A Dual-Channel MoS2-Based Selective Gas Sensor for Volatile Organic Compounds.

Significant progress has been made in two-dimensional material-based sensing devices over the past decade. Organic vapor sensors, particularly those using graphene and transition metal dichalcogenides as key components, have demonstrated excellent sensitivity. These sensors are highly active because all the atoms in the ultra-thin layers are exposed to volatile compounds. However, their selectivity needs improvement. We propose a novel gas-sensing device that addresses this challenge. It consists of two side-by-side sensors fabricated from the same active material, few-layer molybdenum disulfide (MoS2), for detecting volatile organic compounds like alcohol, acetone, and toluene. To create a dual-channel sensor, we introduce a simple step into the conventional 2D material sensor fabrication process. This step involves treating one-half of the few-layer MoS2 using ultraviolet-ozone (UV-O3) treatment. The responses of pristine few-layer MoS2 sensors to 3000 ppm of ethanol, acetone, and toluene gases are 18%, 3.5%, and 49%, respectively. The UV-O3-treated few-layer MoS2-based sensors show responses of 13.4%, 3.1%, and 6.7%, respectively. This dual-channel sensing device demonstrates a 7-fold improvement in selectivity for toluene gas against ethanol and acetone. Our work sheds light on understanding surface processes and interaction mechanisms at the interface between transition metal dichalcogenides and volatile organic compounds, leading to enhanced sensitivity and selectivity.

Reduced trap-density and boosted performance of CH3NH3PbI3solar cells by 1-Pentanethiol enhanced anti-solvent washing route.

Performance and the stability of the perovskite-based photovoltaic devices are directly linked to existing trap-states or defect profiles at the surface and/or in the bulk of perovskite layers. Hence identification of stemming the defects during perovskite formation is crucial for achieving superior and long-lasting performances. Here, we present the effect of 1-Pentanethiol incorporation into the one-step deposition of perovskite layers. A feasible glove box-free route results in high-quality CH3NH3PbI3layers under highly humid conditions (RH > 50%) but at low temperatures (T< 18 °C). 1-Pentanethiol addition into the washing solvent leads to the refinement of I/Pb stoichiometry, elimination of the iodide deficiencies, and reduction of the trap-state densities. Consequently, a precise amount 1-Pentanethiol addition enhances photovoltaic performances, resulting in a 54% PCE improvement for CH3NH3PbI3-based inverted solar cells.

Evaluation of the association COMT Val158Met variant and childhood trauma on aggression in Turkish SCZ patients.

Childhood trauma is a serious form of stress that makes individuals more vulnerable to developing Schizophrenia (SCZ). Many studies have predicted the association between the catechol-O-methyltransferase (COMT) gene Val158Met variant and aggressive attack. We aimed to investigate the association the COMT variant and childhood trauma on aggression in Turkish SCZ patientsThis study included 89 patients diagnosed with SCZ. Childhood Trauma Questionnaire (CTS) and Overt Aggression Scale (OAS) were used to assess childhood trauma and aggression. COMT Val158Met variant was analyzed by PCR-RFLP method from isolated DNAs.There was no statistically significant difference in comparing the COMT genotype distribution and clinical characteristics including suicide attempts, self-destructive behavior, crime history, substance, alcohol and tobacco use. When we evaluate Spearman's rank correlation coefficients between CTQ and OAS, the correlation between the OAS and CTQ scores of the patients was statistically significant except for the sexual abuse subgroup of the CTQ. In the univariate logistic regression analysis, in which the dichotomized OAS score was accepted as the dependent variable, it was found that age, suicide attempt, substance abuse, and CTQ total score significantly predicted the higher OAS scores. In the multivariate logistic regression analysis, which included the variables that predicted OAS significantly, age, suicide attempt, and total CTQ score were determined as independent variables predicting OAS.Because of the phenotypic complexity in SCZ, it is difficult to draw strong conclusions about COMT and to highlight a definitive relationship. Larger-scale studies are needed to examine the multifactorial inheritance pattern of schizophrenia in different dimensions.

Ultraviolet-Ozone Treatment: An Effective Method for Fine-Tuning Optical and Electrical Properties of Suspended and Substrate-Supported MoS2.

