Temporal and spatial tracking of ultrafast light-induced strain and polarization modulation in a ferroelectric thin film

Ultrashort light pulses induce rapid deformations of crystalline lattices. In ferroelectrics, lattice deformations couple directly to the polarization, which opens the perspective to modulate the electric polarization on an ultrafast time scale. Here, we report on the temporal and spatial tracking of strain and polar modulation in a single-domain BiFeO3 thin film by ultrashort light pulses. To map the light-induced deformation of the BiFeO3 unit cell, we perform time-resolved optical reflectivity and time-resolved x-ray diffraction. We show that an optical femtosecond laser pulse generates not only longitudinal but also shear strains. The longitudinal strain peaks at a large amplitude of 0.6%. The access of both the longitudinal and shear strains enables to quantitatively reconstruct the ultrafast deformation of the unit cell and to infer the corresponding reorientation of the ferroelectric polarization direction in space and time. Our findings open new perspectives for ultrafast manipulation of strain-coupled ferroic orders.

O-267 Uterine volume is dramatically decreased in Stem Cell Hematopoietic Transplantation childhood survivors whatever the conditioning regimen. A case-control MRI study in the L.E.A cohort

Study question

What is the impact of the type of myeloablative conditioning (MAC) regimen applied for hematopoietic stem cell transplantation (HSCT) on uterine volume of childhood leukemia survivors?

Summary answer

Uterine volume is significantly decreased after HSCT. Not only Total Body Irradiation (TBI), but also high-dose chemotherapy-based regimens containing alkylating agents induce uterine damage.

What is known already

Premature ovarian failure after HSCT is well known, as well as the uterine damage induced by TBI on uterine volume. A few studies have reported smaller uterus after HSCT in women treated with chemotherapy only. In these studies, uterus volume was assessed by a transabdominal and/or transvaginal ultrasonography, and primary diagnosis, age at treatment and chemotherapy regimen were heterogeneous. These preliminary results suggested that alkylating agents could induce uterine damage, as well as they induce fibrosis and vascular damage in ovarian stroma. The impact of chemotherapy on myometrium and uterus is still few investigated.

Study design, size, duration

A prospective multicentric national study was conducted between 2017, November and 2021, June in 16 University Teaching Hospitals that are following more than 4 500 childhood acute leukemia survivors enrolled in the L.E.A cohort. We included 88 adult women treated for a childhood acute leukemia with HSCT and who agreed a pelvic MRI assessment. Every case was matched 1:1 to control women who underwent MRI for benign ovarian cysts or benign pelvic pathology.

Participants/materials, setting, methods

Pelvic MRI scans were performed with a 1.5-T or 3T magnetic resonance scanner, including diffusion-weighted imaging sequences. Scans were centralized for a double-blinded lecture by two radiologists. The main outcome was the uterine volume. The secondary outcomes were uterine body-to-cervix ratio and apparent diffusion coefficient (ADC). Univariate and multivariate analyses have investigated the association of clinical and imaging variables with conditioning regimen and age at HSCT.

Main results and the role of chance

The mean age in HSCT group was 26.5 + 6.3 years. Mean age at HSCT was 9.1 + 0.3 years with a mean follow-up of 16.4 + 0.5 years. Among the 88 women included in HSCT group, two groups of conditioning regimens have been compared to the control group: a chemotherapy-only MAC regimen group with high dose of alkylating agents (n = 34) and one TBI-based regimen group (n = 52). Two MRI scans were not available. Among HSCT group, 75 women were considered as “normally impregnated” by estrogens, by hormone replacement therapy (HRT) for premature ovarian insufficiency (POI) or thanks to a residual ovarian function. Uterine volume was significantly decreased both after chemotherapy-only MAC regimen and after TBI, with respectively 45.3 + 5.6 and 19.6 + 1.9 mL Vs 79.7 + 3.3 mL in control population (p < 0.01). In chemotherapy-only MAC regimen group, uterine volume was dramatically decreased in POI women without HRT compared to those having a hormonal impregnation (15.2 + 2.6 Vs 49.3 + 6 mL, p < 0.05). In contrast, after TBI, uterine volume was similar in all women, with no positive effect of HRT on uterine volume (respectively 16.3 + 2.6 Vs 20.1 + 2.2 mL).

Limitations, reasons for caution

The number of pregnancies obtained spontaneously or after oocyte donation in our study population was too low to evaluate the obstetrical impact of uterine damage caused by non-TBI regimens.

