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Resume Objectifs Decrire les arthrites microcristallines (AM) dues aux depots synoviaux et/ou intra-articulaires de cristaux : de pyrophosphate de calcium dihydrate (PPCD) (chondrocalcinose), d’urate de sodium (goutte) ou d’hydroxyapatite survenant sur protheses articulaire. Methodes Il s’agit d’une etude retrospective de 7 observations d’AM sur prothese articulaire observees entre 1993 et 2013 dans un centre medicochirurgical specialise dans la prise en charge des infections osteoarticulaires. Resultats Ces arthrites concernent 3 hommes et 4 femmes âges de 67 a 79 ans. La crise d’AM est survenue au genou dans 6 cas (prothese totale dans 5 cas et prothese unicompartimentale dans 1 cas) ; sur une prothese totale de hanche (PTH) dans un cas. Le delai de survenue par rapport a l’arthroplastie est variable, de 7 jours a 9 ans. Le debut est toujours brutal caracterise par une douleur et une impotence fonctionnelle totale associees a de signes inflammatoires locaux. Une fievre a ete observee chez un patient. Un syndrome inflammatoire biologique a ete observe dans 6 cas. La ponction articulaire a revele une hemarthrose (3 cas) ; une arthrite inflammatoire avec polynucleose comprise entre 20 000 et 79 000 polynucleaires/mm3 (6 cas). La culture du liquide articulaire est sterile dans 6 cas. Des cristaux de PPCD sont retrouves dans 5 cas associes chez une malade a des cristaux d’hydroxyapatite reveles par la coloration au rouge d’alizarine en microscopie electronique, des cristaux d’urate de sodium dans un cas. Dans un cas une infection a Campylobacter fetus etait associee a la presence de cristaux de PPCD. La colchicine ou un anti-inflammatoire non steroidien a permis une amelioration rapide des symptomes et du syndrome inflammatoire 5 fois. Une hemarthrose sur PTH a eu une ponction evacuatrice. Une infiltration de corticoide (Hexacetonide de triamcinolone) dans 1 cas a permis une amelioration des symptomes et du syndrome inflammatoire biologique. La patiente presentant l’infection sur prothese a C. fetus a ete traitee par antibiotherapie, excision de l’abces et synovectomie. Conclusion La survenue d’une AM est possible meme apres arthroplastie car il persiste un residu synovial ou il va se constituer une neo-synoviale periprothetique. Les AM sont le temoin d’une maladie metabolique qui persiste et qui peut se reactiver en postoperatoire. Les cristaux sont rarement systematiquement recherches dans un contexte d’arthrite sterile sur prothese et sont difficiles a identifier sur hemarthrose. La frequence de cette affection est peut-etre sous-estimee. Bien que rare, le diagnostic d’AM doit systematiquement etre evoque devant une arthrite « pseudo-septique » sur prothese afin d’eviter une antibiotherapie prolongee et parfois un geste chirurgical inutiles. Le traitement est le plus souvent simple.

Background Variable prophylaxis regimens have been adapted to guard against cytomegalovirus (CMV) after renal transplantation. High-dose valganciclovir (VGCV) is the gold standard, but it is of very high cost. Herein, we compared another low-cost regimen [low-dose valacyclovir (VCV)] with low-dose VGCV to assess the efficacy and safety of VCV. Patients and methods This is a single-center randomized controlled trial that was held in Urology and Nephrology Center, Mansoura University, Egypt. The patients were divided into two groups according to CMV prophylaxis regimen used. Group I included 40 kidney transplant recipients who received low-dose VCV (2 g b.i.d.), and group II included 40 kidney transplant recipients who received low-dose VGCV (450 q.d.). Results Our patients’ age ranged from 18 to 58 years, and the majority were males. The median years of transplantation were 1.9 years. Efficacy of both regimens was similar. Interruption of VCV was more frequent, with significant difference, and it was associated with increased incidence of CMV infection but without any statistical significance. The cost of low-dose VGCV was very high in comparison with low-dose VCV. Conclusion Low-dose VCV showed the same efficacy and safety of low-dose VGCV as CMV prophylaxis protocol after kidney transplantation.

