321 research outputs found

    Manual for Thin Asphalt Overlays

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    This manual presents best practices on project selection, mix design, and construction to ensure a superior product when constructing thin asphalt overlays. Experience shows these treatments provide excellent performance when placed on pavements in fair to good condition using proper construction techniques. Though sometime referred to by other names, thin asphalt overlays have been widely used for pavement preservation throughout the world for over 50 years. Limited infrastructure funding at the local, state, and federal levels has resulted in greater emphasis on the use of pavement preservation techniques to extend pavement life and reduce maintenance costs. Thin asphalt overlays are one of many preventative maintenance treatments. Thin asphalt overlays are placed directly on existing pavement and can range from 1/2 inch to 1 1/2 inches in thickness. Thin asphalt overlays have proven to be an economical means for maintaining and improving the functional condition of an existing pavement since the 1960s. Specifically, this manual provides guidance for engineers regarding where and when to use thin asphalt overlays including: (1) Types and variations of thin overlays; (2) Materials and the design process; (3) Construction; (4) Quality Assurance; and (5) Troubleshooting. This chapter by chapter guidance enables an Agency’s engineers to design and construct a successful thin asphalt overlay project to completion. This manual is one of four new manuals prepared by the California Pavement Preservation Center (CP2Center) using funding from California Senate Bill 1 (SB-1), passed in April 2017. The other three manuals provide detailed design and construction information for (1) chip seals, (2) slurry surfacing, and (3) Cape seals. The creation of these manuals was a task funded entirely from SB-1 monies for the purpose of disseminating training and technical information on highway pavement preservation to local agencies throughout California

    Update of High Resolution (e,e'K^+) Hypernuclear Spectroscopy at Jefferson Lab's Hall A

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    Updated results of the experiment E94-107 hypernuclear spectroscopy in Hall A of the Thomas Jefferson National Accelerator Facility (Jefferson Lab), are presented. The experiment provides high resolution spectra of excitation energy for 12B_\Lambda, 16N_\Lambda, and 9Li_\Lambda hypernuclei obtained by electroproduction of strangeness. A new theoretical calculation for 12B_\Lambda, final results for 16N_\Lambda, and discussion of the preliminary results of 9Li_\Lambda are reported.Comment: 8 pages, 5 figures, submitted to the proceedings of Hyp-X Conferenc

    From 3-Port to New Laparoendoscopic Single-Site (LESS) Cholecystectomy : A Critical Analysis of Available Evidence.

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    In recent years, laparoendoscopic single-site surgery (LESS) has gained greater interest and diffusion for the treatment of gallstones. This critical review aims to evaluate the feasibility and safety of LESS cholecystectomy versus the 3-port technique (TPT) through a comparative analysis of 5 parameters: mean operative time, intraoperative and postoperative complications, conversion to open, conversion to the 4-trocar technique and postoperative hospital stay. The authors performed a systematic search of the medical literature through a search of PubMed and Ovid EMBASE. Inclusion criteria were as follows: publication date between January 1, 2005, and December 31, 2010; English or Italian language; human participants and series of 20 operations or more. There were 5 manuscripts meeting the inclusion criteria for TPT and 23 for LESS. Only one prospective randomized controlled trial comparing TPT and LESS was identified. Operative time is significantly longer in the single-incision group. Complications and conversion rates to the 4-port technique are higher in LESS. Postoperative hospital stay is similar in the 2 groups. Rate of conversion to open is higher in TPT. Despite the number of publications on LESS cholecystectomy, the vast majority of data available in the literature are from small case series without any comparative data. Although LESS cholecystectomy is a fashionable technique there are few data available for an evidence-based determination as to the real benefits of this technique. Well-designed comparative studies are suggested to validate the clinical benefits and ensure that there are no new complications or added costs associated with the new technique

    Thyroid surgery in geriatric patients: a literature review.

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    BACKGROUND: Thyroid disease is common in the elderly population. The incidence of hypothyroidism and multinodular goitre gradually increases with age. In view of a growth of aging population, we performed a literature review about the feasibility of thyroid surgery in the elderly. METHODS: We conducted a literature search in the PubMed database in September 2012 and all English-language publications on thyroidectomy in geriatric patients since 2002 were retrieved. The potential original articles mainly focusing on thyroidectomy in elderly patients were all identified and full texts were obtained and reviewed for further hand data retrieving. RESULTS: We retrieved five papers based on different primary end-point. Four were retrospective non randomized studies and one was prospective non randomized study. At last 65, 70, 75 and 80 years were used as an age cut-off. All studies evaluate the indications of thyroidectomy in geriatric patients, postoperative morbility and mortality. Only one study specifically assesses the rate of the rehospitalization after thyroidectomy among the elderly. CONCLUSIONS: Thyroid nodules are particularly important in elderly patients, as the incidence of malignancy increases and they are usually more aggressive tumors. An age of at least 70 years is an independent risk factor for complications after general surgery procedures. Thyroid surgery in patients aged 70 years or older is safe and the relatively high rate of thyroid carcinoma and toxic goiter may justify an aggressive approach. A programmed operation with a careful pre-operative evaluation and a risk stratification should make the surgical procedures less hazardous, specially in 80 years old patients with an high ASA score