Ultraviolet-ozone (UV-O3) treatment is a simple but effective technique for surface cleaning, surface sterilization, doping, and oxidation, and is applicable to a wide range of materials. In this study, we investigated how UV-O3 treatment affects the optical and electrical properties of molybdenum disulfide (MoS2), with and without the presence of a dielectric substrate. We performed detailed photoluminescence (PL) measurements on 1-7 layers of MoS2 with up to 8 min of UV-O3 exposure. Density functional theory (DFT) calculations were carried out to provide insight into oxygen-MoS2 interaction mechanisms. Our results showed that the influence of UV-O3 treatment on PL depends on whether the substrate is present, as well as the number of layers. Additionally, 4 min of UV-O3 treatment was found to be optimal to produce p-type MoS2, while maintaining above 80% of the PL intensity and the emission wavelength, compared to pristine flakes (intrinsically n-type). UV-O3 treatment for more than 6 min not only caused a reduction in the electron density but also deteriorated the hole-dominated transport. It is revealed that the substrate plays a critical role in the manipulation of the electrical and optical properties of MoS2, which should be considered in future device fabrication and applications.

Evaluation of the relationship between mesenchymal stem cells and immune system in vitro conditions.

BACKGROUND: Mesenchymal stem cells (MSCs), are a novel therapeutic option as the most common cell source, play an important role in the immunomodulation. In this study, it was aimed to determine the effect of MSCs on cytokines secreted by the immune system cells. METHODS: Intracellular cytokine levels (Interleukin-4 (IL-4), Interferon-γ (IFN-γ), and Interleukin-17 (IL-17)) detected by flow cytometry before and after co-culture between peripheral blood mononuclear cells (PBMCs) and MCSs. At the same time, supernatant cytokine levels were measured using the ELISA. RESULTS: In our study, MSCs were isolated from cord blood (CB) and Wharton's Jelly (WJ), and their surface markers (CD44 (100%), CD73 (99.6%), CD90 (100%), CD105 (88%)) shown by flow cytometry method. Both CB-MSCs and WJ-MSCs were used in co-culture MSC/PBMC ratios of 1/5 and 1/10, incubation times of 24 h and 72 h. In the present study, when we compared co-cultures of CB-MSC or WJ-MSC with PBMCs, intracellular levels of cytokines IFN-γ, IL-17 (pro-inflamatory) and IL-4 (anti-inflamatory) were increased, and supernatant levels were decreased significantly (p < 0.05). The level of transforming growth factor beta (TGF-ß) (anti-inflamatory) was significantly decreased for both CB-MSC and WJ-MSC in supernatant (p < 0.05). CONCLUSIONS: It was investigated pro-inflammatory and anti-inflammatory effects of CB-MSCs and WJ-MSCs on PBMCs with the obtained results. According to the results, MSCs demonstrated different immunologic effects after the incubation time and ratios. For further studies, it should be known between interaction of MSCs and immune system.

The in vitro treatment of mesenchymal stem cells for colorectal cancer cells.

Colorectal cancer is the most common tumor of the gastrointestinal system. The conventional treatment options for colorectal cancer are troublesome for both patients and clinicians. Recently, mesenchymal stem cells (MSCs) have been the novel focus for cell therapy due to their migration to tumor sites. In this study, the apoptotic effect of MSCs on colorectal cancer cell lines has been aimed. HCT-116 and HT-29 were selected as the colorectal cancer cell lines. Human umbilical cord blood and Wharton's jelly were used as mesenchymal stem cell sources. To discriminate against the apoptotic effect of MSC on cancer, we also used peripheral blood mononuclear cells (PBMC) as a healthy control group. Cord blood-MSC and PBMC were obtained by ficoll-paque density gradient, and Wharton's jelly-MSC by explant method. Transwell co-culture systems were used as cancer cells or PBMC/MSCs at ratios of 1/5 and 1/10, with incubation times of 24 h and 72 h. The Annexin V/PI-FITC-based apoptosis assay was performed by flow cytometry. Caspase-3 and HTRA2/Omi proteins were measured by ELISA. For both ratios in both cancer cells, it was found that the apoptotic effect of Wharton's jelly-MSC was significantly higher in 72-h incubations (p < 0.006), whereas the effect of cord blood mesenchymal stem cell in 24-h incubations were higher (p < 0.007). In this study, we showed that human cord blood and tissue-derived MSCs treatment led to colorectal cancers to apoptosis. We anticipate that further in vivo studies may shed light on the apoptotic effect of MSC.

