笔形束剂量算法中物理学参数的计算

高能电子束具有有限的射程,因而可以有效地避免靶区后深部组织的照射,在治疗体表肿瘤和体内浅部肿瘤方面,具有不可替代的作用.研究了基于Hogstrom笔形束电子剂量计算算法中的物理学参数计算问题,分析了物理学参数的基本原理,并根据实际的临床条件,讨论了物理学参数的计算方法.实验结果表明,Hogstrom算法能够有效地解决电子束的剂量计算问题.

物理学参数对食管癌调强放射治疗放射性肺炎的临床价值分析

评价放射性肺炎患者治疗中,物理学参数对食管癌强调放射治疗的重要价值。 方法:选取26 例本院收治的食管癌调强放射治疗者,将其按照有无放射性肺炎进行分组,13 例 / 组,观察组为食管癌强调放射治疗放射性肺炎患者,对照组为食管癌调强放射治疗非放射性肺炎患者。 结果:对比后,分割剂量、处方剂量比较,对照组与观察组无较大差异(P>0.05);D80、V5、V20、V30、MLD 比较,较对照组,观察组高(P<0.05)。 结论:食管癌调强放射治疗中,为预防放射性肺炎,需要重点关注 D80、V5、V20、V30、MLD 等物理学参数,以保障患者安全。

食管癌调强放射治疗物理学参数对放射性肺炎的预测价值

目的探讨物理学参数对食管癌调强放射治疗放射性肺炎的临床预测价值。方法收集2015年12月至2016年12月收治的70例食管癌患者的临床资料进行回顾性研究。入组患者均实施调强放射治疗,根据是否发生放射性肺炎,将患者分为发生发现放射性组(16例)和未发生放射性肺炎组(54例)。分析调强放射治疗物理学参数对放射性肺炎发生的影响,比较不同程度放射性肺炎患者调强放射治疗物理学参数,观察放射性肺炎发生的相关因素。结果对两组患者的调强放射治疗物理学参数进行统计比较,可得两组在分割剂量、处方剂量、D10、D20、D30方面经比较差异均无统计学意义(P>0.05);但D40等其余参数检测水平经比较发生放射性肺炎组的水平均明显高于未发生放射性肺炎组(P<0.05);对不同程度放射性肺炎患者调强放射治疗物理学参数进行统计比较,可得3级及以上放射性肺炎组的D60、D70、D80、V5、V10、V15、MLD参数水平均明显高于2级以上放射性肺炎组(P<0.05);多因素分析结果显示,V5与3级及以上放射性肺炎的发生之间具有一定的相关性,(P<0.05)。结论调强放射治疗过程中物理学参数会对食管癌放射性肺炎的发生产生一定的影响,其中低剂量区域的大小与放射性肺炎的发生以及严重程度之间均存在一定的关系。

食管癌调强放射治疗物理学参数对放射性肺炎的预测价值分析

分析食管癌调强放射治疗物理学参数对放射性肺炎的预测价值。方法 选取2022年1月至2022年12月38例食管癌患者进行研究,观察组(12例,发生放射线肺炎)与对照组(26例,未发生放射线肺炎)。分析调强放射治疗物理学参数对患者的影响、不同程度放射线肺炎患者调强放射治疗物理学参数。结果 各项指标对比,(P<0.05)。结论 调强放射治疗中的物理参数会导致食管癌患者出现放射性肺炎造成一定影响,且低剂量区域的大小与放射线肺炎的发生率及病情程度之间存在较大的关联。

钱江源国家公园体制试点区日间声景观的质量评价及其空间格局特征

声景观在现行国家公园景观评价体系中,是一个十分重要但又薄弱的环节,关系着国家公园的精细化管理水平。以钱江源国家公园体制试点区为例,采用调查问卷法对国家公园日间的53种声景观进行主观愉悦度评价,考察并选取描述声景观质量的客观心理物理学指标,通过多元线性回归方法建立二者主客观关系,并得到国家公园声景观质量评价模型。结果表明:(1)不同类型声景观表现为不同的声学特征,并在响度、尖锐度、粗糙度指标上具有显著性差异。虫鸣声响度最大(5.829)、尖锐度最大(2.667)、粗糙度最大(0.018),鸟鸣声的尖锐度与其余六种声景观均显著差异。(2)采用响度、尖锐度、粗糙度、波动度作为描述声景观质量的客观心理物理学指标具有适宜性。其中,响度是影响公众对国家公园声景观主观愉悦度认知的主要因素,二者呈负相关关系。(3)采用K-均值聚类等级划分发现,国家公园声景观质量处于较高水平。其中,虫鸣声质量最高(3.86)、鸟鸣声其次(3.58)、交谈声最低(2.43)。自然声景观质量整体高于人工声景观。(4)国家公园声景观质量在空间上具有南部高、北部其次、中部低的格局特征,且与区域生态保护等级水平存在较强空间重叠性。研究结果为国家公园体制试点结束后,未来声景观科学管理与规划设计提供重要参考,同时为其它类型自然保护地的声景观评价提供方法借鉴。

