CMV infection and cytomegalovirus disease in immunodepressed patients

An active entomologic survey was conducted by a team of trained health workers in a rural area endemic for Chagas' disease in central Brazil. They used pyrethrum as a flushing agent and 4,232 houses were inspected for triatomine bugs both inside and in the immediate environs. Houses with Triatoma infestans or evidence of an established colony were identified and defined as infested houses (cases). The building and environmental characteristics of 161 randomly selected infested houses were compared with 161 matched, noninfested houses (controls) that were the shortest distance from the infested house. Domestic and peridomestic potential risk factors associated with house infestation by Triatoma infestans were assessed by logistic regression analysis. Incomplete house construction (odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.5-4.1) was confirmed as a risk factor related to the presence or evidence of Triatoma infestans in the dwellings. The study also disclosed a statistically significant association between the presence of rats (OR = 1.6, 95% CI = 1.1-2.6) and indoor crop storage (OR = 2.3, 95% CI = 1.1-5.2) and house infestation. Further experimental field studies using tagged rodents should be conducted to assess their epidemiologic role in the domestic chain of Trypanosoma cruzi transmission.     

Current human and canine seroprevalence of Chagasic infection in San Pedro de Atacama County, II Region of Antofagasta, Chile, 1995

In order to assess the impact of a control program against Triatoma infestans launched in 1988, based on insecticide spraying of dwellings, a serological survey for chagasic infection was carried out during 1995 in three localities from San Pedro de Atacama County (22 degrees 55' South lat., 68 degrees 12' West long.), II Region of Antofagasta in northern Chile. Blood samples from 531 children and adolescents and 65 dogs were subjected to ELISA test and indirect immunofluorescent test for Chagas' disease respectively. Tests resulted positive in 12 (2.3%) persons, all above 5 years old, in contrast with the 16.8% serological positivity observed in 1985. Three (4.6%) dogs (two 0-12 months old) resulted positive. These results indicate that dwelling sprayings with long-term activity insecticides against T. infestans is a good tool to prevent new human infections with T. cruzi. However, active vector transmission among domestic animals (canines) could be recently acquired.     

Differentiation induction therapy with all-trans retinoic acid (ATRA) in a patient with secondary 11q23 leukemia

This study was performed in an urban neighborhood of the capital city of the province of San Juan, Argentina. Erected as a housing complex, the place consists of 768 flats distributed in buildings of three and seven floors each. A survey was carried out in 33% of the dwellings, enquiring about the number of Triatoma infestans found indoors, stage of the bug development-nymph or adult- and how these insects had entered their homes. Adult T.infestans were found on all floors; 163 people (64%) had found them at least once, and 130 (51%) several times. Dispersal flight seems to have been the main mechanism of infestation by adult bugs in this area, and a total of 51% of the surveyed inhabitants reported that the insects had flown into their flats.     

金属矿山深井开采过程中的顶板事故浅析

对有色金属矿山深井开采过程中的顶板事故进行分类,并对其产生的原因进行分析;阐述深井开采过程中进行顶板管理研究的重要性,并对国内深井开采的金属矿山顸板管理研究现状进行总结．提出实施顶板动态分级管理的研究方法和不同级别项板的对应处理措施,为深井开采矿山的顶板管理提供新的解决途径．     

Design and Wind Tunnel Performance Testing of a New Omnidirectional Roof Vent

Low-slope roofs are subjected to potentially high levels of suction pressure as reported by Baskaran and Savage in 2003 in “Wind pressure measurements on full scale flat roofs.” Traditional roof assemblies are prone to failure when the low pressure on the roof surface instigates a transfer of forces to the roof membrane. Existing pressure-equalized roof systems use the power of the wind to transmit low pressure to the space immediately beneath the roof membrane, pulling the membrane down to the roof surface. The object of this study is the design of a wind vent which, when coupled with a single-ply roof membrane in a complete roof assembly, will successfully equalize low pressure throughout the entire field of the roof. The proposed wind vent differs from existing equalizer valves in its use of the Bernoulli effect to create low pressure. The vent is omnidirectional and contains no moving parts. Future study will be required to determine the tributary area of each vent and other roof system parameters.     