Increasing Apoptotic Effect of Cord Blood and Wharton's Jelly-derived Mesenchymal Stem Cells on HT-29.

BACKGROUND: Colorectal cancer (CRC) is the third most common cancer worldwide. Recently, mesenchymal stem cells (MSCs) have been considered a suitable cell therapy option for cancer due to their high migration rate to the tumor site. OBJECTIVES: The study aimed to compare the effects of human umbilical cord blood derived-MSC (UCMSC) and human Wharton's Jelly derived-MSC (WJ-MSC) on the HT-29 cell line. METHODS: UC-MSC was obtained by Ficoll-Paque density gradient and WJ-MSC by explant method. The characterizations of MSCs and apoptosis assays were performed by flow cytometry, and caspase-3 protein levels were measured by ELISA. RESULTS: After 72 hours of HT-29 cancer cells incubation, it was indicated that WJ-MSC was more effective at 1:5 and 1:10 ratios. Similar results were found for caspase-3 by ELISA. Moreover, WJ-MSC (1:5, p < 0.006; 1:10, p < 0.007) was found to be more effective at both doses compared to UC-MSC. CONCLUSION: In this study, we used two different MSC sources at two different ratios to evaluate the apoptotic effect of MSC in vitro on HT-29 CRC cells. As a result, WJ-MSC indicated a more apoptotic effect on HT-29 cells compared to CB-MSC. We anticipated that this preliminary in vitro study would be extended in future in vitro/in vivo studies. Moreover, investigating the behavior of MSC in colorectal tumor microenvironment will be beneficial for the stem cell therapy approach.

Boron- and Boric Acid-Treated Titanium Implant Surfaces in Sheep Tibia: A Histologic, Histomorphometric and Mechanical Study.

The aim of this study was to compare the topographical, chemical and osseointegration characteristics of sandblasting and acid-etching (SLA) surfaces and dental implants treated by boron compounds. Titanium (Ti) disks (n = 20) were modified using boron (B) and boric acid (H3BO3) and then compared with the conventional SLA surface via surface topographic characterizations. Dental implants (3.5 mm in diameter and 8 mm in length) with the experimental surfaces (n = 96) were inserted into the tibias of six sheep, which were left to heal for 3 and 7 weeks. Histologic, histomorphometric (bone−implant contact (BIC%)) and mechanical tests (removal torque value (RTV)) were performed. The boron-coated surface (BC group) was smoother (Rz: 4.51 µm ± 0.13) than the SLA (5.86 µm ± 0.80) and the SLA-B (5.75 µm ± 0.64) groups (p = 0.033). After 3 weeks, the highest mean RTV was found in the SLA group (37 N/cm ± 2.87), and the difference compared with the BC group (30 N/cm ± 2.60) was statistically significant (p = 0.004). After 7 weeks, the mean RTV was >80 N/cm in all groups; the highest was measured in the H3BO3-treated (BS) group (89 N/cm ± 1.53) (p < 0.0001). No statistically significant differences were found in the BIC%s during both healing periods between the groups. H3BO3 seems to be a promising medium for dental implant osseointegration.

Blood and bone marrow donor registry of Istanbul medical faculty activity and experience in past 3 years : A cross-sectional documentation of TRIS activity: the first blood and marrow registry in Turkey.

Allogeneic stem cell transplantation (SCT) offers a potential cure for some hematological malignancies. For those patients without a family donor, unrelated donor (MUD) registries serve for identifying the best donor. In the present study, we aimed to give a cross-sectional report of our registry's activity and experience as the first established national MUD registry in the country. The study is retrospective and covers the period of 2016 to 2019. A total of 1855 donor searches were performed, and 642 were included in the study. All data were electronically obtained from the institutional database system. All SCTs were either 10/10 or 9/10 HLA matched and originated from an international registry. The most preferred stem cell source was peripheral blood (70.2%). A quarter of transplants were performed using bone marrow, and cord blood was used with a rate of 1.4%. The pandemic-related problems were similar for the other two national registries. During the pandemic, 71 of 432 patients who were searched for donors underwent stem cell transplant(SCT). The low number was related mostly with postponing of SCTs and/also difficulties in continuing of volunteering and in achievement of stem cells from international registry. During the Covid19 pandemic, the SCT activity of centers decreased according to the national, and international guidelines. The study revealed an organized, and multidirectional capacity of the registry and also the adaptation to unpredicted conditions such as pandemic. On the other hand, there is a need for more effective strategies for donor recruitment and retention programme.

