210 research outputs found

    Brown muscle disease and Manila clam Ruditapes Philippinarum dynamics in Arcachon Bay, France

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    Brown Muscle Disease (BMD) affects Manila clam Ruditapes philippinarum. It was described for the first time in 2005 in Arcachon Bay, France. The pathology consists in a progressive necrosis of the posterior adductor muscle, valve gaping, clam migration to the sediment surface, and death. This study aims to quantify the prevalence of BMD in the bay and to evaluate the effect of BMD on Manila clam dynamics. The prevalence was assessed on 50 stations spread within Arcachon Bay. About 62% of Manila clam habitat surface was infected by BMD. A survey of buried and surface clams was conducted from November 2006 to March 2008 in Lanton, a site infected by BMD. Modal progression analysis separated confidently cohorts from 2003 to 2005 recruitments. This pathology only affected adult clams (>25 mm, >2 years). For both buried and surface individuals, shell length was significantly correlated with BMD infection. Surface clams had prevalence (67%) higher than buried clams (23%) and showed greater mortality rate after 15 d in running water: 82% against 12% for buried individuals. The final disease index (FDI) and the condition index (CI) were monthly evaluated on 50 clams located at each position in the sediment. CI displayed a significant decrease after BMD's infection from light to severe disease stages. Length data analysis through Bhattacharya's method (FISAT II software) allowed identifying four cohorts. The 2003s cohort enabled to calculate mortality rate that was 39% for 5 months and to estimate that BMD was responsible of 95% of that mortality. The temperature was certainly an important factor in BMD transmission, because cohort dynamics results argued that BMD developed during spring and summer

    Josephson dynamics for coupled polariton modes under the atom-field interaction in the cavity

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    We consider a new approach to the problem of Bose-Einstein condensation (BEC) of polaritons for atom-field interaction under the strong coupling regime in the cavity. We investigate the dynamics of two macroscopically populated polariton modes corresponding to the upper and lower branch energy states coupled via Kerr-like nonlinearity of atomic medium. We found out the dispersion relations for new type of collective excitations in the system under consideration. Various temporal regimes like linear (nonlinear) Josephson transition and/or Rabi oscillations, macroscopic quantum self-trapping (MQST) dynamics for population imbalance of polariton modes are predicted. We also examine the switching properties for time-averaged population imbalance depending on initial conditions, effective nonlinear parameter of atomic medium and kinetic energy of low-branch polaritons.Comment: 10 pages, 6 postscript figures, uses svjour.cl

    Polariton condensation and lasing in optical microcavities - the decoherence driven crossover

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    We explore the behaviour of a system which consists of a photon mode dipole coupled to a medium of two-level oscillators in a microcavity in the presence of decoherence. We consider two types of decoherence processes which are analogous to magnetic and non-magnetic impurities in superconductors. We study different phases of this system as the decoherence strength and the excitation density is changed. For a low decoherence we obtain a polariton condensate with comparable excitonic and photonic parts at low densities and a BCS-like state with bigger photon component due to the fermionic phase space filling effect at high densities. In both cases there is a large gap in the density of states. As the decoherence is increased the gap is broadened and suppressed, resulting in a gapless condensate and finally a suppression of the coherence in a low density regime and a laser at high density limit. A crossover between these regimes is studied in a self-consistent way analogous to the Abrikosov and Gor'kov theory of gapless superconductivity.Comment: 17 pages, 8 figures, submitted to PR

    Human Embryonic Stem Cell Technology: Large Scale Cell Amplification and Differentiation

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    Embryonic stem cells (ESC) hold the promise of overcoming many diseases as potential sources of, for example, dopaminergic neural cells for Parkinson’s Disease to pancreatic islets to relieve diabetic patients of their daily insulin injections. While an embryo has the innate capacity to develop fully functional differentiated tissues; biologists are finding that it is much more complex to derive singular, pure populations of primary cells from the highly versatile ESC from this embryonic parent. Thus, a substantial investment in developing the technologies to expand and differentiate these cells is required in the next decade to move this promise into reality. In this review we document the current standard assays for characterising human ESC (hESC), the status of ‘defined’ feeder-free culture conditions for undifferentiated hESC growth, examine the quality controls that will be required to be established for monitoring their growth, review current methods for expansion and differentiation, and speculate on the possible routes of scaling up the differentiation of hESC to therapeutic quantities

    Enhanced delivery of peptide-morpholino oligonucleotides with a small molecule to correct splicing defects in the lung

