Exploring the potential of standalone and tandem solar cells with Sb2S3 and Sb2Se3 absorbers: a simulation study

Thin-film antimony chalcogenide binary compounds are potential candidates for efficient and low-cost photovoltaic absorbers. This study investigates the performance of Sb2S3 and Sb2Se3 as photovoltaic absorbers, aiming to optimize their efficiency. The standalone Sb2S3 and Sb2Se3 sub-cells are analyzed using SCAPS-1D simulations, and then a tandem structure with Sb2S3 as the top-cell absorber and Sb2Se3 as the bottom-cell absorber is designed, using the filtered spectrum and the current matching technique. The optimal configuration for maximum efficiency is achieved by adjusting the thickness of the absorber layer. The results show that antimony chalcogenide binary compounds have great potential as photovoltaic absorbers, enabling the development of efficient and low-cost solar cells. A remarkable conversion efficiency of 22.2% is achieved for the optimized tandem cell structure, with absorber thicknesses of 420 nm and 1020 nm for the top and bottom sub-cells respectively. This study presents a promising approach towards high-performance tandem solar cells.

Fish-like three-dimensional swimming with an autonomous, multi-fin, and biomimetic robot

Fish migrate across considerable distances and exhibit remarkable agility to avoid predators and feed. Fish swimming performance and maneuverability remain unparalleled when compared to robotic systems, partly because previous work has focused on robots and flapping foil systems that are either big and complex, or tethered to external actuators and power sources. By contrast, we present a robot-the Finbot-that combines high degrees of autonomy, maneuverability, and biomimicry with miniature size (160 cm³). Thus, it is well-suited for controlled three-dimensional experiments on fish swimming in confined laboratory test beds. Finbot uses four independently controllable fins and sensory feedback for precise closed-loop underwater locomotion. Different caudal fins can be attached magnetically to reconfigure Finbot for swimming at top speed (122 mm s^-1≡ 1 BL s^-1) or minimal cost of transport (CoT = 8.2) at Strouhal numbers as low as 0.53. We conducted more than 150 experiments with 12 different caudal fins to measure three key characteristics of swimming fish: (i) linear speed-frequency relationships, (ii) U-shaped CoT, and (iii) reverse Kármán wakes (visualized with particle image velocimetry). More fish-like wakes appeared where the CoT was low. By replicating autonomous multi-fin fish-like swimming, Finbot narrows the gap between fish and fish-like robots and can address open questions in aquatic locomotion, such as optimized propulsion for new fish robots, or the hydrodynamic principles governing the energy savings in fish schools.

Electron scattering in a superlattice of line defects on the surface of topological insulators

The electron scattering from periodic line defects on the surface of topological insulators with hexagonal warping effect is investigated theoretically by means of a transfer matrix method. The influence of surface line defects, acting as structural ripples on propagation of electrons are studied in two perpendicular directions due to the asymmetry of warped energy contour under momentum exchange. The transmission profiles and the details of resonant peaks which vary with the number of defects and the strength of their potentials are strongly dependent on the direction in which the line defects extend. At low energies, the quantum interference between the incident and reflected propagating electrons has the dominant contribution in transmission resonances, while at high energies the multiple scattering processes on the constant-energy contour also appear because of the strong warping effect. By increasing the spatial separation between the line defects, the minimum value of electrical conductance remains significantly high at low incident energies, while the minimum value may approach zero at high energies as the number of defects is increased. Our findings suggest that the potential ripples on the surface of topological insulators can be utilized to control the local electronic properties of these materials.

Test-retest reliability of Kinect's measurements for the evaluation of upper body recovery of stroke patients

Background

Performance indices provide quantitative measures for the quality of motion, and therefore, assist in analyzing and monitoring patients’ progress. Measurement of performance indices requires costly devices, such as motion capture systems. Recent developments of sensors for game controllers, such as Microsoft Kinect, have motivated many researchers to develop affordable systems for performance measurement applicable to home and clinical care. In this work, the capability of Kinect in finding motion performance indices was assessed by analyzing intra-session and inter-session test–retest reliability.

Method

Eighteen stroke patients and twelve healthy subjects participated in this investigation. The intra-session and inter-session reliability of eight performance indices, namely mean velocity (MV), normalized mean speed (NMS), normalized speed peaks (NSP), logarithm of dimensionless jerk (LJ), curvature (C), spectral arc length (SAL), shoulder angle (SA), and elbow angle (EA), were assessed using intra-class correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV).