Some Bryophytes Trigger Cytotoxicity of Stem Cell-like Population in 5-Fluorouracil Resistant Colon Cancer Cells.

Colorectal cancer is the third most common cancer worldwide. Cancer stem cells are known to play an important role in relapse, and metastases of the disease after chemotherapy. Investigation of new drugs, and their combinations targeting these cells and thus eliminating cancer is one of the most urgent needs of today's chemotherapy. The aim of the present study was to evaluate the effects of Bryophytes like Abietinella abietina (AA), Homolothecium sericeum (HS), Tortella tortuosa (TT), Syntrichia ruralis (SR), and Bryoerythrophyllum rubrum (BR) species extracted with ethyl alcohol on 5-fluorouracil(5-FU) resistant colorectal cancer cell lines (HCT116 and HT29). After extraction, stock solutions of bryophytes were prepared, and IC50 values were detected in drug-resistant cells obtained with 5-FU application. CD24+, CD44+/CD133+ surface markers and P-glycoprotein (P-gp) mediated efflux were isolated from both 5-FU treated cells and analyzed using the flow cytometry. In all bryophyte-treated groups, the binding Rho123low (low Rho fluorescence) and Rhohigh (high Rho fluorescence) were sorted from 5-FU resistant HCT116, and HT-29 cells. All types of bryophytes were found cytotoxic. Bryophyte extract reduced the percentage of Rholow cells in cultures incubated with 5-FU. In summary, the implementation of these bryophytes might be regarded as an effective approach for treatment of colorectal cancer due to their cytotoxic effect that decreases the recurrence of the disease.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1933098.

Investigation of inflammation related gene polymorphism of the mannose-binding lectin 2 in schizophrenia and bipolar disorder.

OBJECTIVES: To investigate the association between mannose-binding lectin 2 (MBL2) codon 54 polymorphism and clinical features of patients diagnosed with schizophrenia (SCZ) or bipolar disorder (BD). METHODS: One hundred and eighteen patients with SCZ, 100 patients with BD, and 100 healthy volunteers were included in the case-control study. The patients consecutively admitted to the outpatient clinic in December 2017-May 2018 and were evaluated with some scales for clinical parameters. Polymerase chain reaction and RFLP were used to determine MBL2 polymorphism in DNA material. RESULTS: The MBL2 gene polymorphism distributions in SCZ or BD patients were significantly different from the control group. The heterozygous genotype percentages were significantly higher in the control group than in the SCZ or BD patients (OR: 0.450; 95% Cl: 0.243-0.830; p=0.010; OR: 0.532; 95%Cl: 0.284-0.995; p=0.047, respectively), and there were statistically significant differences in the MBL2 polymorphism distributions between treatment-responsive SCZ or BD patients and treatment-resistant patients diagnosed with SCZ or BD. The heterozygous genotype percentages were also significantly higher in the treatment-responsive group than in the treatment-resistant group in SCZ or BD patients (OR: 7.857; 95% Cl: 1.006-61.363; p=0.023; OR: 8.782; 95% Cl: 1.114-69.197; p=0.016, respectively). CONCLUSION: The presence of a heterozygous MBL2 genotype seems to be favorable both in terms of the absence of SCZ and BD in the healthy population and treatment response for Turkish patients.

Association of MIF and MBL2 gene polymorphisms with attempted suicide in patients diagnosed with schizophrenia or bipolar disorder.

