Effect of Diffusion Length in Modeling of Equiaxed Dendritic Solidification under Buoyancy Flow in a Configuration of Hebditch–Hunt Experiment

Metallurgical and Materials Transactions B - Modeling of equiaxed solidification is vital for understanding the solidification process of metallic alloys. In this work, an extended literature...     

2-Chlorodeoxyadenosine therapy in advanced chronic lymphocytic leukaemia

The therapeutic potential of 2-chlorodeoxyadenosine (CdA) in patients with advanced chronic lymphocytic leukaemia (CLL) remains controversial with response rates in clinical trials ranging from 44 to 67%. This report describes our experience with CdA in 22 CLL patients having already undergone previous treatment. CdA was given by continuous intravenous infusion at a dose of 4 mg/m2/day for 7 days (4 patients) or as 2-h intravenous infusions at a dose of 5.6 mg/m2/day for 5 days (18 patients). Partial (n = 5) or complete (n = 2) response was obtained in 7 cases. As compared to unresponsive patients, responding subjects received CdA earlier in the course of their disease (mean interval between diagnosis and CdA therapy 58 vs 102 months), were less thrombocytopenic at initiation of CdA (mean platelet count 165 x 10(9)/L vs 81 x 10(9)/L) and experienced less severe neutropenia during the first course of therapy (mean minimal neutrophil count 1.55 x 10(9)/L vs 0.43 x 10(9)/L). None of 6 patients with CLL refractory to fludarabine responded to CdA. An evaluation of haematological toxicity during the first course of treatment showed grade 4 neutropenia (< 0.5 x 10(9)/L) in 7 cases and grade 4 thrombocytopenia (< 25 x 10(9)/L) in one of 19 cases where the platelet count was greater than 25 x 10(9)/L at initiation of CdA. In comparison with earlier reports, the present series of patients had received relatively heavy prior therapy, experienced more severe haematological toxicity and demonstrated a lower total response rate.     

Real-time acousto-optical image conversion

We report a new means of visualising, in real time, the potential distribution induced by an ultrasonic wave on the surface of a piezoelectric quartz wafer. The absence of scanning and a shutter function make this new system an original acousto-optical component.     

Impact of ultrafiltration and nanofiltration of an industrial fish protein hydrolysate on its bioactive properties

BACKGROUND: Numerous studies have demonstrated that in vitro controlled enzymatic hydrolysis of fish and shellfish proteins leads to bioactive peptides. Ultrafiltration (UF) and/or nanofiltration (NF) can be used to refine hydrolysates and also to fractionate them in order to obtain a peptide population enriched in selected sizes. This study was designed to highlight the impact of controlled UF and NF on the stability of biological activities of an industrial fish protein hydrolysate (FPH) and to understand whether fractionation could improve its content in bioactive peptides. RESULTS: The starting fish protein hydrolysate exhibited a balanced amino acid composition, a reproducible molecular weight (MW) profile, and a low sodium chloride content, allowing the study of its biological activity. Successive fractionation on UF and NF membranes allowed concentration of peptides of selected sizes, without, however, carrying out sharp separations, some MW classes being found in several fractions. Peptides containing Pro, Hyp, Asp and Glu were concentrated in the UF and NF retentates compared to the unfractionated hydrolysate and UF permeate, respectively. Gastrin/cholecystokinin‐like peptides were present in the starting FPH, UF and NF fractions, but fractionation did not increase their concentration. In contrast, quantification of calcitonin gene‐related peptide (CGRP)‐like peptides demonstrated an increase in CGRP‐like activities in the UF permeate, relative to the starting FPH. The starting hydrolysate also showed a potent antioxidant and radical scavenging activity, and a moderate angiotensin‐converting enzyme (ACE)‐1 inhibitory activity, which were not increased by UF and NF fractionation. CONCLUSION: Fractionation of an FPH using membrane separation, with a molecular weight cut‐off adapted to the peptide composition, may provide an effective means to concentrate CGRP‐like peptides and peptides enriched in selected amino acids. The peptide size distribution observed after UF and NF fractionation demonstrates that it is misleading to characterize the fractions obtained by membrane filtration according to the MW cut‐off of the membrane only, as is currently done in the literature. Copyright © 2010 Society of Chemical Industry     

