Management of chylous ascites following laparoscopic presacral neurectomy

Chylous ascites is an extremely rare complication of laparoscopic presacral neurectomy (LPSN), and treatment is still controversial. Four patients undergoing LPSN for dysmenorrhoea or chronic pelvic pain were complicated with chylous ascites. Two were successfully treated with bipolar cauterization and one, after the failure of initial treatment by bipolar cauterization, was then effectively managed by compression with Gelform and closure of the peritoneum of the presacral area by suture through laparoscopy. The fourth patient had persistent chyle leakage from the drainage tube after electrocauterization and was finally cured by conservative management including removal of the drainage tube and a low-fat diet for 3 weeks. Chylous ascites has not been reported in laparoscopic presacral neurectomy. Management that is quick, effective and subjects the patients to the least amount of suffering is still unresolved. Repeated laparoscopy can be considered to identify the possibility of injury to lymphatic vessels, to relieve abdominal distention due to chyle accumulation, and to apply electrocauterization or compression with Gelform and closure of the peritoneum. Conservative treatment with a low-fat diet may need a longer time. The use of a drainage tube may provide negative pressure allowing a continuous leakage of chyle. However, more controlled study is required to identify the most proper and effective management.      

The molecular basis of beta-thalassemia in Lebanon: application to prenatal diagnosis

A study of the molecular lesions of beta-thalassemia in Lebanon revealed the presence of eight different mutations in 25 patients with Cooley's anemia. The IVS1 position 110 mutation predominated with a frequency of 62% and was almost invariably associated with Mediterranean chromosome haplotype I. Five other mutations commonly found in the Mediterranean area occurred with frequencies of 2% to 8%. In addition a G----C substitution in IVS1 position 5 (a lesion previously found in Chinese and Asian Indians) was demonstrated in a patient with Mediterranean haplotype IX. A new mutation at codon 29 was found in two other patients with haplotype II. The characterization of these beta-thalassemia mutations should allow the implementation of a prenatal diagnosis program in that country.     

CuFe2S3 as electrode material for Li-ion batteries

Electrochemical performances of the isocubanite CuFe₂S₃ tested as electrode material for Li-ion batteries have been investigated. A first discharge capacity of 860 mA h g⁻¹ shows a conversion process leading to Li₂S, copper and iron nanoparticles. Interestingly, a reversible capacity of 560 mA h g⁻¹ at 1.5 V is demonstrated with good cyclability up to 30 cycles.

Electrochemical performances of the isocubanite CuFe₂S₃ tested as electrode material for Li-ion batteries have been investigated.

