Strain-induced conduction gap in vertical devices made of misoriented graphene layers.

We investigate the effects of uniaxial strain on the transport properties of vertical devices made of two misoriented (or twisted) graphene layers, which partially overlap each other. We find that because of the different orientations of the two graphene lattices, their Dirac points can be displaced and separated in the k-space by the effects of strain. Hence, a finite conduction gap as large as a few hundred meV can be obtained in the device with a small strain of only a few percent. The dependence of this conduction gap on the strain magnitude, strain direction, channel orientation and twist angle are clarified and presented. On this basis, the strong modulation of conductance and significant improvement of Seebeck coefficient are shown. The suggested devices therefore may be very promising for improving applications of graphene, e.g., as transistors or strain and thermal sensors.

Promoting the Swedish method of physical education throughout France for the benefit of public health (1868-1954).

This article examines the cultural and public health challenges associated with the dissemination of the Swedish approach and methods of physical education throughout France and illustrates the two main methods of influence, both direct through research and study visits and indirect through the creation of an international network entitled the International Federation of Physical Education. More particularly, it studies the roles of Philippe Tissié in 1898 and Pierre Seurin in 1946, and shows how these two major players of French physical education contributed actively to strengthening Swedish influence throughout France. It also highlights their equally essential role in the successful implementation of a pro-Swedish network in France, intended to serve their public health aims. This analysis forms part of the geopolitical and socio-cultural history of foreign physical education models, whose exemplarity was mainly dependent on Franco-Swedish relations and the models' social representations. Using archives from the French Physical Education League, travel logs and the Revue des jeux scolaires et d'hygiène sociale (Journal for School Games and Social Hygiene), it has been shown why the myth of the Swedish Eldorado contributed to creating, in France, "a work of art and of science that was, at the same time, both national and practical."

Graphene nanomesh-based devices exhibiting a strong negative differential conductance effect.

Using atomistic quantum simulation based on a tight binding model, we have investigated the transport characteristics of graphene nanomesh-based devices and evaluated the possibilities of observing negative differential conductance. It is shown that by taking advantage of bandgap opening in the graphene nanomesh lattice, a strong negative differential conductance effect can be achieved at room temperature in pn junctions and n-doped structures. Remarkably, the effect is improved very significantly (with a peak-to-valley current ratio of a few hundred) and appears to be weakly sensitive to the transition length in graphene nanomesh pn hetero-junctions when inserting a pristine (gapless) graphene section in the transition region between n and p zones. The study therefore suggests new design strategies for graphene electronic devices which may offer strong advantages in terms of performance and processing over the devices studied previously.

Heat transfer in rough nanofilms and nanowires using full band ab initio Monte Carlo simulation.

The Boltzmann transport equation is one of the most relevant frameworks to study the heat transport at the nanoscale, beyond the diffusive regime and up to the micrometer-scale. In the general case of 3D devices, the particle Monte Carlo approach of phonon transport is particularly powerful and convenient, and requires reasonable computational resources. In this work, we propose an original and versatile particle Monte Carlo approach parametrized by using ab initio data. Both the phonon dispersion and the phonon-phonon scattering rates have been computed by DFT calculation in the entire 3D Brillouin zone. To treat the phonon transport at rough interfaces, a combination of specular and diffuse reflections has been implemented in phase space. Thermal transport has been investigated in nanowires and thin films made of cubic and hexagonal Silicon, including edge roughness, in terms of effective thermal conductivity, phonon band contributions and heat flux orientation. It is shown that the effective thermal conductivity in quasi-ballistic regime obtained from our Monte Carlo simulation cannot be accurately fitted by simple semi-analytical Matthiessen-like models and that spectral approaches are mandatory to get good results. Our full band approach shows that some phonon branches exhibiting a negative group velocity in some parts of the Brillouin zone may contribute negatively to the total thermal flux. Besides, the thermal flux clearly appears to be oriented along directions of high density of states. The resulting anisotropy of the heat flux is discussed together with the influence of rough interfaces.

The bactericidal capacity of peripheral blood monocytes from HIV positive patients may collapse very soon after the infection.

