Novel experimental setup for megahertz X-ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X-ray Free-Electron Laser (EuXFEL).

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

Measurement of Body-Centered Cubic Gold and Melting under Shock Compression.

We combined laser shock compression with in situ x-ray diffraction to probe the crystallographic state of gold (Au) on its principal shock Hugoniot. Au has long been recognized as an important calibration standard in diamond anvil cell experiments due to the stability of its face-centered cubic (fcc) structure to extremely high pressures (P >600 GPa at 300 K). This is in contrast to density functional theory and first principles calculations of the high-pressure phases of Au that predict a variety of fcc-like structures with different stacking arrangements at intermediate pressures. In this Letter, we probe high-pressure and high-temperature conditions on the shock Hugoniot and observe fcc Au at 169 GPa and the first evidence of body-centered cubic (bcc) Au at 223 GPa. Upon further compression, the bcc phase is observed in coexistence with liquid scattering as the Hugoniot crosses the Au melt curve before 322 GPa. The results suggest a triple point on the Au phase diagram that lies very close to the principal shock Hugoniot near ∼220 GPa.

Identification of Phase Transitions and Metastability in Dynamically Compressed Antimony Using Ultrafast X-Ray Diffraction.

Ultrafast x-ray diffraction at the LCLS x-ray free electron laser has been used to resolve the structural behavior of antimony under shock compression to 59 GPa. Antimony is seen to transform to the incommensurate, host-guest phase Sb-II at ∼11 GPa, which forms on nanosecond timescales with ordered guest-atom chains. The high-pressure bcc phase Sb-III is observed above ∼15 GPa, some 8 GPa lower than in static compression studies, and mixed Sb-III/liquid diffraction are obtained between 38 and 59 GPa. An additional phase which does not exist under static compression, Sb-I^{'}, is also observed between 8 and 12 GPa, beyond the normal stability field of Sb-I, and resembles Sb-I with a resolved Peierls distortion. The incommensurate Sb-II high-pressure phase can be recovered metastably on release to ambient pressure, where it is stable for more than 10 ns.

Femtosecond diffraction studies of solid and liquid phase changes in shock-compressed bismuth.

Bismuth has long been a prototypical system for investigating phase transformations and melting at high pressure. Despite decades of experimental study, however, the lattice-level response of Bi to rapid (shock) compression and the relationship between structures occurring dynamically and those observed during slow (static) compression, are still not clearly understood. We have determined the structural response of shock-compressed Bi to 68 GPa using femtosecond X-ray diffraction, thereby revealing the phase transition sequence and equation-of-state in unprecedented detail for the first time. We show that shocked-Bi exhibits a marked departure from equilibrium behavior - the incommensurate Bi-III phase is not observed, but rather a new metastable phase, and the Bi-V phase is formed at significantly lower pressures compared to static compression studies. We also directly measure structural changes in a shocked liquid for the first time. These observations reveal new behaviour in the solid and liquid phases of a shocked material and give important insights into the validity of comparing static and dynamic datasets.

Cigarette smoking and glaucoma in the United States population.

PurposeTo evaluate the association between cigarette smoking and glaucoma in the United States population.Patients and methodsUS civilian, non-institutionalized population from 2005 to 2008 administrations of the National Health and Nutrition Examination Survey that were ≥40 years of age with visual fields and optic disc photographs were included. Diagnosis of glaucoma was based on the Rotterdam criteria. Logistic regression modeling was performed to assess the association between glaucoma and smoking history, while controlling for age, gender, ethnicity, household income, alcohol consumption, diabetes, and hypertension.ResultsIn 3864 participants, 212 (5.5%) had glaucoma (corresponds to a population weighted glaucoma prevalence of 3.7% in a total of 83 570 127 subjects). Population weighted proportion of current smokers was 20.6% and ex-smokers was 28.3%. Participants with glaucoma were older (63.0±11.6 vs 56.1±11.2, P=0.002), likely to be male (57.1% vs 49.2%, P=0.03), to be Black (36.3% vs 20.7%, P<0.001), and to have diabetes (18.9% vs 12.4%, P=0.006) and hypertension (50.5% vs 39.7%, P=0.003). Current smokers had a lower odds of glaucoma compared to non-smokers (OR=0.61, 95% CI=0.41-0.88, P=0.009), and ex-smokers (OR=0.46, 95% CI=0.28-0.76, P=0.002). The effect estimates were similar in adjusted models, but not statistically significant. Among smokers, greater pack/day of smoking history was associated with statistically significantly higher odds of glaucoma (OR=1.70, 95% CI=1.08-2.67, P=0.02).ConclusionsAmong cigarette smokers, heavy smoking defined by greater number of pack of cigarettes smoked per day is associated with higher odds of glaucoma. Health care providers should include this association when counseling patients on their smoking habit.