The aim of this study to investigate the genetic polymorphisms in macrophage inhibitory factor (MIF) and mannose-binding lectin 2 (MBL2) gene in schizophrenia (SCZ) or bipolar disorder (BD) patients with attempted suicide by comparing with a non-attempted SCZ or BD patients and healthy controls. A sample of 108 patients with SCZ, 100 patients with BD and 100 healthy volunteers were included in the study. SCID-I was used to confirm the diagnosis according to DSM-IV-TR criteria. The patients were evaluated by data forms that included sociodemographic, suicidal behavior and symptom severity information. PCR-RFLP was used to determine MIF and MBL2 gene polymorphisms from DNA material. Our results demonstrated that the distributions of MBL2 genotype (AA, AB, BB), combined genotype (AA, AB/BB) and the allele frequencies (A, B) of attempted suicide patients in SCZ were significantly different from the non-attempted SCZ patients. The distributions of the MBL2 genotype of attempted suicide patients in SCZ were significantly different from the control group. The distributions of MIF genotype (GG, GC, CC), combined genotype (GG, GC/CC) and the allele frequencies (G, C) of attempted suicide patients in BD were significantly different from the non-attempted BD patients or control group. In summary MBL2 gene polymorphism may be associated with attempted suicide in SCZ and MIF gene polymorphism might be associated with attempted suicide in BD. However, further studies with other gene variants in different ethnic populations are needed to address the exact role of these polymorphisms in SCZ or BD.

Well-ordered nanoparticle arrays for floating gate memory applications.

A non-volatile floating gate memory device containing well-ordered Au nanoparticles (NPs) is fabricated as a metal-oxide-semiconductor capacitor structure. With superior control on the size, shape and position of nanoparticles, the presented nano-floating gate memory (NFGM) device possesses almost perfect precision of device geometry. The well-ordered Au NPs embedded within the memory device exhibit large memory window at low operation voltages (8.8V @ ± 15V), fast operation time (<10-4 s) and good retention (up to 107 s). In this work, the structural properties of the NFGM device are correlated with the examined electrical properties. The current results are compared with the other studies in the literature to emphasis the advantages of the precise ordering and geometry of the NPs.

Effects of Thermal Annealing and Selective Chemical Etching on Structural and Optical Properties of GaAsBi Epilayer with Droplet Systems.

A GaAs1-xBix layer was grown by molecular beam epitaxy (MBE) with a low Bi content (2.3%) on GaAs maintaining the substrate at a non-rotating state and was then annealed at 750 °C, 800 °C and 850 °C. Each sample that was covered with droplets was investigated by using the Atomic Force Microscopy (AFM), Electrostatic Force Microscopy (EFM) and Photoluminescence (PL) techniques. The surface properties of the GaAs1-xBix layer were investigated by AFM and observed to have a droplet system, which was composed of a donut and a tail. The optical quality of the samples was enhanced after thermal annealing up to 800 °C, and the maximum PL intensity was obtained at 750 °C. AFM images revealed that the shape of the droplet and tail changed with increasing annealing temperature. EFM images revealed a phase separation on the surface droplet system. To explore the nature of the droplets, previously claimed to be made of Ga and/or Bi, and their effect on PL spectrum, a chemical etch procedure was carried out by using diluted solutions of H2SO4 and/or HCl. We showed that droplets may be efficiently removed from the surface, and PL intensity could be improved by using a proper sequence of chemical etching procedures. Furthermore, the presence of two different phases for the droplet-system observed by EFM was also confirmed by the selective etching procedure.

Thermal oxidation and hydrofluoric acid treatment on the sandblasted implant surface: A histologic histomorphometric and biomechanical study.

OBJECTIVES: This study aimed to analyze and compare the topographical, chemical, and osseointegration characteristics of a sandblasted acid-etched surface (SLA group), a sandblasted thermally oxidized surface (SO group), and a surface chemically modified by hydrofluoric (HF) acid (SOF group). MATERIALS AND METHODS: Following the preparation and characterization of the relevant surfaces, 90 implants (30 for each group) were placed on the pelvic bone of six sheep. Resonance frequency analysis (RFA), insertion (ITV), removal torque value (RTV), and histomorphometric analyses (BIC%) were performed after three and 8 weeks of healing. The results were analyzed by nonparametric tests (p < 0.05). RESULTS: The roughness value (Ra) in the SOF group was significantly lower than the SLA and the SO group (p = 0.136, p < 0.001, respectively). This resulted in a substantially inferior ITV 14.83 N/cm (SD: 4.04) than those achieved in the SLA and SO groups (19.50 (SD: 6.07) and 20.17 N/cm (SD: 8.95), respectively; p = 0.001). A statistically significant change in the RFA from the baseline (47.36 ISQ, SD: 6.93) to the 3rd week (62.56 ISQ, SD: 5.29) was observed in the SOF group only (p = 0.008). The highest postplacement RFA and RTV values were measured from the SLA group (61.11 ISQ, SD: 7.51 and 78.22 N/cm, SD: 28.73). The early-term (3rd week) BIC% was highest in the SO group (39.93%, SD: 16.14). After 8 weeks, the differences in BIC% values were statistically not significant. CONCLUSIONS: Adjunct HF acid application on the thermally oxidized surface did not provide an additional benefit compared to the sandblasted and acid-etched surface (SLA group).

