Diverse biological processes coordinate the transcriptional response to nutritional changes in a Drosophila melanogaster multiparent population.

BACKGROUND: Environmental variation in the amount of resources available to populations challenge individuals to optimize the allocation of those resources to key fitness functions. This coordination of resource allocation relative to resource availability is commonly attributed to key nutrient sensing gene pathways in laboratory model organisms, chiefly the insulin/TOR signaling pathway. However, the genetic basis of diet-induced variation in gene expression is less clear. RESULTS: To describe the natural genetic variation underlying nutrient-dependent differences, we used an outbred panel derived from a multiparental population, the Drosophila Synthetic Population Resource. We analyzed RNA sequence data from multiple female tissue samples dissected from flies reared in three nutritional conditions: high sugar (HS), dietary restriction (DR), and control (C) diets. A large proportion of genes in the experiment (19.6% or 2471 genes) were significantly differentially expressed for the effect of diet, and 7.8% (978 genes) for the effect of the interaction between diet and tissue type (LRT, Padj. < 0.05). Interestingly, we observed similar patterns of gene expression relative to the C diet, in the DR and HS treated flies, a response likely reflecting diet component ratios. Hierarchical clustering identified 21 robust gene modules showing intra-modularly similar patterns of expression across diets, all of which were highly significant for diet or diet-tissue interaction effects (FDR Padj. < 0.05). Gene set enrichment analysis for different diet-tissue combinations revealed a diverse set of pathways and gene ontology (GO) terms (two-sample t-test, FDR < 0.05). GO analysis on individual co-expressed modules likewise showed a large number of terms encompassing many cellular and nuclear processes (Fisher exact test, Padj. < 0.01). Although a handful of genes in the IIS/TOR pathway including Ilp5, Rheb, and Sirt2 showed significant elevation in expression, many key genes such as InR, chico, most insulin peptide genes, and the nutrient-sensing pathways were not observed. CONCLUSIONS: Our results suggest that a more diverse network of pathways and gene networks mediate the diet response in our population. These results have important implications for future studies focusing on diet responses in natural populations.

In vitro performance of prefilled CO2 absorbers with the Aisys®.

Low flow anesthesia increases the use of CO2 absorbents, but independent data that compare canister life of the newest CO2 absorbents are scarce. Seven different pre-packed CO2 canisters were tested in vitro: Amsorb Plus, Spherasorb, LoFloSorb, Medisorb, Medisorb EF, LithoLyme, and SpiraLith. CO2 (160 mL min(-1)) flowed into the tip of a 2 L breathing bag that was ventilated with a tidal volume of 500 mL, a respiratory rate of 10/min, and an I:E ratio of 1:1 using the controlled mechanical ventilation mode of the Aisys (®) (GE, Madison, WI, USA). In part I, canister life of each brand (all of the same lot) was tested with 12 different fresh gas flows (FGF) ranging from 0.25 to 4 L min(-1). In part II, canister life of six canisters each of two different lots of each brand were tested with a 350 mL min(-1) FGF. Canister life is presented as "FCU", fractional canister usage, the fraction of a canister used per hour, and is defined for the inspired CO2 concentration (FICO2) that denotes exhaustion. In part III, canister life per 100 g fresh granule content was calculated. FCU decreased linearly with increasing FGF. The relative position of the FCU-FGF curves of the different brands depends on the FICO2 threshold because the exhaustion rate (the rate of rise once FICO2 starts to increase) differs among the brands. Intra-lot variability was 18 % or less. The different prepacks can be ranked according their efficiency (least to most efficient) as follows: Amsorb Plus = Medisorb EF < LoFloSorb < Medisorb = Spherasorb = LithoLyme < SpiraLith (all for an FICO2 threshold = 0.5 %). Canister life per 100 g fresh granule content is almost twice as long when LiOH is used as the primary absorbent. The most important factors that determine canister life of prepacks in a circle breathing system are the chemical composition of the canister, the absolute amount of absorbent present in the canister, and the FICO2 replacement threshold. The use of the fractional canister usage allows cost comparisons among different prepacks. Results should not be extrapolated to prepacks that fit onto other anesthesia machines.

Effect of titanium carbonitride (Ti(C,N)) decomposition on failure mechanisms in Inconel 617 alloy.