    Indications to total thyroidectomy for multinodular goiter in old patients

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    Background: In Western society, the percentage of elderly people is continually growing. The prevalence of goiter increases with the age and it is estimated that 90% of women over 60 years old and 60% of men over 80 years old have a relief of thyroid nodules. This has great importance for these patients, because the incidence of malignant transformation is higher than younger ones and these are often tumor very aggressive patterns. If thyroidectomy is indicated for patients with suspected neoplasm and severe obstructive symptoms, their surgery should not be delayed since a late urgent operation could raise morbidity and mortality risk. The main indications for young patients are due to obstructive and metabolic causes over and above suspected cancer. Total thyroidectomy is considered by many authors as the treatment of choice. Materials and methods: 75 elderly patients were submitted to thyroidectomy. The indications were metabolic (42.6%), obstructive (32%) and for suspected cancer (25.4%). Results: The most frequent complications observed with respect to young patients in different series have been cardiovascular, pulmonary or urological. Regarding the complications directly related to thyroidectomy, there were no differences compared to younger groups, except transient complications (hypoparathyroidism, seroma). In our experience, the main complication was represented by hypocalcemia (30.6%), permanent in 8% of cases. Cancer was relieved in 21.3% of cases. Prognosis has been excellent in most cases, with immediate remission of symptoms related to thyrotoxicosis and to tracheal and esophageal compression in almost all symptomatic patients. Conclusions: Age is an independent prognostic factor for cancers. It has been demonstrated that elderly patients with PTC that are operated have better prognosis and quality of life due to the resolution of dyspnea and dysphagia. In our experience, we think that age is not a contraindication to thyroid surgery

    Performance of the Two Aerogel Cherenkov Detectors of the JLab Hall A Hadron Spectrometer

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    We report on the design and commissioning of two silica aerogel Cherenkov detectors with different refractive indices. In particular, extraordinary performance in terms of the number of detected photoelectrons was achieved through an appropriate choice of PMT type and reflector, along with some design considerations. After four years of operation, the number of detected photoelectrons was found to be noticeably reduced in both detectors as a result of contamination, yellowing, of the aerogel material. Along with the details of the set-up, we illustrate the characteristics of the detectors during different time periods and the probable causes of the contamination. In particular we show that the replacement of the contaminated aerogel and parts of the reflecting material has almost restored the initial performance of the detectors.Comment: 18 pages, 9 Figures, 4 Tables, 44 Reference

    BAG3 protein regulates stress- induced apoptosis in normal and neoplastic leukocytes

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    Co-chaperone proteins that share the Bcl-2-associated athanogene (BAG) domain are characterized by their interaction with a variety of partners, such as heat shock proteins (Hsp), steroid hormone receptors, Bcl-2, Raf-1 and others, involved in regulating protein folding and a number of cellular processes, including proliferation and apoptosis. Among BAG family members there is BAG3, also known as CAIR-1 or Bis. BAG3 forms a complex with Hsp70,1,2,4,6 a protein able to modulate apoptosis by interfering with cytochrome c release, apoptosome assembly and other events in the death process. In addition, BAG3 polypeptide binds to phospholipase C-g (PLC-g)4 or Bcl-2 protein.3,5 Due to such interaction with more than one apoptosis-modulating factor, BAG3 can participate in apoptosis regulation. Indeed, its hyperexpression can decrease apoptosis induced via Bax or Fas in the human epithelial cell line HeLa3 or by IL-3 deprivation in the murine hematopoietic cell line 32D.5 Furthermore, we recently showed that BAG3 downmodulation enhances the apoptotic response to chemotherapy in human primary B chronic lymphocytic leukemia cell

    A Search for Sigma^0_5, N^0_5 and Theta^++ Pentaquark States

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    A high-resolution (sigma_instr. = 1.5 MeV) search for narrow states (Gamma < 10 MeV) with masses of M_x approx 1500-1850 MeV in ep -> e'K^+ X, e'K^- X and e' pi^+ X electroproduction at small angles and low Q^2 was performed. These states would be candidate partner states of the reported Theta^+(1540) pentaquark. No statistically significant signal was observed in any of the channels at 90% C.L. Upper limits on forward production were determined to be between 0.7% and 4.2% of the Lambda(1520) production cross section, depending on the channel and the assumed mass and width of the state.Comment: 5 pages, 5 figures, to appear in Phys. Rev. C, update with responses to referee suggestion

    Quark-Hadron Duality in Neutron (3He) Spin Structure

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    We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_1 of the neutron and 3^3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c)^2. Global duality is observed for the spin-structure function g_1 down to at least Q^2 = 1.8 (GeV/c)^2 in both targets. We have also formed the photon-nucleon asymmetry A_1 in the resonance region for 3He and found no strong Q^2-dependence above 2.2 (GeV/c)^2.Comment: 13 pages, 3 figure
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