In-plane optical response of Bi2Sr2CuO6

We report on infrared reflectivity measurements of the $ab$-plane response of superconducting Bi$_2$Sr$_2$CuO$_6$ single crystals. The frequency dependent conductivity has a maximum near 700 cm$^{-1}$ at room temperature, which shifts to lower frequency and merges with a Drude-peak below 100 K. We attribute the unusual behaviour of the mid-infrared conductivity to low frequency transitions between electronic bands of mainly BiO character near the $\overline{M}$ point. The linear temperature dependence of the low-frequency resistivity can be followed down to approximately 40 K where it saturates.Comment: Revtex, 4 pages, 4 postscript figures, Phys. Rev. B, in pres

Systematics of c-axis Phonons in the Thallium and Bismuth Based Cuprate Superconductors

We present grazing incidence reflectivity measurements in the far infrared region at temperatures above and below Tc for a series of thallium (Tl2Ba2CuO6, Tl2Ba2CaCu2O8) and bismuth (Bi2Sr2CuO6, Bi2Sr2CaCu2O8, and Bi(2-x)Pb(x)Sr2CaCu2O8) based cuprate superconductors. From the spectra, which are dominated by the c-axis phonons, longitudinal frequencies (LO) are directly obtained. The reflectivity curves are well fitted by a series of Lorentz oscillators. In this way the transverse (TO) phonon frequencies were accurately determined. On the basis of the comparative study of the Bi and Tl based cuprates with different number of CuO2 layers per unit cell, we suggest modifications of the assignment of the main oxygen modes. We compare the LO frequencies in Bi2Sr2CaCu2O8 and Tl2Ba2Ca2Cu3O10 obtained from intrinsic Josephson junction characteristics with our measurements, and explain the discrepancy in LO frequencies obtained by the two different methods.Comment: 8 pages Revtex, 6 eps figures, 3 tables, to appear in Phys. Rev.

PERAN MEDIA SOSIAL DALAM REVOLUSI TUNISIA TAHUN 2011

Awal tahun 2011 ditandai dengan beberapa peristiwa internasional, salah satunya adalah fenomena revolusi yang terjadi di Tunisia. Terdapat berbagai gerakan sosial dalam aksi demonstrasi skala besar yang dilakukan oleh rakyat Tunisia. Dengan media sosial tersebut, masyarakat Tunisia dapat berbagi informasi mengenai Zine El-Abidine Ben Ali (Ben Ali) dan hal-hal yang terkait dengan revolusi tersebut. Rumusan masalah dalam penelitian ini yaitu bagaimana melihat peran media sosial dalam revolusi Tunisia Tahun 2011. Penelitian ini bertujuan untuk mengetahui peran media sosial dalam revolusi yang terjadi di Tunisia tersebut. Selain itu ditujukan untuk mendiskusikan bagaimana media sosial saat ini berperan aktif dalam aktivitas manusia. Dalam penelitian ini, peneliti juga bermaksud menggambarkan media sosial saat ini dapat menjadi alat yang mampu membantu individu dalam berkomunikasi secara aktif tidak seperti media konvensional. Peneliti menggunakan metode penelitian kualitatif dan teknik pengumpulan data melalui studi literatur serta wawancara. Kemudian hasil penelitian ini adalah peran media sosial dalam revolusi Tunisia dianggap penting sebagai fasilitator masyarakat Tunisia dalam menyampaikan pendapatnya disaat sarana media konvensional dibatasi oleh pemerintah. Kemudian peran lain media sosial disini adalah sebagai akselerator yang mempercepat proses revolusi. Sehingga kedua peran tersebut menunjukan adanya hubungan yang nyata antara dunia maya dan dunia nyata. Dalam penelitian ini juga kita dapat lebih mengetahui mengenai kegunaan lain dari media sosial. Saran saya kedepannya bagi peneliti yang memiliki ketertarikan dengan fenomena ini harus mendapatkan data-data yang banyak dan juga informasi lebih lanjut mengenai media sosial. Kata Kunci : Tunisia, Media Sosial, Gerakan Sosial, Revolus

Excretion of hexachlorobenzene and metabolites in feces in a highly exposed human population.

