Strain and Magnetic Field Induced Spin-Structure Transitions in Multiferroic BiFeO3

The magnetic-field-dependent spin ordering of strained BiFeO₃ films is determined using nuclear resonant scattering and Raman spectroscopy. The critical field required to destroy the cycloidal modulation of the Fe spins is found to be significantly lower than in the bulk, with appealing implications for field-controlled spintronic and magnonic devices.

Photovoltaics with Ferroelectrics: Current Status and Beyond

Ferroelectrics carry a switchable spontaneous electric polarization. This polarization is usually coupled to strain, making ferroelectrics good piezoelectrics. When coupled to magnetism, they become so-called multiferroic systems, a field that has been widely investigated since 2003. While ferroelectrics are birefringent and non-linear optically transparent materials, the coupling of polarization with optical properties has received, since 2009, renewed attention, triggered notably by low-bandgap ferroelectrics suitable for sunlight spectrum absorption and original photovoltaic effects. Consequently, power conversion efficiencies up to 8.1% were recently achieved and values of 19.5% were predicted, making photoferroelectrics promising photovoltaic alternatives. This article aims at providing an up-to-date review on this emerging and rapidly progressing field by highlighting several important issues and parameters, such as the role of domain walls, ways to tune the bandgap, consequences arising from the polarization switchability, and the role of defects and contact electrodes, as well as the downscaling effects. Beyond photovoltaicity, other polarization-related processes are also described, like light-induced deformation (photostriction) or light-assisted chemical reaction (photostriction). It is hoped that this overview will encourage further avenues to be explored and challenged and, as a byproduct, will inspire other research communities in material science, e.g., so-called hybrid halide perovskites.

Photostriction in Ferroelectrics from Density Functional Theory

An ab initio procedure allowing the computation of the deformation of ferroelectric-based materials under light is presented. This numerical scheme consists in structurally relaxing the system under the constraint of a fixed n_{e} concentration of electrons photoexcited into a specific conduction band edge state from a chosen valence band state, via the use of a constrained density functional theory method. The resulting change in lattice constant along a selected crystallographic direction is then calculated for a reasonable estimate of n_{e}. This method is applied to bulk multiferroic BiFeO_{3} and predicts a photostriction effect of the same order of magnitude than the ones recently observed. A strong dependence of photostrictive response on both the reached conduction state and the crystallographic direction (along which this effect is determined) is also revealed. Furthermore, analysis of the results demonstrates that the photostriction mechanism mostly originates from the screening of the spontaneous polarization by the photoexcited electrons in combination with the inverse piezoelectric effect.

[Hodgkin disease revealed by a nephrotic syndrome: A case report]

Pediatric nephrotic syndrome (NS) is most often idiopathic or primary but in rare cases, it can be secondary to neoplasia. We report on a case of steroid-resistant NS revealing as a paraneoplastic syndrome of Hodgkin disease (HD) in a 12-year-old boy. The onset of the NS can be earlier, later, or simultaneous to the HD. Treatment of the lymphoma allows the disappearance of the NS. In the case we observed, the diagnosis of HD was delayed because HD presented with an isolated, hilar adenopathy in the absence of retroperitoneal or peripheral locations. In children aged 10 years or more presenting with NS, steroid-resistant or otherwise, a possible paraneoplastic origin such as Hodgkin lymphoma should always be taken into consideration and eventually eliminated.

Childhood acute lymphoblastic leukaemia and indicators of early immune stimulation: the Estelle study (SFCE)

Background:

Factors related to early stimulation of the immune system (breastfeeding, proxies for exposure to infectious agents, normal delivery, and exposure to animals in early life) have been suggested to decrease the risk of childhood acute lymphoblastic leukaemia (ALL).

Methods:

The national registry-based case–control study, ESTELLE, was carried out in France in 2010–2011. Population controls were frequency matched with cases on age and gender. The participation rates were 93% for cases and 86% for controls. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios (OR) were estimated using unconditional regression models adjusted for age, gender, and potential confounders.

Results:

In all, 617 ALL and 1225 controls aged ⩾1 year were included. Inverse associations between ALL and early common infections (OR=0.8, 95% confidence interval (CI): 0.6, 1.0), non-first born (⩾3 vs 1; OR=0.7, 95% CI: 0.5, 1.0), attendance of a day-care centre before age 1 year (OR=0.7, 95% CI: 0.5, 1.0), breastfeeding (OR=0.8, 95% CI: 0.7, 1.0), and regular contact with pets (OR=0.8, 95% CI: 0.7, 1.0) in infancy were observed.

Conclusions:

The results support the hypothesis that conditions promoting the maturation of the immune system in infancy have a protective role with respect to ALL.

[SFGM-TC recommendation on indications for allogeneic stem cell transplantation in children with congenital neutropenia]

In this report, we address the issue of allogeneic stem cell transplantation in children with congenital neutropenia. Constitutional disorders with neutropenia are exceptional. Treatment and prevention of severe infections are a major concern in the management of chronic neutropenia. These disorders, especially Kostmann's disease and Shwachman-Bodian-Diamond syndrome, are associated with an increased risk of leukemia. The role of allogeneic stem cell transplantation in these patients is still unclear. In an effort to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapy (SFGM-TC) set up the fourth annual series of workshops which brought together practitioners from all member centers and took place in September 2013 in Lille.

[Diagnosis and treatment of CMV and EBV Reactivation as well as Post-transplant Lymphoproliferative Disorders following Allogeneic Stem Cell Transplantation: An SFGM-TC report]

In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapy (SFGM-TC) set up the third annual series of workshops which brought together practitioners from all member centers and took place in October 2012 in Lille. Here the SFGM-TC addressed the issue of post-transplant CMV and EBV reactivation, and EBV-related Lymphoproliferative Disorders.

