Strain-Compensated InGaAsP Superlattices for Defect Reduction of InP Grown on Exact-Oriented (001) Patterned Si Substrates by Metal Organic Chemical Vapor Deposition.

We report on the use of InGaAsP strain-compensated superlattices (SC-SLs) as a technique to reduce the defect density of Indium Phosphide (InP) grown on silicon (InP-on-Si) by Metal Organic Chemical Vapor Deposition (MOCVD). Initially, a 2 μm thick gallium arsenide (GaAs) layer was grown with very high uniformity on exact oriented (001) 300 mm Si wafers; which had been patterned in 90 nm V-grooved trenches separated by silicon dioxide (SiO₂) stripes and oriented along the [110] direction. Undercut at the Si/SiO₂ interface was used to reduce the propagation of defects into the III-V layers. Following wafer dicing; 2.6 μm of indium phosphide (InP) was grown on such GaAs-on-Si templates. InGaAsP SC-SLs and thermal annealing were used to achieve a high-quality and smooth InP pseudo-substrate with a reduced defect density. Both the GaAs-on-Si and the subsequently grown InP layers were characterized using a variety of techniques including X-ray diffraction (XRD); atomic force microscopy (AFM); transmission electron microscopy (TEM); and electron channeling contrast imaging (ECCI); which indicate high-quality of the epitaxial films. The threading dislocation density and RMS surface roughness of the final InP layer were 5 × 10⁸/cm² and 1.2 nm; respectively and 7.8 × 10⁷/cm² and 10.8 nm for the GaAs-on-Si layer

Subdynamics as a mechanism for objective description

The relationship between microsystems and macrosystems is considered in the context of quantum field formulation of statistical mechanics: it is argued that problems on foundations of quantum mechanics can be solved relying on this relationship. This discussion requires some improvement of non-equilibrium statistical mechanics that is briefly presented.Comment: latex, 15 pages. Paper submitted to Proc. Conference "Mysteries, Puzzles And Paradoxes In Quantum Mechanics, Workshop on Entanglement And Decoherence, Palazzo Feltrinelli, Gargnano, Garda Lake, Italy, 20-25 September, 199

Anatypical active cell death process underlies the fungicidal activity of ciclopiroxolamine against the yeast Saccharomyces cerevisiae

Ciclopirox olamine (CPO), a fungicidal agent widely used in clinical practice, induced in Saccharomyces cerevisiae an active cell death (ACD) process characterized by changes in nuclear morphology and chromatin condensation associated with the appearance of a population in the sub-G0/G1 cell cycle phase and an arrest in the G2/M phases. This ACD was associated neither with intracellular reactive oxygen species (ROS) signaling, as revealed by the use of different classes of ROS scavengers, nor with a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive phenotype. Furthermore, CPO-induced cell death seems to be dependent on unknown protease activity but independent of the apoptotic regulators Aif1p and Yca1p and of autophagic pathways involving Apg5p, Apg8p and Uth1p. Our results show that CPO triggers in S. cerevisiae an atypical nonapoptotic, nonautophagic ACD with as yet unknown regulators

Tapeworm eggs in a 270 million-year-old shark coprolite

Remains of parasites in vertebrates are rare from the Mesozoic and Paleozoic. Once most parasites that live in – or pass through – the gastrointestinal tract of vertebrates, fossil feces (coprolites) or even intestinal contents (enterolites) can eventually preserve their remains. Here we announce the discovery of a spiral shark coprolite from the Paleozoic bearing a cluster of 93 small oval-elliptical smooth-shelled structures, interpreted as eggs of a tapeworm.The eggs were found in a thin section of an elasmobranch coprolite. Most of the eggs are filled by pyrite and some have a special polar swelling (operculum), suggesting they are non-erupted eggs. One of the eggs contains a probable developing larva. The eggs are approximately 145–155 mm in length and 88–100 mm in width and vary little in size within the cluster. The depositional and morphological features of the eggs closely resemble those of cestodes. Not only do the individual eggs have features of extant tapeworms, but their deposition all together in an elongate segment is typical to modern tapeworm eggs deposited in mature segments (proglottids). This is the earliest fossil record of tapeworm parasitism of vertebrates and establishes a timeline for the evolution of cestodes. This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was hitherto known and that the interaction between tapeworms and vertebrates occurred at least since the Middle-Late Permian

Incoherent dynamics in neutron-matter interaction

Coherent and incoherent neutron-matter interaction is studied inside a recently introduced approach to subdynamics of a macrosystem. The equation describing the interaction is of the Lindblad type and using the Fermi pseudopotential we show that the commutator term is an optical potential leading to well-known relations in neutron optics. The other terms, usually ignored in optical descriptions and linked to the dynamic structure function of the medium, give an incoherent contribution to the dynamics, which keeps diffuse scattering and attenuation of the coherent beam into account, thus warranting fulfilment of the optical theorem. The relevance of this analysis to experiments in neutron interferometry is briefly discussed.Comment: 15 pages, revtex, no figures, to appear in Phys. Rev.