Wider implications of the findings

Our results provide strong evidence that a MAC regimen containing high dose of alkylating agents could induce uterine damage. In these sub-group of women, HRT increases the volume of the uterus compared to non-treated women. After TBI, uterine volume is dramatically decreased, with no benefit of HRT on it.

Trial registration number

NCT 03583294

Long-term morbidity and mortality in 2-year hepatoblastoma survivors treated with SIOPEL risk-adapted strategies

BACKGROUND AND AIMS

Prognosis of hepatoblastoma patients has increased with cisplatin-based chemotherapy and high-quality resection including liver transplant. Consequently current risk-adapted therapeutic strategy aims to reduce long-term side effects in patients with standard risk disease.

METHODS

We report long-term mortality and morbidity data concerning 151 2-year hepatoblastoma survivors treated with SIOPEL risk-adapted strategies (sex-ratio M/F = 1.6, median age at diagnosis = 2.6 years [range 0-17.7], median year at diagnosis = 2008 [1994-2017]). Fifty-three patients had loco-regional risk factors VPEFR, 12 were PRETEXT-IV and 30 were metastatic. All received cisplatin and 84 anthracyclines. Twelve had liver transplant. To assess hearing, renal and cardiac functions, audiograms were performed in 116/151 patients (76.8%), glomerular filtration rate in 113/151 (74.8%) and cardiac ultrasound in 65/84 (77.4%) anthracycline-exposed patients.

RESULTS

With a median follow-up of 9.4 years (range 2.1-25.8), four late relapses, one second malignancy (Acute Myeloid Leukemia AML-M5) and two deaths (one from hepatoblastoma, one from AML) occurred. The 10-years event free survival and overall survival probabilities were 95.5% (95% CI 91.9-99.1) and 98.7% (95% CI 96.8-100), respectively. Sixty-eight non-oncologic health-events included 57 cases of hearing loss (including 25 Brock 3-4), three liver cirrhosis, three pre-operative portal cavernoma, two focal nodular hyperplasia, two grade-1 chronic kidney diseases and one asymptomatic cardiac dysfunction were reported. Ototoxicity was significantly associated with cisplatin cumulative dose (OR = 2.07, 95% CI 1.32-3.24, p = 0.001) and carboplatin exposure (OR = 3.14, 95% CI 1.30-7.58, p = 0.01) in multivariable analysis adjusted for sex and age at diagnosis.

CONCLUSIONS

With current risk-adapted strategies, hepatoblastoma is a highly curable disease, with very rare relapses, and few late effects except hearing loss which remains a serious condition in these very young patients.

P-461 Pre-selected for an award: A 16-year bicentric retrospective analysis of ovarian tissue cryopreservation (OTC) in paediatric patients: indications, results and outcome

Study question

What is the outcome of ovarian tissue cryopreservation (OTC) in paediatric patients from the beginning of its setting in two different French centres?

Summary answer

In our cohort of 75 paediatric patients who underwent OTC, the mean age, malignancy rate and survival rate were 9.7 years, 70.7% and 77.3% respectively.

What is known already

Cancer treatments of last decades improve the survival rate of children and adolescents;

however chemo- and radiotherapy result in gonadal damage leading to acute ovarian failure and sterility. The preservation of fertility is now an integral part of care of children requiring gonadotoxic treatments.

Currently OTC represents the only possibility of preserving the potential fertility in prepubertal girls. OTC is an effective fertility preservation option which allows long-term storage of primordial follicles, subsequent transplantation restores endocrine function and fertility. The efficacy of these techniques is well-demonstrated within adult population but the data are poor for paediatric patients.

Study design, size, duration

This is a retrospective study of OTC practice of two French centres from January 2004 to May 2020.

Participants/materials, setting, methods

A total of 75 patients from paediatrics units underwent cryopreservation of ovarian tissue before gonadotoxic therapy for malignant or benign diseases. The ovarian cortex was cut into fragments and the number of follicles per square millimeter was evaluated histologically. The long-term follow-up includes survival rate, hormonal and fertility status.

Main results and the role of chance

The mean age at OTC of 75 patients was 9.7 years [0.2 – 20], 32% were postpubertal. 53 had malignant disease and 22 had non-malignant disease. The most frequent diagnoses in this cohort included acute leukemia, hemoglobinopathies and neuroblastoma. Indication for OTC was stem cell transplantation for 78.7% (n = 59) girls.