Ultrafast X-Ray Diffraction Studies of the Phase Transitions and Equation of State of Scandium Shock Compressed to 82 GPa.

Using x-ray diffraction at the Linac Coherent Light Source x-ray free-electron laser, we have determined simultaneously and self-consistently the phase transitions and equation of state (EOS) of the lightest transition metal, scandium, under shock compression. On compression scandium undergoes a structural phase transition between 32 and 35 GPa to the same bcc structure seen at high temperatures at ambient pressures, and then a further transition at 46 GPa to the incommensurate host-guest polymorph found above 21 GPa in static compression at room temperature. Shock melting of the host-guest phase is observed between 53 and 72 GPa with the disappearance of Bragg scattering and the growth of a broad asymmetric diffraction peak from the high-density liquid.

Role of lens vault in subtypes of angle closure in Iranian subjects.

PURPOSE: The purpose of this study is to quantify anterior chamber (AC) parameters and to determine the proportion of eyes with exaggerated lens vault (LV) in different subtypes of angle closure disease using anterior segment optical coherence tomography (AS-OCT). PATIENTS AND METHODS: In this prospective study, 115 eyes of 115 Iranian patients with angle closure disease were included and categorized into three groups: (1) fellow eyes of acute angle closure (AAC; 40 eyes); (2) primary angle closure glaucoma (PACG; 39 eyes); and (3) primary angle closure suspect (PACS; 36 eyes). Complete ophthalmic examination including gonioscopy, A-scan biometry, and AS-OCT were performed. Angle parameters, LV, and iris thickness (IT) were measured using AS-OCT. An exaggerated LV was defined as LV more than one-third the distance between the corneal endothelium and a line drawn to connect the nasal and temporal scleral spurs. RESULTS: Fellow eyes of AAC had the shallower AC (P=0.01), greater iris curvature (I-curve; P=0.01), and higher LV (P=0.02) as compared with PACS and PACG eyes. There was no statistically significant difference in the mean IT at 750 µm from scleral spur among the three groups (P=0.45). Exaggerated LV was found in 67.5, 35.9, and 40% of fellow eyes of AAC, PACG, and PACS, respectively, (P=0.008) with an odds ratio of 1.92 (P=0.005) for fellow vs PACG and 1.68 (P=0.01) for fellow vs PACS. CONCLUSIONS: Exaggerated LV is highly prevalent in fellow eyes of AAC. These eyes have shallower AC depth, greater I-curve, and higher LV when compared with PACG and PACS.

Amnestic effect of cocaine after the termination of its stimulant action.

The effects of cocaine on memory are controversial. Furthermore, the psychostimulant action of cocaine can be a critical issue in the interpretation of its effects on learning/memory models. The effects of a single administration of cocaine on memory were investigated during the presence of its motor stimulating effect or just after its termination. The plus-maze discriminative avoidance task (PM-DAT) was used because it provides simultaneous information about memory, anxiety and motor activity. In Experiment I, mice received saline, 7.5, 10, 15 or 30 mg/kg cocaine 5 min before the training session. In Experiment II, mice were trained 30 min after the injection of saline, 7.5, 10, 15 or 30 mg/kg cocaine. In Experiment III, mice received 30 mg/kg cocaine 30 min pre-training and pre-test. In Experiment IV, mice received 30 mg/kg cocaine immediately post-training. Tests were always conducted 24 h following the training session. Given 5 min before training, cocaine promoted a motor stimulant effect at the highest dose during the training session but did not impair memory. When cocaine was injected 30 min pre-training, the drug did not modify motor activity, but produced marked amnestic effects at all doses tested. This amnesia induced by cocaine given 30 min pre-training was not related to a state-dependent learning because it was not abolished by pre-test administration of the drug. Post-training cocaine administration did not induce memory deficits either. Our results suggest that the post-stimulant phase is the critical moment for cocaine-induced memory deficit in a discriminative task in mice.

