Ab initio reconstruction from one-dimensional crystal diffraction data.

Filamentary and rod-like assemblies are ubiquitous in biological systems, and single such assemblies can form one-dimensional (1D) crystals. New, intense X-ray sources, such as X-ray free-electron lasers, make it feasible to measure diffraction data from single 1D crystals. Such experiments would present some advantages, since cylindrical averaging of the diffraction data in conventional fiber diffraction analysis is avoided, there is coherent signal amplification relative to single-particle imaging, and the diffraction data are oversampled compared with those from a 3D crystal so that the phase problem is better determined than for a 3D crystal [Millane (2017). Acta Cryst. A73, 140-150]. Phasing of 1D crystal diffraction data is examined, by simulation, using an iterative projection algorithm. Ab initio phasing is feasible with realistic noise levels and little envelope information is required if a shrink-wrap algorithm is also incorporated. Some practical aspects of the proposed experiments are explored.

Macromolecular phasing using diffraction from multiple crystal forms.

A phasing algorithm for macromolecular crystallography is proposed that utilizes diffraction data from multiple crystal forms - crystals of the same molecule with different unit-cell packings (different unit-cell parameters or space-group symmetries). The approach is based on the method of iterated projections, starting with no initial phase information. The practicality of the method is demonstrated by simulation using known structures that exist in multiple crystal forms, assuming some information on the molecular envelope and positional relationships between the molecules in the different unit cells. With incorporation of new or existing methods for determination of these parameters, the approach has potential as a method for ab initio phasing.

Prevalence and predictors of penile nodules in French Guiana's sole prison facility.

PURPOSE: Penile implants or nodules are objects inserted beneath the skin of the penis mostly for erotic purposes. The procedure is painful and there may be complications. It is often associated with prison. Our objectives were to describe the prevalence of penile nodules among inmates in French Guiana, and to study factors associated with this practice, notably psychiatric diagnoses. METHODS: The study was cross-sectional. All consenting new adult prisoners incarcerated between 01/01/2014 and 31/12/2014 at the penitentiary centre of French Guiana were included. The Mini International Neuropsychiatric Interview (MINI) was used to screen for psychiatric diagnoses. RESULTS: Of 492, 29.6% declared having penile nodules. The median number was 4 (IQR = 2-7). The number of nodules correlated with age. There was no statistical link between the presence of penile nodules and the reasonforincarceration. Multivariate analysis showed that persons <45years with prior incarcerations, with substance addiction, and those with a history of death in the family were more likely to have penile nodules. Those with psychosis and those with suicidal risk were less likely to have penile nodules. Prisoners speaking English or Maroon languages seemed more likely to have penile implants in the multivariate model. CONCLUSIONS: Overall, 29.6% of arriving inmates had penile nodules. The practice was linked to drug addiction and was less frequent among those with psychosis and suicidal risk. Given the high HIV prevalence in prison, penile nodule may be an obstacle to condom-based prevention.

The phase problem for two-dimensional crystals. II. Simulations.

Phasing of diffraction data from two-dimensional crystals using only minimal molecular envelope information is investigated by simulation. Two-dimensional crystals are an attractive target for studying membrane proteins using X-ray free-electron lasers, particularly for dynamic studies at room temperature. Simulations using an iterative projection algorithm show that phasing is feasible with fairly minimal molecular envelope information, supporting recent uniqueness results for this problem [Arnal & Millane (2017). Acta Cryst. A73, 438-448]. The effects of noise and likely requirements for structure determination using X-ray free-electron laser sources are investigated.

High prevalence rates for multiple psychiatric conditions among inmates at French Guiana's correctional facility: diagnostic and demographic factors associated with violent offending and previous incarceration.

BACKGROUND: French Guiana has the highest incarceration rate among French territories, it is higher than that of Brazil, Colombia or Venezuela. It is well known that mental health problems are over-represented in correctional facilities. Our objectives were to describe the prevalence of various psychiatric conditions and to study factors associated with violence and repeated offenses among arriving detainees at the sole correctional facility of French Guiana. METHODS: The study was cross-sectional. All consenting new adult prisoners incarcerated between 18/09/2013 and 31/12/2014 at the penitentiary centre of French Guiana were included. The Mini International Neuropsychiatric Interview (MINI) was used to screen for psychiatric diagnoses. In addition sociodemographic data was collected. RESULTS: Overall 647 men and 60 women were included. The participation rate was 90%.Overall 72% of patients had at least one psychiatric diagnosis (Fig. 2). Twenty percent had three or more diagnoses. Violent index offences were not more frequent among those with a psychiatric diagnosis (crude odds ratio 1.3 (95%CI = 0.9-2), P = 0.11. Multivariate analysis showed that after adjusting for sex and age, psychosis, suicidality and post-traumatic stress disorder were independently associated with violent offences. Generalized anxiety disorder was less likely to be associated with incarceration for violent offences. Having a history of a previous incarceration was significantly associated with a psychiatric condition in general (any diagnosis) OR = 3 (95%CI = 2-4.3), P < 0.0001. Calculations of the population attributable risks showed that in the sample 31.4% of repeat incarcerations were attributable to antisocial personality disorder, 28.3% to substance addiction, 17.3% to alcohol addiction, 8.7% to depression and 7% to psychosis. CONCLUSIONS: The very high prevalence of psychiatric disorders observed in our sample, and the relative lack of psychiatric facilities, suggest that part of the problem of very high incarceration rate may be explained by transinstitutionalization. Improving psychiatric care in prison and coordination with psychiatric care in the community after release is likely to be important.