New direct-acting antiviral drugs have become the corner-stone treatment for HCV infection: they show promising results with accepted side-effects and low dropout rates. One of the available regimens is paritaprevir/ombitasvir/ritonavir (PTV/OMV/RTV). Our aim was to study the efficacy and safety of this drug regimen among HCV-positive hemodialysis patients. This prospective single-center study was performed in the Urology and Nephrology Center, Mansoura University, Egypt. Ninety-six maintenance hemodialysis patients were screened for HCV antibodies. Positive results were found in 46 patients (47.9%). HCV PCR was assessed in all HCV-antibody-positive patients; positive results were found positive for 38 (82%); all patients were HCV genotype 4. Four patients were excluded due to advanced liver cirrhosis, liver malignancy, or metastatic breast cancer. Thirty-four patients were prescribed PTV/OMV/RTV for 3 months to treat HCV. Mean age was 43.2 ± 11.9 years. Most patients were male (67.6%). There was a rapid response to treatment: HCV PCR became negative by 4 weeks after starting treatment. By 12 and 24 weeks post-DAA therapy, there was a sustained viral response (SVR 12, SVR 24) in 100% of patients with improved liver-enzyme levels. The PTV/OMV/RTV regimen was safe and effectively treated Egyptian HCV-positive genotype-4 hemodialysis patients.

Direct antivirals showed dramatic response in hepatitis C virus (HCV) eradication, but their effect on extrahepatic manifestations is still unclear. A 49-year-old woman was referred to us suffering from lower limb edema and frothy urine. Renal biopsy was done and she was diagnosed with HCV-related membranoproliferative glomerulonephritis with cryoglobulinemia. Treatment with interferon plus ribavirin, steroid, and cyclophosphamide was tried but failed. After introduction of a sofosbuvir-based regimen to the treatment, sustained virologic response was achieved and nephrotic syndrome remission was induced successfully. We could conclude that HCV-related membranoproliferative glomerulonephritis with cryoglobulinemia could be treated successfully with immunosuppressive drugs plus sofosbuvir and dacalatasvir.

Background Low back pain (LBP) is strongly associated with Modic changes. The hypothesis of local infectious origin was raised, especially with Proprionibacterium acnes (PA).The possibility of contamination with saprophyte germs coming from the skin during surgery by posterior approach or by epidural infiltration preceding the surgery was also discussed, but not proved. Objectives The main objective of this study was to evaluate the prevalence of slow growing bacterias (SGB) in the intervertebral disc (IVD) obtained during a lumbar spine surgery by anterior approach in Modic 1 and 2 changes. A secondary objective was to compare the prevalence of SGB in IVD in lumbar spine surgery obtained by anterior approach to that obtained by posterior approach in herniated disc. Methods 45 patients with chronic LBP or sciatica were included in the study, representing 48 IVD. When patients underwent lumbar spine surgery by an anterior approach, 2 samples of the disc were collected for bacteriological analysis: one sample from the anterior part of the disc distant from epidural space and one sample from the posterior part of the disc. 77 discs samples were obtained, 32 discs samples in Modic 1 or 2 changes by anterior approach, 26 discs samples in no Modic IVD by anterior approach, 19 disc samples obtained by posterior approach. The method to collect disc material was strictly aseptic. Samples were analysed by conventional microbial cultures with specialised enrichmen, molecular detection by universal rRNA gene PCR plus sequencing assay. Additionally, all clinical specimens were specifically tested for PA detection using a highly sensitive specific PCR Results Regarding bacterial cultures, 12 out 77 disc samples were positive (16%), including 10 (13%) for PA. The PA specific PCR was positive for one (1%) specimen obtained by posterior approach. The 16s RNA detection was positive for 6 specimen (8%), including one for PA (1%).Modic 1–2: Cultures were positive in 5 cases (16%) with 3 for PA (10%). No specific PA PCR was positive. Only one sample was positive for PA in both culture and 16s PCR. Comparison between anterior and posterior approach: Among the PA positive cultures, 5 were identified from anterior specimens (8.62%) and 5 from posterior specimens (26.32%). Regarding PA cultures,the posterior fragments were more frequently positive than the anterior fragments (p=0.046). The number of epidural infiltrations of the lumbar spine does not seem to influence the bacterial contamination prevalence p=0.746. The time between the epidural infiltration of the lumbar spine and the surgery does not seem to influence the bacterial contamination prevalence (more or less 6 month) p=0.23. Conclusions SGB has been identified in culture in 16% of the samples obtained in Modic 1 and 2 changes. The prevalence of PA in culture was significantly higher in samples of IVD collected by a posterior approach compared to anterior approach in spine surgery suggesting a contamination. The results of the specific PCR PAs with a single weakly positive sample reinforce the hypothesis of contamination. Disclosure of Interest None declared

