Neutral Silicon-Vacancy Center in Diamond: Spin Polarization and Lifetimes.

We demonstrate optical spin polarization of the neutrally charged silicon-vacancy defect in diamond (SiV^{0}), an S=1 defect which emits with a zero-phonon line at 946 nm. The spin polarization is found to be most efficient under resonant excitation, but nonzero at below-resonant energies. We measure an ensemble spin coherence time T_{2}>100 µs at low-temperature, and a spin relaxation limit of T_{1}>25 s. Optical spin-state initialization around 946 nm allows independent initialization of SiV^{0} and NV^{-} within the same optically addressed volume, and SiV^{0} emits within the telecoms down-conversion band to 1550 nm: when combined with its high Debye-Waller factor, our initial results suggest that SiV^{0} is a promising candidate for a long-range quantum communication technology.

Long-term follow-up of the Medical Research Council CLASICC trial of conventional versus laparoscopically assisted resection in colorectal cancer.

BACKGROUND: Laparoscopic resection is used widely in the management of colorectal cancer; however, the data on long-term outcomes, particularly those related to rectal cancer, are limited. The results of long-term follow-up of the UK Medical Research Council trial of laparoscopically assisted versus open surgery for colorectal cancer are presented. METHODS: A total of 794 patients from 27 UK centres were randomized to laparoscopic or open surgery in a 2:1 ratio between 1996 and 2002. Long-term follow-up data were analysed to determine differences in survival outcomes and recurrences for intention-to-treat and actual treatment groups. RESULTS: Median follow-up of all patients was 62·9 (interquartile range 22·9 - 92·8) months. There were no statistically significant differences between open and laparoscopic groups in overall survival (78·3 (95 per cent confidence interval (c.i.) 65·8 to 106·6) versus 82·7 (69·1 to 94·8) months respectively; P = 0·780) and disease-free survival (DFS) (89·5 (67·1 to 121·7) versus 77·0 (63·3 to 94·0) months; P = 0·589). In colonic cancer intraoperative conversions to open surgery were associated with worse overall survival (hazard ratio (HR) 2·28, 95 per cent c.i. 1·47 to 3·53; P < 0·001) and DFS (HR 2·20, 1·31 to 3·67; P = 0·007). In terms of recurrence, no significant differences were observed by randomized procedure. However, at 10 years, right colonic cancers showed an increased propensity for local recurrence compared with left colonic cancers: 14·7 versus 5·2 per cent (difference 9·5 (95 per cent c.i. 2·3 to 16·6) per cent; P = 0·019). CONCLUSION: Long-term results continue to support the use of laparoscopic surgery for both colonic and rectal cancer.

An open-source high-frequency lock-in amplifier.

We present characterization of a lock-in amplifier based on a field programmable gate array capable of demodulation at up to 50 MHz. The system exhibits 90 nV/√Hz of input noise at an optimum demodulation frequency of 500 kHz. The passband has a full-width half-maximum of 2.6 kHz for modulation frequencies above 100 kHz. Our code is open source and operates on a commercially available platform.

Electron paramagnetic resonance and photochromism of N3V0 in diamond.

The defect in diamond formed by a vacancy surrounded by three nearest-neighbor nitrogen atoms and one carbon atom, [Formula: see text], is found in the vast majority of natural diamonds. Despite [Formula: see text] being the earliest electron paramagnetic resonance spectrum observed in diamond, to date no satisfactory simulation of the spectrum for an arbitrary magnetic field direction has been produced due to its complexity. In this work, [Formula: see text] is identified in [Formula: see text]-doped synthetic diamond following irradiation and annealing. The [Formula: see text] spin Hamiltonian parameters are directly determined and used to refine the parameters for [Formula: see text], enabling the latter to be accurately simulated and fitted for an arbitrary magnetic field direction. Study of [Formula: see text] under excitation with green light indicates charge transfer between [Formula: see text] and [Formula: see text]. It is argued that this charge transfer is facilitated by direct ionization of [Formula: see text], an as-yet unobserved charge state of [Formula: see text].