Comparison of long-term surgical success of Ahmed Valve implant versus trabeculectomy in open-angle glaucoma.

AIM: To compare the long-term intraocular pressure (IOP) outcomes of Ahmed Glaucoma Valve (AGV) implantation to trabeculectomy with mitomycin C (MMC) in open-angle glaucoma (OAG). METHODS: 78 OAG patients who underwent AGV implantation were matched with respect to age, preoperative surgery, preoperative IOP and preoperative medicines to 88 OAG patients who underwent trabeculectomy with MMC with a minimum of 3 years' follow-up. The cumulative probability of success between the two groups with different criteria was analysed: (1) an IOP < or =21 mm Hg and a reduction of IOP>/=15% from baseline; and (2) an IOP < or =18 mm Hg and a reduction of IOP > or =20% from baseline. No loss of light perception, no additional glaucoma surgery and no hypotony were also required. RESULTS: The 5-year cumulative probability of success was not statistically significant between eyes that had an AGV or trabeculectomy with MMC when success was defined as criteria A (p = 0.094). However, when success was defined according to criteria B, eyes undergoing trabeculectomy with MMC had a higher rate of success (p = 0.024). CONCLUSIONS: Trabeculectomy with MMC has a significantly higher 5-year cumulative probability of success compared with AGV implants when greater reduction IOP is necessary.

Dissociation of the effects of ethanol on memory, anxiety, and motor behavior in mice tested in the plus-maze discriminative avoidance task.

RATIONALE: Several studies have shown the amnestic effects of ethanol (ETOH). However, while memory tasks in rodents can be markedly influenced by anxiety-like behavior and motor function, ETOH induces anxiolysis and different effects on locomotion, depending on the dose. OBJECTIVE: Verify the effects of ETOH in mice tested in the plus-maze discriminative avoidance task (PMDAT) concomitantly evaluating memory, anxiety-like behavior, and motor behavior. METHODS: ETOH acutely or repeatedly treated mice were submitted to the training session in a modified elevated plus-maze with two open and two enclosed arms, aversive stimuli in one of the enclosed arms, and tested 24 h later without aversive stimuli. Learning/memory, locomotion, and anxiety-related behavior were evaluated by aversive arm exploration, number of entries in all the arms and open arms exploration, respectively. RESULTS: Acute ETOH: (1) either increased (1.2-1.8 g/kg) or decreased (3.0 g/kg) locomotion; (2) decreased anxiety levels (1.2-3.0 g/kg); and (3) induced learning deficits (1.2-3.0 g/kg) and memory deficits (0.3-3.0 g/kg). After repeated treatment, sensitization and tolerance to hyperlocomotion and anxiolysis induced by 1.8 g/kg ETOH were observed, respectively, and tolerance to the amnestic effect of 0.6 (but not 1.8) g/kg ETOH occurred. CONCLUSION: Neither the anxiolytic nor the locomotor effects of ETOH seem to be related to its amnestic effect in the PMDAT. Additionally, data give support to the effectiveness of the PMDAT in simultaneously evaluating learning, memory, anxiety-like behavior, and motor activity by different parameters. Possible relationships between the behavioral alterations found are discussed.

Effects of morphine on the plus-maze discriminative avoidance task: role of state-dependent learning.