Can decisions be made solely by chance? Can variability be intrinsic to the decision-maker or is it inherited from environmental conditions? To investigate these questions, we designed a deterministic setting in which mice are rewarded for non-repetitive choice sequences, and modeled the experiment using reinforcement learning. We found that mice progressively increased their choice variability. Although an optimal strategy based on sequences learning was theoretically possible and would be more rewarding, animals used a pseudo-random selection which ensures high success rate. This was not the case if the animal is exposed to a uniform probabilistic reward delivery. We also show that mice were blind to changes in the temporal structure of reward delivery once they learned to choose at random. Overall, our results demonstrate that a decision-making process can self-generate variability and randomness, even when the rules governing reward delivery are neither stochastic nor volatile.

Considering the performance decay of the chromatography resins in the downstream purification of biopharmaceutical manufacturing, the maintenance decisions should be made at appropriate times to achieve a good performance of the whole manufacturing process. In this paper, on the basis of the literature work on production planning, a mixed integer linear programming optimization model is developed to address the production and maintenance planning of biopharmaceutical manufacturing under performance decay, in which the total operating profit is maximized. The batch production profiles are tracked by binary variables introduced in the proposed model. The proposed model is then applied to two literature-based illustrative examples. Two scenarios are investigated and compared with the optimal solutions. A discussion about the effects of the maintenance duration and cost and the resin’s lifetime is also presented.

Resume La nevralgie d’Arnold (NA) est une cephalee paroxystique unilaterale d’origine cervicale secondaire a une irritation ou une compression du grand nerf occipital (GNO) posterieur et/ou du petit nerf occipital. Le diagnostic est evoque devant une symptomatologie clinique unilaterale occipito parietale et une imagerie concordante. Un test anesthesique positif confirme le diagnostic. Les causes en sont multiples. Le diagnostic ne doit etre retenu qu’apres avoir elimine les autres causes de cephalees, et notamment les autres causes de cephalees d’origine cervicale. La NA representerait 8,7 % des nevralgies d’origine cervicale, essentiellement le GNO dans 90 % des cas. La prise en charge therapeutique est parfois difficile d’autant qu’il existe peu de preuves scientifiques de l’efficacite des therapeutiques proposees. Le rhumatologue peut etre amene a intervenir dans la prise en charge de la NA notamment en realisant des infiltrations locales.

The B-Lynch brace suture technique is a life-saving procedure. It is a simple and safe alternative to hysterectomy. Thus, it preserves fertility with less surgical morbidity. In this case series, we evaluated the use of a novel modification of the B-Lynch brace suture to minimise its potential reported complications. Five women with intractable primary atonic postpartum haemorrhage were reported. They were initially managed with bilateral uterine artery ligation. The procedure was resorted to women who did not respond to ligation. The procedure is efficient. Women were followed up for up to 24 months to report any complications.

In this contribution, we report full details of the ethylene, 1,3-butadiene, and propylene homopolymerization processes mediated by alkylated bis(trimethyl)silylamide lanthanide-grafted complexes using a density functional theory (DFT) study of the initiation and first propagation steps. These systems allows us (i) to examine the role of the grafting mode on the kinetics and thermodynamics of the three processes considered, (ii) to confirm the catalytic behavior of these grafted complexes in ethylene polymerization, (iii) to rationalize the experimental preference for 1,4-cis polymerization of 1,3-butadiene, and (iv) to provide unprecedented information on the catalytic activity of the lanthanide-grafted complex as a propylene hompolymerization catalyst.

Cesarean section for obstructed labor remains a difficult procedure that may be associated with serious fetal and maternal injuries. In this case series, we evaluated the use of abdominal disimpaction with lower segment support as a novel technique to minimize morbidities. Eight patients who underwent cesarean section for obstructed labor were recruited. Impacted fetal head was delivered using this technique and uterine extensions, bladder injury, vaginal injury, and intraoperative bleeding were reported. Maternal and neonatal outcomes were observed postoperatively. No major morbidities were reported. Accordingly, we consider this technique as a promising step to minimize complications during cesarean section for obstructed labor.