Trauma history as a predictor of psychologic symptoms in women with breast cancer.

PURPOSE: To identify predictors of psychiatric problems in women with early-stage breast cancer. PATIENTS AND METHODS: One hundred sixty women with early-stage breast cancer were recruited from three treatment centers. They filled out self-report questionnaires, including a medical history and demographic survey, the Trauma History Questionnaire, Life Event Questionnaire, Brief Symptom Inventory, Beck Depression Inventory, and Duke-UNC Functional Social Support Questionnaire, and were evaluated using the Structured Clinical Interview for DSM-III-R. RESULTS: Hierarchical regression analyses indicated that four of five variable sets made a significant incremental contribution to outcome prediction, with 35% to 37% of the variance explained. Outcomes were predicted by demographic variables, trauma history variables, precancer psychiatric diagnosis, recent life events, and perceived social support. Cancer treatment variables did not predict outcome. CONCLUSION: The findings highlight the important roles of trauma history and recent life events in adjustment to cancer and have implications for screening and treatment.

Human CYP1B1 Leu432Val gene polymorphism: ethnic distribution in African-Americans, Caucasians and Chinese; oestradiol hydroxylase activity; and distribution in prostate cancer cases and controls.

Cytochrome P4501B1 (CYP1B1) is involved in the activation of many carcinogens and in the metabolism of steroid hormones, including 17beta-oestradiol (E2) and testosterone. We report a significant difference in the allele frequencies of two point mutations in the coding region of the CYP1B1 gene among Caucasian (n = 189), African-American (n = 52) and Chinese (Linxian) (n = 109) populations. A (C to G) transversion at position 1666 in exon 3, which results in an amino acid substitution of Leu432 to Val, was present in African-Americans with an allele frequency for Va1432 of 0.75, in Caucasians of 0.43, and in Chinese of 0.17. A (C to T) transition at position 1719 in exon 3, with no amino acid change (Asp449), appeared to be closely linked with the Val432 variant. Results using human lung microsomal preparations from individuals with the CYP1B1Val/Val and CYP1B1Leu/Leu genotypes indicate that Val432 variant may be a high activity allele and thus may contribute to the interindividual differences in CYP1B1 activity. Because CYP1B1 is involved in hormone and carcinogen metabolism, and given the disparate rates of prostate cancer among ethnic groups, we also evaluated the association of the CYP1B1 Leu432Val polymorphism with prostate cancer risk in a pilot case-control study. Among Caucasians, 34% of men with cancer (n = 50) were homozygous for the Val432 polymorphism, while only 12% of matched control subjects (n = 50) had this genotype. These preliminary data indicate that genetic polymorphisms in CYP1B1 might play an important role in human prostate carcinogenesis.

The internship: some disquieting findings.

A natural experiment in psychiatric education took place nationally between 1970 and 1976, when one group of residents entered psychiatry with an internship, and the other without one. In this study 22 psychiatry residents with an internship and 25 without one were compared during their first two years of training. Initial faculty evaluations of the two groups' responsibility, insight, teachability, and knowledge were virtually identical, as were those of their overall performance in inpatient, consultation, and emergency psychiatry. However, ratings of outpatient psychotherapy showed several significant and differences favoring the noninternship group. The authors find these results disquieting. They suggest that interferences with empathy may be an untoward side effect of the internship.

Risk factors for PTSD and other diagnoses in a general sample of Vietnam veterans.

This study examined the contribution of premilitary, military, and postmilitary risk factors to posttraumatic stress disorder (PTSD) and other postwar diagnoses in a sample of Vietnam veterans. PTSD was explained primarily by war stressors, including threat to life and exposure to grotesque death, but premilitary and postmilitary factors also contributed to the likelihood of a current diagnosis of PTSD. Panic disorder was also highly predicted by war experiences, whereas prewar functioning played a stronger role in several non-PTSD diagnoses. The study supported the notion that PTSD is specifically linked to intense stressors. Mechanisms for interactions among risk factors are discussed.