术中放疗(IORT)限光筒的设计及其剂量学分析

1995年4月,我院参考国内外文献,自行设计了一种术中治疗(IORT)专用限光筒,适用于菲利浦直线加速器,规格为(?)6cm园形限光筒。经过系统测量,各项有关的物理学参数均符合国家剂量学标准。在实际应用中,具有对肿瘤部位定位准确、方便快捷、经济实用等优点。也为以后设计更加完善,更加适应多种需要的IORT限光筒提供了经验。

Spatio-temporal distribution of net-collected phytoplankton community and its response to marine exploitation in Xiangshan Bay

To explore the spatial-temporal distribution of the phytoplankton community and evaluate the combined effects of marine resource exploitation, net-collected phytoplankton and physical-chemical parameters were investigated in the Xiangshan Bay during the four seasons of 2010. A total of eight phyla, 97 genera, and 310 species were found, including 232 diatom species, 45 dinoflageUate species and 33 other taxa. The phytoplankton abundances presented a significant （P〈0.001） seasonal difference with the average of 60.66x104 cells/m3. Diatoms （mainly consisting of Coscinodiscus jonesianus, Cerataulina pelagica, Skeletonema costatum, and genus Chaetoceros） dominated the phytoplankton assemblage in all seasons. We found great spatio-temporal variation in community composition based on the multidimensional scaling and similarity analysis. Canonical correspondence analysis show that temperature, nutrition, illumination, and salinity were the main variables associated with microalgal assemblage. Compared with the previous studies, an increase in phytoplankton abundance and change in the dominant species coincided with increased exploitation activities in this bay （e.g. operation of coastal power plants, intensive mariculture, tidal fiat reclamation, and industrial and agricultural development）. The present findings suggest that the government should exercise caution when deciding upon developmental patterns in the sea-related economy.

Experimental study on remodeling strength of granular materials under different loads and lengths of time

Remodeled clay and sand rock specimens were prepared by designing lateral confinement and water drainage experiments based on the stress exerted on granular materials in a waste dump.An in situ test was conducted in an internal waste dump;the physical and mechanical parameters of the remodeled rock mass dumped at different time and depths were measured.Based on statistics,regression analysis was performed with regard to the shearing stress parameters acquired from the two tests.Other factors,such as remodeling pressure(burial depth),remodeling time(amount of time since waste was dumped),and the corresponding functional relationship,were determined.Analysis indicates that the cohesion of the remodeled clay and its remodeling pressure are correlated by a quadratic function but are not correlated with remodeling time length.In situ experimental results indicate that the shear strength of reshaped granular materials in the internal dump is positively correlated with burial depth but poorly correlated with time length.Cohesion Cand burial depth H follow a quadratic function,specifically for a short time since waste has been dumped.As revealed by both in situ and laboratory experiments,the remodeling strength of granular materials varies in a certain pattern.The consistency of such materials verifies the reliability of the remodeling experimental program.

Cosmological Constraints on the Sign-Changeable Interactions

Recently, Cai and Su [Phys. Rev. D 81 （2010） 103514] found that the sign of interaction Q in＇the dark sector changed in the approximate redshift range of 0.45 ≤ z ≤0.9, by using a modeMndependent method to deal with the observational data. In fact, this result raises a remarkable problem, since most of the familiar interactions cannot change their signs in the whole cosmic history. Motivated by the work of Cai and Su, we have proposed a new type of interaction in a previous work [H. Wei, Nucl. Phys. B 845 （2011） 381]. The key ingredient is the deceleration parameter q in the interaction Q, and hence the interaction Q can change its sign when our universe changes from deceleration （q 〉0） to acceleration （q 〈 0）. In the present work, we consider the cosmologicai constraints on this new type of sign-changeable interactions, by using the latest observational data. We find that the cosmological constraints on the model parameters are fairly tight. In particular, the key parameter β can be constrained to a narrow range.