A simplified cell culture model for research on intestinal inflammation

Background/aim: The aim of this study was to combine some easy and economical defined methods and constitute a comprehensive cell culture model to use in the bowel diseases characterized by inflammation. Materials and methods: Induction of inflammation was performed using lipopolysaccharide (LPS) or a cytokine mixture (TNF-α: 10 ng/mL; IFN-γ: 100 ng/mL; IL-1ß: 1 ng/mL). IEC-6 cells were grown to confluence and serum-starved, wounds were constituted, and progress of cell migration into the wounds was photographed at 0, 2, 4, 6, 8, 10, 12, and 24 h in the presence or absence of an inflammatory environment. Cells were then grown and multiple scratches were performed to replicate the conditions of migration assay. Nitric oxide synthase-2 (iNOS) and cyclooxygenase-2 (COX-2) protein expressions were assessed. Results: Cells covered 88% of the initial wound at 24 h in the control group, 54% in the LPS group, and 35% in the cytokine mixture group. LPS and the cytokine mixture were also found to independently increase iNOS and COX-2 expressions. Conclusion: Our study, being inexpensive and practical, describes a model that integrates some methods to constitute a basic model for bowel diseases characterized by inflammation. It can be integrated as a preliminary experiment for etiopathogenesis and drug research studies.

Ribosome biogenesis mediates antitumor activity of flavopiridol in CD44+/CD24- breast cancer stem cells.

Flavopiridol is a synthetically produced flavonoid that potently inhibits the proliferation of human tumor cell lines. Flavopiridol exerts strong antitumor activity via several mechanisms, including the induction of cell cycle arrest and apoptosis, and the modulation of transcriptional regulation. The aim of the present study was to determine the effect of flavopiridol on a subpopulation of cluster of differentiation (CD)44+/CD24- human breast cancer MCF7 stem cells. The CD44+/CD24- cells were isolated from the MCF7 cell line by fluorescence-activated cell sorting and treated with 100, 300, 500, 750 and 1,000 nM flavopiridol for 24, 48 and 72 h. Cell viability and proliferation assays were performed to determine the inhibitory effect of flavopiridol. Gene expression profiling was analyzed using Illumina Human HT-12 v4 Expression BeadChip microarray. According to the results, the half maximal inhibitory concentration (IC50) value of flavopiridol was 500 nM in monolayer cells. Flavopiridol induced growth inhibition and cytotoxicity in breast cancer stem cells (BCSCs) at the IC50 dose. The present study revealed several differentially regulated genes between flavopiridol-treated and untreated cells. The result of the pathway analysis revealed that flavopiridol serves an important role in translation, the ribosome biogenesis pathway, oxidative phosphorylation, the electron transport chain pathway, carbon metabolism and cell cycle. A notable result from the present study is that ribosome-associated gene expression is significantly affected by flavopiridol treatment. The data of the present study indicate that flavopiridol exhibits antitumor activity against CD44+/CD24- MCF7 BCSCs through different mechanisms, mainly by inhibiting translation and the ribosome biogenesis pathway, and could be an effective chemotherapeutic molecule to target and kill BCSCs.

JAK/STAT pathway interacts with intercellular cell adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) while prostate cancer stem cells form tumor spheroids.