The activity of peripheral blood monocytes from HIV positive patients was measured by the intensity of the chemoluminescence those cells emit when they ingest a foreign particle. In most patients (84%) that value was impaired. Such an alteration may occur very early in the course of the disease. The anti-p24 antibody titer was correlated with monocyte phagocytic potential as measured by the chemoluminescent value thus indicating the need for adequate monocyte activity in order to obtain antibody formation. The severity of opportunistic infections that HIV positive subjects may develop is a clear indication that their immune systems are abnormal. The most frequently affected cells are those which bear the viral receptor, the CD4 antigen. Those cells are mainly the helper T cells and monocytes. The monocytes are the immune system phagocytic cells which actively control infections, in part by the release oxidative radicals. Those radicals can easily be measured by the chemoluminescence (CL) the cells emit when they ingest a foreign particle. This study examines the CL emitted by peripheral blood monocytes from HIV-positive and control subjects while they phagocytose opsonized zymosan in vitro and correlates these values with other laboratory parameters.

Serum levels of IL-2, IL-1 alpha, TNF-alpha, and soluble receptor of IL-2 in HIV-1-infected patients.

Serum levels of the interleukins (IL-1 alpha, IL-2), tumor necrosis factor-alpha (TNF-alpha), and soluble receptor of IL-2 (sIL-2R) were studied by enzyme-linked immunosorbent assay (ELISA) in 12 normal healthy controls and 52 HIV-1 seropositive patients. Results indicated that: (1) sIL-2R levels were significantly increased in most HIV-1 seropositive patients. This increase appeared to be correlated with low CD4 cell counts and with the presence of detectable levels of p25 antigen. Furthermore, initially high levels of sIL-2R appeared to be correlated with progression of disease. (2) IL-2 levels were found to be increased in about 43% of asymptomatic carriers (ASY) and subjects with lymphoadenopathy-associated syndrome (LAS) compared with 12% in the case of AIDS-related complex (ARC) and AIDS patients. (3) There was a positive correlation between serum levels of TNF-alpha and IL-1 alpha in nearly all patients. Detectable levels of both cytokines were found in 34% of ASY and LAS patients and only rarely were detectable in ARC and AIDS patients. (4) Sixteen patients in whom progression of disease was observed were studied initially and at the moment they upstaged. No significant modification of serum levels of the three cytokines and sIL-2R studied could be evidenced. It was concluded that sIL-2R could be a useful marker of disease activity and progression, though a prospective study is necessary. For IL-2, IL-1 alpha, and TNF-alpha, this study indicated the presence of variable alterations in serum levels in HIV-1-infected patients.

Platelet antibodies in serum of patients with human immunodeficiency virus (HIV) infection.

Between 10 and 15% of human immunodeficiency virus (HIV) seropositive individuals develop an immune thrombocytopenic purpura; however, the mechanism involved in platelet destruction is not yet established. In the present work, we have analyzed 208 sera from HIV seropositive individuals, including 85 thrombocytopenic patients, for the presence of autoantibodies against platelet proteins by using the Western blot technique. Our results indicate that: (1) antibodies against platelet proteins were found in 8 of 123 (6.5%) nonthrombocytopenic patients, as compared with 17 of 85 (20%) of thrombocytopenic patients (p less than 0.03); (2) these antibodies appeared to be more frequently found in advanced stages of disease (p less than 0.02); (3) the reactivity of positive sera with antigenic determinants implicated several distinct platelet proteins; (4) antigens thus recognized are unrelated to the major membrane glycoproteins IIb and IIIa, as well as absent in vero cells and trypsin-sensitive cells. Such results underscore the difficulties in establishing the mechanisms involved in platelet destruction during HIV infection.

[Ventricular tachycardia of the infant. 2 new cases]. / Les tachycardies ventriculaires du nourrisson. Deux nouvelles observations

Two new cases of ventricular tachycardia (VT) in the infant are reported, and reviewed in the light of the 23 case histories found in the literature. The diagnosis rests upon eliminating a pre-excitation syndrome, which is so common in this age group. The VTs found in infants are rapid, irregular, and take many different forms. They often necessitate urgent treatment with electric shocks. Preventive treatment consists of a combination of procainamide and beta-blockers in relatively large doses. The search for an aetiological agent should include a haemodynamic and angiocardiographic study of all the chambers of the heart to exclude cardiomyopathy, tumours, papyraceous right ventricle and congenital heart defects. Where no cause can be demonstrated, preventive treatment should be given, with regular electrical testing and other follow-up investigations. An attempt to reduce the drug dosage should be made every 6 months, in hospital. In cases which prove resistant despite adequate treatment, it seems justifiable to carry out a pericardial exploration with the aim of diathermising the ectopic focus; this approach is suggested because of the poor natural history of this type of case.