Wind Damage to Masonry Buildings

An examination has been made of the methods of construction of masonry‐walled buildings, and their performance in severe windstorms. Particular emphasis was placed on low‐rise buildings using unreinforced concrete block walls and light roofs, which suffer the majority of wind damage. It is shown that traditionally built, nonengineered buildings have become more wind sensitive in recent years as the result of a reduction in the number of internal walls and a lowering of roof weights. Empirical design procedures regarding wall height‐to‐thickness ratios and roof anchorage have not changed to reflect this increased sensitivity, leaving many modern, nonengineered buildings with insufficient wind resistance. Professionally designed structures often have a similar structural form to traditionally built structures, since the same empirical design rules are often used to size walls and roof anchors. The longer roof spans in these buildings render them even more sensitive to wind uplift loads, and subject to progressive collapse. The inadequacies of present building code requirements are discussed and recommendations for improvements are made.     

Evaluation of vectors of Chagas' disease eradication programs in Chile by serological study of children under 10 years old

Chagas' disease is a parasitic zoonosis with high prevalence in Chile. It is distributed in rural and periurban section in the northern most seven out of thirteen regions in which the country is divided, and affects about 142,000 individuals dispersed in most of the 165 counties sited in the chagasic zone. Triatoma infestans--intradomiciliary species--is the main and practically exclusive vector of Trypanosoma cruzi. Diverse tools may be utilized in order to interrupt the domestic cycle of transmission of T. cruzi: health education, housing improvement and elimination of vectors by dwelling insecticide sprayings. This last resource has received priority in Chile in the last 12 years. To evaluate the effectivity of the programs for eliminating T. infestans a serological study for Chagas' disease--comprising 8,767 children less than 10 years old from 27 rural counties insecticide sprayed in the last 12 years--was carried out. A global total of 125 (1.4%) children resulted positive, figure significantly lower than 5.4% found in 1982-1990 in the same age group. Distribution by regions of positive individuals showed a decrease of prevalence in each of them: III Region, from 9.8 to 1.0%, IV Region, 7.2 to 2.0%, V Region, 5.2 to 1.9%, and Metropolitan Region, 1.4% to 0.6. Even though positive children have still been found in 46.7% of localities of the studied counties, it is possible to affirm that the vector control programs have been effective and must be maintained, and increased in those localities with T. cruzi infection in children under 10 years of age, with the general aim of eradicate Chagas' disease transmission in Chile before 2000.     

Temperature Distribution in Walls and Roofs

Temperatures in the walls and roofs of an experimental shed were measured. An “average” mathematical model was established for the determination of heat flow through wall and roof elements with different surface finishes. The input meteorological data and parameters used in calculation are discussed. The measured data were used to calibrate the model and check the assumptions involved. Based on the established model, heat flow through wall and roof elements and efficiency of different surface finishes are compared. The thermal inertia of a 150-mm-thick concrete wall is significant. Heat transmitted through a wall also depends greatly on the color of its surface. The insulation layers reduce heat flow into the interior and increase considerably the thermal inertia of a roof. The study focused on the summer period.     

The risk of Parkinson's disease with exposure to pesticides, farming, well water, and rural living

We assessed exposure to pesticides, farming, well water use, and rural living as risk factors for Parkinson's disease (PD) in a population-based case-control study consisting of men and women > or = 50 years of age who had primary medical care at Henry Ford Health System in metropolitan Detroit. Enrolled PD patients (n = 144) and control subjects (n = 464) were frequency-matched for age, race, and sex. When adjusted for these variables and smoking status, there was a significant association of occupational exposure to herbicides (odds ratio [OR], 4.10; 95% CI, 1.37, 12.24) and insecticides (OR, 3.55; 95% CI, 1.75, 7.18) with PD, but no relation was found with fungicide exposure. Farming as an occupation was significantly associated with PD (OR, 2.79; 95% CI, 1.03, 7.55), but there was no increased risk of the disease with rural or farm residence or well water use. The association of occupational exposure to herbicides or insecticides with PD remained after adjustment for farming. The association of farming with PD was maintained after adjustment for occupational herbicide exposure and was of borderline significance after adjustment for occupational insecticide exposure. These results suggest that PD is associated with occupational exposure to herbicides and insecticides and to farming and that the risk of farming cannot be accounted for by pesticide exposure alone.     