Progressive multifocal leukoencephalopathy (PML) is a subacute central nervous system infection due to reactivation of the JC virus. Most reported cases occurred in HIV-infected patients (80% of cases), patients with lymphoid malignancies (13%) and transplant recipients taking immunosuppressants (5%). Less often, PML has been described in patients with chronic inflammatory joint diseases associated with autoimmune disorders (lupus, rheumatoid arthritis [RA] and vasculitis) (2%). Magnetic resonance imaging of the brain shows suggestive changes and confirmation of the diagnosis is obtained by performing PCR tests to identify the JC virus in the cerebrospinal fluid or, when necessary, a brain biopsy. No treatments have been proven effective. Most patients experience progressive disease that is fatal within a few months or induces incapacitating neurological impairments. The risk of PML is 0.4/100,000 in patients with RA. In the few case-reports of PML in RA patients, the treatments used included methotrexate (five cases) combined with a biological agent such as infliximab (one case), rituximab (four cases), or leflunomide (two cases including one with concomitant rituximab). PML is an extremely rare but devastating complication. Rituximab therapy is associated with an increased prevalence of PML in RA patients (4/100,000), who should be informed of this risk. In patients with lupus, the risk of PML is higher than in RA (4/100,000) and 40% of cases of PML occur during low-dose glucocorticoid therapy without immunosuppressive therapy.

Placenta accreta/percreta is a serious cause of intractable post-partum haemorrhage during caesarean section and acommon cause of peripartum hysterectomy. In this case series, we evaluated the use of multiple 8 sutures as a novelprocedure to preserve the uterus in these cases. Seven women with placenta accreta/percreta were initially managed withbilateral uterine artery ligation. The procedure was resorted to in cases that did not respond to ligation (five women).Women were followed up for up to 24 months to report complications.Key words: multiple 8 suture, placenta accreta, post-partum haemorrhage, transverse lower uterine segment suture.

Resume La leucoencephalite multifocale progressive (LEMP) est une infection subaigue du systeme nerveux central due a la reactivation du virus JC. Elle a ete principalement decrite chez les patients infectes par le VIH (80 % des cas), au cours des maladies hematologiques lymphoides malignes (13 %), chez les transplantes sous traitement immunosuppresseur (5 %) mais egalement dans les rhumatismes inflammatoires chroniques a composante auto-immune (lupus, polyarthrite rhumatoide [PR], vascularite) (2 %). Le diagnostic repose sur l’aspect IRM evocateur et la mise en evidence du virus JC par PCR dans le LCR ou a la biopsie cerebrale qui est parfois necessaire. En l’absence de traitement reconnu, l’evolution se fait dans la majorite des cas vers l’aggravation et est le plus souvent fatale en quelques mois ou s’accompagne dans les meilleurs cas de sequelles neurologiques invalidantes. Le risque de developper une LEMP est de 0,4/100 000 dans la PR. Quelques cas rapportes au cours de la PR ont detaille les traitements utilises : methotrexate (cinq cas), associes a une biotherapie comme l’infliximab (un cas), le rituximab (quatre cas) et, le leflunomide (deux cas) dont un cas en association au rituximab. La survenue de cette complication tres grave est tres rare. En cas de traitement par rituximab, la prevalence est augmentee (4/100 000) dans la PR ce qui necessite d’en informer le patient. Au cours du lupus, le risque de LEMP est plus eleve (4/100 000) qu’au cours de la PR et peut survenir dans 40 % des cas en l’absence de traitement immunosuppresseur sous une corticotherapie a faible dose.

INTRODUCTION: The purpose of this in vitro study was to evaluate the sealing ability of the readymade temporary filling and hand mixed materials by assessing coronal microleakage. MATERIALS & METHODS: Standardized access cavities were prepared in 80 intact human permanent premolar teeth. They were divided randomly into four experimental groups (n=20). The teeth were restored using one of the temporary materials including Cavisol, Litrak, Zinc phosphate cement, Zinconol (IRM). Thermocycling was applied on the specimens. Methylene blue dye was applied and penetration was evaluated under stereomicroscope. Grading of the microleakage pattern was from 1 to 3, with 3 providing the best seal. Results were analyzed using one-way ANOVA test (P < 0.05). RESULTS: Microleakage of Cavisol and Litrak samples achieved grade 3; whereas zinc phosphate cement and Zinconol samples absorbed the dye into the bulk of the materials. Cavisol was found to exhibit the best seal amongst the four tested materials followed by Litrak, zinc phosphate cement, and Zinconol. There was a statistically significant difference in the microleakage scores obtained between the materials (P < 0.01). CONCLUSION: Among the four materials tested, readymade temporary filling provided the best sealing ability over hand-mixed. This study emphasizes the importance of correct placement and sufficient thickness of temporary filling materials in endodontic access cavities to ensure a tight seal.

