Structural and electrical properties of Nb-substituted LiTa1-xNbxO3

Single phase LiTa1-xNbxO3 solid solution with 0.00 ≤ x ≤ 1.00 was successfully synthesised via conventional solid-state method at 950°C for 24 h. These materials were refined and fully indexed with hexagonal crystal system, space group of R3c; lattice parameters, a ranging from 5.1410(6) Ǻ to 5.1471(3) Ǻ and c ranging from 13.7467(1) Ǻ to 13.8341(1) Ǻ; with α = β = 90° and γ = 120°. Variation of the lattice parameters in these materials was found to be negligibly small throughout the subsolidus solution. No thermal event was detected within the studied temperature range of 50 to 1000°C. The electrical properties of samples were characterised by AC impedance analyser, HP4192A at temperature ranging from room temperature to 850°C over a frequency range of 5 Hz to 13 MHz. LiTa1-xNbxO3 materials exhibited bulk response with associated capacitances in the order of 10-12 F cm-1 and the temperature-dependent conductivities were found to increase with increasing temperatures. The results showed that LiTa1-xNbxO3 samples were of typical ferroelectrics

Somatostatin Is Expressed in FRTL-5 Thyroid Cells and Prevents Thyrotropin-Mediated Down-Regulation of the Cyclin-Dependent Kinase Inhibitor p27kip11

9 pages, 8 figures, 3 tables.Using RT and amplification, we have detected specific RNA transcripts encoding somatostatin in FRTL-5 thyroid cells. This observation indicates that within the thyroid context, expression of somatostatin is not restricted to the parafollicular C cells. Transfection of FRTL-5 cells with constructs containing either the complete somatostatin gene promoter or deletions carrying the cAMP response element-binding site allowed us to demonstrate that transcription of the somatostatin gene is hormonally regulated by TSH. Blockage of somatostatin by specific antibodies resulted in an increased capacity of TSH-induced FRTL-5 cell-conditioned medium to promote cell proliferation, demonstrating that under physiological conditions, somatostatin exerts a cytostatic effect on FRTL-5 cells growth. Somatostatin treatment of FRTL-5 cells resulted in a growth retardation, caused by a dose-response delay in the G1 phase of the cell cycle. This effect appears to be mediated by the cyclin-dependent kinase inhibitor p27kip1, which is clearly down-regulated in FRTL-5 cells treated with TSH and whose expression is reestablished by somatostatin in a dose-dependent manner. Participation of somatostatin in the control of FRTL-5 cell proliferation is in agreement with the detection of specific somatostatin receptor type 2. Flow cytometric assays reveal that FRTL-5 cells transformed with the K-ras oncogene are still sensitive to somatostatin treatment, whereas fully neoplastic FRT cells no longer respond to this peptide. Taking together, the results demonstrate the participation of an autocrine loop in the control of thyroid cell proliferation, and the possibility that this mechanism could be altered in the process of thyroid carcinogenesis.This work was supported by Grants DGICYT (PM97–0065), CAM (08.1/0025/1997), and Fundación Salud 2000 (Spain).Peer reviewe

Phylogenetics of Archerfishes (Toxotidae) and Evolution of the Toxotid Shooting Apparatus

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Archerfishes (Toxotidae) are variously found in the fresh- and brackish-water environments of Asia Pacific and are well known for their ability to shoot water at terrestrial prey. These shots of water are intended to strike their prey and cause it to fall into the water for capture and consumption. While this behavior is well known, there are competing hypotheses (blowpipe vs. pressure tank hypothesis) of how archerfishes shoot and which oral structures are involved. Current understanding of archerfish shooting structures is largely based on two species, Toxotes chatareus and T. jaculatrix. We do not know if all archerfishes possess the same oral structures to shoot water, if anatomical variation is present within these oral structures, or how these features have evolved. Additionally, there is little information on the evolution of the Toxotidae as a whole, with all previous systematic works focusing on the interrelationships of the family. We first investigate the limits of archerfish species using new and previously published genetic data. Our analyses highlight that the current taxonomy of archerfishes does not conform to the relationships we recover. Toxotes mekongensis and T. siamensis are placed in the synonymy of T. chatareus, Toxotes carpentariensis is recognized as a species and removed from the synonymy of T. chatareus, and the genus Protoxotes is recognized for T. lorentzi based on the results of our analyses. We then take an integrative approach, using a combined analysis of discrete hard- and soft-tissue morphological characters with genetic data, to construct a phylogeny of the Toxotidae. Using the resulting phylogenetic hypothesis, we then characterize the evolutionary history and anatomical variation within the archerfishes. We discuss variation in the oral structures and the evolution of the mechanism with respect to the interrelationships of archerfishes, and find that the oral structures of archerfishes support the blowpipe hypothesis but soft-tissue oral structures may also play a role in shooting. Finally, by comparing the morphology of archerfishes to their sister group, we find that the Leptobramidae has relevant shooting features in the oral cavity, suggesting that some components of the archerfish shooting mechanism are examples of co-opted or exapted traits

Control of immune cell entry through the tumour vasculature: a missing link in optimising melanoma immunotherapy?