A set of 53 individuals from a population highly exposed to airborne hexachlorobenzene (HCB) were selected to study the elimination kinetics of this chemical in humans. The volunteers provided blood, 24-hr urine, and feces samples for analysis of HCB and metabolites. The serum HCB concentrations ranged from 2.4 to 1,485 ng/mL (mean +/- SD, 124 +/- 278), confirming that this human population has the highest HCB blood levels ever reported. All analyzed feces samples contained unchanged HCB (range, 11-3,025 ng/g dry weight; mean +/- SD, 395 +/- 629). The HCB concentration in feces strongly correlated with HCB in serum (r = 0.85; p < 0.001), suggesting an equilibrium in feces/serum that is compatible with a main pulmonary entrance of the chemical and low intestinal excretion of nonabsorbed foodborne HCB. The equilibrium is also compatible with a nonbiliary passive transfer of the chemical to the intestinal lumen. Two HCB main metabolites, pentachlorophenol (PCP) and pentachlorobenzenethiol (PCBT), were detected in 51% and 54% of feces samples, respectively. All urine samples contained PCP and PCBT, confirming the conclusions of a previous study [Environ Health Perspect 105:78-83 (1997)]. The comparison between feces and urine showed that whereas daily urinary elimination of metabolites may account for 3% of total HCB in blood, intestinal excretion of unchanged HCB may account for about 6%, thus showing the importance of metabolism in the overall elimination of HCB. The elimination of HCB and metabolites by both routes, however, appears to be very small (< 0.05%/day) as compared to the estimated HCB adipose depots. Features of HCB kinetics that we present in this study, i.e., nonsaturated intestinal elimination of HCB and excretion in feces and urine of inert glutathione derivatives, may explain, in part, the absence of porphyria cutanea in this human population heavily exposed to HCB

Affective pathology and quality of life at chronic heart failure patient’s with sex-taking account during antidepressant therapy

In order to determine the severity of affective pathology by sex, with further assessment of the dynamics of the clinical status and quality of life in chronic heart failure (CHF) patient’s during therapy, including the antidepressant escitalopram (Selectra) 117 patients were examined. Methods: HADS scale and Zung; questionnaire MLHFQ; SACS scale. From the respondents patients were selected with chronic heart failure in combination with increased levels of anxiety and depression, which in addition to traditional treatment of CHF were receiving escitalopram (Selectra) for two months at a dose of 20 mg per day. All patients underwent a test of 6-minute walk, echocardiography. Statistical analysis of results was carried out using Statistica 6.0. Results: In women with CHF severity of affective pathology was 1.8 higher than in men, largely due to anxiety. In men with CHF reduced QoL is mainly due to its physical component, while in women changes all three aspects of QOL. Regardless of gender in patients with chronic heart failure, coupled with anxiety and depression treatment, including escitalopram (Selectra), accompanied by improved affective status, indicators of QOL, as well as decrease the severity of clinical symptoms of cardiac decompensation. For women compared with men positive changes in the indices of QOL during therapy with antidepressants were more pronounced.С целью определения выраженности аффективной патологии с умётом пола с дальнейшей оценкой динамики клинического состояния и качества жизни у больных с хронической сердечной недостаточностью (ХСН) на фоне терапии, включающей антидепрессант зсциталопрам (Селектра) обследовано 117 пациентов. Методы: шкалы HADS и Цунга; опросник MLHFQ; шкала ШОКС. Из опрошенных были выбраны пациенты с ХСН в сочетании с повышенным уровнем тревоги и депрессии, которые помимо традиционного лечения ХСН получали зсциталопрам (Селектра) в течение двух месяцев в дозе до 20 мг в сутки. Всем больным проводился тест 6-минутной ходьбы (ТШХ), эхокардиографическое исследование (ЗХО-КГ). Статистическая обработка результатов проводилась с помощью программы Statistica 6.0. Результаты: У женщин с ХСН выраженность аффективной патологии в 1,8 выше, чем у мужчин, в большей степени за счёт тревоги. У мужчин с ХСН снижение КЖ в основном обусловлено его физическим компонентом, в то время как у женщин изменяются все три аспекта КЖ. Независимо от пола больных с ХСН, сочетающейся с тревогой и депрессией, лечение, включающее зсциталопрам (Селектра), сопровождается улучшением аффективного статуса, показателей КЖ, а также уменьшением выраженности клинической симптоматики сердечной декомпенсации. У женщин в сравнении с мужчинами позитивные изменения показателей КЖ на фоне терапии антидепрессантом более выражены

Genotyping by sequencing in almond : SNP discovery, linkage mapping, and marker sesign

