Direct Structural Identification and Quantification of the Split-Vacancy Configuration for Implanted Sn in Diamond.

We demonstrate formation of the ideal split-vacancy configuration of the Sn-vacancy center upon implantation into natural diamond. Using ß^{-} emission channeling following low fluence ^{121}Sn implantation (2×10^{12} atoms/cm^{2}, 60 keV) at the ISOLDE facility at CERN, we directly identified and quantified the atomic configurations of the Sn-related centers. Our data show that the split-vacancy configuration is formed immediately upon implantation with a surprisingly high efficiency of ≈40%. Upon thermal annealing at 920 °C ≈30% of Sn is found in the ideal bond-center position. Photoluminescence revealed the characteristic SnV^{-} line at 621 nm, with an extraordinarily narrow ensemble linewidth (2.3 nm) of near-perfect Lorentzian shape. These findings further establish the SnV^{-} center as a promising candidate for single photon emission applications, since, in addition to exceptional optical properties, it also shows a remarkably simple structural formation mechanism.

[Type 1 neurofibromatosis: Onset of two tumors before the age of 5years]. / Neurofibromatose de type 1 : survenue de deux tumeurs avant l'âge de 5 ans.

Neurofibromatosis type 1 (NF1) is a frequent autosomal dominant genetic disorder that predisposes to the development of benign and malignant tumors. Mutation of the NF1 gene affects the RAS-MAPK signaling pathway and leads to a dysfunction in cell proliferation and induces tumor development. Epidemiology of cancer in children with NF1 is very different from the general pediatric population, which requires regular and specific monitoring. Neurofibroma is the most frequent benign tumor. It can be very invalidating depending on the size and location of the tumor. Currently, there is no specific treatment for these tumors. The most frequent malignancies in children with NF1 are leukemias, rhabdomyosarcomas, malignant peripheral nerve sheath tumors and gliomas. The treatment of these tumors should consider the risk of second cancers induced by radio- and chemotherapy. We report on the case of a 5-year-old boy with NF1 developing two tumors.

Early outcomes of spinal growth tethering for idiopathic scoliosis with a novel device: a prospective study with 2 years of follow-up.

QUESTIONS/PURPOSES: Adolescent idiopathic scoliosis is a 3D spine deformity that worsens during the whole growth. New methods for spinal growth modulation with flexible spinal implants have been described to avoid progression of the deformity during growth spurt. The main limitations are that no specific ancillaries and devices are available, which makes the surgery technically demanding. METHODS: We have developed a new method of spinal growth tethering using minimal invasive videothoracoscopic approach. Fixation is performed with staples and synthetic ligament on the lateral aspect of vertebral bodies on main curvature convexity. Patients with progressive thoracic idiopathic scoliosis despite the brace treatment were included. The clinical and radiological examinations were compared before and 2 years after surgery. RESULTS: Six patients with flexible thoracic curves with a mean age 11.2 ± 1.2 years and a mean Cobb angle 45° ± 10° (35-60) were operated. All were skeletally immature. At last follow-up, the Cobb angle was stable. None of the patient underwent fusion. CONCLUSIONS: The procedure allowed a stabilization of the deformity during growth spurt. Validated devices and further studies with longer term follow-up are needed to confirm the efficiency of this technique. This small cohort of patients is a source of reflection for further medical devices developments. LEVEL OF EVIDENCE: Level 4 case series comparing to not randomized studies.

[Pitfalls in the diagnosis of occult elbow fractures in children]. / Pièges diagnostiques de la traumatologie du coude le l'enfant.

Elbow injuries are frequent but occult fractures are difficult to diagnose on x-rays. However, any delay in the diagnosis may severely impair the prognosis of some fractures. Simple tips may help the clinician read x-rays properly and avoid the classical pitfalls of elbow injuries in children. The chronology of appearance of ossification nuclei around the elbow is important to distinguish normal features from abnormality. Drawing simple geometric constructions on the x-rays may clarify most occult elbow fractures in children.

Assessment of a polyelectrolyte multilayer film coating loaded with BMP-2 on titanium and PEEK implants in the rabbit femoral condyle.

