Classification of perovskite structural types with dynamical octahedral tilting.

Perovskites ABX3 with delocalized positions of the X atoms represent a distinct class of dynamically distorted structures with peculiar structural relations and physical properties. The delocalization originates from atoms crossing shallow barriers of the potential energy surface. Quantum mechanically, they can be treated similar to light atoms in diffusive states. Many of these perovskite structures are widely used functional materials thanks to their particular physical properties, such as superconductivity, ferroelectricity and photo-activity. A number of these properties are related to static or dynamic motion of octahedral units. Yet, a full understanding of the relationships between perovskite crystal structure, chemical bonding and physical properties is currently missing. Several studies indicate the existence of dynamic disorder generated by anharmonic motion of octahedral units, e.g. in halide perovskite structures. To simplify structural analysis of such systems we derive a set of space groups for simple perovskites ABX3 with dynamical octahedral tilting. The derived space groups extend the well established space group tables for static tiltings by Glazer [Acta Cryst. B (1972). 28, 3384-3392], Aleksandrov [Ferroelectrics (1976). 24, 801-805] and Howard & Stokes [Acta Cryst. B (1998). 54, 782-789]. Ubiquity of dynamical tilting is demonstrated by an analysis of the structural data for perovskites reported in recent scientific publications and the signature of dynamic tilting in the corresponding structures is discussed, which can be summarized as follows: (a) volume increase upon a lowering of temperature, (b) apparent distortion of octahedra (where Jahn-Teller distortions can be ruled out), (c) mismatch between observed instantaneous symmetry and average symmetry, (d) deviation of the experimental space group from the theoretically predicted structures for static tilting, (e) inconsistency of lattice parameters with those suggested by the theory of static tilts, and (f) large displacement parameters for atoms at the X and B sites. Finally, the possible influence of dynamic disorder on the physical properties of halide perovskites is discussed.

Anharmonic effects on the dynamics of solid aluminium fromab initiosimulations.

Two approaches to simulations of phonon properties of solids beyond the harmonic approximation, the self-consistentab initiolattice dynamics (SCAILD) and decoupled anharmonic mode approximation (DAMA) are critically benchmarked against each other and molecular dynamics simulations using a density-functional-theory description of electronic states, and compared to experimental data for fcc aluminium. The temperature-dependence of phonon dispersion and the phonon density-of-states, heat capacity, and the mean atomic displacement for fcc aluminium are examined with these approaches at ambient pressure. A comparison of results obtained with the harmonic approximation to the ones predicted by SCAILD and DAMA reveal a negligible anharmonic contribution to phonon frequencies, a small, but significant influence on heat capacity, and a strong effect on atomic mean-square displacement. The phase space accessed with SCAILD and DAMA is reduced relative to molecular and harmonic lattice dynamics simulations. In particular the DAMA results are in good agreement with displacement amplitudes determined by the Debye-Waller factor in x-ray diffraction experiments.

[An Uncommon Case of Pneumonia]. / Eine seltene Form einer pulmonalen Infektion.

Pneumocystis jirovecii pneumonia is a common cause of respiratory disease in immunocompromised hosts. We describe a case of an HIV negative, immunocompetent patient and discuss the probable cause.

Metastatic neuroblastoma in infants: are survival rates excellent only within the stringent framework of clinical trials?

Introduction. SIOPEN INES protocol yielded excellent 5-year survival rates for MYCN-non-amplified metastatic neuroblastoma. Patients deemed ineligible due to lack or delay of MYCN status or late registration were treated, but not included in the study. Our goal was to analyse survival at 10 years among the whole population. Materials and methods. Italian and Spanish metastatic INES patients’ data are reported. SPSS 20.0 was used for statistical analysis. Results. Among 98 infants, 27 had events and 19 died, while 79 were disease free. Five- and 10-year event-free survival (EFS) were 73 and 70 %, and overall survival (OS) was 81 and 74 %, respectively. MYCN status was significant for EFS, but not for OS in multivariate analysis. Conclusions. The survival rates of patients who complied with all the inclusion criteria for INES trials are higher compared to those that included also not registered patients. Five-year EFS and OS for INES 99.2 were 87.8 and 95.7 %, while our stage 4s population obtained 78 and 87 %. Concerning 99.3, 5-year EFS and OS were 86.7 and 95.6 %, while for stage 4 we registered 61 and 68 %. MYCN amplification had a strong impact on prognosis and therefore we consider it unacceptable that many patients were not studied for MYCN and probably inadequately treated. Ten-year survival rates were shown to decrease: EFS from 73 to 70 % and OS from 81 to 74 %, indicating a risk of late events, particularly in stage 4s. Population-based registries like European ENCCA WP 11-task 11 will possibly clarify these data (AU)

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Metastatic neuroblastoma in infants: are survival rates excellent only within the stringent framework of clinical trials?

