Noise characterization of “effective quiet” areas on a U.S. Navy aircraft carrier

The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (L_eq) measurements were collected during flight operations (L_{eq (flt ops)}), non-flight operations (L_{eq (non-flt ops)}), and over 24-hr periods (L_{eq (24-hr)}). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH^®) Threshold Limit Value (TLV^®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The L_eq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between L_{eq (flt ops)}, L_{eq (non-flt ops)}, and L_{eq (24-hr)} and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) L_{eq (24-hr)}: 70.8–105.4 dBA; (2) L_{eq (flt ops)}: 70–101.2 dBA; and (3) L_{eq (non-flt ops)}: 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean L_eqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The L_eqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.     

Integrating in vitro testing and physiologically-based pharmacokinetic (PBPK) modelling for chemical liver toxicity assessment—A case study of troglitazone

In vitro to in vivo extrapolation (IVIVE) for next-generation risk assessment (NGRA) of chemicals requires computational modeling and faces unique challenges. Using mitochondria-related toxicity data of troglitazone (TGZ), a prototype drug known for liver toxicity, from HepaRG, HepG2, HC-04, and primary human hepatocytes, we explored inherent uncertainties in IVIVE, including cell models, cellular response endpoints, and dose metrics. A human population physiologically-based pharmacokinetic (PBPK) model for TGZ was developed to predict in vivo doses from in vitro point-of-departure (POD) concentrations. Compared to the 200–800 mg/d dose range of TGZ where liver injury was observed clinically, the predicted POD doses for the mean and top one percentile of the PBPK population were 28–372 and 15–178 mg/d respectively based on C_max dosimetry, and 185–2552 and 83–1010 mg/d respectively based on AUC. In conclusion, although with many uncertainties, integrating in vitro assays and PBPK modeling is promising in informing liver toxicity-inducing TGZ doses.     

胶片剂量测量和验证方法的研究

目的设计和实现基于通用激光扫描仪的胶片剂量测量和验证系统。方法采用胶片饱和冲洗、非线性光学校正、多分辨率阈值滤波、离散傅里叶逆变换图像复原等方法,消除了普通扫描仪用于胶片剂量学定量处理中的各种伪影、噪声和畸变;采用过响应系数校正方法消除测量胶片对低能散射光子的过响应,改善了胶片剂量测量的准确性;采用γ结合NAT指标的方法对放疗计划进行二维定量验证,给出可视化图形表达和具有定量数据的验证结果。结果和三维水箱系统、VeriSoft胶片测量系统相比较,研制系统对放疗剂量的测量结果在±2%内符合一致,对IMRT放疗计划的定量验证结果在±3%内符合一致。结论该系统能够实现对放疗剂量的高精度测量和对适形调强放疗计划剂量的可靠验证。     

Mobilization and evolutionary history of miniature inverted-repeat transposable elements (MITEs) in Beta vulgaris L.

We have identified three families of miniature inverted-repeat transposable elements (VulMITEs) in the genome of sugar beet (Beta vulgaris L.), evidently derived from a member of the Vulmar family of mariner transposons. While VulMITEs I are typical stowaway-like MITEs, VulMITEs II and VulMITEs III are rearranged stowaway elements of increased size. The integration of divergent moderately and highly repetitive sequences into VulMITEs II and, in particular in VulMITEs III, respectively, shows that amplification of repetitive DNA by MITEs contribute to the increase of genome size with possible implications for plant genome evolution. Fluorescent in-situ hybridization (FISH), for the first time visualizing stowaway MITE distribution on plant chromosomes, revealed a dispersed localization of VulMITEs along all B. vulgaris chromosomes. Analysis of the flanking sequences identified a dispersed repeat as target site for the integration of the stowaway element VulMITE I. Recent transposition of VulMITE I, which most likely occurred during the domestication of cultivated beets, was concluded from insertional polymorphisms between different B. vulgaris cultivars and species. ^†Sequence data from this article have been deposited in the EMBL/GenBank Data Library under the accession nos. AM231630-AM231653 and AM259123-AM259125.     