UNLABELLED: The aim of this study was to evaluate the osseointegration of titanium implants (Ti-6Al-4V, noted here TA6V) and poly(etheretherketone) PEEK implants induced by a BMP-2-delivering surface coating made of polyelectrolyte multilayer films. The in vitro bioactivity of the polyelectrolyte film-coated implants was assessed using the alkaline phosphatase assay. BMP-2-coated TA6V and PEEK implants with a total dose of 9.3µg of BMP-2 were inserted into the femoral condyles of New Zealand white rabbits and compared to uncoated implants. Rabbits were sacrificed 4 and 8weeks after implantation. Histomorphometric analyses on TA6V and PEEK implants and microcomputed tomography on PEEK implants revealed that the bone-to-implant contact and bone area around the implants were significantly lower for the BMP-2-coated implants than for the bare implants. This was confirmed by scanning electron microscopy imaging. This difference was more pronounced at 4weeks in comparison to the 8-week time point. However, bone growth inside the hexagonal upper hollow cavity of the screws was higher in the case of the BMP-2 coated implants. Overall, this study shows that a high dose of BMP-2 leads to localized and temporary bone impairment, and that the dose of BMP-2 delivered at the surface of an implant needs to be carefully optimized. STATEMENT OF SIGNIFICANCE: The presentation of growth factors from material surfaces currently presents significant challenges in academia, clinics and industry. Applying osteoinductive factors to different types of implants, made of metals or polymers, may improve bone repair in difficult situations. Here, we show the effects of an osteoinductive coating made of polyelectrolyte multilayer films on two widely used materials, titanium TA6V alloys and PEEK implants, which were implanted in the rabbit femoral condyle. We show that a too high dose of BMP-2 delivered from the screw surface has a negative short-term effect on bone regeneration in close vicinity of the screw surface. In contrast, bone formation was increased at early times in the empty spaces around the screw. These results highlight the need for future dose-dependence studies on bone formation in response to osteoinductive coatings.

Photoelectric detection of electron spin resonance of nitrogen-vacancy centres in diamond.

The readout of negatively charged nitrogen-vacancy centre electron spins is essential for applications in quantum computation, metrology and sensing. Conventional readout protocols are based on the detection of photons emitted from nitrogen-vacancy centres, a process limited by the efficiency of photon collection. We report on an alternative principle for detecting the magnetic resonance of nitrogen-vacancy centres, allowing the direct photoelectric readout of nitrogen-vacancy centres spin state in an all-diamond device. The photocurrent detection of magnetic resonance scheme is based on the detection of charge carriers promoted to the conduction band of diamond by two-photon ionization of nitrogen-vacancy centres. The optical and photoelectric detection of magnetic resonance are compared, by performing both types of measurements simultaneously. The minima detected in the measured photocurrent at resonant microwave frequencies are attributed to the spin-dependent ionization dynamics of nitrogen-vacancy, originating from spin-selective non-radiative transitions to the metastable singlet state.

Spica cast as an alternative to general anesthesia for lower limb MRI in young children.

BACKGROUND: The conventional approach for MRI procedures in very young children is to use general anesthesia which comes with inherent risks. Non-pharmacological strategies to reduce anxiety in children have also been described, but they all require patient cooperation. The purpose of the study was to evaluate the ability to complete diagnosis using temporary spica cast immobilization (TSCI) in children less than 3 years old undergoing MRI procedures for lower limb disorders. MATERIALS AND METHODS: A retrospective review identified 14 children under 3 years old that had required an MRI for a lower limb disorder, using TSCI. The MRI procedure was performed for evaluation of hip dysplasia, bone infections, limping, evaluation of soft tissue tumor and femoral head osteonecrosis. A spica cast was fitted by the pediatric orthopedic team. The MRI procedure was subsequently performed. RESULTS: Diagnosis was achieved in all cases. The radiologist identified movement artifacts (14 %) that did not impair the image quality enough to prevent interpretation. CONCLUSION: TSCI is a safe, effective and costless procedure avoiding general anesthesia for young patients under 3 years old who require MRI for pelvis or lower limb disorders. LEVEL OF EVIDENCE: IV.

Minimal alveolar concentration of sevoflurane inhibiting the reflex pupillary dilatation after noxious stimulation in children and young adults.

BACKGROUND: In children, sevoflurane is the most commonly used anaesthetic. Its excellent haemodynamic tolerance gives it a wide therapeutic index. This halogenated agent can abolish movement [minimal alveolar concentration (MAC)] or haemodynamic responses (MACBAR) to noxious stimulus in children as in adults. Reflex pupillary dilatation (RPD) has been demonstrated as a very sensitive measure of noxious stimulation. In order to investigate the effect of sevoflurane on the RPD, a subcortical reflex, we determined the MAC of sevoflurane inhibiting the RPD in 50% of the subjects in response to skin incision (MACpup) in pre- and post-pubertal subjects. METHODS: We included 30 pre-pubertal children and 19 post-pubertal subjects. Patients received sevoflurane at preselected concentrations according to an 'up and down' design, and after a steady-state period, skin incision was performed. The RPD was considered as significant when the pupillary diameter increased by more than 100%. Heart rate (HR) and bispectral index (BIS) changes were analysed according to the pupillary response. RESULTS: The MACpup of sevoflurane was 4.8% (95% confidence interval, 4.6-5.1%) in pre-pubertal children vs 3.4% (3.5-3.3%) in post-pubertal subjects (P<0.001). Inhibition of RPD was always associated with lack of significant HR response. In pre-pubertal children receiving high concentrations of sevoflurane, RPD in response to noxious stimulation was frequently associated with lack of HR response and low BIS values. CONCLUSIONS: MACpup was higher than MAC and close to the MACBAR. Inhibition of RPD in pre-pubertal children required higher sevoflurane concentrations compared with post-pubertal subjects, suggesting that the relationship between the brain structure sensitivities may differ with brain maturation.