Titanium Carbonitride (Ti(C,N)) decomposition in Inconel 617 alloy creep-exposed at 650°C for 574 hours is reported using analytical electron microscopy techniques. Cr-enriched M23C6-type carbides enveloped in fine gamma prime particles thought to be precipitated from the decomposition reaction are observed in the alloy. The morphology of the M23C6 carbides is irregular and blocky and the particle size up to 5 µm, whereas the morphology of gamma prime particles is mostly spherical and up to 30 nm in size. Intergranular carbides are mostly secondary precipitates of the M23Cc type (M predominantly Cr) and these respond to solution heat treatment and precipitate on the grain boundaries as a result of ageing. The ability of intragranular MX to decompose is sensitive to the N content, high N resists decomposition. Decomposed intragranular MX provides an excess source of C which can react locally with Cr to form heat treatable intragranular fine Cr23C6 precipitates. M6C can segregate in interdendritic locations during melting which may be the reason for high content of Mo in M23C6. These precipitates are generally very small and contribute to an additional hardening effect and are the reason for the onset of voiding and cracking along the grain boundaries that ultimately lead to a reduced creep rupture life.

The association between community-level economic hardship and childhood obesity prevalence in Los Angeles.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Neighbourhood social, economic and environmental factors are associated with childhood obesity. Childhood obesity disproportionately impacts those living in low-income neighbourhoods. WHAT THIS STUDY ADDS: Childhood obesity prevalence is strongly associated with community-level social and economic conditions as measured using a composite Economic Hardship Index. Childhood obesity prevalence among communities in the highest hardship quartile was more than double the prevalence among communities in the lowest hardship quartile (26.9 vs. 12.5%). The relationship between economic hardship and obesity differs by race/ethnicity. OBJECTIVE: The association between community-level economic hardship and childhood obesity prevalence was examined in Los Angeles County, one of the largest and most racially and ethnically diverse regions in the United States. METHODS: Data from the 2008-2009 California Department of Education's Physical Fitness Testing Program were analyzed to assess obesity prevalence among 5th, 7th and 9th grade students attending public schools (n = 298,485). Community-level socioeconomic conditions were compared using a census-tract-based Economic Hardship (EH) index. Mixed-effects modelling was used to examine the association between obesity prevalence and gender, grade, race/ethnicity and EH. RESULTS: Higher community-level EH was associated with higher childhood obesity prevalence (P < 0.001). The obesity prevalence among communities in the highest EH quartile (26.9%) was more than double the obesity prevalence among communities in the lowest EH quartile (12.5%). The slope of the association between EH and childhood obesity differed by racial/ethnic group. The slope was higher for non-Hispanic White students, Hispanics, and non-Hispanic Asians, and lower for non-Hispanic Black students. Racial/ethnic disparities were observed across the socioeconomic spectrum. CONCLUSIONS: Findings suggest that efforts to improve community socioeconomic conditions could reduce childhood obesity prevalence. Prevention efforts should target communities with high economic hardship and also focus on providing culturally relevant interventions that address disparities in obesity prevalence across communities.

An asynchronous high-speed synchrotron shutter.

A high-repetition-rate mechanical shutter with asynchronous control and sub-millisecond operation has been developed and tested for specialist X-ray systems in the field of medical diagnostics and radiation therapy. Capacitor-coupled linear voice coil actuators are utilized to achieve opening and closing speeds as fast as 700 micros for an aperture height of 4 mm. The design allows for asynchronous control, permitting slave operation of the shutter, a feature that is distinctly suitable for a number of applications including particle image velocimetry, where high-frame-rate operation must be accurately synchronized and triggered by the image acquisition sequence of the detector or timing device. The design and construction of the shutter also makes it ideal, with simple and limited modifications, for applications requiring larger apertures, in particular wide beams as found in many synchrotron beamlines.

Learning and retention of associations between auditory icons and denotative referents: implications for the design of auditory warnings.

OBJECTIVE: This study examined the way in which the type and preexisting strength of association between an auditory icon and a warning event affects the ease with which the icon/event pairing can be learned and retained. BACKGROUND: To be effective, an auditory warning must be audible, identifiable, interpretable, and heeded. Warnings consisting of familiar environmental sounds, or auditory icons, have potential to facilitate identification and interpretation. The ease with which pairings between auditory icons and warning events can be learned and retained is likely to depend on the type and strength of the preexisting icon/event association. METHOD: Sixty-three participants each learned eight auditory-icon/denotative-referent pairings and attempted to recall them 4 weeks later. Three icon/denotative-referent association types (direct, related, and unrelated) were employed. Participants rated the strength of the association for each pairing on a 7-point scale. RESULTS: The number of errors made while learning pairings was greater for unrelated than for either related or direct associations, whereas the number of errors made while attempting to recall pairings 4 weeks later was greater for unrelated than for related associations and for related than for direct associations. Irrespective of association type, both learning and retention performance remained at very high levels, provided the strength of the association was rated greater than 5. CONCLUSION: This suggests that strong preexisting associations are used to facilitate learning and retention of icon/denotative-referent pairings. APPLICATION: The practical implication of this study is that auditory icons having either direct or strong, indirect associations with warning events should be preferred.