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    Pulmonary diseases offer many targets for oligonucleotide therapeutics. However, effective delivery of oligonucleotides to the lung is challenging. For example, splicing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) affect a significant cohort of Cystic Fibrosis (CF) patients. These individuals could potentially benefit from treatment with splice switching oligonucleotides (SSOs) that can modulate splicing of CFTR and restore its activity. However, previous studies in cell culture used oligonucleotide transfection methods that cannot be safely translated in vivo. In this report, we demonstrate effective correction of a splicing mutation in the lung of a mouse model using SSOs. Moreover, we also demonstrate effective correction of a CFTR splicing mutation in a pre-clinical CF patient-derived cell model. We utilized a highly effective delivery strategy for oligonucleotides by combining peptide-morpholino (PPMO) SSOs with small molecules termed OECs. PPMOs distribute broadly into the lung and other tissues while OECs potentiate the effects of oligonucleotides by releasing them from endosomal entrapment. The combined PPMO plus OEC approach proved to be effective both in CF patient cells and in vivo in the mouse lung and thus may offer a path to the development of novel therapeutics for splicing mutations in CF and other lung diseases

    Pertuzumab, trastuzumab, and standard anthracycline- and taxane-based chemotherapy for the neoadjuvant treatment of patients with HER2-positive localized breast cancer (BERENICE) : a phase II, open-label, multicenter, multinational cardiac safety study

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    Background: Anti-HER2 therapies are associated with a risk of increased cardiac toxicity, particularly when part of anthracycline-containing regimens. We report cardiac safety of pertuzumab, trastuzumab, and chemotherapy in the neoadjuvant treatment of HER2-positive early breast cancer. Patients and methods: BERENICE (NCT02132949) is a nonrandomized, phase II, open-label, multicenter, multinational study in patients with normal cardiac function. In the neoadjuvant period, cohort A patients received four cycles of dose-dense doxorubicin and cyclophosphamide, then 12 doses of standard paclitaxel plus four standard trastuzumab and pertuzumab cycles. Cohort B patients received four standard fluorouracil/epirubicin/cyclophosphamide cycles, then four docetaxel cycles with four standard trastuzumab and pertuzumab cycles. The primary end point was cardiac safety during neoadjuvant treatment, assessed by the incidence of New York Heart Association class III/IV heart failure and of left ventricular ejection fraction declines ( 6510 percentage-points from baseline and to a value of\u2009<50%). The main efficacy end point was pathologic complete response (pCR, ypT0/is ypN0). Results are descriptive. Results: Safety populations were 199 and 198 patients in cohorts A and B, respectively. Three patients [1.5%; 95% confidence interval (CI) 0.31% to 4.34%] in cohort A experienced four New York Heart Association class III/IV heart failure events. Thirteen patients (6.5%; 95% CI 3.5% to 10.9%) in cohort A and four (2.0%; 95% CI 0.6% to 5.1%) in cohort B experienced at least one left ventricular ejection fraction decline. No new safety signals were identified. pCR rates were 61.8% and 60.7% in cohorts A and B, respectively. The highest pCR rates were in the HER2-enriched PAM50 subtype (75.0% and 73.7%, respectively). Conclusion: Treatment with pertuzumab, trastuzumab, and common anthracycline-containing regimens for the neoadjuvant treatment of early breast cancer resulted in cardiac and general safety profiles, and pCR rates, consistent with prior studies with pertuzumab. Clinical Trial Information: NCT02132949

    Cancer-associated fibroblasts are key determinants of cancer cell Invasion in the earliest stage of colorectal cancer

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    BACKGROUND & AIMS: Improving clinical management of early stage colorectal cancers (T1CRCs) requires a better understanding of their underlying biology. Accumulating evidence shows that cancer-associated fibroblasts (CAFs) are important determinants of tumor progression in advanced colorectal cancer (CRC), but their role in the initial stages of CRC tumorigenesis is unknown. Therefore, we investigated the contribution of T1CAFs to early CRC progression. METHODS: Primary T1CAFs and patient-matched normal fibroblasts (NFs) were isolated from endoscopic biopsy specimens of histologically confirmed T1CRCs and normal mucosa, respectively. The impact of T1CAFs and NFs on tumor behavior was studied using 3-dimensional co-culture systems with primary T1CRC organoids and extracellular matrix (ECM) remodeling assays. Whole-transcriptome sequencing and gene silencing were used to pinpoint mediators of T1CAF functions. RESULTS: In 3-dimensional multicellular cultures, matrix invasion of T1CRC organoids was induced by T1CAFs, but not by matched NFs. Enhanced T1CRC invasion was accompanied by T1CAF-induced ECM remodeling and up-regulation of CD44 in epithelial cells. RNA sequencing of 10 NF-T1CAF pairs revealed 404 differentially expressed genes, with significant enrichment for ECM-related pathways in T1CAFs. Cathepsin H, a cysteine-type protease that was specifically up-regulated in T1CAFs but not in fibroblasts from premalignant lesions or advanced CRCs, was identified as a key factor driving matrix remodeling by T1CAFs. Finally, we showed high abundance of cathepsin H-expressing T1CAFs at the invasive front of primary T1CRC sections. CONCLUSIONS: Already in the earliest stage of CRC, cancer cell invasion is promoted by CAFs via direct interactions with epithelial cancer cells and stage-specific, cathepsin H-dependent ECM remodeling. RNA sequencing data of the 10 NF-T1CAF pairs can be found under GEO accession number GSE200660.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