RATIONALE: The amnesic effects of morphine may be related to its action on nociception, anxiety, or locomotion. This effect is also suggested to be related to state dependency. OBJECTIVES: The aims of this study were to verify the effects of morphine on mice tested in the plus-maze discriminative avoidance task (DAT) that uses light and noise as aversive stimuli and allows the concomitant evaluation of learning, memory, anxiety, and locomotion and also to verify the possible role of state-dependent learning in the effects of morphine. METHODS AND RESULTS: The DAT was conducted in a modified elevated plus-maze. In the training, the aversive stimuli were applied when mice entered in one of the enclosed arms, whereas in the test, no stimuli were applied. The main results showed that (1) pretraining morphine (5-20 mg/kg i.p.) induced retrieval deficits (evaluated by the time spent in the aversive arm in the test) but not acquisition deficits (evaluated by the decrease in aversive arm exploration along the training); (2) pretest morphine (5-10 but not 20 mg/kg) counteracted this deficit; (3) morphine induced hypolocomotion (decreased number of entries in the arms), irrespective of memory alterations; and (4) morphine did not alter anxiety-like behavior (evaluated by the time spent in the open arms) during the training. CONCLUSIONS: Morphine given before training induces retrieval deficits in mice tested in the DAT, and these deficits could be related to morphine-induced state-dependent learning. Neither the memory deficit induced by pretraining morphine nor the reversal of this deficit by pretest morphine seems to be related to anxiety levels or locomotor alterations.

Effect of laser photocoagulation treatment for diabetic macular oedema on patient's vision-related quality of life.

PURPOSE: To evaluate the effect of laser photocoagulation for diabetic macular oedema (DME) on patients' Vision Related Quality Of Life (VR-QOL) and to investigate associations between changes in self reported VR-QOL and changes in visual acuity following application of laser treatment. METHODS: Prospective cohort study of 55 subjects who underwent laser treatment for DME. Eligible patients with no history of previous laser photocoagulation self-administered the 51-item field-test version of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) prior to treatment and 3 months following the last session of laser application. Visual acuity was measured by means of the Early Treatment of Diabetic Retinopathy (ETDRS) chart. Multi-item scales rating different aspects of VR-QOL were compared prior and after photocoagulation and the change in questionnaire's composite score following treatment was correlated to change in visual acuity and other determinants previously reported as risk factors in the diabetic population. RESULTS: Scale scores associated with general vision, near vision, distance vision, peripheral vision, vision-specific social functioning, vision-specific mental health, expectations for visual function and dependency due to vision were significantly improved following laser treatment. Multivariate models revealed that improvement of the NEI-VFQ composite score was significant in subjects younger than 65 years of age (p = 0.04) who received more laser burns (p = 0.02) and had worse vision-related QOL prior to laser treatment as expressed by the baseline NEI- VFQ composite score (p = 0.03). There was no statistically significant association between change in the composite score following laser treatment and stage of diabetic retinopathy, duration of diabetes or laser settings used during photocoagulation. CONCLUSIONS: Photocoagulation for DME has a beneficial effect on patients' subjective perception of visual function. The use of vision-targeted health status questionnaires in conjunction with the clinical examination appears to provide a more comprehensive overview of individuals' daily well- being following laser treatment.

Reproducibility of the Heidelberg retinal flowmeter in determining low perfusion areas in peripapillary retina.

AIM: To evaluate the interobserver variability and retest reproducibility of confocal scanning laser Doppler flowmeter in measuring capillary perfusion of the peripapillary retina. METHODS: Blood flow measurements were performed in one eye of 10 normal subjects by two investigators on two different days (visits). Five separate measurements of the peripapillary blood flow parameters were recorded by each observer at each visit. The Heidelberg retina flowmeter was used to record capillary perfusion in a 2560x640 microm area of the superotemporal peripapillary region and pixel by pixel analysis was done from an area adjacent to the optic disc, with a minimum of 1600 pixels. The percentage of pixels with less than 1 arbitrary unit of flow (no flow) and 10, 25, 50, 75, 90th percentiles of flow values was calculated. Interobserver measurements were compared by paired t test. Intraclass correlations (ICC) were used to determine the interobserver variability and retest reproducibility of the measurements. Intrasession coefficients of variations (CV) were also calculated. RESULTS: There were no statistically significant differences between the two observers for all measurements and between visits for the percentage of pixels with no flow. ICC was 66% (range 57.09%-77.1%) for pixels with no flow. For the 10, 25, 50, 75, 90th percentiles of flow the ICC was 63.07% (53.91%-77.81%), 71.3% (64.23%-80.85%), 72.61% (66.02%-78.96%), 65.86% (58.53%-74.77%), and 60.05% (54.34%-70.06%), respectively. CV was 16.59%, 11.47%, 9.32%, 9.03%, 11.58%, and 16.05% for the percentage of no flow pixels and the 10, 25, 50, 75, 90th percentiles of flow, respectively. CONCLUSIONS: The Heidelberg retinal flowmeter allows reproducible measurements of all levels of capillary perfusion areas when pixel by pixel analysis is used.