Results

The results showed that, among the performance indices, MV, LJ, C, SA and EA have more than 0.9 ICC together with an acceptable SEM and CV in both stroke patients and healthy subjects. Comparing the results of different therapy sessions showed that MV, LJ and C are more sensitive than other indices, and hence, more capable of reflecting the progress of a patient during the rehabilitation process.

Conclusion

The results of this study shows acceptable reliability and sensitivity across the sessions for MV, LJ and C measured by Kinect for both healthy subjects and stroke patients. The results are promising for the development of home-based rehabilitation systems, which can analyze patient’s movements using Kinect as an affordable motion capture sensor.

Glutathione S-transferase Omega 2 Genetic Polymorphism and Risk of Hepatic Failure that Lead to Liver Transplantation in Iranian Population

BACKGROUND

Liver transplantation is the treatment of choice for both acute and chronic hepatic failure. GSTs family is one of the most important genes in phase II detoxification interfering with the xenobiotics and free radical metabolism. GSTO2 (N142D) is a member of this family the polymorphism of which may influence the metabolism of active components and free radicals and may contribute to hepatic failure.

OBJECTIVE

To investigate the association between GSTO2 genetic polymorphism and the susceptibility of hepatic failure that would lead to liver transplantation.

METHODS

This case-control study included 330 healthy people and 302 patients with liver transplantation as a result of hepatic failure. To determine the variants of GSTO2, we used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

There was a significant association between D allele and hepatic failure, thus, people with DD genotype are more susceptible to develop heaptic failure leading to liver transplantation (OR=1.8, 95% CI: 1.10-2.95, p=0.02). We also observed that male sex increases the chance of hepatic failure (OR=2.69, 95% CI: 1.95-3.71, p=0.001).

CONCLUSION

D allele may reduce the detoxification ability of liver so people with mutant D allele are more prone to develop hepatic failure.

Occupational sunlight exposure, polymorphism of glutathione S-transferase M1, and senile cataract risk

BACKGROUND

The pathogenesis of cataract is influenced by a number of factors including oxidative stress. Glutathione S-transferase (GST) catalyses the nucleophilic addition of the thiol of GST to electrophilic acceptors. It is important for detoxification of xenobiotics in order to protect tissues from oxidative damage.

OBJECTIVES

To examine whether the interaction of polymorphism of GSTM1 gene and occupational sunlight exposure modulate the risk of cataract.

METHODS

Blood samples from 95 subjects with cataract and 95 age and sex matched healthy persons were collected. The genotypes of GSTM1 were determined using PCR.

RESULTS

The null genotype of GSTM1 was associated with an increase in cataract risk in the indoor workplace, but this association was not significant in the outdoor subjects.

CONCLUSION

The active genotype of GSTM1 has lost its protective role in persons who work outdoors. It is suggested that activity of the GSTmu enzyme may be inhibited in the human lens after occupational exposure to UV light.

Consanguineous marriage in Iran

Consanguineous marriage is a major feature of family systems in south-west Asia. The aim of the present study was to determine the current prevalence and patterns of consanguinity in Iran as a means of assessing the associated requirement for genetic counselling services. Consanguinity was studied in 12 ethnic/religious populations, the Persians (Shi'a and Sunni), Kurds (Shi'a and Sunni), Lurs, Azaris, Baluchis, Zabolis, Turkamans, Bakhtiaris, Ghashghais and Arabs. A multi-stage sampling design was used with a representative total sample of 306 343 couples. The overall rate of consanguineous marriage was 38.6% with a mean inbreeding coefficient (alpha) of 0.0185. First cousin marriages (27.9%) were the most common form of consanguineous union, with parallel patrilateral marriage especially favoured. Statistically significant differences were observed in the prevalence and patterns of consanguinity between ethnic/religious populations and geographical regions. There also were significant differences for proportions of consanguineous marriages between Shi'a and Sunni populations within the same ethnic group. The highest rates of consanguineous union were in the least affluent sections of the population.

