Controllable skyrmion chirality in ferroelectrics.

Chirality, an intrinsic handedness, is one of the most intriguing fundamental phenomena in nature. Materials composed of chiral molecules find broad applications in areas ranging from nonlinear optics and spintronics to biology and pharmaceuticals. However, chirality is usually an invariable inherent property of a given material that cannot be easily changed at will. Here, we demonstrate that ferroelectric nanodots support skyrmions the chirality of which can be controlled and switched. We devise protocols for realizing control and efficient manipulations of the different types of skyrmions. Our findings open the route for controlled chirality with potential applications in ferroelectric-based information technologies.

Telemedicine framework using case-based reasoning with evidences.

Telemedicine is the medical practice of information exchanged from one location to another through electronic communications to improve the delivery of health care services. This research article describes a telemedicine framework with knowledge engineering using taxonomic reasoning of ontology modeling and semantic similarity. In addition to being a precious support in the procedure of medical decision-making, this framework can be used to strengthen significant collaborations and traceability that are important for the development of official deployment of telemedicine applications. Adequate mechanisms for information management with traceability of the reasoning process are also essential in the fields of epidemiology and public health. In this paper we enrich the case-based reasoning process by taking into account former evidence-based knowledge. We use the regular four steps approach and implement an additional (iii) step: (i) establish diagnosis, (ii) retrieve treatment, (iii) apply evidence, (iv) adaptation, (v) retain. Each step is performed using tools from knowledge engineering and information processing (natural language processing, ontology, indexation, algorithm, etc.). The case representation is done by the taxonomy component of a medical ontology model. The proposed approach is illustrated with an example from the oncology domain. Medical ontology allows a good and efficient modeling of the patient and his treatment. We are pointing up the role of evidences and specialist's opinions in effectiveness and safety of care.

Autophagy supports survival and phototransduction protein levels in rod photoreceptors.

Damage and loss of the postmitotic photoreceptors is a leading cause of blindness in many diseases of the eye. Although the mechanisms of photoreceptor death have been extensively studied, few studies have addressed mechanisms that help sustain these non-replicating neurons for the life of an organism. Autophagy is an intracellular pathway where cytoplasmic constituents are delivered to the lysosomal pathway for degradation. It is not only a major pathway activated in response to cellular stress, but is also important for cytoplasmic turnover and to supply the structural and energy needs of cells. We examined the importance of autophagy in photoreceptors by deleting the essential autophagy gene Atg5 specifically in rods. Loss of autophagy led to progressive degeneration of rod photoreceptors beginning at 8 weeks of age such that by 44 weeks few rods remained. Cone photoreceptor numbers were only slightly diminished following rod degeneration but their function was significantly decreased. Rod cell death was apoptotic but was not dependent on daily light exposure or accelerated by intense light. Although the light-regulated translocation of the phototransduction proteins arrestin and transducin were unaffected in rods lacking autophagy, Atg5-deficient rods accumulated transducin-α as they degenerated suggesting autophagy might regulate the level of this protein. This was confirmed when the light-induced decrease in transducin was abolished in Atg5-deficient rods and the inhibition of autophagy in retinal explants cultures prevented its degradation. These results demonstrate that basal autophagy is essential to the long-term health of rod photoreceptors and a critical process for maintaining optimal levels of the phototransduction protein transducin-α. As the lack of autophagy is associated with retinal degeneration and altered phototransduction protein degradation in the absence of harmful gene products, this process may be a viable therapeutic target where rod cell loss is the primary pathologic event.

[Prevalence and morbidity of G6PD deficiency in sickle cell disease in the homozygote]. / Prevalence et morbidite du deficit en g6pd au cours de la drepanocytose homozygote.

Sickle cell disease and G6PD deficiency have similar prevalence of 8 to 10% in Senegalese population. Our objectives were to determine the prevalence of G6PD deficiency in Hb S carriers and normal subjects, and to assess the interaction of G6PD deficiency on clinical severity of sickle cell disease. G6PD activity was measured in 319 sickle cell patients and in 318 subjects without HbS. Clinical severity was compared in male homozygous sickle cell patients (11 with G6PD deficiency and 19 without deficit). In homozygous sickle cell patients, the G6PD status was assessed after correction of reticulocyte count following the micro-centrifugation method of Herz. We found that prevalence of G6PD deficiency was higher in sickle cell disease patients (21.6 %) than in normal subjects (12.3 %) (p = 0.001). No difference was found in the two groups of male sickle cell disease patients concerning number of vaso-occlusive crisis, number of transfusion, frequency of infectious episodes, number of chronic complications, disturbances on patient's activity and total index severity.

Potentiometric determination of potassium cations using a nickel(II) hexacyanoferrate-modified electrode.

Electroactive nickel(II) hexacyanoferrate (NiHCF) thin film modified electrodes are effective potentiometric sensors for the determination of potassium ions. The NiHCF films are deposited onto glassy carbon electrodes by repetitive potential cycling in K(3)Fe(CN)(6)/NaNO(3)/Ni(NO(3))(2) solution. The modified electrodes exhibit a linear response to potassium ions in the concentration range 1x10(-3) to 2.0 mol dm(-3), with a near-Nernstian slope (45-49 mV per decade) at 25 degrees C. In the determination of potassium ion in syrups used for treatment of potassium deficiency, the NiHCF-modified electrode gave comparable results to those obtained using flame emission spectrophotometry.