Effects of pre- or post-training paradoxical sleep deprivation on two animal models of learning and memory in mice.

The aim of the present study was to verify the effects of pre- or post-training paradoxical sleep (PS) deprivation in mice tested in the passive and the plus-maze discriminative avoidance tasks. Three-month-old Swiss male mice were placed in narrow platforms in a water tank for 72 h to prevent the occurrence of PS. Control animals were kept in the same room, but in their home cages. Before or after this period, the animals were submitted to the training session of one of the behavioral tasks. The test sessions were performed 3 and 10 days after the training. The animals that were PS-deprived before the training session showed retention deficits in the test sessions performed 3 days later in both tasks (decreased latency to enter the dark chamber of the passive avoidance apparatus or increased percent time spent in the aversive arm of the plus-maze discriminative avoidance apparatus). Animals that were PS deprived after the training session showed no differences from control animals in the test sessions performed 3 days after the training in any of the tasks, but showed passive and discriminative avoidance retention deficits in the test performed 10 days after the training. The results suggest that both pre- and post-training paradoxical sleep deprivation produce memory deficits in mice. However, these effects have different temporal characteristics.

Quality of care in institutionalized deliveries: the paradox of the Dominican Republic.

OBJECTIVES: To better understand the paradox in the Dominican Republic of a relatively high maternal mortality ratio despite nearly universal institutionalized deliveries with trained attendants, a rapid assessment using an adaptation of the strategic assessment method was conducted. METHODS: A multi-disciplinary team reviewed national statistics and hospital records, inventoried facilities, and observed peripartum client-provider interactions at 14 facilities. RESULTS: The major referral hospitals, where more than 40% of births in the country occur, were overcrowded and understaffed, with inexperienced residents overseeing care provided by medical students, interns and nurses. Uncomplicated labor and deliveries were overmedicalized, while complicated ones were not managed appropriately; emergencies were not dealt with in a timely fashion. In the peripheral hospitals physicians were seldom present and clients were either turned away or delivered by unprepared nursing staff. Providers in the busiest facilities suffered from compassion fatigue, and were demoralized and overworked. In all facilities, quality of care was lacking and the delivery and birthing process was dehumanized. CONCLUSIONS: Access and availability of institutional delivery alone is not enough to decrease MMR, it is also the quality of emergency obstetric care that saves lives.

Relationship between aqueous humor protein level and outflow facility in patients with uveitis.

PURPOSE: To determine whether there is a relationship between the aqueous humor protein level and outflow facility in patients with uveitis. METHODS: Aqueous humor protein levels were determined by laser flare photometry, and outflow facility was determined by Schiotz tonography. RESULTS: Thirty patients with uveitis and 10 control subjects were studied. Outflow facility was lower in patients with uveitis (0.21 +/- 0.12 microl/min x mm Hg) than in control subjects (0.33 +/- 0.05 microl/min x mm Hg, P < 0.001). Patients with uveitis and laser flare photometry results (flare) more than 20 photon units/msec (n = 21) had a lower outflow facility (0.17 +/- 0.07 microl/min x mm Hg) than patients with uveitis and flare less than 20 photon units/msec (n = 9, 0.32 +/- 0.14 microl/min x mm Hg, P = 0.004). Furthermore, no difference was identified between outflow facility in patients with active uveitis (those who had anterior chamber cells) and flare less than 20 photon units/msec and outflow in control subjects. In patients with uveitis, there was a linear correlation between flare and outflow facility (r = -0.50, P = 0.005). There was no relationship between flare measurements and either intraocular pressure or aqueous humor cell levels when scored with a clinical, semiquantitative system. CONCLUSIONS: Outflow facility is significantly reduced in patients with uveitis who have high aqueous humor protein levels. Outflow facility appears to be normal in patients with active uveitis whose flare levels are low, and therefore the association between flare and outflow facility does not appear to be an indirect reflection of elevated anterior chamber cells. It is possible that elevated aqueous humor protein levels contribute to the development of uveitic glaucoma in some individuals by decreasing aqueous humor outflow facility, although a causal relationship cannot be established on the basis of this study.