Influence of GSTT1 null genotype on the offspring sex ratio of gasoline filling station workers

The aim of this study was to investigate whether the occupational exposure to gasoline of men employed at filling stations affects the sex of their children. Altogether 115 offspring (47 males, 68 females) were identified within families of 49 men working in filling stations in Shiraz (Fars province, south of Iran) and 345 offspring (178 males, 167 females) from 147 families of unexposed persons from the general population of Shiraz, which were matched by age of fathers (+/-2 years) and number of children as a control group. The offspring sex ratio at birth (male proportion) in the filling station workers was significantly lower than the ratio in control group (OR = 0.65; 95% confidence intervals (CI) 0.42 to 0.99). Genotypes of glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) were investigated on extracted genomic DNA of 37 exposed workers using the polymerase chain reaction based method. In exposed group with active GSTM1 and GSTT1 genes, offspring sex ratio was the same as the ratio in the control group (OR = 0.66; 95% CI 0.34 to 1.28). However, in the exposed group with active GSTM1 and null genotype of GSTT1, the offspring sex ratio statistically decreased (OR = 0.45; 95% CI = 0.21 to 0.96). It seems that the GSTT1 null genotype has an effect on offspring sex ratio in the filling station workers.

Glutathione S-transferase M1 and T1 null genotypes and the risk of gastric and colorectal cancers

Several polymorphic glutathione S-transferase (GST) enzymes are involved in the detoxification of active metabolites of many potential carcinogens and may therefore be important in modulating susceptibility to cancers. GSTM1 and GSTT1 are polymorphic, and the null alleles result in a lack of corresponding enzyme activities. Previous studies demonstrated that the GSTM1 and GSTT1 null genotypes correlated with an increased risk of developing some cancers. In this study, we determined GSTM1 and GSTT1 polymorphisms in a population of 131 healthy controls from the south of Iran, 46 patients with colorectal cancers, and 42 patients with gastric cancer. The gastric cancer risk statistically increased due to the GSTM1 null genotype (odds ratio (OR)=2.3, 95% confidence interval (CI): 1.15--4.95). On the other hand, the GSTT1 null genotype in gastric cancer and null genotypes of GSTM1 and GSTT1 in colorectal cancer were not statistically significant. Moreover, individuals showing the GSTM1 and GSTT1 null genotypes might exhibit a greater predisposition to gastric (OR=3.31, 95% CI: 1.14--9.57) and colorectal (OR=2.73, 95% CI: 0.94--7.95, P=0.07) cancers.

Occult micro medullary thyroid carcinoma: therapeutic strategy and follow-up

Twenty micro medullary thyroid carcinomas (MTCs) were found in histologic specimens of 19 patients in our department from 1990 to 1998. There were 14 women and 5 men, with a median age of 63 years. The indication for surgery was goiter in 12 patients and a solitary nodule in 7 patients (three differentiated cancers). Altogether, 18 patients had unifocal micro-MTCs with a median diameter of 3.6 mm. One patient had a bilateral MTC (3 and 5 mm, respectively). Surgical procedures consisted of 9 total thyroidectomies and 10 lobectomies or subtotal thyroidectomies. Of these 10 patients, 4 underwent reoperation (totalization). One was operated on 48 months after a positive pentagastrin test: There was no thyroid residual tumor but three lymph node micrometastases. Among the six patients in whom thyroid tissue was left, a 91-year-old woman died of unrelated cause and the five others remain disease-free without biologic abnormalities at follow-ups of 18 to 70 months. Considering the aggressiveness of MTCs, total thyroidectomy with central compartment dissection is theoretically indicated. However, among the nine total thyroidectomies and four secondary totalizations associated with at least central compartment dissection, no other thyroid lesion was observed and only one case of lymph node microinvasion was found. Because of the morbidity associated with reoperation and neck dissection, we propose that it is indicated only for microcarcinomas > 5 mm in diameter, in cases of an abnormal response to pentagastrin, or when it is difficult to ensure prolonged follow-up of the patient.

The glutathione S-transferase mu polymorphism and susceptibility to acute lymphocytic leukemia

It has been postulated that the absence of glutathione S-transferase mu (GSTmu), which impairs detoxification of some carcinogens, might predispose some individuals to the development of certain cancers. In the present study, polymorphism of GSTM1 were detected by polymerase chain reaction (PCR) in 38 patients with acute lymphocytic leukemia and 75 normal subjects. The null genotype of GSTM1 was significantly more common among leukemic patients compared with the normal control group (55.3 vs. 32.0%; P<0.025). The absence of the GSTmu enzyme may increase the risk of the development of leukemia.