Synthesis and preliminary in vitro cytotoxic activity of novel cisplatin and carboplatin analogues.

Six new platinum(II) complexes were synthesized from a common triphenylethylene precursor using various diamines. The cytotoxicity of the compounds, evaluated on human breast cancer cell lines (MCF-7 and MDA-MB-231), was greatly influenced by the nature of the diamine ligand. Two derivatives presented cytotoxic activity greater than tamoxifen and, for the first time, as potent as cisplatin.

Ultrastructure of spermiogenesis and the spermatozoon of Nomimoscolex sp. (Cestoda, Proteocephalidea) intestinal parasite of Clarotes laticeps (Fish, Teleost) in Senegal.

Spermiogenesis in Nomimoscolex sp. begins with the formation of a differentiation zone delimited at the front by arched membranes. It is bordered by cortical microtubules and contains two centrioles surmounted each by striated roots. The latter are linked together at their bases by a thin layer of electron-dense material. The two centrioles give each a flagellum that rotates and fuses with the median cytoplasmic extension. The nucleus elongates, becomes filiform and migrates between the axonemes in the cytoplasmic extension. During the nuclear migration, crested-like bodies form. After the migration of the nucleus, the old spermatid separates from the residual cytoplasm by strangulation of the ring of arched membranes. The mature spermatozoon of Nomimoscolex sp. lacks mitochondria, is filiform and tapered at both its extremities. Its anterior end exhibits an apical cone of electron-dense material and three crested-like bodies of unequal length coiled in a spiral on its periphery. The axoneme is of the 9 + 1' pattern. The cortical microtubules are parallel to the spermatozoon axis. The nucleus is a fibrous cord of partly condensed chromatin. The cytoplasm is slightly dense but contains many electron-dense granules in regions II and III of the spermatozoon. Crested-like bodies and striated roots linked together by an electron-dense material have never been reported during the spermiogenesis in a proteocephalidean. In addition we describe for the first time the existence of three crested-like bodies in the Proteocephalidea.

Blood transfusion does not have an adverse effect on survival after operation for colorectal cancer.

The effect of perioperative blood transfusion on cancer progression remains controversial because retrospective clinical studies have produced conflicting results. We have collected data prospectively on 379 patients undergoing curative surgery for colorectal adenocarcinoma and assessed the effect of variables, including blood transfusion, on survival. Univariate and multivariate survival analysis has been carried out. When the end-point for analysis used was death due to recurrent colorectal carcinoma and non-cancer deaths were censored, there was no difference in cancer-specific survival between transfused and non-transfused patients. Survival analysis was also carried out without censoring the non-cancer deaths and clearly demonstrated how the statistical analysis and data interpretation could be distorted by age-related non-cancer deaths. The incidence of recurrence of colorectal carcinoma was not greater in the transfused group than in the non-transfused group. We conclude that blood transfusion should not be withheld in colorectal surgery for fear of worsening the prognosis.

Renal carcinoma in patients undergoing nephrectomy: analysis of survival and prognostic factors.

A series of 155 patients who underwent nephrectomy for renal carcinoma between 1965 and 1985 at Manchester Royal Infirmary were analysed for survival in relationship to presenting features, surgical staging and histopathology. Univariate and multivariate analyses were carried out. Five-year survival estimates for stage 1 disease were 81%, for stage 2 disease 65%, for stage 3 disease 39% and for stage 4 disease 6%. An erythrocyte sedimentation rate (ESR) greater than 30 mm/h was associated with worse survival and a history of hypertension was associated with better survival. Renal vein invasion alone was related to worse survival. Perinephric fat invasion was also associated with worse survival and this association in the multivariate analysis was more significant than expected, suggesting that the principles of radical surgery should be observed. The presence of granular cells as opposed to clear cells worsened survival. Patients with papillary tumours had a better survival than those with solid tumours.

Adenocarcinoma of the pancreas with osteoclast-like giant cells: a case report with immunocytochemistry.

Histological examination of a tumor centered in the body of the pancreas of a 65-year-old Iranian man revealed it to have a substantial component in which osteoclast-like giant cells were set within a stroma of pleomorphic mononuclear cells though other areas were composed of conventional adenocarcinoma. Immunocytochemistry was used to investigate the differentiation of the various component cells of the tumor. The carcinoma cells of the usual type expressed epithelial antigens (EMA and cytokeratin). The giant cells expressed vimentin and showed membrane staining with anti-LCA, in common with examples of cells originating from the mononuclear phagocytic system, including normal osteoclasts. The accompanying stromal cells expressed vimentin only. This implies that the giant cells are likely to have their origin in the bone marrow, whereas the mononuclear stromal cells that separate them may represent tumor cells that have lost their epithelial phenotype. The giant cells are therefore an unusual tissue response to the presence of the carcinoma.

The treatment of recurrent tonsillitis in adults.

A prospective study comparing surgical and antibiotic treatment for recurrent tonsillitis in adults suggests that, whilst tonsillectomy is very effective, adequate medical treatment provides an equally good alternative in the majority of patients.