INTRODUCTION: SIOPEN INES protocol yielded excellent 5-year survival rates for MYCN-non-amplified metastatic neuroblastoma. Patients deemed ineligible due to lack or delay of MYCN status or late registration were treated, but not included in the study. Our goal was to analyse survival at 10 years among the whole population. MATERIALS AND METHODS: Italian and Spanish metastatic INES patients' data are reported. SPSS 20.0 was used for statistical analysis. RESULTS: Among 98 infants, 27 had events and 19 died, while 79 were disease free. Five- and 10-year event-free survival (EFS) were 73 and 70 %, and overall survival (OS) was 81 and 74 %, respectively. MYCN status was significant for EFS, but not for OS in multivariate analysis. CONCLUSIONS: The survival rates of patients who complied with all the inclusion criteria for INES trials are higher compared to those that included also not registered patients. Five-year EFS and OS for INES 99.2 were 87.8 and 95.7 %, while our stage 4s population obtained 78 and 87 %. Concerning 99.3, 5-year EFS and OS were 86.7 and 95.6 %, while for stage 4 we registered 61 and 68 %. MYCN amplification had a strong impact on prognosis and therefore we consider it unacceptable that many patients were not studied for MYCN and probably inadequately treated. Ten-year survival rates were shown to decrease: EFS from 73 to 70 % and OS from 81 to 74 %, indicating a risk of late events, particularly in stage 4s. Population-based registries like European ENCCA WP 11-task 11 will possibly clarify these data.

[Czech Hospital in Uganda and quality of obstetric care]. / Ceská nemocnice v Ugande a kvalita porodnické péce.

OBJECTIVE: The target was to evaluate the present state of obstetric care in Czech Hospital in Buikwe in Uganda. We evaluated a professional level of hospital physicians, their obstetric expertise and technical equipment of delivery theatre and mobile surgery and we provided a short 4 months evaluation of deliveries in main view of obstetric pathologies, frequency of caesarean sections and maternal mortality. METHODS AND RESULTS: In period from October 2014 to January 2015 there was evaluated a group of 374 women, admited to labour at delivery theatre. We evaluated parity of women, number and indications of caesarean sections, age of women and obstetric finding by admission. The most of our patients were primiparas and secundiparas, the caesarean section was performed in 23,8% of cases and the most frequent indication of it was threatened rupture of the uterus, state after caesarean section, cephalopelvic disproportion and obstructed labour. Two women died. By evaluation of quality of obstetric care we have found some serious lacks. Ugandan doctors are not obstetricians, they have no experience with vaginal obstetric operations, the Hospital has no fetal-monitor and no possibility for a transport of emergency cases. CONCLUSIONS: The Hospital needs expert help from Czech Republic, as doctors-obstetricians so as some equipment for delivery theatre and above all suitable car for urgent transport and for use of mobile surgery.

Insight into structural phase transitions from the decoupled anharmonic mode approximation.

We develop a formalism (decoupled anharmonic mode approximation, DAMA) that allows calculation of the vibrational free energy using density functional theory even for materials which exhibit negative curvature of the potential energy surface with respect to atomic displacements. We investigate vibrational modes beyond the harmonic approximation and approximate the potential energy surface with the superposition of the accurate potential along each normal mode. We show that the free energy can stabilize crystal structures at finite temperatures which appear dynamically unstable at T = 0. The DAMA formalism is computationally fast because it avoids statistical sampling through molecular dynamics calculations, and is in principle completely ab initio. It is free of statistical uncertainties and independent of model parameters, but can give insight into the mechanism of a structural phase transition. We apply the formalism to the perovskite cryolite, and investigate the temperature-driven phase transition from the P21/n to the Immm space group. We calculate a phase transition temperature between 710 and 950 K, in fair agreement with the experimental value of 885 K. This can be related to the underestimation of the interaction of the vibrational states. We also calculate the main axes of the thermal ellipsoid and can explain the experimentally observed increase of its volume for the fluorine by 200-300% throughout the phase transition. Our calculations suggest the appearance of tunneling states in the high temperature phase. The convergence of the vibrational DOS and of the critical temperature with respect of reciprocal space sampling is investigated using the polarizable-ion model.

[Czech model for decrease of maternal mortality in Uganda]. / Ceský model pro snízení materské úmrtnosti v Ugande.