In crop plant genetics, linkage maps provide the basis for the mapping of loci that affect important traits and for the selection of markers to be applied in crop improvement. In outcrossing species such as almond (Prunus dulcis Mill. D. A. Webb), application of a double pseudotestcross mapping approach to the F progeny of a biparental cross leads to the construction of a linkage map for each parent. Here, we report on the application of genotyping by sequencing to discover and map single nucleotide polymorphisms in the almond cultivars "Nonpareil" and "Lauranne." Allele-specific marker assays were developed for 309 tag pairs. Application of these assays to 231 Nonpareil × Lauranne F progeny provided robust linkage maps for each parent. Analysis of phenotypic data for shell hardness demonstrated the utility of these maps for quantitative trait locus mapping. Comparison of these maps to the peach genome assembly confirmed high synteny and collinearity between the peach and almond genomes. The marker assays were applied to progeny from several other Nonpareil crosses, providing the basis for a composite linkage map of Nonpareil. Applications of the assays to a panel of almond clones and a panel of rootstocks used for almond production demonstrated the broad applicability of the markers and provide subsets of markers that could be used to discriminate among accessions. The sequence-based linkage maps and single nucleotide polymorphism assays presented here could be useful resources for the genetic analysis and genetic improvement of almond

Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al

Molecular interactions of ASPP1 and ASPP2 with the p53 protein family and the apoptotic promoters PUMA and Bax

The apoptosis stimulating p53 proteins, ASPP1 and ASPP2, are the first two common activators of the p53 protein family that selectively enable the latter to regulate specific apoptotic target genes, which facilitates yes yet unknown mechanisms for discrimination between cell cycle arrest and apoptosis. To better understand the interplay between ASPP- and p53-family of proteins we investigated the molecular interactions between them using biochemical methods and structure-based homology modelling. The data demonstrate that: (i) the binding of ASPP1 and ASPP2 to p53, p63 and p73 is direct; (ii) the C-termini of ASPP1 and ASPP2 interact with the DNA-binding domains of p53 protein family with dissociation constants, Kd, in the lower micro-molar range; (iii) the stoichiometry of binding is 1:1; (iv) the DNA-binding domains of p53 family members are sufficient for these protein–protein interactions; (v) EMSA titrations revealed that while tri-complex formation between ASPPs, p53 family of proteins and PUMA/Bax is mutually exclusive, ASPP2 (but not ASPP1) formed a complex with PUMA (but not Bax) and displaced p53 and p73. The structure-based homology modelling revealed subtle differences between ASPP2 and ASPP1 and together with the experimental data provide novel mechanistic insights

A deletion affecting an LRR-RLK gene co-segregates with the fruit flat shape trait in peach

Altres ajuts: CERCA Programme/Generalitat de CatalunyaIn peach, the flat phenotype is caused by a partially dominant allele in heterozygosis (Ss), fruits from homozygous trees (SS) abort a few weeks after fruit setting. Previous research has identified a SSR marker (UDP98-412) highly associated with the trait, found suitable for marker assisted selection (MAS). Here we report a ∼10 Kb deletion affecting the gene PRUPE.6G281100, 400 Kb upstream of UDP98-412, co-segregating with the trait. This gene is a leucine-rich repeat receptor-like kinase (LRRRLK) orthologous to the Brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) group. PCR markers suitable for MAS confirmed its strong association with the trait in a collection of 246 cultivars. They were used to evaluate the DNA from a round fruit derived from a somatic mutation of the flat variety 'UFO-4', revealing that the mutation affected the flat associated allele (S). Protein BLAST alignment identified significant hits with genes involved in different biological processes. Best protein hit occurred with AtRLP12, which may functionally complement CLAVATA2, a key regulator that controls the stem cell population size. RT-PCR analysis revealed the absence of transcription of the partially deleted allele. The data support PRUPE.6G281100 as a candidate gene for flat shape in peach

Scanning tunneling spectroscopy of high-temperature superconductors

Tunneling spectroscopy played a central role in the experimental verification of the microscopic theory of superconductivity in the classical superconductors. Initial attempts to apply the same approach to high-temperature superconductors were hampered by various problems related to the complexity of these materials. The use of scanning tunneling microscopy/spectroscopy (STM/STS) on these compounds allowed to overcome the main difficulties. This success motivated a rapidly growing scientific community to apply this technique to high-temperature superconductors. This paper reviews the experimental highlights obtained over the last decade. We first recall the crucial efforts to gain control over the technique and to obtain reproducible results. We then discuss how the STM/STS technique has contributed to the study of some of the most unusual and remarkable properties of high-temperature superconductors: the unusual large gap values and the absence of scaling with the critical temperature; the pseudogap and its relation to superconductivity; the unprecedented small size of the vortex cores and its influence on vortex matter; the unexpected electronic properties of the vortex cores; the combination of atomic resolution and spectroscopy leading to the observation of periodic local density of states modulations in the superconducting and pseudogap states, and in the vortex cores.Comment: To appear in RMP; 65 pages, 62 figure