Meeting the data needs of a local health department: the Los Angeles County Health Survey.

Monitoring the health status of populations is a core function of all public health agencies but is particularly important at the municipal and community levels, where population health data increasingly are used to drive public health decision making and community health improvement efforts. Unfortunately, most local health jurisdictions lack important data for developing population health profiles, such as data on chronic disease prevalence, quality-of-life measures, functional status, and self-perceptions of health status. In addition, data on important determinants of health, including health behaviors and access to health care services, are rarely available locally. These data frequently are collected in national and state surveys (e.g., the National Health Interview Survey and the Behavioral Risk Factor Surveillance System) and provide critical information to assess progress toward achieving state and national health objectives. The surveys rarely serve local data needs, however, because of insufficient sample size and lack of flexibility to address local health issues. To address gaps in local health data, in 1997 the Los Angeles County Department of Health Services inaugurated the Los Angeles County Health Survey.

Comparison of AIDS progression and survival in persons with pulmonary versus extrapulmonary tuberculosis in Los Angeles.

The objective of this research was to compare the demographics, acquired immune deficiency syndrome (AIDS) progression, and survival in persons with AIDS with pulmonary tuberculosis (PTB) versus extrapulmonary tuberculosis (EPTB), because there are limited population-based data on this topic. A population-based longitudinal study with 3 years of follow-up was performed. Data were collected every 6 months from medical records of persons with AIDS and TB treated at private and public medical facilities throughout Los Angeles County (LAC). Participants included a population-based sample of 216 persons with AIDS and PTB and 166 persons with AIDS and EPTB (including 113 persons with both PTB and EPTB), with an AIDS diagnosis reported in 1993. Compared to persons with AIDS with PTB, persons with AIDS and EPTB were 2.2 times more likely to be Latino than white (95% confidence intervals [CIs]: 1.2, 4.0) and 1.7 times more likely to be foreign-born (95% CIs: 1.1, 2.5). Compared to persons with AIDS with PTB, persons with AIDS and EPTB had similar antiretroviral and PCP prophylaxis use; lower CD4 counts at time of AIDS diagnosis (p = 0.0004); no differences in CD4 counts over the total follow-up period (p = 0.4); higher rates of total opportunistic infections (OIs) (incidence density ratio [IDR] = 2.0; 95% CIs: 1.6, 2.4); and comparable survival curves (p = 0.07). Persons with AIDS and EPTB had a more complicated medical course with lower CD4 counts at time of AIDS diagnosis and more OIs over the follow-up period than persons with AIDS and PTB, however the survival profiles for the two groups were comparable.

Prevalence of unprotected sex among men with AIDS in Los Angeles County, California 1995-1997.

OBJECTIVE: To determine the prevalence of unprotected sex among men with AIDS in Los Angeles County. DESIGN: Cross-sectional study. METHODS: All men aged > or = 18 years who were newly reported to the local health department with AIDS and completed a standardized interview between January 1995 and June 1997 were included in the study. Men were classified as having unprotected sex if they reported one or more sex partners during the past year with whom they had vaginal or anal sex and did not always use a condom. RESULTS: Of 617 men interviewed, 29% reported unprotected sex in the past year. The prevalence of unprotected sex was highest among men < 30 years of age (43%) and those who had first learned of their HIV-positive status < 12 months prior to interview (44%). In all, 323 (52%) men reported one or more male sex partners in the past year. Of these, 22% reported unprotected insertive anal sex and 27% unprotected receptive anal sex. One or more female partners in the past year was reported by 131 (21%) men. Of these, 53% reported unprotected vaginal sex and 18% unprotected anal sex. CONCLUSIONS: The findings highlight the importance of early HIV detection efforts, coupled with targeted and sustained HIV prevention services for those who test positive, to prevent ongoing transmission of the virus.

High-risk sexual behavior in Los Angeles: who receives testing for HIV?

No recent population-based data on HIV testing in people with high-risk sexual behavior are available. We sought predictors of testing using data from the 1997 Los Angeles County Health Survey, a random-digit telephone survey of 8004 county households. An estimated 2.3 million (35.5%) adults were tested for HIV in the past 2 years and approximately 370,000 (5.6%) engaged in high-risk sexual behavior (defined as having > or =2 partners in the past 12 months and not always using condoms). Among high-risk persons, an estimated 46% of heterosexual men, 56% of heterosexual women, and 72% of men who had sex with men (MSM) were tested for HIV. In a multivariable model of high-risk people, both heterosexual men (odds ratio [OR], 0.31; 95% confidence interval [CI], 0.16-0.61) and women (OR, 0.41; 95% CI, 0.19-0.87) had significantly lower proportions of testing than MSM. Although African Americans and Hispanics had significantly higher testing proportions than whites overall among all county residents, those reporting high-risk sexual behavior did not test at higher proportions. We conclude that the proportion of adults with high-risk sexual behavior tested for HIV is higher than almost a decade ago. However, testing among this group remains suboptimal. Future public health campaigns should intensify efforts to encourage HIV testing among this population.