Tagging sentinel lymph nodes: a study of 100 patients with breast cancer

The aim of this study was to evaluate in breast cancer patients the feasibility of sentinel lymph node (SLN) identification and the sensitivity of this technique to detect node metastases. Between January and July 1997, SLNs were tracked with Evans Blue dye in 100 patients with breast cancer who then underwent complete level I/II axillary lymph node dissection (ALND). All SLNs were examined by haematoxylin-phloxin-saffron (HPS) staining and immunohistochemistry (IHC) of multiple sections. The findings for the SLNs were compared with results on ANLD. Axillary SLNs were identified in 83 patients (detection rate = 83%; 95% confidence interval (CI) 74-90%). Axillary SLNs were detected in 58/83 cases (70%) at level I only, and in 69/83 (83%) at levels including level I. Histologically positive axillary SLNs were found in 45% (37/83) of patients, including 2 patients with malignancy (micro-metastases) detected by IHC only. The sensitivity of axillary SLN to detect axillary lymph nodes metastases was 37/39 = 95% (95% CI 83-99%). SLNs of the internal mammary chain (IMC) were dissected for 33 tumours of the median or inner quadrants and detected in 26/33 = 79% of cases (95% CI 61-91%). In our experience, the overall sensitivity of SLN identification as a predictor of node (axillary or IMC) metastases was 41/43 = 95% (95% CI 84-99%), confirming the usefulness of the procedure.

Gene expressions and activities of protein phosphatases 1 alpha, 2A and 2C in hepatocarcinogenesis and regeneration after partial hepatectomy

The mRNA levels of protein phosphatases (PP) 1 alpha, 2A, and 2C were determined both in hepatocarcinogenesis and in liver regeneration. In the precancerous stage and during regeneration, the mRNA levels of PP1 alpha, PP2A, and PP2C were markedly increased compared with those in normal livers. In primary hepatomas, all three of these mRNA levels were decreased to the control levels. In poorly differentiated hepatomas, however, only PP1 alpha mRNA was specifically increased, in contrast to PP2A and PP2C, which were at the control levels or below. While PP1 activity in the non-nuclear fraction of partially hepatectomized livers was nearly constant, the activity in nuclei was increased about 2.5-fold over control levels at 12 h after partial hepatectomy, the time that corresponds to the G1 to S transition in the cell cycle of hepatocytes. On the other hand, PP2A activity in both fractions was nearly constant throughout. These results appear to suggest some involvement of protein phosphatases in regulation of hepatocyte proliferation.

Assignment of the gene encoding type 1 gamma protein phosphatase catalytic subunit (PPP1CC) on human, rat, and mouse chromosomes

Using fluorescent in situ hybridization (FISH) method, a gene encoding the catalytic subunit of protein phosphatase type 1 gamma (PPP1CC) was mapped to human 12q24.1-q24.2, rat 7 q22, and mouse 10C. These results indicate that the PPP1CC is a member of conserved synteny group between rat chromosome 7, mouse chromosome 10 and human chromosome 12. These data and mapping data about other members of PP1 family show that in spite of the high identity of PP1 isoforms, each isoform is encoded by different genes which located on different chromosomes in human, rat, and mouse.

Effect of exercise on bone mineral metabolism in diabetes

The authors attempt to assess the relationship between exercise, diabetes, and bone metabolism. An animal model system was developed to study the relationship. Animals given streptozotocin to induce a type I diabetic state show elevated plasma glucose and triglyceride levels and a decrease in body weight. Analysis of femurs revealed alterations in copper, phosphorus, and zinc levels in animals with diabetes compared with controls. Mineral analysis of femurs from diabetic animals placed on an exercise regimen revealed values closer to control levels.

Regional localization of rat and mouse protein-tyrosine phosphatase PTP alpha/LRP gene (Ptpra) by fluorescence in situ hybridization

Protein tyrosine phosphatases (PTPases) negatively regulate the effect(s) of protein tyrosine kinases and are implicated in the regulation of a variety of biological events including cell activation, differentiation, and neoplastic transformation. To gain insight into the role(s) of the PTPases, we mapped the gene encoding for the widely expressed receptor-like protein tyrosine phosphatase PTP alpha/LRP (locus symbol Ptpra) to rat chromosome 3q36 and mouse chromosome 2G by fluorescence in situ hybridization method. These results indicate that there is a conserved syntenic group between human 20p13, rat 3q36, and mouse 2G.