Empathy and outcome in brief focal dynamic therapy.

In an attempt to test the hypothesis that therapist empathy is an important variable in successful dynamic therapy, the authors collected outcome measures and empathy ratings in the brief focal dynamic therapy of 59 patients. There was no significant agreement among patients, therapists, and clinical supervisors when they used the same scale to rate therapist empathy for the same sessions. Only the patients' ratings correlated significantly with some of the outcome measures, and they added modest but statistically significant predictive variance on multiple regression analysis. The authors discuss the implications of these findings for the traditional mode of supervision of dynamic therapy.

Minority recruitment in clinical trials: a conference at Tuskegee, researchers and the community.

PURPOSE: This article describes the planning, implementation, and evaluation of a 2-day conference designed to examine the factors related to the participation of African Americans in cancer clinical trials. METHODS: Pre-conference formative evaluations (e.g., focus group discussions and key informant interviews with community leaders and health providers) were conducted in several rural and urban counties in the state of Alabama to determine African Americans' perceptions of participation in clinical research. The findings from these evaluations were used to develop a conference format and agenda. The 2-day conference included: (i) a pretest of African Americans' perceptions of cancer research, participation factors, and communication and recruitment issues; (ii) individual presentations high-lighting community leaders, church leaders, and researchers' perspectives regarding minority participation in research; (iii) working group discussions regarding the barriers and solutions to minority participation in research; and (iv) a posttest evaluation to measure changes in African Americans' perceptions of research. RESULTS: Several recruitment barriers and solutions were identified and reported by the working groups. Comparisons of the pretest and posttest measures showed significant (p > .05) and favorable shifts in the areas of perceptions of cancer research, participation factors, communication issues, and recruitment issues. Participation in the conference reflected a positive change in attitudes on these measures. However, the theme, "barriers that contributed to nonparticipation," did not show any significant changes during the two testing periods. The most critical lesson that resulted from this conference was the need for researchers and community members to have open dialogue about participation in research. CONCLUSIONS: This conference demonstrated that progress can be made when all parties are at the "table" and can be heard. In this model, community members proved to be valuable resources in providing researchers with information that was vital to the success of recruitment and retention studies and trials.

Children's responses to a nuclear waste disaster: PTSD symptoms and outcome prediction.

OBJECTIVE: To examine the psychological impact of living near a nuclear waste disaster that involved ongoing threat of radioactive contamination. METHOD: Participants were an exposed sample (residence within a 5-mile radius of the nuclear plant) of 120 children (7-15 years old) and their parents and a nonexposed comparison sample of 60 children and their parents. Parent and self-ratings of the children's psychological functioning and posttraumatic stress disorder (PTSD) symptoms were obtained, along with cognitive variables. RESULTS: Minimal differences between the 2 samples were found. In the exposed sample, stress responses for the child self-reports showed several age group by gender interactions. Girls' PTSD symptoms tended to increase with age while boys' symptoms decreased, with intrusion showing the strongest effects. While child and parent PTSD symptom ratings were correlated, children reported approximately twice as many symptoms. Cognitive understanding increased with age and was greater in boys. Exposure and parent functioning significantly predicted outcome. CONCLUSIONS: Age and gender effects after disaster might best be explored as an interaction. While disaster effects were mild, the psychological health of the parents may be an important determinant of psychological health in children in this type of disaster.

Children and disaster: age, gender, and parental effects on PTSD symptoms.

Psychiatric reports of 179 children aged 2 to 15 who were exposed to the Buffalo Creek dam collapse in 1972 were rated for post-traumatic stress disorder (PTSD) symptoms 2 years after the disaster. Age and gender effects and the impact of the level of exposure and parental functioning were examined according to a conceptual model addressing factors contributing to adaptation to a traumatic event. Results showed fewer PTSD symptoms in the youngest age group and higher symptom levels for girls than boys. Approximately 37% of the children were given a "probable" diagnosis of PTSD. Multiple regression analysis showed that life threat, gender, parental psychopathology, and an irritable and/or depressed family atmosphere all contributed to the prediction of PTSD symptomatology in the children.