A third of each ovary was collected for 62,7% (n = 47) patients, a whole ovary for 33,3% (n = 25) patients and a third of one ovary alone for 4,0% (n = 3) patients. An average of 17 fragments [5-35] per patient was cryoconserved. A correlation was found between age and the number of fragments (p < 0.001). More fragments were obtained from partial bilateral harvesting than from whole ovary harvesting (p < 0.05). Histological analysis of ovarian tissue showed a median of 6.0 primordial follicles/mm2 [0.0–106.5] and no malignant cells were identified. A negative correlation was found between age and follicular density (p < 0.001).

Median post-harvest follow-up was 92 months [1–188]

17 girls had died, 12 were still treated for their pathology and 46 were in complete remission. Of all patients, 29 have been subject to hormonal status evaluation and 26 were diagnosed with premature ovarian insufficiency (p < 0.001). One patient had undergone thawed ovarian tissue transplantation.

Limitations, reasons for caution

This study is a retrospective analysis. The cohort was not compared with a control group who did not undergo OTC or with an adult population. Furthermore, many of these girls are still young and do not intend to use the transplantation of thawed ovarian tissue yet.

Wider implications of the findings

OTC should be proposed to all girls with high risk of developing premature ovarian insufficiency following gonadotoxic therapies in order to give them the possibility of fertility and endocrine restoration.

Trial registration number

Not applicable

P–461 A 16-year bicentric retrospective analysis of ovarian tissue cryopreservation (OTC) in paediatric patients: indications, results and outcome

Study question

What is the outcome of ovarian tissue cryopreservation (OTC) in paediatric patients from the beginning of its setting in two different French centres?

Summary answer

In our cohort of 75 paediatric patients who underwent OTC, the mean age, malignancy rate and survival rate were 9.7 years, 70.7% and 77.3% respectively.

What is known already

Cancer treatments of last decades improve the survival rate of children and adolescents; however chemo- and radiotherapy result in gonadal damage leading to acute ovarian failure and sterility. The preservation of fertility is now an integral part of care of children requiring gonadotoxic treatments.

Currently OTC represents the only possibility of preserving the potential fertility in prepubertal girls. OTC is an effective fertility preservation option which allows long-term storage of primordial follicles, subsequent transplantation restores endocrine function and fertility. The efficacy of these techniques is well-demonstrated within adult population but the data are poor for paediatric patients.

Study design, size, duration

This is a retrospective study of OTC practice of two French centres from January 2004 to May 2020.

Participants/materials, setting, methods

A total of 75 patients from paediatrics units underwent cryopreservation of ovarian tissue before gonadotoxic therapy for malignant or benign diseases. The ovarian cortex was cut into fragments and the number of follicles per square millimeter was evaluated histologically. The long-term follow-up includes survival rate, hormonal and fertility status.

Main results and the role of chance

The mean age at OTC of 75 patients was 9.7 years [0.2 – 20], 32% were postpubertal. 53 had malignant disease and 22 had non-malignant disease. The most frequent diagnoses in this cohort included acute leukemia, hemoglobinopathies and neuroblastoma. Indication for OTC was stem cell transplantation for 78.7% (n = 59) girls.

A third of each ovary was collected for 62,7% (n = 47) patients, a whole ovary for 33,3% (n = 25) patients and a third of one ovary alone for 4,0% (n = 3) patients. An average of 17 fragments [5–35] per patient was cryoconserved. A correlation was found between age and the number of fragments (p < 0.001). More fragments were obtained from partial bilateral harvesting than from whole ovary harvesting (p < 0.05). Histological analysis of ovarian tissue showed a median of 6.0 primordial follicles/mm2 [0.0–106.5] and no malignant cells were identified. A negative correlation was found between age and follicular density (p < 0.001).

Median post-harvest follow-up was 92 months [1–188]: 17 girls had died, 12 were still treated for their pathology and 46 were in complete remission. Of all patients, 29 have been subject to hormonal status evaluation and 26 were diagnosed with premature ovarian insufficiency (p < 0.001). One patient had undergone thawed ovarian tissue transplantation.

Limitations, reasons for caution

This study is a retrospective analysis. The cohort was not compared with a control group who did not undergo OTC or with an adult population. Furthermore, many of these girls are still young and do not intend to use the transplantation of thawed ovarian tissue yet.