Background As 70–90% of patients with carcinomas of the head of the pancreas and ampullary region have jaundice at presentation and going to have gastric outlet obstruction, palliation that ensures biliary and gastric drainage represents a large proportion of the hepatobiliary surgeon’s workload. As barely 20% of patients with pancreatic cancer are suitable for curative resection, good palliative therapy is extremely important. Aim of the work To compare the effectiveness of palliation between patients with advanced head of pancreas cancer who underwent surgical bypass and those who underwent dual stenting and morbidity and mortality rates of both procedures. Patients and methods This prospective study was conducted between April 2015 and April 2017. Only 38 patients were eligible for this study. Follow-up was at 1, 3, and 6 months after each procedure. Evaluation of patients regarding efficacy and feasibility, morbidity, mortality, hospital stay, ICU admission, readmission rate, and survival was done. Results We identified 38 patients, of whom 19 underwent endoscopic stenting and 19 underwent a surgical bypass either by choledechojejunostomy or cholecystojejunostomy-en-Y with gastrojejunostomy. There were no significant differences in complications or mortality rates; however, all results were in favor of dual stenting, owing to short procedure time, hospital stay, ICU admission, and survival rates being better than surgical bypass, although without significance. Conclusion Dual stenting was found to be more feasible and efficient in palliation of advanced head of pancreas cancer with short procedure time and short hospital stay and less morbidity and mortality and ICU admission with higher cost in comparison with surgical bypass. Surgical bypass is mandatory in patient with gastric outlet obstruction or failed Endoscopic Retrograde Cholangiopancreatography (ERCP) trial due to huge mass obstructing the duodenum.

Applying DFT methods, the reductive elimination reaction of bis(pyridyl) rare-earth metal cation [Ln( η 2 -C,N-pyridyl) 2 (THF) 3 ] + (Ln = Y, La) was studied. The effect of both electron-donating and electron-withdrawing substituents in the para -position of the pyridine ring was considered. An alternative mechanism for the C–C coupling reaction between pyridine derivatives (pyridine, DMAP and 4-trifluoromethyl-pyridine) and [LnMe 2 (THF) 5 ] + (Ln = Y or La) is suggested. The reaction involves a single electron reductive C–C coupling to form of Ln(II) complexes with a bipyridine radical anion.

Selective C-H bond activation of pyridines by organometallic complexes is a reaction of synthetic importance for the synthesis of functionalized pyridines. By reacting the dicationic methyl complex of yttrium [YMe(thf)6][BPh4]2 with substituted pyridines, both selectivity and kinetics have been studied. Electron donating properties of para-substituents of pyridines increase the rates of reaction. Hammett linear free energy relationship was found with ρ = –2.72. DFT calculations confirmed the two-step reaction consisting of ligand substitution followed by σ-bond metathesis. DFT calculations furthermore revealed for the C-H bond activation step an unusual transition state structure with a nearly linear methyl carbon-hydrogen-ortho-carbon arrangement.

A predictive reactivity of Cp 2 An(IV)Me 2 (with An = uranium [U], neptunium [Np] and plutonium [Pu]) with pyridine N-oxide has been studied at the theoretical level. The predictive reaction, which consists in the formation of a formaldehyde complex, begins after the initial formation of a cyclometalated complex produced by a C-H activation of the pyridine N-oxide. A difference of reactivity between U/Pu and Np has been observed and has been attributed to the presence of a more covalent bond between Np and the carbene group in the transition state of formation of a transient carbene intermediate.

The reactions between [1,2,4-(Me3C)3C5H2]2CeH, referred to as Cp′2CeH, and CH3X, where X is Cl, Br, I, OMe, and NMe2, are described. The reactions fall into three distinct classes. Class a, where X = Cl, Br, and I, rapidly form Cp′2CeX and CH4 without formation of identifiable intermediates in the 1H NMR spectra. Class b, where X = OMe, proceeds rapidly to Cp′2Ce(η2-CH2OMe) and H2 and then to Cp′2CeOMe and CH4. The methoxymethyl derivative is sufficiently stable to be isolated and characterized, and it is rapidly converted to Cp′2CeOMe in the presence of BPh3. Class c, where X = NMe2, does not result in formation of Cp′2CeNMe2, but deuterium labeling experiments show that H for D exchange occurs in NMe3. Density functional calculations DFT(B3PW91) on the reaction of (C5H5)2CeH, referred to as Cp2CeH, and CH3X show that the barrier for α-CH activation, resulting in formation of Cp2Ce(η2-CH2X), proceeds with a relatively low activation barrier (ΔG⧧), but the subsequent ejection of CH2 and trapping by H2 has...