Water Quality Index and Absorption of Zinc from Electroplating Industry Effluent Using Fungi

The present study deals with the Water Quality Index （WQI） and absorption of zinc from electroplating industry effluent using ftmgi. The physico-chemical parameters such as EC （Electrical Conductivity）, TDS （Total Dissolved Solids）, total hardness, magnesium, calcium, chloride, sodium, potassium, nickel, chromium and zinc content was above the permissible limits of BIS （Bureau of Indian Standards）. The WQI was 13, which showed that the pollution level of the electroplating industry effluent was severe in the rating scale and the effluent was not suitable for disposal without treatment. Three fungal species such as Aspergillus niger, Peinicillium chrysogenum and Rhizopus nigricans were used for absorption studies. Different concentrations （25, 50, 75 and 100%） of electroplating industry effluent along with 1 gm of fungal mycelium with （1%） and without carbon source was incubated in a shaker for a period of 7 days in order to observe zinc absorption capacity. The absorption capacity of zinc was found to be higher in Aspergillus niger followed by Rhizopus nigricans and Penicillium chrysogenum. Among the three fungal species Aspergillus niger had high （50%） potential of zinc absorption with carbon source and low concentration （25%） of electroplating industry effluent.

Experimental and numerical analysis of secondary disasters induced by oxygen rich combustion within a tunnel

Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire test tunnel. Both experimental measurements and numerical simulations are discussed. The numer- ical analysis was performed with the computational fluid dynamics software package ''FLUENT''. The results show that the experimental data agree with the simulation results. The results verify that Roberts' theory of burning is correct. They also prove that the air velocity is the key factor that determines the type of combustion. Also, it is shown that secondary disasters are unlikely for oxygen rich combustion with a limited fire load.

Phytoplankton abundance and community structure in the Antarctic polar frontal region during austral summer of 2009

The Antarctic polar front region in the Southern Ocean is known to be most productive. We studied the phytoplankton community structure in the Indian sector at this frontal location during late austral summer (February, 2009) onboard R/V Akademic Boris Petrov. We used the phytoplankton and microheterotrophs abundance, as also the associated physico-chemical parameters to explain the low phytoplankton abundance in the study region. This study emphasizes the shift of phytoplankton, from large (>10 μm) to small (<10 μm) size. The phytoplankton abundance appears to be controlled by physical parameters and by nutrient concentrations and also by the microheterotrophs (ciliates and dinoflagellates) which exert a strong grazing pressure. This probably reduces small (<10 μm) and large (>10 μm) phytoplankton abundance during the late austral summer. This study highlights the highly productive polar front nevertheless becomes a region of low phytoplankton abundance, due to community shifts towards pico-phytoplankton (<10 μm) during late austral summer.

Seasonal changes in Porteresia coarctata (Tateoka) beds along a subtropical coast

Shoot density, standing crop （above- and below-ground biomass） and habitat of salt marsh grass Porteresia coarctata were investigated along the coast of Bakkhali estuary, Cox＇s Bazar, Bangladesh from January to December 2006. Shoot density of P. coarctata was influenced by season and was found to be higher （〉2 500 shoots/m2） in post-monsoon and minimal in monsoon season; plants were particularly active in vegetative propagation during pre-monsoon. Above-ground biomass was greater along the protected coast compared with the exposed one in this estuary. Below-ground biomass was higher （7.75-269.53 g DW/m2） than that above ground （2.20-114.75 g DW/m2）. Standing crops ofP. coarctata showed a negative relationship （R=-0.77; P〈0.05） with sedimentation rate, while seasonal activity influenced sedimentation. The recorded sedimentation rate was lower （6.09 mg/（cm2·d）） in pre-monsoon and highest （14.55 mg/（cm2·d）） in monsoon season. The mean value of pore water salinity was higher （34.25±65.05） during post-monsoon and lowest （18.0±3.71） in monsoon season. The soil was sandy clay in this P. coarctata bed; it consisted of 86% sand, 13% clay and 1% silt. Soil organic matter dropped during the monsoon season （0.78%-0.67%） and was highest （（2.17±1.42）%-（2.3±1.47）%） during post-monsoon, probably owing to accumulation of decomposed peat on the marsh surface. The mean pore water NH4-N concentration ranged from 2.444-1.65 to 3.33±1.82 μg/L, with a minimum air temperature of 22.09℃ in post-monsoon and a maximum of 31.16℃ in pre-monsoon. Variations of physico-chemical parameters in the soil, water, and climate governed biological parameters of P. coarctata in the Bakkhali estuary, and were comparable with estuarine environments elsewhere.

A Study of Physico-Chemical Parameters of Newaj River Water in Rajgarh District, Madhya Pradesh

Present paper deals with the study of some physico-chemical parameters in Newaj River Water in Rajgarh District, Madhya Pradesh in the month of November and December 2008.The parameters like temperature, pH, electrical conductivity, turbidity, total hardness, Ca- hardness, Mg-hardness and chloride were determined. The results were compared with standards of IS： 10500 and WHO. From the results it was found that the most of the parameters of Newaj River water were within the permissible limit.

