The Time of Flight System of the AMS-02 Space Experiment

The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to the read out electronics and measures velocity, direction and charge of the crossing particles. The new version of the detector (called AMS-02) will be installed on the International Space Station on March 2004. The fringing field of the AMS-02 superconducting magnet is $1.0\div2.5$ kG where the photomultiplers (PM) are installed. In order to be able to operate with this residual field, a new type of PM was chosen and the mechanical design was constrained by requiring to minimize the angle between the magnetic field vector and the PM axis. Due to strong field and to the curved light guides, the time resolution will be $150\div180$ ps, while the new electronics will allow for a better charge measurement.Comment: 5 pages, 4 figures. Proc. of 7th Int. Conf. on Adv. Tech. and Part. Phys., 15-19 October 2001,Como (Italy

SerpinB3 as hepatic marker of post-resective shear stress

Post-resective liver failure is a frequent complication of liver surgery and it is due to portal hyperperfusion of the remnant liver and to arterial vasoconstriction, as buffer response of the hepatic artery. In this context, splenectomy allows a reduction of portal flow and increases the survival chance in preclinical models. SerpinB3 is over-expressed in the liver in oxidative stress conditions, as a mechanism of cell defense to provide survival by apoptosis inhibition and cell proliferation. In this study, the expression of SerpinB3 was assessed as predictor of liver damage in in vivo models of major hepatic resection with or without splenectomy. Wistar male rats were divided into 4 groups: group A received 30% hepatic resection, group B > 60% resection, group C > 60% resection with splenectomy and group D sham-operated. Before and after surgery liver function tests, echo Doppler ultrasound and gene expression were assessed. Transaminase values and ammonium were significantly higher in groups that underwent major hepatic resection. Echo Doppler ultrasound showed the highest portal flow and resistance of the hepatic artery in the group with > 60% hepatectomy without splenectomy, while the association of splenectomy determined no increase in portal flow and hepatic artery resistance. Only the group of rats without splenectomy showed higher shear-stress conditions, reflected by higher levels of HO-1, Nox1 and of Serpinb3, the latter associated with an increase of IL-6. In conclusion, splenectomy controls inflammation and oxidative damage, preventing the expression of Serpinb3. Therefore, SerpinB3 can be considered as a marker of post-resective shear stress

Artrópodes predadores em milho Bt em sucessão a soja transgênica e submetido a diferentes manejos fitossanitários.

O aumento do cultivo de geneticamente modificadas (GM), resistentes a lagartas (Bt) e a glifosato (RR), e a possibilidade de seu uso continuado na sucessão soja-milho, no Brasil, motivou a realização deste trabalho com o objetivo de avaliar a densidade populacional de artrópodes predadores ocorrentes em milho Bt e não-Bt, em sucessão a soja Bt, RR e não-GM e conduzidas em diferentes sistemas de manejo fitossanitário. Foi utilizado o delineamento em blocos ao acaso, com quatro repetições e parcelas de 18x18m. Os tratamentos consistiram de diferentes combinações de plantas transgênicas, na sucessão soja-milho: (T1) soja não-GM e milho não-Bt; (T2) soja não-GM e milhoBt; (T3) sojaRR e milho não-Bt; (T4) sojaRR e milhoBt; (T5) sojaBtRR e milho não-Bt; (T6) sojaBtRR e milho Bt; (T7) sojaRR e milhoBt com aplicação de inseticidas junto com herbicida e fungicida, totalizando 5 aplicações em soja e 3 em milho. De T1 a T6 os inseticidas foram aplicados de acordo com o nível de controle. Nos estágios de V4, V6 e V8 do milho foram quantificados os predadores presentes em 10 plantas coletadas aleatoriamente na parcela. Os dados foram submetidos à análise exploratória, transformados quando necessário, submetidos a ANOVA e as médias foram comparadas por Tukey (?=5%). De um total de 392 indivíduos, de 10 táxons, a Anthocoridae (Orius sp.) foi a família mais frequente (47,2%), seguida por Dermaptera (24,7%), Syrphidae (11%) e Staphylinidae (6,4%). Coccinellidae, Araneae, Carabidae, Lygaeidae, Crysopidae e Reduvidae foram pouco frequentes. Houve diferença significativa entre os tratamentos apenas para Anthocoridae e total de predadores, com menores densidade de predadores em milho Bt, devido, provavelmente, a sua menor disponibilidade de alimento (lagartas). Não há evidências do efeito da cultivar de soja (Bt, RR ou não-GM), cultivada anteriormente, e do manejo fitossanitário sobre a densidade de predadores em milho