The reaction of various actinide and transition metal bisalkyl complexes with pyridine N-oxide has been investigated at the DFT level for M = Zr, Th, and U. Rather than the expected oxygen transfer...

Joint Bone Spine - In Press.Proof corrected by the author Available online since mercredi 14 octobre 2015

The heterobimetallic complexes [{UO2Ln-(py)2(L)}2], combining a singly reduced uranyl cation and a rare-earth trication in a binucleating polypyrrole Schiff-base macrocycle (Pacman) and bridged through a uranyl oxo-group, have been prepared for Ln = Sc, Y, Ce, Sm, Eu, Gd, Dy, Er, Yb, and Lu. These compounds are formed by the single-electron reduction of the Pacman uranyl complex [UO2(py)(H2L)] by the rare-earth complexes LnIII(A)3 (A = N(SiMe3)2, OC6H3But2-2,6) via homolysis of a Ln-A bond. The complexes are dimeric through mutual uranyl exo-oxo coordination but can be cleaved to form the trimetallic, monouranyl "ate" complexes [(py)3LiOUO(μ-X)Ln(py)(L)] by the addition of lithium halides. X-ray crystallographic structural characterization of many examples reveals very similar features for monomeric and dimeric series, the dimers containing an asymmetric U2O2 diamond core with shorter uranyl U=O distances than in the monomeric complexes. The synthesis by LnIII-A homolysis allows [5f1-4fn]2 and Li[5f1-4fn] complexes with oxo-bridged metal cations to be made for all possible 4fn configurations. Variable-temperature SQUID magnetometry and IR, NIR, and EPR spectroscopies on the complexes are utilized to provide a basis for the better understanding of the electronic structure of f-block complexes and their f-electron exchange interactions. Furthermore, the structures, calculated by restricted-core or all-electron methods, are compared along with the proposed mechanism of formation of the complexes. A strong antiferromagnetic coupling between the metal centers, mediated by the oxo groups, exists in the UVSmIII monomer, whereas the dimeric UVDyIII complex was found to show magnetic bistability at 3 K, a property required for the development of single-molecule magnets.

Introduction Twin pregnancy with complete hydatidiform mole represents a very rare obstetric problem. Management of such cases is always problematic because the possibility of fetal survival should always be weighed against the risk of complications of molar pregnancy. Case presentation A 34-year-old Caucasian woman presented to our center with mild vaginal bleeding. Our patient was 16 weeks pregnant after a seven-year period of primary infertility. She became pregnant following a non-prescribed regimen of clomiphene citrate extending from the second day to the 13th day of her last cycle. A transabdominal ultrasound examination revealed a twin pregnancy with complete hydatidiform mole and a coexisting fetus. Serum β human chorionic gonadotropin was falsely low as identified by serial dilution of the sample (the 'hook effect'). Our patient refused termination of pregnancy and she was hospitalized for strict observation and follow-up. Unfortunately, she developed an attack of severe vaginal bleeding and a hysterotomy was performed. The fetus died shortly after birth. Conclusions Twin pregnancy with complete hydatidiform mole represents a matter of controversy. We suggest that conservation should always be considered whenever tertiary care services and strict observation are available.

AIM To assess the effectiveness and safety of pre-resection endoscopic third ventriculostomy (ETV) in permanently relieving hydrocephalus in children with posterior fossa tumors. MATERIAL AND METHODS 17 pediatric patients with posterior fossa tumors and associated triventricular obstructive hydrocephalus underwent ETV before definitive tumor resection, and ETV was repeated after tumor resection if hydrocephalus with increased intracranial pressure persisted or recurred. The medical records, operative notes and imaging studies were retrospectively reviewed. RESULTS 18 ETV procedures were performed in 17 patients, consisting of 11 males and 6 females, age range (1.5 to 13 years; mean 6±3.86). Follow-up periods ranged from 6 to 23 months (mean follow-up 13.9±5.4 months). ETV was successful in relieving hydrocephalus during the follow-up period in 15 out of 17 patients (88.2%). Prior to surgical excision of the posterior fossa tumors, no failures of ETV were detected and all of the 17 patients showed marked clinical improvement and radiological disappearance of signs of active hydrocephalus. CONCLUSION Preoperative ETV is a highly effective long-term CSF diversion procedure for treatment of hydrocephalus associated with posterior fossa tumors in children. In experienced hands, ETV has a very low complication rate.