High maternal and perinatal mortality is the leading problem of the health care in developing countries of Sub-Saharan Africa, including Uganda. The main condition for decrease of maternal mortality is availability of an emergency obstetrical care in hospital accompanied by skilled team of specialists (gynaecologist, anaesthesiologist, paediatrician), which are able to treat all obstetrical complications and provide an intensive care to risk newborns. The Czech Hospital and School for midwives in Uganda was founded and build with the aim to accomplish a grant project for the decrease of maternal, perinatal and child mortality. Our project to connect emergency obstetrical care in hospital to villages and traditional delivery attendants by mobile phones shows a simple and original model, which can help to decrease maternal mortality in Uganda and in the other countries of Sub-Saharan Africa as well. The Czech-Uganda Hospital started its work on 19th February 2007 with a team of Slovak doctors; however, till now, after 2 years of work, it doesn't fulfil its role of a specialised obstetrical department, which would be able to join its partners in villages and start the grant project for decrease of maternal and perinatal mortality.

[Risk factors of metabolic estrogen-deficiency syndrome in women after menopause and its relationship to hormone replacement therapy]. / Rizikové faktory metabolického estrogen-deficitního syndromu u zen po menopauze a jejich vztah k hormonální substitucní terapii.

OBJECTIVE: The aim of the study was to review health state in postmenopausal women with long-term hormone replacement therapy and compare it with health state of control group without hormone replacement therapy. We focused on metabolic estrogen-deficiency syndrome and its influence on risk of cardiovascular disease, risk of osteoporosis and memory dysfunction. DESIGN: Epidemiology study. SETTING: Department of Obstetrics and Gynecology, University Hospital, Hradec Králové. METHODS: Pursuant to clinic and laboratory investigation we evaluated blood pressure, BMI, lipid profile, blood sugar, CRP and homocysteine in women with EPT, ET and compared the data it with controls. Due to dual X-ray absorptiometry we determined bone mineral density and by the memory quiz we evaluated memory function in examined postmenopausal women. RESULTS: Our results indicate that use of hormone replacement therapy in postmenopausal women may be of benefit in cardiovascular risk factors, especially with better plasma lipid profile, blood sugar, atherogenity index, BMI and diastolic blood pressure. We found protective role of HT on decrease of bone mineral density in lumbal spine. We didn't prove this influence in hip. There is no evidence of HT influence on memory dysfunction, but we found, that culture and social life of older women in East Bohemia region is at low level. We did not register any heart attack, stroke and breast cancer under long-term treatment. CONCLUSION: Women with hormone replacement therapy have less of cardiovascular risk factors and better status of mineral bone density than women in control group.

Long-term results of high-dose chemotherapy and autologous stem cell rescue for high-risk neuroblastoma patients: a report of the Spanish working party for BMT in children (Getmon).

The authors retrospectively analyzed the long-term outcome of 67 patients over 1 year of age at diagnosis with high-risk neuroblastoma (stage 4 or stage 3 with N-myc amplification) who were treated with megatherapy and stem cell rescue from 1984 to 1998. Median age at transplant was 4 years (range 1.6-15 years). The source of cells was peripheral stem cells in 29 and bone marrow in 38 patients. In 12 patients, an in vitro purging of bone marrow harvest was performed. Most patients were conditioned with melphalan, BCNU, and VM-26. After transplant 19 patients received complementary treatment with IL-2 (16) or 13-cis-retinoic acid (3). Six patients (8%) died from transplant-related toxicity and 39 from disease progression. Three patients were alive with active disease at the time of analysis. Nineteen patients are alive and disease-free at a median follow-up of 104 months. Five-year event-free survival is 0.30. Survival of patients who received a purged graft was not significantly better than the rest. Post-transplant complementary treatment significantly improved overall and event-free survival (p = .01 and p = .04, respectively).

Oculoleptomeningeal amyloidosis in a large kindred with a new transthyretin variant Tyr69His.

OBJECTIVE: To describe the clinical, radiologic, and pathologic findings of a kindred with oculoleptomeningeal amyloidosis and a newly associated transthyretin mutation. BACKGROUND: Transthyretin (TTR) amyloidosis can present in the form of oculoleptomeningeal amyloidosis. Clinical features include dementia, seizures, stroke-like episodes, subarachnoid hemorrhage, ataxia, myelopathy, deafness, radiculopathy, and ocular amyloidosis. Eight TTR mutations associated with oculoleptomeningeal amyloidosis have been described. METHODS: Fourteen individuals from a kindred with oculoleptomeningeal amyloidosis were examined clinically and radiologically. Analysis of the TTR gene was performed. Neuropathologic examination was obtained on the index patient. RESULTS: Affected individuals had vitreous amyloid, radiculopathy, seizures, stroke-like episodes, encephalopathy, and dementia. Severely affected individuals died by the end of the fifth decade. Leptomeningeal enhancement on contrast MRI and elevated CSF protein were the defining features on investigations. Sequencing of exon 3 in the TTR gene found a base pair substitution at codon 69. This resulted in heterozygosity for normal tyrosine and variant histidine (ATTR Tyr69His) in affected family members. Domino liver transplantation was attempted as treatment for one family member. CONCLUSIONS: The ATTR Tyr69His mutation is associated with oculoleptomeningeal amyloidosis. Expression of the genotype is variable. This has implications for treatment of affected individuals and counseling of family members. Efficacy of liver transplantation in patients with oculoleptomeningeal amyloidosis remains unknown. The authors advocate the investigation of liver transplantation in patients with severe symptoms due to oculoleptomeningeal amyloidosis.