[Cerebral neuroblastoma in the newborn infant]. / Neuroblastome cérébral du nouveau-né.

The authors report the exceptional case of a cerebral neuroblastoma responsible for intracranial hypertension at birth. In spite of neurosurgical intervention on the seventh day the newborn died. Histological and immunohistochemical study with Protein S 100 and "anti LEU 7" are consistent with the diagnosis of neuroblastoma.

[Pediatric emergency admission: results of two national surveys on a "given day"]. / L'accueil des enfants aux urgences: résultats de deux enquêtes nationales "Un jour donné".

BACKGROUND: Recently, several measures were implemented to restructure the frame-work of hospital emergency admissions. However, these measures concern primarily adults. Pediatricians made on their own several proposals to improve admission of children. They felt that these proposals should be supported by statistical numbers. Several investigations were then conducted. POPULATION AND METHODS: The authors report the results of two investigations conducted in January 1994 and January 1995 in all French hospitals admitting children in emergency. RESULTS: The results shows that 60% of the purposes for consultations are of a general medical nature which does not require emergency assistance. The emergency cases were estimated genuine in only 10% of all incoming patients while all other cases were benign or treated merely as simple outpatient consultations. Accidental pathology represented 30% of all cases. More than half of the children were less than five years old. In most cases, a pediatrician was readily available night and day in all University hospitals which was, unfortunately, not the case in most general hospitals where the number of pediatricians was insufficient to assure night duties. CONCLUSION: The result of these investigations does not provide an exhaustive picture of the overall pediatric emergencies. It demonstrates, however, the quantitative importance of pediatric emergencies while emphasizing on their differentiation in qualifications and specialization of the practicians and nurses in charge of incoming patients from one hospital to another. It demonstrates that serious efforts need to be made so that the child may be readily directed to an hospital emergency center with appropriate medical and paramedical personnel, a situation which, unfortunately, does not always prevail at present.

[Giant cell hepatitis and autoimmune hemolytic anemia: efficacy of splenectomy on hemolysis]. / Hépatite à cellules géantes et anémie hémolytique auto-immune: efficacité de la splénectomie sur l'hémolyse.

BACKGROUND: The previously reported cases of giant cell hepatitis with autoimmune hemolytic anemia were improved by prednisone plus azathioprine. CASE REPORT: A 14-month-old boy suffered from giant cell hepatitis with auto-immune hemolytic anemia and positive direct Coombs test. Prednisone and azathioprine administration improved the liver disease but failed to control hemolysis so that repeated blood transfusions were necessary. Persistance of severe degree of hemolysis required splenectomy that was promptly and definitively effective. Azathioprine and prednisone were pursued for a total duration of five years. Twelve years after the onset of the disease, the child is well without any treatment. CONCLUSION: This is the first reported case of such an association in which poorly controlled auto-immune hemolytic anemia benefited from splenectomy.

[Pseudo-aneurysm of the internal carotid artery]. / Pseudo-anévrysme de la carotide interne.

The authors recall the anatomy of the deep neck spaces and report the case of a 3-year-old girl with a parapharyngeal abscess followed by a pseudo-aneurism of the carotide artery. Ultrasonography, CT scan and angiography findings are described. This case puts in mind of the seriousness of neck abscesses. Each specific anatomical location must be definite for a better therapeutic approach on account of hemorrhagic risks of parapharyngeal abscesses.

[Idiopathic thrombocytopenic purpura: long-term outcome]. / Purpura thrombopénique idiopathique chez 87 enfants: évolution à long terme.

BACKGROUND: Idiopathic thrombocytopenic purpura (ITP) has usually an excellent prognosis even when no specific therapy is given. We studied, in 1996, the outcome of 87 patients with ITP observed between 1973 and 1995. PATIENTS AND METHODS: These 87 cases represented all the thrombocytopenic purpura observed during 23 years in the same pediatric unit not specialized in hematology. The outcome of these children was investigated in 1996 by phone or writing to the patients themselves or to their physician. Adequate information was obtained for 63 patients (72.4%). RESULTS: Two cerebral hemorrhages were observed, one was lethal while the other, observed after several years of course, healed completely. All these patients became free from clinical signs but 11 were not cured in 1996. None of these 63 patients had developed autoimmune disease. One patient died in a traffic accident, his thrombocytopenic purpura had been cured. CONCLUSION: In spite of two cerebral hemorrhages, ITP remains in the great majority of cases a benign disease not requiring grave therapeutic decisions.