International audience; The oxo groups in the uranyl ion [UO$_2$]$^{2+}$ , one of many oxo cations formed by metals from across the periodic table—are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a ‘Pacman’ environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C–H bond activation reactions are occurring.

International audience; The addition of diethylether to [1,2,4(Me3C)3C5H2]2CeH, abbreviated Cp′2CeH, gives Cp′2CeOEt and ethane. Similarly, di-n-propyl- or di-n-butylether gives Cp′2Ce(O-n-Pr) and propane or Cp′2Ce(O-n-Bu) and butane, respectively. Using Cp′2CeD, the propane and butane contain deuterium predominantly in their methyl groups. Mechanisms, formulated on the basis of DFT computational studies, show that the reactions begin by an α- or β-CH activation with comparable activation barriers, but only the β-CH activation intermediate evolves into the alkoxide product and an olefin. The olefin then inserts into the Ce–H bond forming the alkyl derivative, Cp′2CeR, which eliminates alkane. The α-CH activation intermediate is in equilibrium with the starting reagents, Cp′2CeH and the ether, which accounts for the deuterium label in the methyl groups of the alkane. The one-step σ-bond metathesis mechanism has a much higher activation barrier than either of the two-step mechanisms.

The ortho C-H bond activation of several pyridine and pyridine N-oxide derivatives mediated by Cp(2)An(IV)(CH(3))(2) and Cp(2)An(III)(CH(3)) (Cp = C(5)H(5) and An = U, Np, Pu) have been investigated at the DFT level. For uranium(IV) complex, an excellent agreement with experimental observations is found, and particularly in the case of 2-picoline where only ortho sp(2) C-H activation is observed without any sp(3) C-H activation. These differences of reactivity can be explained by the charges distribution at the metathesis transition state level. A predictive study of the reactivity of neptunium and plutonium complexes with pyridine and pyridine N-oxide is reported. This study shows that neptunium and plutonium have almost the same reactivity. The C-H activation mediated by actinide (III) complexes have found to be more kinetically and thermodynamically favorable than for actinide (IV) complexes. The influence of 5f electrons on organoactinide reactivity is found to be small by comparing implicit and explicit treatment of 5f electrons.

A theoretical investigation of the reductive oxo-group silylation reaction of the uranyl dication held in a Pacman macrocylic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single oxo group identified as a key component in promoting the reaction between the Si X and uranium-oxo bonds. This reductive silylation reaction is also proposed to occur in an aqueous environment but was found not to operate on bare ions; in this latter case, substitution of a ligand in the equatorial plane was the most likely reaction. These results demonstrate the importance of the presence but not the identity of the equatorial ligands upon the silylation of the uranyl U-O bond.

Schistosoma mansoni infestation may induce liver fibrosis and portal hypertension, with possible elevation of liver enzymes.The aim of this study was to evaluate the serum gammaglutamyl transpeptidase (GGT) activity in a group of non-alcoholic and non-obese patients with hepatointestinal schistosomiasis.Medical records of 174 patients diagnosed to have hepatointestinal schistosomiasis on the basis of clinical and laboratory data were reviewed. Body mass index (BMI) was calculated for all patients. Direct stool smear and formol-ether concentration (FEC) methods and hematological and biochemical blood tests were performed. Other studies including abdominal ultrasonography, upper and lower gastrointestinal endoscopy was also performed when feasible. All (174) patients were adults with male to female ratio of 3.8:1. BMI was similar in both groups. Patients were divided into two groups: group 1 (57) with elevated GGT and group 2 (117) patients with normal GGT. Both groups had positive indirect hemagglutination test (IHA) for schistosomiasis. Other causes of liver disease were excluded.Group 1 had significant elevation of alanine aminotransferase (ALT), alkaline phosphatase (ALP) and reduction in platelets (p0.001), low albumin and high globulin levels (p0.01) compared to group 2. Abnormal ultrasonographic findings were more frequently encountered in group 1 (p0.001).The above data indicated that GGT elevation was most likely secondary to hepatobiliary involvement by Schistosoma mansoni and may indicate chronicity. Therefore schistosomiasis has to be considered in our community whenever GGT is elevated in non-alcoholic population.

