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J C Thomas

Publications and source records attributed to J C Thomas.

122 records · Page 7Linked to original sources
PubMed1975

Leaf Age as a Determinant in Stomatal Control of Water Loss from Cotton during Water Stress.

The stomatal resistance of individual leaves of young cotton plants (Gossypium hirsutum L. var. Stoneville 213) was measured during a period of soil moisture stress under conditions of constant evaporative demand. When plants were subjected to increasing soil water stress, increases in stomatal resistance occurred first on the lower leaves and the stomata on the upper surfaces were the most sensitive to decreasing leaf-water potential. Stomatal closure proceeded from the oldest leaves to the youngest as the stress became more severe. This apparent effect of leaf age was not due to radiation differences during the stress period. Radiation adjustments on individual leaves during their development altered the stomatal closure potential for all leaves, but did not change the within-plant pattern. Our data indicate that no single value of leaf water potential will adequately represent a threshold for stomatal closure in cotton. Rather, the stomatal resistance of each leaf is uniquely related to its own water potential as modified by age and radiation regime during development. The effect of age on stress-induced stomatal closure was not associated with a loss of potassium from older leaves. Increases in both the free and bound forms of abscisic acid were observed in water-stressed plants, but the largest accumulations occurred in the youngest leaves. Thus, the pattern of abscisic acid accumulation in response to water stress did not parallel the pattern of stomatal closure induced by water stress.

Journal Article↗
PubMedDate not supplied

Cognitive-behavior therapy of obsessive-compulsive disorder in private practice: an effectiveness study.

A controversy exists over whether or not the results of randomized controlled trials (RCTs) are generalizable to routine clinical practice. The present study examines the effectiveness of cognitive-behavior therapy (CBT) for obsessive-compulsive disorder (OCD) in a private practice setting. Twenty-six consecutive clients referred to a private anxiety disorders specialty clinic began treatment for OCD. Of the 19 (73%) clients who completed treatment, 84% were treatment responders. Clients, treatment, and outcome of the present study are compared with those of representative RCTs, and it is concluded that there are more similarities than differences. It is concluded that CBT can be effectively delivered in routine clinical practice.

Adult↗
PubMedDate not supplied

High-resolution particle size analysis in biotechnology process control.

Many industrially important proteins can now be expressed intracellularly as insoluble protein inclusion bodies. In production, large-scale centrifugation is commonly used to separate and recover the inclusion bodies. Recovery efficiency depends critically on the centrifuge feed rate, which must be optimized to minimize production costs. We have used a disc centrifuge photosedimentometer to make high-resolution measurements of the particle size distribution (PSD) of the supernatant during the production of porcine somatotropin (pST) inclusion bodies. These measurements readily monitor the breakthrough of inclusion bodies into the supernatant and allow the centrifugation operation to be optimized.

Biotechnology↗
PubMedDate not supplied

Domestic violence and sexually transmitted diseases: the experience of prenatal care patients.

OBJECTIVES: The authors analyzed interview responses of patients at a prenatal care clinic to explore whether women who had been victims of sexual and physical abuse were more likely than non-victimized women to have experienced a sexually transmitted disease (STD). METHODS: A consecutive sample of 774 prenatal patients of a large health department in North Carolina were interviewed concerning a variety of health issues, including violence and STDs. Logistic regression analysis was used to model the women's STD status as a function of their experiences of sexual and physical abuse, controlling for several potentially confounding factors. RESULTS: Thirty percent of the women reported having experienced at least one STD, with the most common infections being chlamydia and gonorrhea. Twenty-eight percent of the women reported having been victims of abuse; 16% reported physical abuse only, while 12% reported both physical and sexual abuse. The majority of violence was domestic in nature, perpetrated by the victims' husbands, boyfriends, male friends, and relatives. After controlling for confounding variables, the authors found that women who reported both physical and sexual abuse were significantly more likely to have experienced STDs than non-victims (odds ratio [OR] = 2.25; 95% confidence interval [CI] 1.37, 3.69). The logistic regression analysis also showed a relationship of borderline statistical significance between non-sexual physical abuse and STDs. CONCLUSIONS: Health care providers should routinely screen patients for both abuse and STDs, and they should assist identified women in accessing appropriate health, social, and legal services.

Adult↗
PubMedDate not supplied

Trust and collaboration in the prevention of sexually transmitted diseases.

High rates of sexually transmitted diseases (STDs) are sustained in communities by a relatively small group of people, referred to as the core of transmission. Definitions of the core vary but inevitably include people who are socially marginalized and who distrust people in authority, such as public health practitioners and university researchers. Having an effect on a marginalized group usually depends on effective collaboration with people they trust. Researchers from the University of North Carolina School of Public Health developed a trust-based collaboration with community members of a rural county in North Carolina to implement an STD prevention program that, in turn, relied on trust in local social networks. As part of the STD prevention demonstration project, the research team established a community resource group made up of local African Americans who helped design, implement, and evaluate the intervention. The group identified 21 women to whom others in the community turned for advice on sex and STDs. These women were trained as lay health advisors to disseminate information and skills for preventing STDs among their social networks. Through face-to-face structured interviews before and after the intervention, the authors measured improvements in STD treatment and prevention behaviors. The proportion of people practicing each of the targeted behaviors improved during the evaluation period. In addition to disseminating information through their own social networks, the lay health advisors demonstrated new skills and a desire to interact with local care providers to influence the provision of care for STDs for low-income African Americans in this county. Each participant in the collaboration played a role in establishing or building upon trust with others. These trusting relationships were critical for empowering a marginalized group at high risk for STDs.