[Adoption and chronic hepatitis B carrier state]. / Adoption et portage chronique du virus B.

AIM: Because there are few adoptable children in France, parents, for the last 20 years, have turned to international adoption. Alerted by the generally poor health of these children, we paid particular attention to their health problems and especially to infection by hepatitis B virus (HBV). POPULATION AND METHODS: The 60 internationally-adopted children seen from June 1993 to June 1997 were included in this study. All had hemogram and serum iron dosage, and search for intestinal parasites and tuberculosis was performed in each child, as were HBs antigen and HBs antibody screening. When HBs antigen was positive, HBe antigen and antibodies, HBV DNA and hepatitis C and delta serology were also studied. RESULTS: Six out of the 60 children were HBV chronic carriers. The six presented HBs antigen and five out of the six presented viral DNA. One child was co-infected with delta virus. Serum aminotransferase was normal in three children and increased in the three others. DISCUSSION: Some internationally adopted children are exposed to chronic infection by HBV. This concerns children coming from countries known for the high frequency of the disease, but also children with long stay in Eastern European nurseries. Chronic HBV carriage puts the child, as well as the family and other children in institutions and/or schools at risk, thus necessitating preventive measures.

[In utero death of one twin and cerebral complications in the surviving twin]. / Mort d'un jumeau in utero et complications cérébrales chez le survivant.

When one of two twin foetuses dies in utero, the survivor may present with a number of abnormalities, including severe lesions of the nervous system. These lesions are of vascular origin and seem to be due to tissue emboli from the dead foetus. Monochorionic pregnancies are those at the highest risk of this pathology. The surviving twin must be examined both clinically and by ultrasonography.

CRM1 inhibition induces tumor cell cytotoxicity and impairs osteoclastogenesis in multiple myeloma: molecular mechanisms and therapeutic implications.

The key nuclear export protein CRM1/XPO1 may represent a promising novel therapeutic target in human multiple myeloma (MM). Here we showed that chromosome region maintenance 1 (CRM1) is highly expressed in patients with MM, plasma cell leukemia cells and increased in patient cells resistant to bortezomib treatment. CRM1 expression also correlates with increased lytic bone and shorter survival. Importantly, CRM1 knockdown inhibits MM cell viability. Novel, oral, irreversible selective inhibitors of nuclear export (SINEs) targeting CRM1 (KPT-185, KPT-330) induce cytotoxicity against MM cells (ED50<200 nM), alone and cocultured with bone marrow stromal cells (BMSCs) or osteoclasts (OC). SINEs trigger nuclear accumulation of multiple CRM1 cargo tumor suppressor proteins followed by growth arrest and apoptosis in MM cells. They further block c-myc, Mcl-1, and nuclear factor κB (NF-κB) activity. SINEs induce proteasome-dependent CRM1 protein degradation; concurrently, they upregulate CRM1, p53-targeted, apoptosis-related, anti-inflammatory and stress-related gene transcripts in MM cells. In SCID mice with diffuse human MM bone lesions, SINEs show strong anti-MM activity, inhibit MM-induced bone lysis and prolong survival. Moreover, SINEs directly impair osteoclastogenesis and bone resorption via blockade of RANKL-induced NF-κB and NFATc1, with minimal impact on osteoblasts and BMSCs. These results support clinical development of SINE CRM1 antagonists to improve patient outcome in MM.

[Interindividual pharmacokinetic variability in long-term antibiotherapy]. / Variabilité pharmacocinétique intra-individuelle et traitement antibiotique prolongé.

OBJECTIVE: The authors wanted to assess intraindividual pharmacokinetic variability, with a case of long-term amikacin therapy. DESIGN: A 92-year-old female patient, weighing 44kg, with renal failure, was treated by amikacin for 52 days. Her individual pharmacokinetic parameters were assessed 12 times in the course of therapy. The intraindividual variability of key parameters was quantified and compared with published interindividual variability. RESULTS: Intraindividual volume and clearance variability was measured at about one fourth to one third of the value observed for interindividual variability. Half-life intraindividual variability was almost equivalent to the interindividual variability: 24.5% versus 32%. CONCLUSIONS: The high pharmacokinetic variability observed has important potential clinical consequences. This case illustrates the need to ensure the effectiveness of treatment, to re-evaluate periodically the patient's status in order to take into account the intraindividual variability of pharmacokinetics parameters.