Wider implications of the findings: OTC should be proposed to all girls with high risk of developing premature ovarian insufficiency following gonadotoxic therapies in order to give them the possibility of fertility and endocrine restoration.

Trial registration number

Not applicable

CNS-3 status remains an independent adverse prognosis factor in children with acute lymphoblastic leukemia (ALL) treated without cranial irradiation: Results of EORTC Children Leukemia Group study 58951

AIM

To evaluate the prognostic significance of initial central nervous system (CNS) involvement of children with acute lymphoblastic leukemia (ALL) enrolled in the EORTC 58951 trial.

PATIENTS AND METHODS

From 1998 to 2008, 1930 ALL patients were included in the randomized EORTC 58951 trial. Overall treatment intensity was adjusted according to known prognostic factors including the level of minimal residual disease after induction treatment. CNS-directed therapy comprised four to 11 courses of i.v. methotrexate (5g/m²), and 10 to 19 intrathecal chemotherapy injections, depending on risk group and CNS status. Cranial irradiation was omitted for all patients.

RESULTS

The overall 8-year event-free survival (EFS) and overall survival (OS) rates were 81.3% and 88.1%, respectively. In the CNS-1, TPL+, CNS-2, and CNS-3 groups, the 8-year EFS rates were 82.1%, 77.1%, 78.3%, and 57.4%, respectively. Multivariable analysis indicated that initial CNS-3 status, but not CNS-2 or TLP+, was an independent adverse predictor of outcome. The 8-year incidence of isolated CNS relapse was 1.7% and of isolated or combined CNS relapse it was 3.7%. NCI high-risk group, male sex, CNS-2 and CNS-3 status were independent predictors for a higher incidence of any CNS relapse.

CONCLUSIONS

CNS-3 status remains associated with poor prognosis and requires intensification of both systemic and CNS-directed therapy. This trial was registered at https://clinicaltrials.gov/under/NCT00003728.

A MALDI-TOF MS database for fast identification of Vibrio spp. potentially pathogenic to marine mollusks

In mollusk aquaculture, a large number of Vibrio species are considered major pathogens. Conventional methods based on DNA amplification and sequencing used to accurately identify Vibrio species are unsuitable for monitoring programs because they are time-consuming and expensive. The aim of this study was, therefore, to develop the MALDI-TOF MS method in order to establish a rapid identification technique for a large panel of Vibrio species. We created the EnviBase containing 120 main spectra projections (MSP) of the Vibrio species that are potentially responsible for mollusk diseases, comprising 25 species: V. aestuarianus, V. cortegadensis, V. tapetis and species belonging to the Coralliilyticus, Harveyi, Mediterranei, and Orientalis clades. Each MSP was constructed by the merger of raw spectra obtained from three different media and generated by three collaborating laboratories to increase the diversity of the conditions and thus obtain a good technique robustness. Perfect discrimination was obtained with all of the MSP created for the Vibrio species and even for very closely related species as V. europaeus and V. bivalvicida. The new EnviBase library was validated through a blind test on 100 Vibrio strains performed by our three collaborators who used the direct transfer and protein extraction methods. The majority of the Vibrio strains were successfully identified with the newly created EnviBase by the three laboratories for both protocol methods. This study documents the first development of a freely accessible database exclusively devoted to Vibrio found in marine environments, taking into account the high diversity of this genus. KEY POINTS: • Development of a MALDI-TOF MS database to quickly affiliate Vibrio species. • Increase of the reactivity when faced with Vibrio associated with mollusk diseases. • Validation of MALDI-TOF MS as routine diagnostic tool.

Purely Cubic Spin Splittings with Persistent Spin Textures

Purely cubic spin splittings in the band structure of bulk insulators have not been extensively investigated yet despite the fact that they may pave the way for novel spin-orbitronic applications and can also result in a variety of promising spin phenomena. By symmetry analysis and first-principles simulations, we report symmetry-enforced purely cubic spin splittings (SEPCSS) that can even lead to persistent spin textures. In particular, these SEPCSS can be thought to be complementary to the cubic Rashba and cubic Dresselhaus types of spin splittings. Strikingly, the presently discovered SEPCSS are expected to exist in the large family of materials crystallizing in the 6[over ¯]m2 and 6[over ¯] point groups, including the Ge_{3}Pb_{5}O_{11}, Pb_{7}Br_{2}F_{12}, and Pb_{7}Cl_{2}F_{12} compounds.