Necrotizing fasciitis and septic shock related to the uncommon gram-negative pathogen Sphingobacterium multivorum.

We report the first case of necrotizing fasciitis due to the uncommon Gram-negative pathogen Sphingobacterium multivorum in an immunocompromised patient, who presented with septic shock. This case adds necrotizing fasciitis to the spectrum of S. multivorum-related infections and highlights the emergence of Gram-negative bacteria in severe soft tissue infections.

[Pseudoxanthoma elasticum-like syndrome associated with hemoglobinopathy: a case report]. / Syndrome pseudoxanthome élastique like et drépanocytose: à propos d'un cas ?

INTRODUCTION: We report a case of hemoglobinopathy which could be associated with a pseudoxanthoma elastic-like syndrome. EXEGESIS: We report the case of a 26-year-old male patient with sickle cell anemia for which the supra-aortic-doppler ultrasonography suggested an asymptomatic left carotid artery of 70% stenosis. The magnetic resonance imaging and angiography showed a left megadolichocarotid with plicature suggestive of pseudoxanthoma elastic or a dilatation relative to a high rate of blood explaining the acceleration speed. There was a cutaneous infiltration but other vasculopathies of neither carotide, nor cerebral, nor ocular have been discovered while they were sometimes found in pseudoxanthoma elastic-like syndrome. This acquired form is different of rare hereditary disease by a later diagnosis, a clinical expression often very incomplete and a frequent association with hemoglobinopathies. CONCLUSION: This observation shows that RMA could be necessary to perform in adults, when cervical and transcranial Doppler ultrasonography is abnormal, particularly before deciding to start long term blood transfusions. The hemoglobinopathy and pseudoxanthoma elastic-like syndrome must not be ignored because the control of cardiovascular factors reduce the risks of arterial complications.

Superconductivity in doped cubic silicon.

Although the local resistivity of semiconducting silicon in its standard crystalline form can be changed by many orders of magnitude by doping with elements, superconductivity has so far never been achieved. Hybrid devices combining silicon's semiconducting properties and superconductivity have therefore remained largely underdeveloped. Here we report that superconductivity can be induced when boron is locally introduced into silicon at concentrations above its equilibrium solubility. For sufficiently high boron doping (typically 100 p.p.m.) silicon becomes metallic. We find that at a higher boron concentration of several per cent, achieved by gas immersion laser doping, silicon becomes superconducting. Electrical resistivity and magnetic susceptibility measurements show that boron-doped silicon (Si:B) made in this way is a superconductor below a transition temperature T(c) approximately 0.35 K, with a critical field of about 0.4 T. Ab initio calculations, corroborated by Raman measurements, strongly suggest that doping is substitutional. The calculated electron-phonon coupling strength is found to be consistent with a conventional phonon-mediated coupling mechanism. Our findings will facilitate the fabrication of new silicon-based superconducting nanostructures and mesoscopic devices with high-quality interfaces.

Cytolytic function and survival of natural killer cells are severely altered in myelodysplastic syndromes.

Natural Killer (NK) cells are critical in host defense against malignant transformation and are potent antileukemic cytotoxic effectors. In the present study, we investigated the peripheral NK function in patients with myelodysplastic syndromes (MDS). We demonstrated that the peripheral NK cell population was quantitatively normal in MDS patients. Furthermore, NK cells displayed an expression of the activating natural cytotoxicity receptors (NCR) NKp46 and NKp30 as well as NKG2D similar to that observed in donors, but exert a highly decreased constitutive cytolytic activity compared to resting normal NK cells. Although activation with IL-2 resulted in the upregulation of NKp46 expression by MDS-NK cells, their cytolytic function remained deeply altered as compared to activated donor NK cells. In addition, MDS NK cells did not proliferate in vitro, and displayed an increased rate of apoptosis in response to IL-2 stimulation although the spontaneous apoptosis was not significantly increased. Interestingly, a proportion of peripheral MDS-NK cells were derived from the MDS clone as the cytogenetic anomaly found in bone marrow karyotype was also detected in 20-50% of circulating NK cells. In conclusion, NK cells' cytolytic function and proliferative capacities in response to activation by cytokines are profoundly altered in MDS.