Heavy Metal Analysis in Groundwater in the Vicinity of Distillery Spent Wash Evaporation Ponds

The study was conducted to assess the effect of evaporation ponds of an ethanol distillery spent wash on groundwater, with a reference to heavy metal contamination. The distillery discharging 11,880 m3 spent wash per day is extremely loaded with minerals and chemical oxygen demanding organic substances. The groundwater around the evaporation ponds is used for drinking and irrigation purposes. Thirty-five representative samples （three spent wash, two drainage water and 30 groundwater） were examined for 13 different parameters： pH, TDS （total dissolved solids）, COD （chemical oxygen demand）, the heavy metal Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Pb and As concentrations. The physico-chemical parameters were found in following range pH 7.2-7.7 ＆ 6.8-7.7, TDS 24,448-28,608 mg/L ＆ 302-4,406 mg/L, COD 20,080-24,320 mg/L ＆ 0.0-53 mg/L, Cd 190-140 μg/L ＆ 1.5-8.7 μg/L, Co 1,240-1,987 μg/L ＆ 20.5-87.2 μg/L, Cr 1,020-1,330 μg/L ＆ 14.4-38.1 μg/L, Cu 5,200-6,300 μg/L ＆ 15.0-109.3 μg/L, Fe 2,910-3,242 μg/L ＆ 0-860 μg/L, Mn 49,900-59,500 μg/L ＆ 16.3-138.7 μg/L, Ni 1,430-1,760 μg/L ＆ 8.0-107.7 μg/L, Zn 3,359-5,250 μg/L ＆ 0.0-850 μg/L, Pb 8.9-9.8 μg/L ＆ BD （below detection）-8.7 μg/L, As 5.0 μg/L ＆ BD-10.0 μg/L for spent wash and groundwater samples, respectively. The drainage water samples had parameters within limits for industrial effluents. The spent wash samples contained metal ions higher than the permissible limits for industrial effluents and the samples of groundwater collected around the evaporation ponds contained higher concentrations of metal ions as compared to samples collected away from the evaporation ponds. Coefficient of correμtion among 11 parameters was calcuμted and contamination index was also determined, 33.3% of groundwater samples mostly collected around evaporation ponds had a contamination index above 3 and are considered extremely polluted.

Surgical Management of Obstructive Urolithiasis in Small Ruminants by Tube Cystostomy in Chittagong, Bangladesh

The present study was conducted to evaluate minimally invasive tube cystostomy technique in goats and calves suffering from obstructive urolithiasis having intact and ruptured urinary bladder. This clinical study was carried out on 84 clinical cases （61 goats and 23 calves） based on the history, clinical signs and physical examination along with common laboratory techniques at the Chittagong Veterinary and Animal Sciences University during January 2015-December 2016. Physical parameters like heart rate, respiratory rate, rectal temperature and dehydration status of animals were noted and corrected abnormality before surgery. Some cases had slightly higher haemoglobin （Hb）, packed cell volume （PCV） and uric acid and epithelial casts in urine. The study revealed that abnormal calcium-phosphorus ratio was predisposing the animals to urolithiasis. It was found that young ruminants （3-5 months） were most commonly affected in both species. All affected animals were male in this study, in which calves were not castrated but in goats 95.08% animals were castrated. Rupture of bladder was more common in calves as compared to goats. Postoperatively all cases were administered with broad-spectrum antibiotic, anti-inflammatory agent and caliculolytic agents like ammonium chloride. Tube cystostomy with Foley’s catheter was the most satisfactory technique for the management of obstructive urolithiasis in small ruminants. Postoperative complications were recorded only in four animals and remaining 80 animals had a normal recovery from tube cystostomy. Tube cystostomy is a simple, inexpensive and very effective procedure for the treatment of urolithiasis in ruminants.