Linear Versus Nonlinear Electro-Optic Effects in Materials

Two schemes are proposed to compute the nonlinear electro-optic (EO) tensor for the first time. In the first scheme, we compute the linear EO tensor of the structure under a finite electric field, while we compute the refractive index of the structure under a finite electric field in the second scheme. Such schemes are applied to Pb(Zr,Ti)O_{3} and BaTiO_{3} ferroelectric oxides. It is found to reproduce a recently observed feature, namely, why Pb(Zr_{0.52}Ti_{0.48})O_{3} adopts a mostly linear EO response while BaTiO_{3} exhibits a strongly nonlinear conversion between electric and optical properties. Furthermore, the atomistic insight provided by the proposed ab initio scheme reveals the origin of such qualitatively different responses, in terms of the field-induced behavior of the frequencies of some phonon modes and of some force constants.

External pH modulation during the growth of Vibrio tapetis, the aetiological agent of brown ring disease

AIMS

Brown ring disease (BRD) is an infection of the Manila clam Ruditapes philippinarum due to the pathogen Vibrio tapetis. During BRD, clams are facing immunodepression and shell biomineralization alteration. In this paper, we studied the role of pH on the growth of the pathogen and formulated hypothesis on the establishment of BRD by V. tapetis.

METHODS AND RESULTS

In this study, we monitored the evolution of pH during the growth of V. tapetis in a range of pH and temperatures. We also measured the pH of Manila clam haemolymph and extrapallial fluids (EPFs) during infection by V. tapetis. We highlighted that V. tapetis modulates the external pH during its growth, to a value of 7·70. During the development of BRD, V. tapetis also influences EPFs and haemolymph pH in vitro in the first hours of exposure and in vivo after 3 days of infection.

CONCLUSIONS

Our experiments have shown a close interaction between V. tapetis CECT4600, a pathogen of Manila clam that induces BRD, and the pH of different compartments of the animals during infection. These results indicate that the bacterium, through a direct mechanism or as a consequence of physiological changes encountered in the animal during infection, is able to interfere with the pH of Manila clam fluids. This pH modification might promote the infection process or at least create an imbalance within the animal that would favour its persistence. This last hypothesis should be tested in future experiment.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is the first observation of pH modifications in the context of BRD and might orient future research on the fine mechanisms of pH modulation associated with BRD.

A proteomic study of resistance to Brown Ring disease in the Manila clam, Ruditapes philippinarum

Marine mollusk aquaculture has more than doubled over the past twenty years, accounting for over 15% of total aquaculture production in 2016. Infectious disease is one of the main limiting factors to the development of mollusk aquaculture, and the difficulties inherent to combating pathogens through antibiotic therapies or disinfection have led to extensive research on host defense mechanisms and host-pathogen relationships. It has become increasingly clear that characterizing the functional profiles of response to a disease is an essential step in understanding resistance mechanisms and moving towards more effective disease control. The Manila clam, Ruditapes philippinarum, is a main cultured bivalve species of economic importance which is affected by Brown Ring disease (BRD), an infection induced by the bacterium Vibrio tapetis. In this study, juvenile Manila clams were subjected to a 28-day controlled challenge with Vibrio tapetis, and visual and molecular diagnoses were carried out to distinguish two extreme phenotypes within the experimental clams: uninfected ("RES", resistant) and infected ("DIS", diseased) post-challenge. Total protein extractions were carried out for resistant and diseased clams, and proteins were identified using LC-MS/MS. Protein sequences were matched against a reference transcriptome of the Manila clam, and protein intensities based on label-free quantification were compared to reveal 49 significantly accumulated proteins in resistant and diseased clams. Proteins with known roles in pathogen recognition, lysosome trafficking, and various aspects of the energy metabolism were more abundant in diseased clams, whereas those with roles in redox homeostasis and protein recycling were more abundant in resistant clams. Overall, the comparison of the proteomic profiles of resistant and diseased clams after a month-long controlled challenge to induce the onset of Brown Ring disease suggests that redox homeostasis and maintenance of protein structure by chaperone proteins may play important and interrelated roles in resistance to infection by Vibrio tapetis in the Manila clam.