Study of the Electromagnetic Coupling in an Inductively Coupledplasma Torch at Atmospheric Pressure

This work is devoted to study the behaviour of an inductively coupled plasma torch using argon,hydrogen and oxygen at atmospheric pressure.Thermal plasmas are generally used to form highly reactive species and to transfer enthalpy.Precise characterisation of the plasma behaviour is thus relevant to evaluate chemical and thermal effects of the plasma.For equivalent configurations in terms of torch geometry and gas flows,a transition between two different coupling modes is identified affecting atomic species distribution and energy transmitted to a copper target.These two modes are affected by total electrical power input and oxygen and hydrogen flow rates,showing up hysteresis behaviour.Electrical current and frequency progress are analysed to highlight the transition between the two coupling modes.Optical spectroscopy is used to measure temperature profiles and radial atomic oxygen concentration profiles for different coupling modes.We observe that-depending on the coupling mode-temperature profile,atomic species distribution as well as the power transmission to a copper target are affected.     

Reducibility of supported gold (III) precursors: influence of the metal oxide support and consequences for CO oxidation activity

The origin of CO oxidation performance variations between three different supported Au catalysts (Au/CeO₂, Au/Al₂O₃, Au/TiO₂) was examined by in situ XAFS and DRIFTS measurements. All samples were prepared identically, by deposition-precipitation of an aqueous Au(III) complex with urea, and contained the same gold loading (~1 wt %). The as-prepared supported Au(III) precursors exhibited different reduction behaviour during exposure to the CO/O₂/He reaction mixture at 298 K. The reducibility of the Au(III) precursor was found to decrease as a function of the support material in the order: titania > ceria > alumina. The as-prepared samples were inactive catalysts, but Au/TiO₂ and Au/CeO₂ developed catalytic activity as the reduction of Au(III) to metallic Au proceeded. Au/Al₂O₃ remained inactive. The developed catalytic CO oxidation activity at 298 K varied as a function of the support as follows: titania > ceria > alumina ~ 0. The EXAFS of samples pretreated in air at 773 K and in H₂ at 573 K reveals the presence of only metallic particles for Au/TiO₂ and Au/Al₂O₃. Au(III) supported on CeO₂ remains unreduced after calcination, but reduces during the treatment with H₂. CO oxidation experiments performed at 298 K with the activated samples show that the presence of metallic gold is necessary to obtain active catalysts (Au/CeO₂ is not active after calcination) and that the reducible supports facilitate the genesis of active catalysts, while metallic gold particles on alumina are not active.     

Cancer-Associated Glycosphingolipids as Tumor Markers and Targets for Cancer Immunotherapy

Aberrant expression of glycosphingolipids is a hallmark of cancer cells and is associated with their malignant properties. Disialylated gangliosides GD2 and GD3 are considered as markers of neuroectoderm origin in tumors, whereas fucosyl-GM1 is expressed in very few normal tissues but overexpressed in a variety of cancers, especially in small cell lung carcinoma. These gangliosides are absent in most normal adult tissues, making them targets of interest in immuno-oncology. Passive and active immunotherapy strategies have been developed, and have shown promising results in clinical trials. In this review, we summarized the current knowledge on GD2, GD3, and fucosyl-GM1 expression in health and cancer, their biosynthesis pathways in the Golgi apparatus, and their biological roles. We described how their overexpression can affect intracellular signaling pathways, increasing the malignant phenotypes of cancer cells, including their metastatic potential and invasiveness. Finally, the different strategies used to target these tumor-associated gangliosides for immunotherapy were discussed, including the use and development of monoclonal antibodies, vaccines, immune system modulators, and immune effector-cell therapy, with a special focus on adoptive cellular therapy with T cells engineered to express chimeric antigen receptors.     