A liquid-scintillation-based primary standardization of Pb

A new radioactivity solution standard of ²¹⁰Pb has been developed and will be disseminated by the National Institute of Standards and Technology (NIST) as standard reference material (SRM) 4337. This new ²¹⁰Pb solution standard is contained in a 5 mL flame-sealed borosilicate glass ampoule, consists of (5.133±0.002) g of a nominal 1 mol L⁻¹ nitric acid solution, has a density of (1.028±0.002) g mL⁻¹ at 20 °C, has carrier ion concentrations of about 11 μg Pb²⁺ and 21 μg Bi³⁺ per gram of solution, and is certified to contain a massic activity (9.037±0.22) kBq g⁻¹ as of the reference time 1200 EST, 15 June 2006. All of the uncertainties cited above correspond to standard uncertainties multiplied by a coverage factor k=2. The standardization for the ²¹⁰Pb content of the solution was based on 4πβ liquid scintillation (LS) measurements using CIEMAT/NIST ³H-standard efficiency tracing (CNET). Confirmatory determinations were also performed by high-resolution HPGe γ-ray spectrometry, by 2π spectrometry with a Si surface barrier detector of separated ²¹⁰Po, and by 4πβ(LS)–γ(NaI) anticoincidence counting.     

个体患者适形调强放疗计划模体内剂量实测验证技术的建立

目的建立个体患者适形调强放疗（IMRT）计划的模体内剂量实测验证技术。方法选择1例鼻咽癌患者，设计IMRT计划。将患者计划转移到模体上设计杂交计划。执行杂交计划时，用针点电离室测量感兴趣点的剂量，并与该点的计算剂量比较。用胶片剂量测量系统测量杂交计划中感兴趣平面的剂量，胶片与计划剂量矩阵登记后，依次进行计划，胶片分析、计划，胶片剖面分析和计划／胶片等剂量线分析。采用复合判断标准评价验证结果。结果针点电离室测量得到杂交计划单次照射的总剂量为121．5cGy，比计算值低约4％。计划，胶片分析得到高剂量、高梯度区域的距离差别均在4mm以内；计划／胶片剖面分析显示，计划与胶片在通过靶区的剖面具有较好的一致性；计划，胶片等剂量线分析显示，计划与胶片对应值的等剂量线重合良好。按照复合判断标准，该计划验证通过。结论初步建立了个体患者IMRT计划的模体内剂量实测验证技术，建立并优化了剂量登记技术、剂量归一方法和评价方法。     

Peritonsillar abscess — Do we need anaerobic cover?

Objective To find out the usability and advantage with regard to the advent of new and more costly antibiotics. In the treatment of Peritonsillar abscess the demonstration of, both aerobic and anaerobic organisms has raised the question of possible need to treat with antibiotics effective against anaerobes. It was in this very context that this study was planned to find out if we still have an economically and easily available antibiotic to treat Peritonsillar abscess. Conclusions Injectable penicillin is the drug of choice in PTA as GABHS and staphylococcus aureus coagulase positive are the most common organism associated with this condition. Even where penicillin resistant organism is present, effective management of the abscess is possible if it is drained well and weak hydrogen peroxide gargles are used along with injectable penicillin.     

Clinical considerations in the use of missing tissue compensators for head and neck cases

The irregular shape or contour of the patient’s surface in the treatment field can alter the dose distribution resulting in non-uniformity of dose in the treatment volume. Missing tissue compensators have been most commonly used to improve this non-uniformity, especially in head & neck, breast, lung and supraclavicular regions. Two or three dimensional compensators have been typically designed to make the dose uniform at a specific depth. This compensation shifts the dose distribution within the treatment volume so that some structures may be under or over compensated. This study will examine how various sites in head and neck cases are affected by compensators. We have also analyzed the uncertainty in compensated dose due to the daily variations in patient repositioning. Computer isodose plans using Cobalt-60 gamma rays and 6 and 18 MV x-rays were generated using coronal contours. Results show that the dose uniformity is improved for the treatment sites, especially for the thinner sites, like the larynx and the anterior cervical neck nodes. Finally, patient movement or positioning errors of ±1.0 cm will cause a change in dose distribution.