Because of their low cost and high theoretical capacity, metal sulfides are considered as one potential future electrode material for Li-ion batteries (LIBs). Therefore, numerous materials containing sulfur have been studied in the last decades as cathode materials such as MnS,¹ Cu_xS,² CoS,³ NiS,⁴ and Fe_xS.⁵ Moreover, some metal sulfides have also been reported as anode materials such as SnS₂ (ref. 6) and ZnS.⁷ Their reductions happen through a conversion process at low working voltage (under 1 V vs. Li⁺/Li) leading to formation of lithium sulfide and native metal.⁸Among the conversion materials based on transition metal sulfur, copper and iron are the most cost effective, light and non-toxic elements that one can find. For these reasons, Cu_xS^2,9,10 and Fe_xS^5,11,12 have been well studied in the last few decades using either polymer or liquid electrolytes. From these studies, we know that the reduction of these transition metal sulfides forms nanoparticles of metal and lithium sulfides through a conversion process.⁸ Therefore, recent articles have been focusing on improving the electrochemical performance of metal sulfides by using hydrothermal,¹¹ sol–gel¹³ or ball-milling¹⁴ synthetic methods.Copper/iron sulfides are interesting electrode materials because of their higher electrical conductivity and electrochemical activity compared to monometal sulfides.¹⁵ In recent years, only a few studies have been reported on chalcopyrite CuFeS₂, first as a cathode in a primary battery¹⁶ then as an anode and cathode in a secondary battery.^15,17,18 Different synthetic routes from solvothermal to nanocrystal growth and different electrolytes have proven the potential of chalcopyrite as electrode material for lithium batteries.Herein, we report the electrochemical performance of the cubic cubanite, so-called isocubanite CuFe₂S₃, as the first ternary metal sulfide electrode material for lithium batteries. This Li/CuFe₂S₃ system exhibits a high reversibility (up to 560 mA h g⁻¹ at C/20/Li) and a good cyclability over 30 cycles. Ex situ X-ray diffraction (XRD)^† measurements allow a better understanding of the electrochemical mechanism.The cubanite CuFe₂S₃ phase crystallizes within an orthorhombic structure (space group: Pcmn), with a = 6.467 Å, b = 11.110 Å and c = 6.230 Å.¹⁹ When the orthorhombic CuFe₂S₃ is heated above 473 K, an irreversible structural transition occurs and CuFe₂S₃ adopts a cubic structural type (space group: F$\bar{4}$3m, a = 5.296 Å). It should be noticed that cubanite and its cubic polymorph isocubanite are usually found in their natural states intimately intergrown with other sulfides such as chalcopyrite and pyrrhotite. Synthesis of isocubanite CuFe₂S₃ has been first reported by S. Pareek et al.²⁰ In this paper, we chose a synthetic protocol recently described by Barbier et al.²¹ Following precursors: Cu (99.0%), Fe (99.5%), and S (99.5%) from Alfa Aesar, were mixed in the appropriate ratio. After sealing the cold pressed powder in a silica tube, the latter was heated at 873 K for 48 h. The room temperature powder X-ray diffraction pattern of CuFe₂S₃ (depicted in Fig. 1) shows that CuFe₂S₃ crystallizes within the cubic form. Rietveld refinements were therefore carried out using F$\bar{4}$3m space group. However, extra peaks and peak shoulders which may be attributed to the chalcopyrite phase can be observed (inset Fig. 1). Thus, from the refinements, the CuFe₂S₃ isocubanite (around 72 wt% – 63 at%) is the majority phase, while the minority one is the chalcopyrite (around 28 wt% – 37 at%). The structural refinement leads to unit cell parameters a = 5.3018(1) Å and a = 5.2927(3) Å, c = 10.4340 Å for the isocubanite and chalcopyrite phases, respectively. The aforementioned unit cell parameters are close to those reported in the literature and then confirms their good crystallinity.²² The isocubanite structure can be described as a tetragonal close-packed stacking of S²⁻ anions, which occupy the 4a (0, 0, 0) crystallographic site while Cu and Fe cations are randomly distributed over the two structurally equivalent tetrahedral sites 4c (1/4, 1/4, 1/4) and 4d (3/4, 3/4, 3/4). Different Rietveld refinements were therefore performed with both 4c and 4d crystallographic sites, and best result through low isotropic displacement parameters and reliability factors (χ² = 2.303 and R_Bragg factor = 6.98%) was obtained with all Cu and Fe atoms on the 4d crystallographic site. Although the obtained sample is intergrown with chalcopyrite; as previously studied, the chalcopyrite phase forms submicronic domains, this isocubanite sample is well crystallized.²¹ Note that the average particle size is about 1–2 μm without any particular shape.Open in a separate windowFig. 1Powder X-ray diffraction pattern of CuFe₂S₃ isocubanite. Vertical bars, respectively, indicate the Bragg peak positions corresponding to the chalcopyrite CuFeS₂ (bottom green bars – space group: I$\bar{4}$2d no. 122) and to the cubic cubanite so-called isocubanite CuFe₂S₃ (top green bars space group: F$\bar{4}$3m no. 216). Inset shows a zoomed-in portion of the aforementioned figure, showing the coexistence of the CuFe₂S₃ isocubanite and CuFeS₂ chalcopyrite.The charge–discharge profiles of Li/CuFe₂S₃ (Fig. 2a) have been performed by a galvanostatic cycling at C/20/Li per formula unit (f.u.) in the potential window 0.5–3.0 V versus Li⁺/Li. Starting from our material, the first discharge is fragmented in a series of two main processes happening between 1.80 and 0.50 V. The first one is a slope (A) from 1.80 to 1.50 V, it is attributed to the insertion of one lithium into CuFe₂S₃ through a solid solution, accordingly to literature.¹⁵ This insertion follows the eqn (1):CuFe₂S₃ + Li⁺ + e⁻ → LiCuFe₂S₃1Open in a separate windowFig. 