Designing Multifunctionality via Assembling Dissimilar Materials: Epitaxial AlN/ScN Superlattices

First-principles calculations are performed to investigate the effect of epitaxial strain on energetic, structural, electrical, electronic, and optical properties of 1×1 AlN/ScN superlattices. This system is predicted to adopt four different strain regions exhibiting different properties, including optimization of various physical responses such as piezoelectricity, electro-optic and elasto-optic coefficients, and elasticity. Varying the strain between these four different regions also allows the creation of an electrical polarization in a nominally paraelectric material, as a result of a softening of the lowest optical mode, and even the control of its magnitude up to a giant value. Furthermore, it results in an electronic band gap that cannot only change its nature (direct vs indirect), but also cover a wide range of the electromagnetic spectrum from the blue, through the violet and near ultraviolet, to the middle ultraviolet. These findings thus point out the potential of assembling two different materials inside the same heterostructure to design multifunctionality and striking phenomena.

Photoinduced Phase Transitions in Ferroelectrics

Ferroic materials naturally exhibit a rich number of functionalities, which often arise from thermally, chemically, or mechanically induced symmetry breakings or phase transitions. Based on density functional calculations, we demonstrate here that light can drive phase transitions as well in ferroelectric materials such as the perovskite oxides lead titanate and barium titanate. Phonon analysis and total energy calculations reveal that the polarization tends to vanish under illumination, to favor the emergence of nonpolar phases, potentially antiferroelectric, and exhibiting a tilt of the oxygen octahedra. Strategies to tailor photoinduced phases based on phonon instabilities in the electronic ground state are also discussed.

Novel Dynamical Magnetoelectric Effects in Multiferroic BiFeO_{3}

An atomistic effective Hamiltonian scheme is employed within molecular dynamics simulations to investigate how the electrical polarization and magnetization of the multiferroic BiFeO_{3} respond to time-dependent ac magnetic fields of various frequencies, as well as to reveal the frequency dependency of the dynamical (quadratic) magnetoelectric coefficient. We found the occurrence of vibrations having phonon frequencies in both the time dependency of the electrical polarization and magnetization (for any applied ac frequency), therefore making such vibrations of electromagnonic nature, when the homogeneous strain of the system is frozen (case 1). Moreover, the quadratic magnetoelectric coupling constant is monotonic and almost dispersionless in the sub-THz range in this case 1. In contrast, when the homogeneous strain can fully relax (case 2), two additional low-frequency and strain-mediated oscillations emerge in the time-dependent behavior of the polarization and magnetization, which result in resonances in the quadratic magnetoelectric coefficient. Such additional oscillations consist of a mixing between acoustic phonons, optical phonons, and magnons, and reflect the existence of a new quasiparticle that can be coined an "electroacoustic magnon." This latter finding can prompt experimentalists to shape their samples to take advantage of, and tune, the magnetostrictive-induced mechanical resonance frequency, in order to achieve large dynamical magnetoelectric couplings.

Photostriction and elasto-optic response in multiferroics and ferroelectrics from first principles

The present work reviews a series of recent first-principles studies devoted to the description of the interaction of light and strain in ferroelectric and multiferroic materials. Specifically, the modelling schemes used in these works to describe the so-called photostriction and elasto-optic effects are presented, in addition to the results and analysis provided by these ab initio calculations. In particular, the large importance of the piezoelectric effect in the polar direction in the photostriction of ferroelectric materials is stressed. Similarly, the occurrence of low-symmetry phases in lead titanate thin films under tensile strain is demonstrated to result in large elasto-optic constants. In addition, first-principle calculations allow to gain microscopic knowledge of subtle effects, for instance in the case of photostriction, where the deformation potential effect in directions perpendicular to the polar axis is shown to be almost as significant as the piezoelectric effect. As a result, the numerical methods presented here could propel the design of efficient opto-mechanical devices.

Vacancies and holes in bulk and at 180° domain walls in lead titanate

Domain walls (DWs) in ferroic materials exhibit a plethora of unexpected properties that are different from the adjacent ferroic domains. Still, the intrinsic/extrinsic origin of these properties remains an open question. Here, density functional theory calculations are used to investigate the interaction between vacancies and 180° DWs in the prototypical ferroelectric PbTiO₃, with a special emphasis on cationic vacancies and released holes. All vacancies are more easily formed within the DW than in the domains. This is interpreted, using a phenomenological model, as the partial compensation of an extra-tensile stress when the defect is created inside the DW. Oxygen vacancies are found to be always fully ionized, independently of the thermodynamic conditions, while cationic vacancies can be either neutral or partially ionized (oxygen-rich conditions), or fully ionized (oxygen-poor conditions). Therefore, in oxidizing conditions, holes are induced by neutral and partially ionized Pb vacancies. In the bulk PbTiO₃, these holes are more stable as delocalized rather than small polarons, but at DWs, the two forms are found to be possible.

