4 had AI at D18S70 and D18S39 only. Close physical mapping of these three regions may pinpoint one or more previously unidentified tumor suppressor genes.

Efficacy of ultrasound-guided core needle gun biopsy in diagnosing cervical lymphadenopathy.

OBJECTIVE: Ultrasound-guided fine needle aspiration cytology (US-FNA) is useful for diagnosing cervical lymphadenopathy. However, FNA, has a high false negative rate, especially in patients with lymphoma. Ultrasound-guided core needle gun biopsy (US-CNB) has recently become important for diagnosing cancers, but its value remains undetermined. This study evaluates the efficacy of US-CNB, performed in an outpatient setting, in diagnosing cervical lymphadenopathy and the spectrum of related diseases. MATERIALS AND METHODS: This retrospective study included 79 subjects who were not squamous cell carcinoma suspects and did not have a history of malignancy between January 2006 and July 2009. A US-CNB was performed on enlarged cervical lymph nodes (>1.0cm) in all subjects. Diagnostic sensitivity, specificity, and accuracy of US-CNB in differentiating between malignant and benign lymphadenopathy were evaluated. All enrolled subjects underwent a planned US-FNA before the study US-CNB was performed. Results of US-CNB and US-FNA were compared. RESULTS: The correct histopathological diagnoses were made in 73 of 79 subjects (91.1%) using US-CNB samples. Of these, the most common diagnoses were reactive hyperplasia (26 subjects), Kikuchi's disease (17 subjects), tuberculous lymphadenitis (15 subjects), lymphoma (8 subjects), and metastatic carcinoma (3 subjects). The US-CNB was very good at differentiating between malignant and benign lymphadenopathy, with a diagnostic sensitivity, specificity, and accuracy of 91.6%, 100%, and 98.6%, respectively. Additionally, US-CNB was more accurate than US-FNA in identifying lymphoma (88.8% vs. 11.1%) and Kikuchi's disease (89.4% vs. 29.4%). No US-CNB related-complications were observed. CONCLUSION: The US-CNB is safe, effective, and has a high diagnostic yield for cervical lymphadenopathy. The US-CNB may also be useful for diagnosing lymphoma and Kikuchi's disease.

Prognostic significance of tumour progression and human papillomavirus in advanced tonsillar cancer classified as stage IVa.

OBJECTIVE: To identify clinical factors that can explain the differences in treatment outcome, and examine the value of human papillomavirus infection as a prognostic biomarker in stage IVa tonsillar carcinomas. METHODS: Fifty-nine patients with tonsillar carcinoma classified as stage IVa were retrospectively analysed for survival outcomes according to various clinical factors. Human papillomavirus infection was evaluated using a human papillomavirus DNA chip test and immunohistochemical staining for p16 and p53. RESULTS: Lower disease-free survival rates were associated with increasing local invasiveness and nodal status. Although human papillomavirus positivity and p16 expression was more common in locally advanced tonsillar carcinomas with advanced nodal status, the overall survival rate was better for patients with human papillomavirus positive, p16-positive tumours. CONCLUSION: The disease-free survival rate may differ according to local tumour invasiveness and nodal status, even for stage IVa tonsillar cancers. Human papillomavirus infection may be a useful biomarker for predicting treatment outcomes for stage VIa tumours.