Identification of differentially expressed cDNA sequences and histological characteristics of Hevea brasiliensis calli in relation to their embryogenic and regenerative capacities.

Different friable Hevea callus lines from the same genotype can display different embryogenic and regenerative potentials. These lines can not be distinguished on the basis of macroscopic criteria. A histological and molecular study was undertaken to characterize the differences existing between five callus lines with different potentials. The genes differentially expressed during induction were analyzed using the differential display (DD-RT) technique. Twenty-eight cDNAs were found to be differentially expressed during induction in the embryogenic regenerating line (ER). Embryogenic nodules were formed earlier in the ER lines than in the embryogenic non-regenerating lines and were completely absent in the non-embryogenic line. Of these 28 cDNAs, five could be used to distinguish between calli prior to induction, thereby enabling an early diagnosis of friable Hevea callus embryogenic potential.

Role of splenectomy in the treatment of myelodysplastic syndromes with peripheral thrombocytopenia: a report on six cases.

Thrombocytopenia is generally of central origin in MDS, but can be due to peripheral platelet destruction in some cases. We studied platelet lifespan in 61 MDS cases with platelets < 70,000/mm3 and marrow blasts < 10%. Nine of them (15%) had a major platelet lifespan reduction (< 3.5 days), and were considered for splenectomy. Three of them were not splenectomized due to rapid death, patient refusal and older age plus liver predominance of platelet sequestration, respectively. The remaining six patients (two females and four males, median age 50 years, range 32 to 65) were splenectomized 3 to 21 months after diagnosis. Before splenectomy, five of them had RA and one had CMML. Platelets counts ranged from 5000 to 30,000/mm3 and did not durably respond to other treatments. Three of the patients has a relapse of platelet counts, concomitantly required platelet transfusion due to recurrent blending, whereas three had anemia (two required erythrocyte transfusion) and four had neutropenia. Three months after surgery, platelet counts ranged from 55,000 to 160,000/mm3 (> 100,000/mm3 in four cases), no patient required platelet or erythrocyte transfusion, but there was no effect on neutrophil counts. Three patients had a relapse of platelet counts, concomitant with progression to AML in two of them, whereas the third relapsing case achieved normal platelet counts with further danazol. One patient died with normal platelet counts 12 months after splenectomy (from sepsis, probably related to neutropenia rather than splenectomy). Two patients remained with normal platelet counts 10 and 52 months after surgery. Our findings suggest that the mechanism of thrombocytopenia should be studied more often in 'low risk' MDS (i.e. with low bone marrow blast counts) with thrombocytopenia, as about 15% of them appear to have peripheral platelet destruction. Some of those patients may benefit from splenectomy.

Gemcitabine as a single agent in the treatment of relapsed or refractory low-grade non-Hodgkin's lymphoma.

A multicentre phase II trial was conducted to evaluate the efficacy and toxicity of gemcitabine in patients with refractory or relapsed indolent non-Hodgkin's lymphoma. Thirty-six patients were enrolled onto the study, including 11 cases of mantle cell lymphoma (MCL), 10 cases of chronic lymphocytic leukaemia (CLL)/lymphocytic lymphoma, nine cases of follicular lymphoma, four cases of lymphoplasmacytic lymphoma and two cases of T-cell lymphoma. Gemcitabine 1 g/m(2) was administered as a 30-min infusion on d 1, 8 and 15 of a 28-d schedule, up to a maximum of six cycles. Complete responses were observed in two patients with MCL, and partial responses were observed in seven patients, including three patients with CLL/lymphocytic lymphoma, two patients with T-cell lymphoma, one patient with MCL and one patient with follicular lymphoma. Minor responses were observed in three patients, including two patients with MCL and one patient with CLL. The median duration of response was 150 d and the overall progression-free survival was 342 d. Haematological toxicity was observed as grade 3-4 leucopenia in 12 patients (33%) and grade 3-4 thrombocytopenia in 18 patients (50%). Severe non-haematological toxicity included one case of fatal veno-occlusive disease, one case of thrombotic microangiopathy leading to terminal renal failure, one case of capillary leak syndrome, one case of myocardial infarction and drug-induced fever in two patients. These data suggest that gemcitabine displays activity in patients with MCL and CLL/lymphocytic lymphoma. Haematological toxicity was frequent in these heavily treated patients. Severe non-haematological toxicity was significant and should be taken into account in the design of future trials.