PURPOSE: JAK/STAT is an evolutionarily conserved pathway and very important for second messenger system. This pathway is important in malignant transformation and accumulated evidence indicates that this pathway is involved in tumorigenesis and progression of several cancers. It was possible to assume that activation of JAK/STAT pathway is associated with increase in the expressions of ICAM/1 and VCAM-1. In this study we hypothesized that when cells were maintained as spheroids or monolayers, the structure of cancer stem cells (CSCs) could show differentiation when compared with non-CSCs. METHODS: DU-145 human prostate cancer cells were cultured using the Ege University molecular embryology laboratory medium supplemented with 10% fetal bovine serum. Clusters of differentiation 133 (CD133)(+high)/CD44(+high) prostate CSCs were isolated from the DU145 cell line by using BD FACSAria. CD133//CD44+ CSCs were cultured until confluent with 3% noble agar. The expression of these proteins in CSCs and non-CSCs was analyzed by immunohistochemistry. RESULTS: Different expression profiles were observed in the conventional two-dimensional (2D) and three-dimensional (3D) experimental model system when CSCs and non-CSCs were compared. Human prostate CSCs exhibited intense ICAM-1 and VCAM-1 immunoreaction when compared with non-CSCs. These findings were supported by the fact that VCAM-1 on the surface of cancer cells binds to its counterreceptor, the α4ß1 integrin (also known as very-late antigen, VLA-4), on metastasis-associated macrophages, triggering VCAM-1-mediated activation of the phosphoinositide 3-kinase growth and survival pathway in cancer cells. CONCLUSIONS: The results of this study showed that changes in JAK/STAT pathway are related with adhesion molecules and could affect cancer progression.

Magnetotransport study on as-grown and annealed n- and p-type modulation-doped GaInNAs/GaAs strained quantum well structures.

We report the observation of thermal annealing- and nitrogen-induced effects on electronic transport properties of as-grown and annealed n- and p-type modulation-doped Ga1 - xInxNyAs1 - y (x = 0.32, y = 0, 0.009, and 0.012) strained quantum well (QW) structures using magnetotransport measurements. Strong and well-resolved Shubnikov de Haas (SdH) oscillations are observed at magnetic fields as low as 3 T and persist to temperatures as high as 20 K, which are used to determine effective mass, 2D carrier density, and Fermi energy. The analysis of temperature dependence of SdH oscillations revealed that the electron mass enhances with increasing nitrogen content. Furthermore, even the current theory of dilute nitrides does not predict a change in hole effective mass; nitrogen dependency of hole effective mass is found and attributed to both strain- and confinement-induced effects on the valence band. Both electron and hole effective masses are changed after thermal annealing process. Although all samples were doped with the same density, the presence of nitrogen in n-type material gives rise to an enhancement in the 2D electron density compared to the 2D hole density as a result of enhanced effective mass due to the effect of nitrogen on conduction band. Our results reveal that effective mass and 2D carrier density can be tailored by nitrogen composition and thermal annealing-induced effects. PACS: 72.00.00; 72.15.Gd; 72.80.Ey.

Bismuth-induced effects on optical, lattice vibrational, and structural properties of bulk GaAsBi alloys.

Bulk GaAs1 - xBix/GaAs alloys with various bismuth compositions are studied using power- and temperature-dependent photoluminescence (PL), Raman scattering, and atomic force microscopy (AFM). PL measurements exhibit that the bandgap of the alloy decreases with increasing bismuth composition. Moreover, PL peak energy and PL characteristic are found to be excitation intensity dependent. The PL signal is detectable below 150 K at low excitation intensities, but quenches at higher temperatures. As excitation intensity is increased, PL can be observable at room temperature and PL peak energy blueshifts. The quenching temperature of the PL signal tends to shift to higher temperatures with increasing bismuth composition, giving rise to an increase in Bi-related localization energy of disorders. The composition dependence of the PL is also found to be power dependent, changing from about 63 to 87 meV/Bi% as excitation intensity is increased. In addition, S-shaped temperature dependence at low excitation intensities is observed, a well-known signature of localized levels above valence band. Applying Varshni's law to the temperature dependence of the PL peak energy, the concentration dependence of Debye temperature (ß) and thermal expansion coefficient (α) are determined. AFM observations show that bismuth islands are randomly distributed on the surface and the diameter of the islands tends to increase with increasing bismuth composition. Raman scattering spectra show that incorporation of Bi into GaAs causes a new feature at around 185 cm-1 with slightly increasing Raman intensity as the Bi concentration increases. A broad feature located between 210 and 250 cm-1 is also observed and its intensity increases with increasing Bi content. Furthermore, the forbidden transverse optical (TO) mode becomes more pronounced for the samples with higher bismuth composition, which can be attributed to the effect of Bi-induced disorders on crystal symmetry. PACS: 78.55Cr 78.55-m 78.20-e 78.30-j.