2Voltage–composition curve for CuFe₂S₃ in the potential window 3.0–0.5 V at C/20/Li and inset: derivative curve |dQ/dE| vs. voltage (a); voltage–composition curve for CuFe₂S₃ in the potential window 3.0–1.0 V at C/2/Li and its corresponding derivative curve |dQ/dE| vs. voltage (b).Note that the phase LiFeCuS₂ has been reported¹⁵ and our sample is an intergrowth between chalcopyrite CuFeS₂ and isocubanite CuFe₂S₃, a complete structural resolution of the lithiated phase is not possible. During the second process, we observe 5 plateaus at 1.50 (B), 1.46 V (C), 1.39 (D), 1.32 (E) and 0.82 (F) volt, respectively as shown on the derivative curve (inset Fig. 2a). These processes correspond to the reaction with 5 lithium and could then be assigned to copper and iron reduction to the metallic level as related in the case of Li/CuFeS₂ system¹⁵ following the eqn (2):LiCuFe₂S₃ + 5Li → Cu⁰ + 2Fe⁰ + 3Li₂S2Because of the nature of our material (intergrowth of isocubanite and chalcopyrite), it is interesting to point out that only two domains are observed in the course of the first discharge of pure CuFeS₂ phase (at 1.7 and 1.5 V, respectively¹⁶). Charging process occurs mainly through one plateau at 1.80 V (G) as shown on the derivative curve (Red curve, Fig. 2b). This plateau could be attributed to copper and iron oxidation leading to a mixture of cupper iron sulfides Cu_xFe_yS_z (ref. 15, 23 and 24) and free sulfur formation. Consequently, this system becomes a hybrid between lithium ion and lithium sulfur battery. As observed on Fig. 2, the first discharge process is different than the second one where only one large plateau at 1.50 V (H) is observed. This can be due to SEI formation occurring at the same time than metal reduction in the first discharge. SEI formation has already been mentioned in similar conversion cathode study to be responsible for extra capacity like CuFeS₂,¹⁵ Co₂SiO₄ (ref. 25) and CuCo₂S₄.²⁶ In our case, an extra capacity of 260 mA h g⁻¹ is observed. We particularly have to consider the presence of CuFeS₂ in our material. CuFeS₂ has been previously investigated and possesses similar electrochemical properties compare to CuFe₂S₃. Even if our material contains a large amount of CuFeS₂, the electrochemical capacity cannot only be due to CuFeS₂ activity. Therefore, this indicates that CuFe₂S₃ is an electroactive material.A reversible capacity of 560 mA h g⁻¹ (C/20/Li) is observed in the potential window of 1.52 V to 1.80 V. Please, note that an additional phenomenon appears below 1.50 V. This latter could correspond to different phenomena like electrolyte degradation or lithium insertion in the surface electrolyte interface as mentioned in previous report.^27,28 We believe that the irreversible capacity is mainly ascribed to this slope and the SEI formation.Study at a rate of C/2/Li and a cut off at 1.0 V are displayed Fig. 2b. The curve of C/2/Li shows a reversible and stable capacity of 400 mA h g⁻¹ upon 9 cycles. Using this rate, a polarization of 340 mV is observed between formation and conversion of Cu_xFe_yS_z. This polarization is quite in accordance with previous electrochemical performance obtained for CuFeS₂.¹⁷ We can notice that cutting off at 1.0 V improves the reversibility of the system. Note that the conversion process is not complete as last discharge plateau at 0.82 V is also cutted off. Consequently, first reduction plateaus appeared at lower voltage and then stabilized at 1.47 V after few cycles (Fig. 2b).The intermittent galvanostatic titration (GITT) reported in Fig. 3a shows a biphasic process and allows us to access to the equilibrium potential in the course of the reduction with a thermodynamic potential of 1.65 V vs. Li⁺/Li. A polarization of 300 mV is observed. The potentiodynamic titration curve (PITT, Fig. 3b) reveals a bell-shape-type response on the reversible phenomenon, and confirms together with the sharpness of the peaks in the derivative curve (Fig. 2) that the reversible process is biphasic.Open in a separate windowFig. 3(a) Potential–composition curve of CuFe₂S₃ performed in a galvanostatic intermittent mode (GITT) with a rate of C/40 for 15 min and relaxation period of 2 h, (b) potentiometric titration curve (PITT) in the range of 3.0–1.0 V vs. Li⁺/Li using 5 mV potential step in duration of 1 h and current limitation equivalent to a galvanic current I_limit = I_C/100.To confirm the structural conversion occurring in the course of the electrochemical process, ex situ X-ray diffraction patterns have been recorded at the end of the first discharge and charge (Fig. 4). We can see on the discharge pattern that CuFe₂S₃ reflections disappeared (green middle curve, Fig. 4). Reflections on discharge pattern are attributed to copper (○), iron (Δ) and Li₂S (+). After recharge (orange upper curve, Fig. 4), reflection close to CuFe₂S₃ and attributed to Cu_xFe_yS_z (*) are observed among undefined products (□). This validates the conversion mechanism.Open in a separate windowFig. 4Powder X-ray diffraction patterns of (a) as prepared isocubanite CuFe₂S₃, (b) discharged phase down to 0.5 V (C/20) (c) charged phase up to 3.0 V (C/20). Cu_xFe_yS_z (*), Li₂S (+), Cu (○), Fe (Δ) and undefined products (□).The specific capacity decreases with the increase in current density (Fig. 5a). The reversible capacity is about 425 mA h g⁻¹ at the current density of C/5/Li and decreases down to 30 mA h g⁻¹ at 10C/Li. When the current density is tuned back at C/5/Li, the specific capacity rebounds to 350 mA h g⁻¹. This rate capability is comparable with previously reported CuFeS₂ rate capabilities.¹⁷ Please note that we observed a capacity fading, which appeared to be not rate depending, and could be attributed to polysulfides formation known to be formed in lithium sulfur battery.⁸ Those polysulfides are the results of Li₂S reduction that can form free sulfur.Open in a separate windowFig. 5Rate (a) and cycling (b) capability versus cycle number at C/Li in 1.2–3.0 V potential window for the discharge (brown square) and charge (blue triangle) capacity versus cycle number.On Fig. 5b, we have reported the cycling performances of CuFe₂S₃ at a current density of C/Li upon 30 cycles and with a cut off at 1.2 V. The cut off was necessary to avoid side reactions to occur as observed on the potential slope observed at the end of the first discharge. The capacity is rising in the first 10 cycles from 100 to 245 mA h g⁻¹ and stabilizes around 250 mA h g⁻¹. We believe this is due to the incomplete reaction together with side reaction despite the high voltage cut off.The electrochemical behaviour of CuFe₂S₃ and CuFeS₂ are relatively close to each other''s. Their working potential is around 1.8 V and similar phenomena (conversion process, SEI formation, extra electrochemical capacity) are observed for both compounds. Furthermore, they are both semi-conductors. Concerning resistivity, our isocubanite sample (containing chalcopyrite) owns a resistivity of 0.7 mohm cm at 300 K while pure chalcopyrite possesses a higher resistivity at room temperature (measured between 20 and 200 mohm cm).²⁹     