Toy model for uncommon spin-orbit-driven spin-torque terms

A toy model combining the angular magneto electric (AME) coupling Hamitonian (Mondal et al 2015 Phys. Rev. B 92 100402) with long-range magnetic dipolar interactions is used to investigate spin-torque phenomena in a magnetic spin valve. It is found that such model (1) gives rise to spin-torque expressions that are analogous in form to those of the common spin-transfer torques; but also (2) predicts additional spin-torque terms, which are generated by an electrical current oriented along unconventional, in-plane directions. The magnitude of the AME induced terms is estimated and the conditions under which they may contribute significantly are explored.

Enhancing data visualisation to capture the simulator sickness phenomenon: On the usefulness of radar charts

The data presented in this article are related to the research article entitled “The use of transdermal scopolamine to solve methodological issues raised by gender differences in susceptibility to simulator sickness” (Chaumillon et al., 2017) [1]. In an outstanding first demonstration, Kennedy et al. [2] showed that the Simulator Sickness Questionnaire (SSQ) is an appropriate tool to suit the purposes of characterizing motion sickness experienced in virtual environments. This questionnaire has since been used in many scientific studies. Recently, Balk et al. [3] suggested that the proposed segregation of SSQ scores into three subclasses of symptoms might limit the accuracy of simulator sickness assessment. These authors performed a factor analysis based on SSQ scores obtained from nine studies on driving simulators. Although their factor analysis resulted in the same three orthogonal classes of symptoms as Kennedy et al. [2], unlike this pioneering study, no items were attributed to more than one factor and five items were not attributed to any class of symptoms. As a result, they claimed that an exploration of each item score should give additional cues on individual profiles. To gain a better characterization of such item-by-item exploration, data utilised in this research are shown using a radar chart visualisation.

Photostrictive Two-Dimensional Materials in the Monochalcogenide Family

Photostriction is predicted for group-IV monochalcogenide monolayers, two-dimensional ferroelectrics with rectangular unit cells (the lattice vector a_{1} is larger than a_{2}) and an intrinsic dipole moment parallel to a_{1}. Photostriction is found to be related to the structural change induced by a screened electric polarization (i.e., a converse piezoelectric effect) in photoexcited electronic states with either p_{x} or p_{y} (in-plane) orbital symmetry that leads to a compression of a_{1} and a comparatively smaller increase of a_{2} for a reduced unit cell area. The structural change documented here is 10 times larger than that observed in BiFeO_{3}, making monochalcogenide monolayers an ultimate platform for this effect. This structural modification should be observable under experimentally feasible densities of photexcited carriers on samples that have been grown already, having a potential usefulness for light-induced, remote mechano-optoelectronic applications.

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.

Pseudomonas aeruginosa and Pseudomonas putida outbreak associated with contaminated water outlets in an oncohaematology paediatric unit

This paper describes an outbreak of Pseudomonas aeruginosa and Pseudomonas putida that occurred in an oncohaematology paediatric unit between January and April 2005. Eight children had nosocomial infections due to P. aeruginosa (N=5) or P. putida (N=3), which were recovered from central venous catheter blood cultures (N=4), the catheter exit site alone (N=2), or the catheter exit site and the catheter tip (N=2). Subsequent investigation showed that contaminated water outlets represented the possible source of spread. Studies of nursing and environmental cleaning practices revealed two modes of catheter contamination. A reduction in the size of the catheter dressing at the exit site gave less protective cover during showers, and a detergent-disinfectant diluted with tap water had contaminated perfusion bottles. Repetitive intergenic consensus polymerase chain reaction indicated two discrete patterns for P. aeruginosa and one for P. putida. The water network was chlorinated, and disposable seven-day filters were fitted on all taps and showers. Due to the deleterious effects of chlorination on the water network and the cost of the weekly filter change, a water loop producing microbiologically controlled water was installed. In addition, the concentration of the detergent-disinfectant was increased and refillable sprayers were replaced with ready-to-use detergent-disinfectant solution for high-risk areas. Following these measures, no Pseudomonas spp. have since been isolated in clinical or environmental samples from the ward.