Complex rearrangement of chromosomes 6 and 11 as the sole anomaly in atypical teratoid/rhabdoid tumors of the central nervous system.

Atypical teratoid/rhabdoid tumor of the central nervous system is a rare childhood tumor with a distinct histologic appearance and an aggressive clinical course. Few tumors have been analyzed cytogenetically. The only consistent chromosomal abnormality identified in some of these tumors has been monosomy or deletions of chromosome 22; in others, a normal chromosome 22 was present. The authors report an atypical teratoid/rhabdoid neoplasm of the central nervous system with a novel complex rearrangement affecting chromosomes 6 and 11 as the sole anomaly. The involvement of region 11p15 could be important in the pathogenesis of this entity.

Oculoleptomeningeal amyloidosis associated with a new transthyretin variant Ser64.

BACKGROUND: A Canadian family with oculoleptomeningeal amyloidosis with both central and peripheral nervous system disorders was described in 1988. Death of affected family members resulted from recurrent cerebral hemorrhage. OBJECTIVE: To determine if oculoleptomeningeal amyloidosis is caused by a mutation in transthyretin (prealbumin). METHODS: DNA isolated from peripheral blood and archival tissues of affected members of the kindred was studied by direct DNA sequencing and restriction fragment length polymorphism analysis. RESULTS: Direct DNA sequencing identified a thymine-to-cytosine transition at the second base of codon 64, which resulted in a replacement of serine for phenylalanine. This mutation, which creates an additional HinfI site was detected by restriction fragment length polymorphism analysis in each affected individual. CONCLUSION: In this kindred, oculoleptomeningeal amyloidosis is related to a mutation in transthyretin (Phe64Ser).

Psychologic factors and oral lichen planus. A psychometric evaluation of 100 cases.

OBJECTIVE: The purpose of this study was to analyze the importance of psychologic factors in patients with oral lichen planus, and attempts were made to identify possible personality features characteristic of patients with oral lichen planus. STUDY DESIGN: The study involved 100 patients with oral lichen planus (group 1) and 50 control subjects (group 2). We applied the following psychometric tests to both groups: Spielberger State-Trait Anxiety Inventory, Cattell Personality Questionnaire 16PF, Hassanyeh Rating of Anxiety-Depression-Vulnerability, Beck Depression Inventory, Raskin Depression Screen, and Covi Anxiety Screen. RESULTS: The patients with oral lichen planus were found to exhibit greater anxiety, as reflected by statistically significant scores with the anxiety tests that were used (Spielberger State-Trait Anxiety Inventory, Cattell Personality Questionnaire 16PF, Hassanyeh Rating of Anxiety-Depression-Vulnerability, and Covi Anxiety Screen). The patients with oral lichen planus likewise exhibited greater depression than the controls in all 3 depression tests applied (Beck Depression Inventory, Hassanyeh Rating of Anxiety-Depression-Vulnerability, and Raskin Depression Screen) and were more vulnerable to psychic disorders on the basis of the PD subscales (vulnerability) of the Hassanyeh questionnaire. Three features (conformity to the group, astuteness, and rebelliousness) defined the personalities of our patients with oral lichen planus, according to the Cattell 16PF questionnaire. Finally, those patients with erosive lichen planus exhibited higher depression scores than patients with nonerosive lichen planus. CONCLUSIONS: Despite the higher anxiety scores observed in patients with oral lichen planus, it was not established that the observed psychologic alterations constitute a direct etiologic factor of oral lichen planus; nor was it established that such alterations are a consequence of oral lichen planus and its lesions.

Serum malondialdehyde in HIV-seropositive children negatively correlates with CD4+ lymphocytes count.

Human immunodeficiency virus (HIV) infection is associated with oxidative stress as it has been demonstrated in adult-seropositive individuals. We show in this study that serum malondialdehyde (MDA) concentration of HIV-infected children was significantly higher than in control children. A negative correlation (r = -0.515) was found in HIV-infected children between their CD4+ lymphocyte count, and MDA concentration but not with serum antioxidant status. The increase of MDA concentration in HIV-seropositive children confirms the involvement of oxidative stress in the pathophysiology of this infection also in childhood. Because of the importance of oxidative stress and antioxidants for HIV viral replication, the adequacy of an adjuvant therapy with antioxidants should be considered; an adequate candidate for it could be N-acetylcysteine.