Neoplastic alterations in subcellular distribution of type 1 alpha protein phosphatase in rat ascites hepatoma cells

Neoplastic alterations of type 1 alpha protein phosphatase (PP1 alpha) have been studied in rat ascites hepatoma cells, using regenerating liver after partial hepatectomy and normal rat liver as controls. In the particulate fraction of hepatomas, potential PP1 activity and the amount of PP1 alpha were remarkably increased compared with either regenerating or normal livers. In the nuclear fraction, PP1 activity and the amount of PP1 alpha were increased in hepatoma compared with the controls. The nuclear PP1 activity in hepatomas was activated by treatment with CO2+/trypsin, whereas that of normal or regenerating liver was not activated. These characteristic alterations of PP1 alpha in its amount and subcellular distribution may be implicated in malignant phenotype(s) such as uncontrolled cell growth.

Comparative mapping of the gene encoding the catalytic subunit of protein phosphatase type 1 alpha (PPP1CA) to human, rat, and mouse chromosomes

Using fluorescence in situ hybridization method, the gene encoding the protein phosphatase type 1 alpha catalytic subunit (PPP1CA) was localized to human chromosome band 11q13, rat chromosome band 1q43, and mouse chromosome band 7E3-F2. These results suggest that PPP1CA is a member of a syntenic group.

Chromosomal localization of human, rat, and mouse protein phosphatase type 1 beta catalytic subunit genes (PPP1CB) by fluorescence in situ hybridization

Using fluorescent in situ hybridization (FISH) method, gene encoding the catalytic subunit of protein phosphatase type 1 beta (PPP1CB) in human and its corresponding gene in rat (PP1 delta) and mouse (dis2m2) were mapped to human 2p23, rat 6q21-q23, and mouse 12D, respectively. These results indicate that PPP1CB is a member of conserved syntenic group. It is shown that the genes encoding catalytic subunit of protein phosphatase type 1 family (PP1 alpha, PP1 beta, and PP1 gamma in human and those corresponding genes in rat and mouse), in spite of their high identity, are located to different chromosomes in these three species.

Selective increases in isoform PP1 alpha of type-1 protein phosphatase in ascites hepatoma cells

The amounts of four isoforms of the catalytic subunit of type-1 protein phosphatases, PP1 alpha, PP1 gamma 1, PP1 gamma 2, and PP1 delta, have been determined in extracts of rat ascites hepatomas, AH131A, AH13, AH13NMOR, AH143A, and Yoshida sarcoma, and compared to those of rat liver by Western blot analysis. The amount of PP1 alpha was increased over three times in all five hepatomas. The amount of PP1 gamma 1 was increased over two times in AH13, AH13NMOR, and AH143A. The amount of PP1 delta was selectively increased about 4 times in AH131A and AH143A. The PP1 gamma 2 protein was undetectable in both liver and hepatomas. There was good parallelism between the general increase in only PP1 alpha protein in the hepatomas and the previous data demonstrating the general increase in PP1 alpha mRNA in numerous ascites hepatomas. These results suggest that PP1 alpha plays important roles in the expression of malignant phenotype, that its amount is under strict control at the transcription level, and that PP1 gamma 1 and PP1 delta play different roles in the expression of some phenotype(s) of the ascites hepatomas.

Diagnosis of adolescent pregnancy--1965 vs 1980

The study compares changes in the accuracy of the diagnosis of pregnancy in adolescents between 1965 and 1980. We compared 44 records of adolescents evaluated in 1965 to those of 44 who were evaluated 15 years later in 1980. The following data were examined: (1) reason for consultation, (2) amount of time prior to making the correct diagnosis, and (3) the most common diagnostic errors. The results showed that (1) the initial diagnosis was correct only 75 per cent of the time in 1965 and 86 per cent in 1980, (2) both in 1965 and 1980 most patients initially consulted for "vague complaints," (3) in 1965 and 1980 the most common diagnostic errors were "gastrointestinal disorder" and "functional symptoms," and (4) pregnancy was diagnosed earlier in 1980 than in 1965. Improvement in diagnostic accuracy should be possible if clinicians screen for pregnancy in adolescent girls consulting for vague symptoms such as nausea, weight gain, urticaria, and somnolence.