Cost-Effectiveness of Green Roofs

Life-cycle assessment was used to evaluate the widespread installation of green roofs in a typical urban mixed-use neighborhood. Market prices of materials, construction, energy conservation, storm-water management, and greenhouse gas (GHG) emission reductions were used to evaluate private and social costs and benefits. Results suggest green roofs are currently not cost effective on a private cost basis, but multifamily and commercial building green roofs are competitive when social benefits are included. Multifamily and commercial green roofs are also competitive alternatives for reducing greenhouse gases and storm-water runoff. However, green roofs are not the most competitive energy conservation techniques. GHG impacts are dominated by the material production and use phases. Energy impacts are dominated by the use phase, with urban heat island (UHI) impacts being an order of magnitude higher than direct building impacts. The quantification of private and social costs and benefits should help guide green roof policy. Results should encourage green roof enthusiasts to set appropriate life-cycle assessment boundaries, including construction material impacts and UHI effects.     

Domestic infestation by Triatoma infestans and prevalence of Trypanosoma cruzi seropositives in a rural area of the Argentinian northeast

An epidemiological study was carried out from April 1991 to December 1993 to obtain a general view of T. cruzi domestic transmission in rural areas of San Miguei Department, Corrientes. From 100 analyzed households, 50.0% was infested by T infestans (Klug, 1834) and 1.0% by T. sordida (Stal, 1859). Domiciliary colonization by T. sordida is reported for first time in Corrientes province. T. cruzi infection of T. infestans was 23.1%. Indirect hemagglutination and indirect immunofluorescence antibody tests were used for detection of anti T. cruzi antibodies in 388 human sera, 23.4% showed serological reactivity. An important high rate (12.9%) was observed in the age group of higher transmission risk. Seropositives percentages increased with age and reached 50.0% in 31-40 years old group. Domestic infestation by T. infestans, seropositive human prevalence to T. cruzi and householders precarious life conditions prove that this endemic disease is still a problem in the studied area.     

Cerebrospinal fluid bearing channels of the pia meter

The pia mater of the human brain hemispheres has liquor canals which form a continuous network communicating with the cisterns of the brain base. The wall of the liquor canals is formed by a fibro-collagenous framework covered from two sides with the arachnoidendothelium. In the canal walls there are openings, through which the lumens of the canals communicate with the lumens of alveoli. The liquor canals are divided into the circulatory and excretory ones. The circulatory canals are disposed in the depth of the cerebral sulci, the secretory canals--on the surface of the convolutions. The liquor moves along the circulatory canals from the cisterns of the brain base onto the surface of cerebral hemispheres. Excretory canals adjoin the arachnoid membrane which is part of its wall (the "roof"). In the "roof" of the liquor canals the fibrocollagenous basis and the number of layers of the arachnoid--endothelium are reduced, the intercellular spaces between the cells of the arachnoidendothelium are dilated. Through the roofs of the liquor canals the liquor is excreted from the subarachnoid space into the subdural space. Inside the liquor canals there are arteries of the pia mater hung up to the canal walls by trabeculae (cords) of a dense connective tissue.     