The phase problem for two-dimensional crystals. I. Theory.

Properties of the phase problem for two-dimensional crystals are examined. This problem is relevant to protein structure determination using diffraction from two-dimensional crystals that has been proposed using new X-ray free-electron laser sources. The problem is shown to be better determined than for conventional three-dimensional crystallography, but there are still a large number of solutions in the absence of additional a priori information. Molecular envelope information reduces the size of the solution set, and for an envelope that deviates sufficiently from the unit cell a unique solution is possible. The effects of various molecular surface features and incomplete data on uniqueness and prospects for ab initio phasing are assessed. Simulations of phase retrieval for two-dimensional crystal data are described in the second paper in this series.

Suicide risk among prisoners in French Guiana: prevalence and predictive factors.

BACKGROUND: Suicide rates in prison are high and their risk factors are incompletely understood. The objective of the present study is to measure the risk of suicide and its predictors in the only prison of multicultural French Guiana. METHODS: All new prisoners arriving between September 2013 and December 2014 were included. The Mini International Neuropsychiatric Interview (MINI) was used and socio-demographic data was collected. In order to identify the predictors of suicide risk multivariate logistic regression was used. RESULTS: Of the 707 prisoners included 13.2% had a suicidal risk, 14.0% of whom had a high risk, 15.1% a moderate risk and 41.9% a low risk. Predictive factors were depression (OR 7.44, 95% CI: 3.50-15.87), dysthymia (OR 4.22, 95% CI: 1.34-13.36), panic disorder (OR 3.47, 95% CI: 1.33-8.99), general anxiety disorder (GAD) (OR 2.19, 95% CI: 1.13-4.22), men having been abused during childhood (OR 21.01, 95%, CI: 3.26-135.48), having been sentenced for sexual assault (OR 7.12, 95% CI: 1.98-25.99) and smoking (OR 2.93, 95%, CI 1.30-6.63). CONCLUSION: The suicide risk was lower than in mainland France, possibly reflecting the differences in the social stigma attached to incarceration because of migrant populations and the importance and trivialization of drug trafficking among detainees. However, there were no differences between nationalities. The results reemphasize the importance of promptly identifying and treating psychiatric disorders, which were the main suicide risk factors.

[Post-Traumatic Stress Disorder among Incomers in Remire-Montjoly Prison, French Guiana]. / Le trouble de stress post-traumatique parmi les détenus en centre pénitentiaire en Guyane française.

Despite the recent interest in psychiatric illness in prison, the psychopathology of the Remire-Montjoly prison population remains largely unknown. Subject to significant population movements, French Guiana and its prison houses a very mixed population in which recent history has left a strong mark (earthquake in Haïti, civil war in Suriname, violence related to gold mining population and drug trafficking). These negative life events appear as potential vectors of psychological trauma. Additionally, strong links have been established in the literature between post-traumatic stress disorder (PTSD) and many other psychiatric disorders, including suicidal behavior and addictions. Under these conditions, we felt it essential to focus on the identification of PTSD in this sensitive population.Through adapted reception interviews, we tried to identify the PTSD, to describe by means of socio-demographic factors the studied population and to detect psychiatric comorbidities. The screening tool was the M.I.N.I. 5.0, which identifies 17 psychiatric disorders including the PTSD, based on the DSM IV definition. The target population was the prison incomers, agreeing to participate in the study, aged more than 18 years old and imprisoned between 18 January 2013 and 31 December 2013. To this date, 549 inmates were included in the study.The main result of this study was a prevalence of PTSD of 17% for incomers in detention. We found that the PTSD+ population is more likely to be female (15% against 7% p = 0.0246), which is consistent with the literature data. The M.I.N.I. 5.0 showed a higher prevalence of psychiatric disorders in the PTSD+ group. This association was confirmed in several types of pathology like mood disorders including: major depressive episode and manic or hypomanic episode, suicidal risk, some anxiety disorders including: panic disorder, obsessive-compulsive disorder and generalized anxiety disorder. Strong association was found for current major depressive episode, current manic or hypomanic episode and suicidal risk (p < 0.005).The prevalence of PTSD is very high in this study, about 24 times higher than in a general population survey using the same screening tool.A large number of comorbidities have been identified, which corresponds to those described in the literature. The specific issues of psychiatry in prison lead us to examine more specifically the significance of the results about suicide risk. A comprehensive suicide risk (sum of medium and high risk screened by the M.I.N.I.) was found in significantly more PTSD+ inmates (17% versus 7%, p = 0.005). This study supports the need for routine screening of PTSD among incomers in detention. This disease is both worrying and common in this population but the real issues are the comorbidities. Suicidal potential is among the most important issues in detention. Its evaluation should be completed by an early recognition of a PTSD.

Uniqueness of the macromolecular crystallographic phase problem.

Uniqueness of the phase problem in macromolecular crystallography, and its relationship to the case of single particle imaging, is considered. The crystallographic problem is characterized by a constraint ratio that depends only on the size and symmetry of the molecule and the unit cell. The results are used to evaluate the effect of various real-space constraints. The case of an unknown molecular envelope is considered in detail. The results indicate the quite wide circumstances under which ab initio phasing should be possible.