Adolescent↗
PubMedDate not supplied

Evidence of thorough reporting of sexually transmitted diseases in a southern rural county.

BACKGROUND AND OBJECTIVES: Private physicians outside the South have been found to report half or fewer of the sexually transmitted diseases that they diagnose. The authors studied whether this is also true in a Southern rural county. STUDY DESIGN: Reports of gonorrhea and chlamydia infection from private physician practices in a rural North Carolina county were compared with laboratory records of positive test results. The proportions reported through 8 months of passive surveillance were compared with the proportion reported during 2 months of active weekly telephone surveillance. RESULTS: A total of 72% of all positive gonorrhea test results and 55% of all chlamydia test results were reported through passive surveillance. The proportions increased to 88% and 79%, respectively, with active surveillance. A separate system of multiple checks ensured complete reporting of syphilis that was not affected by surveillance type. CONCLUSIONS: A relatively high proportion of sexually transmitted diseases diagnosed by private physicians was reported in this rural county. Potential reasons included physician awareness of reporting requirements, delegation of reporting to clinical staff, and personal acquaintance with the health department staff.

Chlamydia Infections↗
PubMedDate not supplied

STEP sisters, sex, and STDs: a process evaluation of the recruitment of lay health advisors.

Individual interviews, field observations, and group debriefings were used in this qualitative study that assessed the accuracy of the recruitment strategy used to identify natural helpers to assist African American women, aged 18-34, to prevent and seek care for sexually transmitted diseases (STDs). The study indicates that the recruitment strategy is effective when a list of natural helpers is generated by advisory groups from the same geographic community. Screening protocols used to interview potential natural helpers appear to reduce later barriers to advising on sensitive topics like STDs. The data suggest the importance of using community members to identify natural helpers and the importance of addressing sensitive topics early in the recruitment process.

Community Health Workers↗
PubMedDate not supplied

The effect of misclassification of diarrhoea on estimates of its occurrence, the identification of risk factors, and the assessment of prevention efforts.

Inaccurate assessment of true diarrhoea status introduces bias into estimates of its occurrence. A cross-sectional study of diarrhoea among 357 children in a rural Kenyan community found the sensitivity and specificity of the mother's report of diarrhoea to be 0.79 and 0.94 respectively, when compared to an independent observation of loose stool consistency. The observed diarrhoea prevalence of 9.5% overestimated the "true" prevalence estimated at 4.8%. With data on an exposure variable, lack of latrine ownership, an observed odds ratio of 2.0 (95% confidence interval (CI) 0.9-4.3) underestimated the "true" odds ratio of 5.4 (95% CI 2.0-14.5). Misclassification of diarrhoea can hinder the identification of communities of high incidence, the determination of risk factors for diarrhoea, and the evaluation of preventive intervention strategies. A precise definition and reliable means of measuring diarrhoea are critical for evaluating prevention or intervention efforts.

Child↗
PubMedDate not supplied

Extirpation of the fibular sesamoid simplified.

This technique allows the surgeon to maintain a firm grasp on the fibular sesamoid during its dissection, thus minimizing surgical trauma to the surrounding tissue and decreasing the chance of an inadvertent tenotomy of the flexor hallucis longus tendon. The authors have used this technique in 30 sesamoidectomies and found it to lower the frustration level significantly. The only instances in which it does not work as well as expected is with severely osteoporotic sesamoids, and partite sesamoids with fragments too small to pierce with the Kirschner wire. This technique has proved to be relatively simplistic. The small diameter of the Kirschner wire permits both excellent vision of the operative field and easy access to dissection.

Bone Wires↗
PubMedDate not supplied

Partner-specific sexual behaviors among persons with both main and other partners.

CONTEXT: If men and women engage in different sexual behavior with main partners than with other types of partners, then programs aimed at preventing the spread of sexually transmitted diseases (STDs) may need to address individuals' differential risk with each partner type. METHODS: Relationship characteristics, partner risk behaviors and sexual behaviors are examined among 123 male and 106 female STD clinic patients who had both main and other partners. Individual-level comparisons are made for two types of partner pairs: main vs. other frequent (side) partners and main vs. casual partners. RESULTS: Among men and women with both main and side partners, the proportion who had known only their main partner for at least a year (48% of men and 41% of women) was significantly higher than the proportion who had known only their side partner for that long (2% and 9%, respectively); no other variable differed significantly by partner type. Among those with main and casual partners, both men and women were more likely to use alcohol or drugs before or during sex with main partners only (15%) than with casual partners only (1-3%). Women with main and casual partners were more likely to have oral sex only with main partners than only with casual partners (37% vs. 3%), and were more likely to use condoms only with casual partners than only with main partners (33% vs. 4%). CONCLUSIONS: Providers need to ask individuals about their sexual behaviors with different partner types, and should tailor prevention messages to an individual's risks and reproductive intentions with each partner.

Chi-Square Distribution↗