Evaluation of methods of insecticide application for control of smokybrown cockroaches (Dictyoptera: Blattidae)

The insecticide components of a previously developed integrated pest management system for smokybrown cockroaches, Periplaneta fuliginosa (Serville), were tested individually and at reduced application rates in 4 separate trials over 2 yr. A 2-bait combination (pellet and gel baits) did not significantly reduce cockroach abundance more than a single constituent bait alone. A targeted spray of trelamethrin was significantly less effective than a 2-bait combination. Residual activity of insecticides was determined with American cockroaches, P. americana (L.), in a laboratory bioassay. Chlorpyrifos wettable powder remained active < 12 d in the field, after which time its activity was not different from an experimental control (no insecticide residues), whereas chlorpyrifos pellet and hydramethylnon paste baits retained initial activity for > 27 d. Nematodes [Steinernema carpocapsae (Weiser)] applied as a spray solution did not effect the abundance of smokybrown cockroaches, and no cockroaches were recovered that exhibited nematode infection. Time needed to apply various insecticide treatments did not differ substantially (15-25 min per house), even for lower application rates.     

Thermal operation of arc foundry furnaces

Experimental data on the temperature distribution over the lining thicknesses of the walls, roof, and bottom of a 6-t arc steel-melting furnace are processed. The time dependence of the heat flux density distribution over the lining thickness is determined, and the change in the enthalpy of the lining during a heat is found. Recommendations for the rational use of the heat accumulated by the lining during furnace downtime are given.     

基于协同回采的深部厚大矿体分段充填采矿法

针对预控顶分段充填法在深部开采存在的预控顶巷道掘进工序繁杂、顶板易受爆破震动影响等缺点,本文提出垂直孔与水平孔协同回采的机械化分段充填采矿法(协同回采分段充填法).该方法通过改变顶板支护工序的顺序,将预控顶变为后压顶,能够有效地解决顶板围岩稳定性问题.进而对协同回采分段充填法进行优化研究:一方面,通过SURPAC到ANSYS的模型转换技术,进行采场稳定性数值分析,获得最佳的结构参数;另一方面,通过分区出矿分区支护的方式,解决两帮支护不到位和出矿效率低的问题.将该方法应用于新城金矿V#矿体开采,结果显示顶板岩移量显著减小,且各项经济技术指标均得到改善,实现了高应力条件下厚大矿体的安全高效开采.      

New Design Procedure for Wind Uplift Resistance of Architectural Metal Roofing Systems

Currently, there are no Canadian national guidelines for the wind uplift resistance of architectural metal roof systems. Thus, it is difficult to judge their suitability and performance based on a common standard. Given the increasing use of metal roofs, it has been determined that there is a need for the development of a design guide, that would be applicable to all regions of Canada. Metal roofs can be classified into two groups: Structural and architectural. This paper focuses on the wind uplift performance of architectural metal roof systems. Several parameters influence the wind uplift performance of the architectural metal roofs. This study finds that air leakage of the structural deck is one of the significant factors that influences the wind uplift performance. This is based on experimental investigations carried out at the Dynamic Roofing Facility of the National Research Council of Canada, using the Special Interest Group on Dynamic Evaluation of Roofing System dynamic wind test protocol. Architectural roofing panels with three different types of commonly used, seam-interlocking mechanisms (joint details) were investigated. It has been noted that the resistance to wind uplift pressure increases dramatically as the air leakage ratio decreases. A modeling method is also described which quantifies system response by simulating the wind gusts over roof specimens with different leakage ratios that can represent field assemblies. The 1995 National Building Code of Canada was utilized for the estimation of the wind-induced loads and the present study provided extensive experimental data for various systems with each type of seam detail. Based on this analysis, a simplified design procedure was developed. The simplified procedure is presented through case studies of metal roof assemblies located in the Canadian provinces of British Columbia, Ontario, and Quebec.     