Metastatic melanoma remains a fatal disease to many worldwide, even after the breakthrough introduction of targeted therapies such as BRAF inhibitors and immune checkpoint blockade therapies such as CTLA-4 and PD-1 inhibitors. With advances in our understanding of this disease, as well as the increasing data gathered from patient studies, the significance of the host immune response to cancer progression and response to treatment is becoming clear. More specifically, the presence of intratumoral CD8⁺ cytotoxic T-cells correlates with better prognosis whereas the accumulation of monocytes/macrophages and neutrophils in the tumour is often associated with worse prognosis. Access and infiltration of circulating leukocytes into the tumour is governed by adhesion molecules and chemokines expressed by the endothelial cells of the vasculature. This review focuses on the adhesion molecules and chemokines which control the homing of CD8⁺ cytotoxic T-cells, monocytes and neutrophils to peripheral tissues, including tumours. We discuss the role of these leukocyte subsets in regulating melanoma growth, and detail the mechanisms used by tumours to selectively recruit or exclude these leukocytes for their own advantage. In doing so, we bring to light an underappreciated component of tumour biology which should be considered in combination with current treatments to selectively alter the leukocyte composition of tumours and ultimately enhance treatment outcome.Lih Yin Tan, Carmela Martini, Zvi G Fridlender, Claudine S Bonder, Michael P Brown and Lisa M Eber

Transport spectroscopy in a time-modulated open quantum dot

We have investigated the time-modulated coherent quantum transport phenomena in a ballistic open quantum dot. The conductance $G$ and the electron dwell time in the dots are calculated by a time-dependent mode-matching method. Under high-frequency modulation, the traversing electrons are found to exhibit three types of resonant scatterings. They are intersideband scatterings: into quasibound states in the dots, into true bound states in the dots, and into quasibound states just beneath the subband threshold in the leads. Dip structures or fano structures in $G$ are their signatures. Our results show structures due to 2$\hbar\omega$ intersideband processes. At the above scattering resonances, we have estimated, according to our dwell time calculation, the number of round-trip scatterings that the traversing electrons undertake between the two dot openings.Comment: 8 pages, 5 figure

Single mode photonic crystal vertical cavity surface emitting lasers

10.1155/2012/280920Advances in Optical Technologies

Psychological status and physical performance are independently associated with autonomic function.

Background: Falls among older adults have become a global concern. While previous studies have established associations between autonomic function indicator; heart rate variability (HRV) and blood pressure variability (BPV) with fall recurrence, as well as physical inactivity and psychological disorders as risk factors for falls, the influence of physical activity and psychological status on autonomic dysfunction observed among older fallers has not been adequately investigated. The aim of this study was to evaluate the relationship between psychological disorder and physical performance on autonomic nervous system (ANS) in older fallers. We hypothesized that older fallers have poorer autonomic function, greater dependency towards others and were associated with psychological disorder. Furthermore, we hypothesized that both physical performance and psychological status can contribute to the worsen of the autonomic function among elderly. Methods: In this cross-sectional survey, adults aged ≥60 years were recruited. Continuous non-invasive BP was monitored over 5 minutes of supine and 3 minutes of standing. Psychological status was assessed in terms of depression, anxiety, stress, and concern about falling, while functional status was measured using time-up-and-go, functional reach, handgrip and Lawton’s Instrumental Activities of Daily Life (IADL) scale. Results: A total of 62 participants were recruited consisting of 37 fallers and 25 non-fallers. Multivariate analysis revealed that Lawton IADL was independently associated with systolic blood pressure variability (SBPV) and diastolic blood pressure variability (DBPV) during both supine (SBPV: r2 = 0.080, p = 0.025; DBPV: r2 = 0.064, p = 0.046) and standing (SBPV: r2 = 0.112, p = 0.008; DBPV: r2 = 0.105, p= 0.011), while anxiety score was independently associated with SBPV and DBPV during standing (SBPV: r2 = 0.112, p = 0.009; DBPV: r2 = 0.105, p = 0.011) as compared to the other parameters. Conclusion: Our findings suggest that fallers had poorer ANS, greater dependence in IADLs, and were more anxious. IADL dependency and anxiety were the most predictive of autonomic dysfunction, and can be used in practice to identify poor autonomic function for the prevention of falls and cardiovascular diseases among older adults

Familial Occurrence of Multiple Sclerosis with Thyroid Disease and Systemic Lupus Erythematosus

Multiple sclerosis (MS) has some features which suggest it is an autoimmune disease. Autoimmune diseases frequently occur in families, and patients and families often have more than one type of autoimmune disease. However, there are few reports of MS occurring in patients or families with other autoimmune conditions. It is difficult to make a separate diagnosis of MS in a patient who has a systemic autoimmune disease such as systemic lupus erythematosus (SLE) or Sjogren's syndrome, because these diseases can affect the nervous system directly. However, it is possible to make independent diagnoses of MS and an autoimmune disease confined to another single organ in the same patient, or diagnoses of MS and SLE (or other autoimmune diseases) in different family members. Here we describe clinically definite MS in 2 sisters, one of whom had Graves' disease, and the other of whom had a daughter with SLE and with a high titre of anti-thyroid antibodies. Other female family members over 4 generations had histories of thyroid disease, MS and Addison's disease. Available family members were HLA typed. The MS patients were positive for HLA DR2. All but one of the affected family members were related to the proband on the maternal side, and all of these affected females shared an HLA haplotype. However, this haplotype was also present in unaffected individuals. Thus HLA type alone cannot account for the familial occurrence of these disorders. We conclude that, in this family, MS, like autoimmune thyroid disease and SLE, may be an autoimmune disease developing in genetically predisposed individuals