Children of disaster in the second decade: a 17-year follow-up of Buffalo Creek survivors.

OBJECTIVE: To conduct a long-term follow-up of child survivors of a devastating human-caused disaster. METHOD: Child survivors (2-15) of the Buffalo Creek dam collapse, first evaluated in 1974, 2 years postdisaster, were reevaluated 17 years postdisaster when they were adults. Of the original 207 children, 99 were located and reevaluated using ratings on the Psychiatric Evaluation Form, the Impact of Event Scale, and the SCL-90 and lifetime and current diagnoses from the Structured Clinical Interview for DSM-III-R. RESULTS: Ratings of psychiatric symptoms at the two points in time showed significant decreases in overall severity ratings and in anxiety, belligerence, somatic concerns, and agitation. A few symptoms, not present in the child sample, increased over time (substance abuse, suicidal ideation). The current rate of disaster-related post-traumatic stress disorder (PTSD) was 7%, down from a postflood rate of 32%. There were no differences by age group in current psychological status; however, women evidenced more PTSD-related symptoms than did men. All current PTSD cases were women. Comparisons with similar subjects from a nonexposed community showed no differences. CONCLUSIONS: The findings indicated that the children studied, although having shown earlier effects, had "recovered" from the event by the time of long-term follow-up.

Predictors and outcomes of posttraumatic stress disorder in World War II veterans exposed to mustard gas.

Current posttraumatic stress disorder (PTSD) associated with participation in secret military tests of mustard gas during World War II was assessed in 363 male military veterans who were randomly sampled from a registry developed by the Department of Veterans Affairs. Current prevalence was 32% for full PTSD and 10% for partial PTSD. Prevalence of PTSD varied as a function of risk and protective factors, including volunteering, physical symptoms during the tests, and prohibited disclosure. Prediction of partial PTSD was weaker than prediction of full PTSD. Veterans with full PTSD reported poorer physical health, a higher likelihood of several chronic illnesses and health-related disability, greater functional impairment, and higher likelihood of health care use than those with no PTSD. Veterans with partial PTSD also had poorer outcomes than did veterans with no PTSD in a subset of these domains. There is discussion of the traumatic elements of experimental mustard gas exposure, vulnerability to PTSD, and the relevance of these findings to understanding the broad range of outcomes associated with PTSD.

Post-traumatic stress disorder in victims of disasters.

Disasters can produce significant, lasting psychological sequelae. Much of the disaster work that mental health professionals can do falls outside of the more traditional roles usually taken by mental health professionals. These roles include reaching out to survivors through a variety of modes and rarely waiting for them to seek traditional forms of help. Much of what can be done does not require labeling individuals as disordered but may be done within the overall response of the community to the survivors on a variety of levels. To be most effective, we need to be involved in planning efforts that can be activated when disaster strikes, rather than being reactive to the situation after it has occurred. The potential range of responses can challenge the professional who wants to help his or her community when it has been affected.

Functioning and well-being of patients in a consultation-liaison psychiatry clinic.

Outpatient consultation-liaison (C-L) psychiatry clinics are valuable settings for research and teaching endeavors. However, little is known about psychiatric symptoms and health status of persons treated in such settings. In this study, 80 persons seen in an outpatient C-L psychiatry clinic were compared with 100 persons seen in a mood disorder clinic on a variety of self-report instruments. Outpatient C-L clinic patients were found to have significantly poorer health status than mood clinic patients on the following domains as measured by the RAND instrument: general health perception, pain, physical functioning, and role functioning due to physical problems. Both groups had poor role functioning due to emotional problems and poor social functioning. The groups did not differ in depressive symptoms but C-L patients were significantly less anxious. Thus, it appears that patients in an outpatient C-L setting not only have significant medical comorbidity, as expected, but have levels of psychiatric distress comparable to that seen in a traditional psychiatry outpatient setting. These findings indicate that such a clinic is a fertile area for research and training in the diagnosis and treatment of persons with comorbid physical and mental disorders.