    Local–regional recurrence in women with small node-negative, HER2-positive breast cancer: results from a prospective multi-institutional study (the APT trial)

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    Purpose: Women with HER2-positive breast cancer treated prior to effective anti-HER2 therapy have higher rates of local–regional recurrence (LRR) than those with HER2-negative disease. Effective systemic therapy, however, has been shown to decrease LRR. This study examines LRR in women with HER2-positive breast cancer treated on a single-arm prospective multicenter trial of adjuvant trastuzumab (H) and paclitaxel (T). Methods: Patients with HER2-positive tumors ≀ 3.0 cm with negative axillary nodes or micrometastatic disease were eligible. Systemic therapy included weekly T and H for 12 weeks followed by continuation of H to complete 1 year. Radiation therapy (RT) was required following breast-conserving surgery (BCS), but dose and fields were not specified. Disease-free survival (DFS) and LRR-free survival were calculated using the Kaplan–Meier method. Results: Of the 410 patients enrolled from September 2007 to September 2010, 406 initiated protocol therapy and formed the basis of this analysis. A total of 272 (67%) had hormone receptor-positive tumors. Of 162 patients undergoing mastectomy, local therapy records were unavailable for two. None of the 160 for whom records were available received RT. Among 244 BCS patients, detailed RT records were available for 217 (89%). With a median follow-up of 6.5 years, 7-year DFS was 93.3% (95% CI 90.4–96.2), and LRR-free survival was 98.6% (95% CI 97.4–99.8). Conclusion: LRR in this select group of early-stage patients with HER2-positive disease receiving effective anti-HER2 therapy is extremely low. If confirmed in additional studies, future investigational efforts should focus on de-escalating local therapy

    Seven-year follow-up analysis of adjuvant paclitaxel and trastuzumab trial for node-negative, human epidermal growth factor receptor 2–positive breast cancer

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    PURPOSE The Adjuvant Paclitaxel and Trastuzumab trial was designed to address treatment of patients with small human epidermal growth factor receptor 2 (HER2)–positive breast cancer. The primary analysis of the Adjuvant Paclitaxel and Trastuzumab trial demonstrated a 3-year disease-free survival (DFS) of 98.7%. In this planned secondary analysis, we report longer-term outcomes and exploratory results to characterize the biology of small HER2-positive tumors and genetic factors that may predispose to paclitaxel-induced peripheral neuropathy (TIPN). PATIENTS AND METHODS In this phase II study, patients with HER2-positive breast cancer with tumors 3 cm or smaller and negative nodes received paclitaxel (80 mg/m2) with trastuzumab for 12 weeks, followed by trastuzumab for 9 months. The primary end point was DFS. Recurrence-free interval (RFI), breast cancer–specific survival, and overall survival (OS) were also analyzed. In an exploratory analysis, intrinsic subtyping by PAM50 (Prosigna) and calculation of the risk of recurrence score were performed on the nCounter analysis system on archival tissue. Genotyping was performed to investigate TIPN. RESULTS A total of 410 patients were enrolled from October 2007 to September 2010. After a median follow-up of 6.5 years, there were 23 DFS events. The 7-year DFS was 93% (95% CI, 90.4 to 96.2) with four (1.0%) distant recurrences, 7-year OS was 95% (95% CI, 92.4 to 97.7), and 7-year RFI was 97.5% (95% CI, 95.9 to 99.1). PAM50 analyses (n = 278) showed that most tumors were HER2-enriched (66%), followed by luminal B (14%), luminal A (13%), and basal-like (8%). Genotyping (n = 230) identified one single-nucleotide polymorphism, rs3012437, associated with an increased risk of TIPN in patients with grade 2 or greater TIPN (10.4%). CONCLUSION With longer follow-up, adjuvant paclitaxel and trastuzumab is associated with excellent long-term outcomes. Distribution of PAM50 intrinsic subtypes in small HER2-positive tumors is similar to that previously reported for larger tumors

    Integrated motor drives: state of the art and future trends

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    With increased need for high power density, high efficiency and high temperature capabilities in Aerospace and Automotive applications, Integrated Motor Drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system. This paper reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics (PE) position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the Matrix converter, 2-level Bridge, 3-level NPC and Multiphase full bridge converters are also reviewed. Wide band gap devices like SiC and GaN and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented
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