Bridges are critical to the transportation system especially at the time of crises. They are essential for rescue missions, evacuations, and rapid distribution of aid and medical supplies. Bridges are highly visible and accessible structures which make them valued potential targets for terrorist attacks as their destruction could have significant impact on the nation. An efficient security system can minimize the potential of terrorism, yet it will not completely eliminate the threat. Consequently, critical bridges should be protected and designed to mitigate probable blast hazards. The primary objective of this investigation is to analyze the effect of blast loads on critical bridge components and bridge global response, and propose protection measures for mitigating blast hazards. This investigation presents an overview of the characteristics of blast loads, pressure distributions, wave propagation and reflection, energy dissipation, and the factors affecting the behavior of structural elements subjected to blast loading. To simplify the analysis of structural elements subjected to blast loads, blast load response spectra were developed. These spectra are used to transform the dynamic blast loads into equivalent static loads. Blast response spectra can be used to analyze and design individual structural components subjected to blast loads, estimate the required ductility, and estimate the minimum standoff distance for the probable blast hazards.The global behavior of a typical highway bridge was evaluated using computer simulation. The bridge model was subjected to various blast scenarios applied above or below the bridge deck. The results from these computer simulations were used to identify the vulnerable components in the bridge during a blast hazard as well as estimating the magnitudes and locations of maximum shear forces and bending moments. The results from the computer simulations were compared to those from the response spectral analysis. Thus, protection measures were proposed and evaluated. Protection measures include preventive measures such as standoff distance and added security. They also include improved redundancy through utilizing multiple column bents with double and triple edge columns, using highly ductile materials, longer seat widths, doubly reinforced decks, hold-down devices, and the use of cable auxiliary systems.

Synthesis, structure, and reactivity of two families of rare-earth metal complexes containing discrete methyl cations [LnMe(2-x)(thf)n]((1+x)+) (x = 0, 1; thf = tetrahydrofuran) have been studied. As a synthetic equivalent for the elusive trimethyl complex [LnMe3], lithium methylates of the approximate composition [Li3LnMe6(thf)n] were prepared by treating rare-earth metal trichlorides [LnCl3(thf)n] with 6 equiv of methyllithium in diethyl ether. Heteronuclear complexes of the formula [Li3Ln2Me9L(n)] (Ln = Sc, Y, Tb; L = Et2O, thf) were isolated by crystallization from diethyl ether. Single crystal X-ray diffraction studies revealed a heterometallic aggregate of composition [Li3Ln2Me9(thf)n(Et2O)m] with a [LiLn2Me9](2-) core (Ln = Sc, Y, Tb). When tris(tetramethylaluminate) [Ln(AlMe4)3] (Ln = Y, Lu) was reacted with less than 1 equiv of [NR3H][BPh4], the dimethyl cations [LnMe2(thf)n][BPh4] were obtained. The coordination number as well as cis/trans isomer preference was studied by crystallographic and computational methods. Dicationic methyl complexes of the rare-earth metals of the formula [LnMe(thf)n][BAr4]2 (Ln = Sc, Y, La-Nd, Sm, Gd-Lu; Ar = Ph, C6H4F-4) were synthesized, by protonolysis of either the ate complex [Li3LnMe6(thf)n] (Ln = Sc, Y, Gd-Lu) or the tris(tetramethylaluminate) [Ln(AlMe4)3] (Ln = La-Nd, Sm, Dy, Gd) with ammonium borates [NR3H][BAr4] in thf. The number of coordinated thf ligands varied from n = 5 (Ln = Sc, Tm) to n = 6 (Ln = La, Y, Sm, Dy, Ho). The configuration of representative examples was determined by X-ray diffraction studies and confirmed by density-functional theory calculations. The highly polarized bonding between the methyl group and the rare-earth metal center results in the reactivity pattern dominated by the carbanionic character and the pronounced Lewis acidity: The dicationic methyl complex [YMe(thf)6](2+) inserted benzophenone as an electrophile to give the alkoxy complex [Y(OCMePh2)(thf)5](2+). Nucleophilic addition of the soft anion X(-) (X(-) = I(-), BH4(-)) led to the monocationic methyl complexes [YMe(X)(thf)5](+).