[Megakaryoblastic acute leukemia: bone and joint manifestations in a 7-month-old child]

Acute megakaryoblastic leukemia accounts for approximately 3-10% of acute myeloid leukemia in children. Its diagnosis may be difficult because of associated myelofibrosis. We report the case of a 7-month-old child who presented hepatomegaly with bicytopenia. She also developed bone and joint pain with recurrent aseptic arthritis. We suggested the diagnosis of megakaryoblastic leukemia early but multiple bone marrow investigations had been processed without positive results because of sampling problems and lack of abnormal cells in the morphological, phenotypic, and cytogenetic examinations. We had a variety of indirect evidence for our assumption: the x-ray showing periosteal new bone, lytic lesions and metaphyseal bands, bone marrow aspirate smears with micromegakaryocytes, and bone marrow biopsy suggesting myelofibrosis. This was very suggestive of leukemia but we could not prove it and we finally found megakaryoblasts on bone marrow aspirate smears after more than 2 months of investigation and initiated a course of corticosteroids.

Genomic and functional analysis of Vibrio phage SIO-2 reveals novel insights into ecology and evolution of marine siphoviruses

We report on a genomic and functional analysis of a novel marine siphovirus, the Vibrio phage SIO-2. This phage is lytic for related Vibrio species of great ecological interest including the broadly antagonistic bacterium Vibrio sp. SWAT3 as well as notable members of the Harveyi clade (V.harveyi ATTC BAA-1116 and V.campbellii ATCC 25920). Vibrio phage SIO-2 has a circularly permuted genome of 80598 bp, which displays unusual features. This genome is larger than that of most known siphoviruses and only 38 of the 116 predicted proteins had homologues in databases. Another divergence is manifest by the origin of core genes, most of which share robust similarities with unrelated viruses and bacteria spanning a wide range of phyla. These core genes are arranged in the same order as in most bacteriophages but they are unusually interspaced at two places with insertions of DNA comprising a high density of uncharacterized genes. The acquisition of these DNA inserts is associated with morphological variation of SIO-2 capsid, which assembles as a large (80 nm) shell with a novel T=12 symmetry. These atypical structural features confer on SIO-2 a remarkable stability to a variety of physical, chemical and environmental factors. Given this high level of functional and genomic novelty, SIO-2 emerges as a model of considerable interest in ecological and evolutionary studies.

[Hodgkin disease and autoimmunity in children: 11 case reports]

The association of lymphoma and autoimmune manifestations has been predominantly studied in adults affected by non-Hodgkin lymphoma. Few publications exist in the literature concerning Hodgkin lymphoma, particularly in children and adolescents. The objectives of this study were to define the characteristics of the link between Hodgkin disease and autoimmunity in childhood. The present 25-year retrospective study was conducted in all centers affiliated with the French Society of Paediatric Oncology (SFCE). Eleven children with Hodgkin disease presented manifestations of disimmunity preceding or following their diagnosis. Four patients had thrombocytopenic purpura, the remaining 7 each had a different autoimmune pathology: lupus syndrome, antiphospholipid syndrome with transient ischemic attack, Evans syndrome, leukocytoclastic vasculitis, autoimmune hemolytic anemia, autoimmune thyroiditis, and juvenile idiopathic arthritis. Lymphoma relapse occurred in 3 patients. Two children died, death being directly attributed to the autoimmune disease in 1 case. Our data suggest that development of autoimmunity is related to significant morbidity. Possible pathophysiological mechanisms include lymphocyte proliferation secondary to chronic inflammation, cell-mediated immune deficiency in Hodgkin disease, molecular mimetics, and antineoplastic phenomena are discussed. A study with a larger patient population is needed to identify the group of children at high risk of autoimmunity for whom additional investigations and modified therapy may be indicated.

Bivalve population health: multistress to identify hot spots

This study investigated some stress (metals, parasites) and response (immunity, metallothionein) factors in two cockle and two Manila clam populations. Data from eight seasons were averaged to obtain global baseline values. Stress/response characteristics of each population were compared to population health status that was determined through population dynamics parameters. Four different scenarios were discussed: (1) a lightly stressed cockle population with correct population health but with a risk of deterioration (hot spot); (2) a lightly stressed introduced cockle population threatened of extinction. In this case ecological factors were suspected; (3) a moderately stressed clam population with moderate adaptative response. The population was sustainable but the level of stress should not increase (hotspot); and (4) a stressed clam population and unfavourable ecological conditions preventing clam settlement. This monitoring highlighted that the discrepancy between population health and stress levels could be due to insufficient response by bivalves and/or by unfavourable ecological factors.

Evidence of a clinical response at one yr after reduced-intensity allogeneic hematopoietic stem cell transplantation in heavily pretreated adolescents with aggressive refractory Hodgkin's lymphoma

We report results of RIC AHSCT in four adolescents with aggressive refractory HL. They all received three or four lines of therapy prior to RIC-AHSCT including autografts. At the time of RIC, they were in partial response except for one patient who had progressive chemoresistant disease. The conditioning regimen consisted of fludarabin, busulfan and ATG. They all had a matched related donor. The median follow-up was 12-16-month post-allograft. All patient transplants engrafted rapidly. The median time of hospitalization was 35 days. The median time to neutrophil recovery (>or=500/muL) was 19 days. All the patients were in complete donor chimerism at day 60. Four patients developed skin (grade <or= II) acute GvHD. All responded and all are alive. Two patients are in CR, one in PR and one relapsed six months after grafting after a PR. Each of the patients in PR received two DLI. These observations, together with the responses after DLI, suggest the presence of a graft vs. lymphoma effect in patients with advanced active HL. Prospective studies are needed to identify the patients likely to benefit most from this treatment approach.