Neurophysiological changes during shortening osteotomies of the spine

Background contextKyphotic deformities with sagittal imbalance of the spine can be treated with spinal osteotomies. Those procedures are known to have a high incidence of neurological complications, in particular at the thoracic level. Motor evoked potentials (MEPs) have been widely used in helping to avoid major neurological deficits postoperatively. Previous reports have shown that a significant proportion of such cases present with important transcranial MEP (Tc-MEP) changes during surgery with some of them being predictive of postoperative deficits.PurposeOur aim was to study Tc-MEP changes in a consecutive series of patients and correlate them with clinical parameters and radiological changes.Study design/settingRetrospective case notes study from a prospective patient register.Patient sampleEighteen patients undergoing posterior shortening osteotomies (nine at thoracic and nine at lumbar levels) for kyphosis of congenital, degenerative, inflammatory, or post-traumatic origin were included.Outcome measuresLoss of at least 80% of Tc-MEP signal expressed as the area under the curve percentual change, of at least one muscle.MethodsWe studied the relation between outcome measure (80% Tc-MEP loss in at least one muscle group) and amount of posterior vertebral body shortening as well as angular correction measured on computed tomography scans, occurrence of postoperative deficits, intraoperative blood pressure at the time of the osteotomy, and hemoglobin (Hb) change.ResultsAll patients showed significant Tc-MEP changes. In particular, greater than 80% MEP loss in at least one muscle group was observed in five of nine patients in the thoracic group and four of nine patients in the lumbar group. No surgical maneuver was undertaken as a result of this loss in an effort to improve motor responses other than verifying the stability of the construct and the extent of the decompression. Four patients developed postoperative deficits of radicular origin, three of them recovering fully at 3 months. No relation was found between intraoperative blood pressure, Hb changes, and Tc-MEP changes. Severity of Tc-MEP loss did not correlate with postoperative deficits. Shortening of more than 10 mm was linked to more severe Tc-MEP changes in the thoracic group.ConclusionsTranscranial MEP changes during spinal shortening procedures are common and do not appear to predict severe postoperative deficits. Total loss of Tc-MEP (not witnessed in our series) might require a more drastic approach with possible reversal of the correction and wake-up test.     

激光诱导间质热疗法治疗结肠直肠癌肝转移的生存率——首次临床经验与常规治疗效果的比较

目的：激光诱导间质热疗法（LITT）是一种治疗局灶性肿瘤的微创性消融术。此报道旨在讨论这种疗法在非手术治疗结肠直肠癌肝转移患者的远期疗效。方法：我们采用MR引导下的LITT法一共治疗了85例患者的163个结肠直肠癌肝转移病灶。     

创伤病人输注浓缩红细胞导致的高钾血症

研究表明病人输注细胞类制品,特别是浓缩红细胞(PRBC)和新鲜全血,将导致钾离子稳态的紊乱.在成人和儿童中,报道的低钾血症比高钾血症常见.我们所知的最大的回顾性研究是肝移植儿童,低钾血症的发生率为72%,高钾血症低于5%.