Failure to learn human immunodeficiency virus test results in Los Angeles public sexually transmitted disease clinics.

BACKGROUND: Early human immunodeficiency virus (HIV) defection is essential for initiating treatment and partner-notification activities. Sexually transmitted disease (STD) clinic attendees are at high risk for infection and should be made aware of their HIV status. GOAL: To determine the characteristics associated with not receiving an HIV test result in an STD clinic setting. STUDY DESIGN: Confidential HIV testing was offered to 6,705 persons attending four public STD clinics in Los Angeles who submitted blood for syphilis serology and were tested for HIV antibody in an unlinked HIV serosurvey. Human immunodeficiency virus test results and return status were anonymously linked to other risk information. RESULTS: Only one-third of attendees were tested and given their results. Those testing HIV positive in the anonymous survey and those requesting HIV testing were most likely to receive a test result (i.e., 41% and 49%, respectively). Those solely requesting an STD examination, repeat testers, and African-Americans were least likely to receive a result (i.e., 32%, 30%, and 26%, respectively). CONCLUSIONS: Most STD clinic patients fail to receive an HIV test result. Other strategies, such as rapid HIV testing, are needed to increase participation and receipt of HIV test results in this high-risk population.

Self-directed work teams: application to a drug information center.

OBJECTIVE: To describe the transition of a drug information center from a traditionally managed center to a self-directed work team responsible for service, education, research, and drug use policy development. SUMMARY: To adapt to economic, educational, and technologic changes, traditional management structures in healthcare organizations are being reassessed. In some instances, a team approach (using self-directed work teams [SDWTs]) is being implemented. SDWTs have the potential to provide a number of benefits to an organization, including reduced costs and greater employee motivation. The University of Illinois at Chicago Drug Information Center had functioned under a traditional management structure. For economic and professional reasons, the management structure of the center was changed to an SDWT, prompting a reevaluation of the mission and activities of the center. DISCUSSION: Although still in transition, the center's change to a team structure has proven to be positive. The nature of the SDWT requires greater involvement by team members in all aspects of the center's operation, adding to the experience of team members. The team structure also allows for greater freedom to pursue projects of personal interest to individual team members. A number of issues still need to be resolved, such as performance-based compensation and peer- and self-evaluations. CONCLUSIONS: SDWTs can provide many benefits. The successful implementation of an SDWT, however, has a number of requirements, the most important of which are a commitment from management and effective communication among team members and with management.

Reasons for HIV antibody test refusal in a heterosexual sexually transmitted disease clinic population.

OBJECTIVE: To evaluate acceptance of confidential HIV antibody testing and reasons for test refusal among heterosexual clients of Los Angeles County sexually transmitted disease (STD) clinics. METHODS: From January 1993 through June 1994, all blood specimens routinely collected for syphilis serology were tested blindly for HIV antibody at seven STD clinics. Patients were counseled and offered a confidential HIV test. Rate of refusal of confidential testing and primary reason for test refusal were examined by demographic group and HIV serostatus, as determined in the blinded survey, for all heterosexual clients. RESULTS: Of 20,125 persons offered confidential testing, 35.6% refused the test. Test refusal was higher among men (38.7%) than women [31.1%; adjusted odds ratio (OR), 1.4; 95% confidence interval (CI), 1.3-1.4] and among blacks (38.6%) than whites (28.6%; adjusted OR, 1.7; 95% CI, 1.5-2.0). The most common reason for refusal was 'already know my HIV status' (40.6%), followed by 'don't want to know' (23.9%), and 'not at risk' (19.4%). Confidentiality concerns were cited as the primary reason for refusal by 2.2%. Among the 180 (0.9%) persons who tested positive in the blinded survey, 99 (55.0%) refused the confidential test. Of the 44 seropositive persons who refused the confidential test because they "already knew their HIV status', 29 (65.9%) reported their previous test to be negative. CONCLUSIONS: Efforts are needed to increase acceptance of confidential HIV testing in this heterosexual population and should (1) include a client-centered counseling approach that facilitates accurate self-assessment of risk and addresses the misperception that a prior negative test result implies an absence of risk, and (2) highlight the potential benefits of early intervention medical and psychosocial services.