Poupança Individual de Aposentadoria : PIÁ

Este artigo apresenta o conceito da poupan\ue7a individual de aposentadoria \u2013 PI\uc1 \u2013 adaptado \ue0 realidade brasileira. Dentro de uma estrutura atuarial, a plataforma do Tesouro Direto \ue9 utilizada como fundamento para a implementa\ue7\ue3o de um sistema apto a proteger os valores dos participantes, evitando-se os hist\uf3ricos de m\ue1-gest\ue3o, corrup\ue7\ue3o, falta de transpar\ueancia ou altas taxas de administra\ue7\ue3o inerentes ao sistema de previd\ueancia privada brasileiro ou mundial. Outro aspecto \ue9 a isen\ue7\ue3o tribut\ue1ria, hoje existente para grandes investidores, que seria estendida para esta plataforma, estimulando a eleva\ue7\ue3o da taxa de poupan\ue7a nacional e diminuindo a depend\ueancia do pa\ueds do capital estrangeiro.This paper presents the concept of individual savings accounts for retirement adapted to the Brazilian reality. Using actuarial framework to corroborate the technical and scientific aspects of the idea, the platform of the \u201cTesouro Direto\u201d in Brazil is taken as the rationale to implement a system that can protect the monies of participants, avoiding the historic mismanagement, corruption, graft, lack of transparency or high fees that are related to the private pension system in Brazil and in the world. Another aspect is the existing tax exemption for large investors, which would be extended to this platform. This should foster the increase of the national savings rate and reduce the country's dependence on foreign capital

A polyalanine peptide derived from polar fish with anti-infectious activities

Due to the growing concern about antibiotic-resistant microbial infections, increasing support has been given to new drug discovery programs. A promising alternative to counter bacterial infections includes the antimicrobial peptides (AMPs), which have emerged as model molecules for rational design strategies. Here we focused on the study of Pa-MAP 1.9, a rationally designed AMP derived from the polar fish Pleuronectes americanus. Pa-MAP 1.9 was active against Gram-negative planktonic bacteria and biofilms, without being cytotoxic to mammalian cells. By using AFM, leakage assays, CD spectroscopy and in silico tools, we found that Pa-MAP 1.9 may be acting both on intracellular targets and on the bacterial surface, also being more efficient at interacting with anionic LUVs mimicking Gram-negative bacterial surface, where this peptide adopts α-helical conformations, than cholesterol-enriched LUVs mimicking mammalian cells. Thus, as bacteria present varied physiological features that favor antibiotic-resistance, Pa-MAP 1.9 could be a promising candidate in the development of tools against infections caused by pathogenic bacteria.National Institute of Allergy and Infectious Diseases (U.S.) (R21AI098701

Involvement of yeast HSP90 isoforms in response to stress and cell death induced by acetic acid

Acetic acid-induced apoptosis in yeast is accompanied by an impairment of the general protein synthesis machinery, yet paradoxically also by the up-regulation of the two isoforms of the heat shock protein 90 (HSP90) chaperone family, Hsc82p and Hsp82p. Herein, we show that impairment of cap-dependent translation initiation induced by acetic acid is caused by the phosphorylation and inactivation of eIF2 alpha by Gcn2p kinase. A microarray analysis of polysome-associated mRNAs engaged in translation in acetic acid challenged cells further revealed that HSP90 mRNAs are over-represented in this polysome fraction suggesting preferential translation of HSP90 upon acetic acid treatment. The relevance of HSP90 isoform translation during programmed cell death (PCD) was unveiled using genetic and pharmacological abrogation of HSP90, which suggests opposing roles for HSP90 isoforms in cell survival and death. Hsc82p appears to promote survival and its deletion leads to necrotic cell death, while Hsp82p is a pro-death molecule involved in acetic acid-induced apoptosis. Therefore, HSP90 isoforms have distinct roles in the control of cell fate during PCD and their selective translation regulates cellular response to acetic acid stress.This work was supported by Fundacao para a Ciencia e Tecnologia and COMPETE/QREN/EU (PTDC/BIA-MIC/114116/2009), and by the Canadian Institute for Health Research (MOP 89737 to MH). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Abdominal angina due to recurrence of cancer of the papilla of Vater: a case report

Abdominal angina is usually caused by atherosclerotic disease, and other causes are considered uncommon. This is the first report of a case of abdominal angina secondary to neoplastic vascular stenosis caused by local recurrence of an adenocarcinoma of the papilla of Vater. CASE PRESENTATION: An 80-year-old woman of Caucasian origin presented with abdominal pain and diarrhea. She had undergone a pancreaticoduodenectomy for adenocarcinoma of the papilla of Vater four years earlier. Computed tomography revealed a mass surrounding her celiac trunk and superior mesenteric artery. Her abdominal pain responded poorly to analgesic drugs, but disappeared when oral feedings were withheld. A duplex ultrasonography of the patient's splanchnic vessels was consistent with vascular stenosis. Parenteral nutrition was started and the patient remained pain free until her death. CONCLUSION: Pain relief is an important therapeutic target in patients with cancer. In this case, abdominal pain was successfully managed only after the ischemic cause had been identified. The conventional analgesic therapy algorithm based on nonsteroidal anti-inflammatory drugs and opioids had been costly and pointless, whereas the simple withdrawal of oral feeding spared the patient of the discomfort of additional invasive procedures and allowed her to spend her remaining days in a completely pain-free state