Trypanosoma cruzi genotypes associated with domestic Triatoma sordida in Bolivia

Triatoma sordida is the second species of Triatominae considered of epidemiological significance in Bolivia. Associated with Triatoma infestans in various regions, it is as yet the only triatomine species established in human dwellings in localities of Velasco province, Department of Santa Cruz. This domestication is considered as primary. Flagellate parasites were detected in 16.2% of domiciliary T. sordida and the kDNA-PCR confirmed the presence of Trypanosoma cruzi. Frequencies of T. cruzi clonets 20 and 39, common clonets in Bolivian domestic cycle (T. infestans), were established by their direct detection in feces using PCR and hybridization. These clonets present low frequencies in T. sordida and synanthropic mammals. Forty-six stocks were isolated and analysed by multilocus enzyme electrophoresis (MLEE). The MLEE showed a higher clonal diversity than in T. infestans domestic cycle and the genotypes were clustered in the two principal lineages of T. cruzi. Within each lineage, a broad variability was observed. Mixture of genotypes was mostly observed in mammals. The large diversity of T. cruzi in this cycle should be related to its sylvatic origin. Moreover, the current limited sample of stocks suggests a lineage association with specific hosts.     

Computer Assistance in Managing the Maintenance of Low-Slope Roofs

Computerized roof management systems (CRMSs) are developed to assist building owners in minimizing their expenditures on roof maintenance while improving the safety and serviceability of their roof stock. Current CRMSs have some limitations that affect their ability to efficiently represent roof data at different manageable levels and to accurately predict the service life of various roof components. A new CRMS, called CBROOF, is developed within the Building Envelope Life Cycle Asset Management (BELCAM) research project to overcome these limitations. CBROOF has an object-oriented conceptual model that supports the hierarchical decomposition of roofs and the representation of their data at different levels of detail. CBROOF also incorporates the use of the case-based reasoning (CBR) approach to predict the future condition of roof components based on the recorded condition of similar components. The design and implementation of the relevant modules of CBROOF are presented, and the CBR deterioration model developed for the service life prediction of built-up roof membranes is validated.     

Reducing the hindsight bias utilizing attorney closing arguments

Dogs, the main domestic reservoirs of Trypanosoma cruzi in the Argentine chaco, may be useful as sentinels of vector-mediated transmission of Trypanosoma cruzi in control programmes if canine infections acquired by all other routes could be excluded. In the present study, in the province of Santiago del Estero, Argentina, the dog populations in the neighbouring villages of Amamá, Trinidad, Mercedes, Villa Matilde and Pampa Pozo were studied immediately before spraying of residual insecticides (in 1992 in Amamá, Trinidad and Mercedes and 1993-1994 in the other villages) and twice during a subsequent programme of triatomine surveillance (in 1994 and 1996). Overall seropositivity for Trypanosoma cruzi infection (i.e. the proportion of dogs found positive by at least two different serological tests in any one survey) steadily declined from 65% (54/83) in 1992 to 39% (70/182) in 1994 and 15% (36/237) in 1996. No seroconversion was detected between the 1994 and 1996 surveys in any dog aged > 2 years. However, among the dogs aged < 2 years (which were born after virtual elimination of Triatoma infestans from the villages), seropositivity fell from 15% (12/81) in 1994 to 5% (6/131) in 1996. Thirteen demographic, behavioural and entomological variables were analysed by logistic multiple-regression analysis for their association with seropositivity in dogs born locally during the surveillance programme. The total number of Triatoma guasayana collected in the bedroom areas of the owner's house, having a mother which was seropositive for Trypanosoma cruzi, and the number of seropositive dogs with which it cohabited were all found to be significant predictors of seropositivity in any dog. The results are the first indication that Triatoma guasayana is the vector responsible for the new cases of Trypanosoma cruzi infection seen in dogs in domestic or peridomestic sites during the surveillance programme.     

Malaria: existing methods of vector control and molecular entomology

In general, the most effective means of malaria vector control is the killing of adult mosquitoes with a residual insecticide applied to bednets or sprayed on house walls and ceilings. Major reductions in all-cause child mortality have been achieved in Africa by these means. In some circumstances, personal protection and larval control may also make a contribution. We discuss the prospects of genetic control by release of sterile male mosquitoes or driving genes for refractoriness to malaria into wild populations. Many major malaria vectors belong to complexes of sibling species which differ in vectorial and biological characteristics. Distinguishing the species by cytogenetic or molecular methods is important for epidemiological studies and could improve the targeting of control.