Modeling the Effects of Nutrient Dynamics and Surface Circulation on the Productivity of Hooghly Estuary

River estuarine environment plays a key role in the cycling of biological and chemical parameters and a significant region for the transaction of freshwater and seawater. In the present study, a first attempt has been made towards the development of a coupled three-dimensional hydrodynamic circulation model with four compartment （nitrate, phytoplankton, zooplankton and detritus） biogeochemical model in the Hooghly estuary （21 °36′-22° 16′1 and 87°42＇-88°15′E） to simulate the varying effect of plankton biomass with the heavy input of anthropogenic litter from industrial effluents of Haldia port which is effecting the chemical and biological processes that control the plankton dynamics in the estuary. In-situ observational data for physico-chemical and biological parameters are collected from Calcutta University during 2010 are assimilated using multiscale OA （objective analysis） for different seasons and incorporated in ROMS （Regional Ocean Modeling System） to develop a high resolution （0.5 km x 0.5 kin） biogeochemical model. Recent analysis on physico-chemical parameters of the estuary is done as it is one of the largest estuaries in India and is the habitat for vast biodiversity. Influence of high nitrate （above 34 μg/L） and phosphate （5.22 μg/L） is predominant whereas DO （dissolved oxygen） is low （4.07 mg/L） in the Haldi River mouth which is sliding the productivity （less than 1 mg/L） and also affects water quality.

Assessment of Water Quality in Shrimp Culture Areas of the Mekong Delta

Water quality was investigated in shrimp culture areas in Cau Ngang, Tra Vinh where three culture systems were found in the same area to assess the impact of intensification of shrimp culture on the surrounding environment. Three culture systems were selected including intensive, semi-intensive and rice-shrimp alternated culture for the study. Monthly assessment of physical and chemical parameters of water and biotic parameters were done for a period of one year from March, 2009 to February, 2010 in the canals surrounding the culture systems. The physical chemical parameters of water recorded include temperature, pH, dissolved oxygen, chemical oxygen demand （COD）, total suspended solids （TSS）, total ammonium （TAN）, nitrite （N-NO2）, nitrate （N-NO3） and total nitrogen （TN）, total phosphorus （TP） in both water and sediment. Zooplankton and zoobenthos were determined quantitatively and qualitatively using zooplankton nets and Petersen grabs, respectively. The results indicated that most of water parameters were not significantly different between culture systems and were in suitable ranges for aquatic life within the national standard criteria except DO, TSS and TP at some periods. DO concentration in rice-shrimp system was significantly lower than that in other systems. TSS and TP concentrations both in water and sediment were high exceeding the limit ranges （〉 100 mg/L）. The occurrence of some zooplankton and zoobenthos species indicated that all systems were polluted at 13 level （mesosaprobic） in which the rice-shrimp alternated culture system subjected to more environmental fluctuation not only by shrimp culture but also rice cultivation and salinity variation between dry and rainy seasons.

Water Quality Monitoring of the Bezerra River （Cascavel, Brazil） Using SR-TXRF Technique

The present study aims to monitor and assess the water quality of the Bezerra River located in the Western Brazilian Parana state. For the monitoring of river waters, six samplings were established per month during one year. As indicators of the water quality, physico-chemical parameters such as water temperature, pH, turbidity, dissolved oxygen and COD （chemical oxygen demand） were chosen, as well as trace and majority element concentrations. It is noteworthy that the mean annual values of conductivity, turbidity and COD have progressively increased along the river with maximum values after the Cascavel western sewage treatment plant. Only 13 elements were found in the six collection points, but the metallic elements Cr, Mn, Fe, Cu and Zn have shown concentrations above the maximum limits recommended by Brazilian environmental legislation, suggesting the presence of highly polluting anthropogenic sources. Correlation analyses were used to determine the spatio-variability of water quality variables. The six collection sites were grouped into two clusters, with the element composition in the first cluster （sites 1, 2 and 6） being due to strong anthropogenic activities. The study of the Bezerra River water quality could help to develop municipal environmental policies and help with the management of water conservation in the Bezerra River basin.

Relationship Population Density of Aquatic Sediment Macrozoobenthos to River Water Quality Parameters： Case Study of Upstream Citarum River in Bandung Regency

The increase in anthropogenic activities occur along the upstream of Citarum River Basin （CRB） in Bandung regency had a negative impact to the water quality caused by the presence of human activity, it will be able to be a disruption to the ecosystem aquatic. The purpose of this study was to determine the relationship of the physical and chemical parameters of water and sediment to the presence of macrozoobenthos populations. Based on the result of Pearson Correlation Analysis （PCA）, the parameters of COD, TOC and silt composition were the highest correlation to the macrozoobenthos population density, the value were 0.966, 0.865 and 0.576. Although PCA analysis is used to determine the relationship between the parameters of water, sediment and sediment particle distribution, the result showed that the water parameters were the mayor component affected the density of macrozoobenthos. While based on the composition of sediment, it is found that substrate as silt, clay and gravel and phosphate parameter affected the density of macrozoobenthos. The measurement of water quality also were calculated by Biotic Monitoring Working Party-Average Score Per Taxon （BMWP-ASPT） index showed that the quality were polluted condition, although by Pollution Index （IP） method showed as a light polluted category.