Prospective social-psychological factors of adolescent smoking progression.

PURPOSE: To evaluate the ability of social-psychological risk factors to predict adolescent smoking behavior. METHODS: Nonsmoking adolescents (n = 4032) who participated in the 1989 and 1993 Teenage Attitudes and Practices Surveys (TAPS I) were selected for analyses. Four multivariate logistic models were used to examine (a) adolescents' smoking initiation, (b) adults' smoking initiation, (c) adolescents' progression to regular smoking, and (d) adults' progression to regular smoking. A series of social-psychological variables were measured. RESULTS: All four models were significant. However, no social-psychological factors were consistently significant in all four models, except white ethnicity. Data showed that social-psychological factors are less able to predict the transition from nonsmoking to experimental smoking than that from nonsmoking to regular smoking. CONCLUSIONS: Future prospective studies should measure both social-psychological and smoking acquisition factors at closer intervals to more accurately examine potential relationships.

Calcium hydroxide and potassium nitrate as desensitizing agents for hypersensitive root surfaces.

The purpose of this investigation was to evaluate calcium hydroxide and potassium nitrate individually as densensitizing agents for hypersensitive root surfaces. The apparatus used in the experiment to measure hypersensitivity was (a) a thermo-electric stimulating device to measure hot and cold stimulation quantitatively and (b) a mechanical stimulating device to measure scratch stimulation quantitatively. The conclusions drawn from the study were: 1. Calcium hydroxide was more consistently effective in decreasing sensitivity then was potassium nitrate or the control. 2. Calcium hydroxide as compared to the control was statistically (99% level of significance) more effective in reducing sensitivity to mechanical, hot and cold stimulation immediately and at the conclusion of the experiment (3 months). 3. It appears that calcium hydroxide could be used as a desensitizing agent initially following periodontal surgery to reduce pain from hypersensitive roots in order that proper oral hygiene could be reestablished.

The comorbidity of post-traumatic stress disorder and suicidality in Vietnam veterans.

Vietnam veterans (N = 232) recruited from three sources were assessed for suicidal thinking and behaviors, and symptoms of posttraumatic stress disorder (PTSD) and depression. Findings support the notion that suicidal thoughts are prevalent in this group, with veterans in psychotherapy reporting a greater likelihood of such symptoms (82.6%) than veterans in the community (35.7%) or those seeking assistance through a veteran's outreach center (66.7%). Thoughts of ending one's life and a previous suicide attempt were significantly correlated with a diagnosis of PTSD (r = .53, p < .001; and r = .33, p < .001, respectively). Veterans with a diagnosis of PTSD and depression or dysthymia were also more likely to report suicidal thinking and behaviors than veterans with only one of the diagnoses.

African-American attitudes regarding cancer clinical trials and research studies: results from focus group methodology.

Despite federal recommendations highlighting the need to include special population groups (mainly minorities and women) in clinical research, recruitment and retention of these groups present a great challenge to researchers. This paper describes a focus group study that was conducted to examine factors related to minority participation and retention in cancer clinical research studies. In 1996, the National Cancer Institute submitted a request for applicants to receive support for regional conferences. The purpose of the proposed conferences was to share current information and strategies to aid cancer clinical investigators in recruiting and retaining minority participants in clinical cancer research and to stimulate local/regional adaptations of these strategies. The University of Alabama at Birmingham (UAB), The University of Alabama, and Tuskegee University collaborated to respond to the request. Funding was granted by NCI for the regional conference in Alabama. The conference was held in Tuskegee, Alabama, the site of the infamous US Public Health Syphilis Study at Tuskegee. In planning for the conference, focus group sessions were conducted with African-American men and women who represented all regions of Alabama. The focus group information was used to identify important issues to be addressed at the conference.