The glaucomas.

Glaucoma is the leading cause of irreversible blindness worldwide. The World Health Organization reported in 1995 that 5.1 million persons were bilaterally blind from glaucoma. Its morbidity and prevalence make it a significant public health problem. Because it is a treatable condition, it is important that medical professionals be familiar with this disease, which in most cases is not associated with signs and symptoms that may alert the patient or the physician of its presence. Glaucoma is a progressive optic neuropathy that leads to blindness if left untreated. Risk factors include elevated intraocular pressure, advanced age, African ancestry and positive family history. Several types of glaucomas have been described: acute and chronic, secondary and primary. Primary (Chronic) Open Angle Glaucoma is the most common, with a prevalence in the USA of 1.55%. Blacks are 4 to 5 times more affected than whites. Treatment of glaucoma consists of topical or systemic intraocular pressure lowering agents, laser treatment or surgery. Primary Open Angle Glaucoma is an often-unrecognized disease due to its slow course and lack of symptoms. Because the decline in vision may be slowed but not restored by treatment, it is important that this condition be diagnosed early in its course.

Surgical undertreatment of glaucoma in black beneficiaries of medicare.

OBJECTIVE: To identify whether there was surgical undertreatment of glaucoma in black beneficiaries of Medicare from 1991 to 1994. METHODS: We performed a retrospective cohort analysis on all argon laser trabeculoplasty or trabeculectomy surgery claims to the Health Care Financing Administration between 1991 and 1994. There were 191 287 Medicare patients who were black or white, at least 65 years of age, and resided in the United States at the time of their glaucoma surgery. Age- and sex-adjusted rates were obtained and compared with surgery rates expected based on disease prevalence. RESULTS: The age-sex-adjusted rate ratio of glaucoma surgical procedures for blacks to whites was 2.14. Assuming that treatments should be done in proportion to age-race prevalence, blacks undergo glaucoma surgery at approximately 47% below the expected rate. CONCLUSIONS: Blacks underwent argon laser trabeculoplasties and trabeculectomies at half the rate of whites from 1991 to 1994. Although in 1993 and 1994 there was a slight trend toward higher surgery rates in blacks, the magnitude of this improvement was small compared with estimated differences in the surgery rates between blacks and whites.

Ahmed glaucoma valve implant for management of glaucoma in Sturge-Weber syndrome.

PURPOSE: To evaluate the safety and efficacy of the Ahmed glaucoma valve implant in patients with glaucoma as a result of Sturge-Weber syndrome. METHODS: Eleven eyes (10 patients) with glaucoma resulting from Sturge-Weber syndrome had placement of an Ahmed glaucoma valve implant from May 1993 to June 1996 at the Jules Stein Eye Institute. Success was defined by intraocular pressure at the last two consecutive visits of less than 21 mm Hg, no additional glaucoma surgery, no expulsive choroidal hemorrhage, and no retinal detachment. RESULTS: Mean intraocular pressure on the first postoperative day was 14.0 mm Hg (SD +/- 6.7). The cumulative probability of success was 79% (95% confidence interval [CI], 52% to 100%) at 24 months, 59% (95% CI, 20% to 98%) at 42 months, and 30% (95% CI, 0% to 75%) at 60 months. CONCLUSIONS: On the basis of limited follow-up, the Ahmed glaucoma valve implant appears to be a relatively useful drainage device in eyes with glaucoma resulting from Sturge-Weber syndrome.