A First Comparison Between LIGO and Virgo Inspiral Search Pipelines

This article reports on a project that is the first step the LIGO Scientific Collaboration and the Virgo Collaboration have taken to prepare for the mutual search for inspiral signals. The project involved comparing the analysis pipelines of the two collaborations on data sets prepared by both sides, containing simulated noise and injected events. The ability of the pipelines to detect the injected events was checked, and a first comparison of how the parameters of the events were recovered has been completed.Comment: GWDAW-9 proceeding

A first comparison of search methods for gravitational wave bursts using LIGO and Virgo simulated data

We present a comparative study of 6 search methods for gravitational wave bursts using simulated LIGO and Virgo noise data. The data's spectra were chosen to follow the design sensitivity of the two 4km LIGO interferometers and the 3km Virgo interferometer. The searches were applied on replicas of the data sets to which 8 different signals were injected. Three figures of merit were employed in this analysis: (a) Receiver Operator Characteristic curves, (b) necessary signal to noise ratios for the searches to achieve 50 percent and 90 percent efficiencies, and (c) variance and bias for the estimation of the arrival time of a gravitational wave burst.Comment: GWDAW9 proceeding

Doxorubicin treatment modulates chemoresistance and affects the cell cycle in two canine mammary tumour cell lines

Background: Doxorubicin (DOX) is widely used in both human and veterinary oncology although the onset of multidrug resistance (MDR) in neoplastic cells often leads to chemotherapy failure. Better understanding of the cellular mechanisms that circumvent chemotherapy efficacy is paramount. The aim of this study was to investigate the response of two canine mammary tumour cell lines, CIPp from a primary tumour and CIPm, from its lymph node metastasis, to exposure to EC50(20h) DOX at 12, 24 and 48 h of treatment. We assessed the uptake and subcellular distribution of DOX, the expression and function of P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP), two important MDR mediators. To better understand this phenomenon the effects of DOX on the cell cycle and Ki67 cell proliferation index and the expression of p53 and telomerase reverse transcriptase (TERT) were also evaluated by immunocytochemistry (ICC). Results: Both cell lines were able to uptake DOX within the nucleus at 3 h treatment while at 48 h DOX was absent from the intracellular compartment (assessed by fluorescence microscope) in all the surviving cells. CIPm, originated from the metastatic tumour, were more efficient in extruding P-gp substrates. By ICC and qRT-PCR an overall increase in both P-gp and BCRP were observed at 48 h of EC50(20h) DOX treatment in both cell lines and were associated with a striking increase in the percentage of p53 and TERT expressing cells by ICC. The cell proliferation fraction was decreased at 48 h in both cell lines and cell cycle analysis showed a DOX-induced arrest in the S phase for CIPp, while CIPm had an increase in cellular death without arrest. Both cells lines were therefore composed by a fraction of cells sensible to DOX that underwent apoptosis/necrosis. Conclusions: DOX administration results in interlinked modifications in the cellular population including a substantial effect on the cell cycle, in particular arrest in the S phase for CIPp and the selection of a subpopulation of neoplastic cells bearing MDR phenotype characterized by P-gp and BCRP expression, TERT activation, p53 accumulation and decrease in the proliferating fraction. Important information is given for understanding the dynamic and mechanisms of the onset of drug resistance in a neoplastic cell population