Optoelectronic properties of sexithiophene single crystals

UV—Vis absorption, photoluminescence (PL) and photoconductivity (PC) measurements have been carried out on sexithiophene (6T) single crystals grown from the vapor phase. UV—Vis absorption data were used to determine the absorption coefficient and refraction index under polarized light. The spectrum at polarization perpendicular to the unique axis b is similar to that measured on polycrystalline films, whereas that at light polarized parallel to b presents a weak structured absorption. The refractive index is 1.656, independent of the wavelength, under parallel polarization, and follows the Sellmeier equation, with n_∞ = 1.867, under perpendicular polarization. The PL excitation spectrum with parallel polarization follows exactly the corresponding weak absorption, whereas, at perpendicular polarization, it saturates when the absorption length compares the crystal thickness, and then decreases down to a minimum at 3.5 eV. This lowering mirrors a decrease of the PL yield at higher energies. The PC action spectrum shows an opposite behavior: it presents first a rise at 2.4 eV, parallel to the absorption onset, then a second rise at 3.0 eV up to a maximum at 3.3 eV. The first rise corresponds to the generation of singlet excitons, which then give birth to charges, through either exciton breaking, or more likely charge detrapping. The second rise could correspond to a direct ionization process. The magnetic field effect on PC has been studied. A relative decrease of up to 6% at a field of 4000 G has been detected. The decrease is attributed to the lowering of the triplet—doublet interaction constant R.     

Oxidation of gold metal particles supported on TiO<Subscript>2</Subscript>: an FTIR study by means of low-temperature CO adsorption

Two Au/TiO₂ samples with different gold loadings (0.7 and 4.0 wt.% Au) were prepared by deposition-precipitation with urea and calcined at 673 K. TEM revealed gold particles of 3.2 and 3.9 nm for the 0.7 and 4.0 wt.% samples, respectively. The samples were subjected to different red-ox treatments and then the state of gold was determined by the FTIR spectra of CO adsorbed at low temperature. Several kinds of gold carbonyl species were detected during the experiments: (i) Au⁰–CO at around 2107 cm⁻¹; (ii) Au⁺–CO at ca. 2175 cm⁻¹; (iii) Au^δ+–CO in the region of 2140–2137 cm⁻¹ and (iv) Au^δ′+–CO (δ^′ > δ) at around 2155 cm⁻¹. The 4.0 wt.% sample contained mainly metallic gold after evacuation at 673 K. Subsequent interaction with oxygen at 373 K leads to oxidation of a fraction of the surface metallic gold sites to Au^δ+ sites. These sites were considered as cations located on the surface of the metal particles with a partially positive charge δ+ (0 < δ < 1) because of electron transfer from the gold bulk. Evacuation at 673 K leads to back reduction of the Au^δ+ sites to metallic gold. The oxidation of gold particles was more efficient when performed with a NO + O₂ mixture. It resulted in creation of Au^δ′+ sites with a higher positive charge than that of the Au^δ+ sites. In this case the oxidation involved a higher number of Au⁰ sites. A similar treatment of the 0.7 wt.% Au sample, however, resulted in formation of “isolated” Au⁺ species. The results indicate that small metal particles are more easily oxidized by a NO + O₂ mixture. A model of the formation of the different sites, explaining well the experimental results, is proposed.     

Identification and molecular characterization of a small 11q23.3 de novo duplication in a patient with Rett syndrome manifestations

BACKGROUND AND STUDY AIMS: Modern fine-caliber endoscopes enable clinicians to directly visualize the pancreatic duct. They allow intraductal manipulation under optical control. We tried to evaluate the additional diagnostic potential of pancreatoscopy in assessing inconclusive intraductal pancreatic changes. PATIENTS AND METHODS: We prospectively performed 20 pancreatoscopies in 18 patients with inconclusive ductal abnormalities that had been previously investigated by computed tomography (CT) scan, abdominal ultrasound and endoscopic retrograde cholangiopancreatography (ERCP). The CHF-BP 30 (Olympus Optical Co., Japan) endoscope with an outer diameter of 3.1 mm and an instrumentation channel of 1.2 mm was used. Biopsies, cytological brushing and fluid collection were carried out, and the site of ductal abnormality was visualized. Endoscopic sphincterotomy (EST) was carried out in every patient prior to insertion of the pancreatoscope. RESULTS: Seven intraductal tumors were histologically confirmed, i.e. five intraductal papillary mucinous tumors and two adenocarcinomas. Benign appearance of the intraductal lesion plus negative histopathological examinations were confirmed by a follow-up of two years in eight patients. Five had chronic pancreatitis, and a further three had pancreatitis with strictures, blood clot obstruction, and idiopathic benign stricture, respectively. There were no complications with the exception of one bleeding episode after EST; no pancreatitis occurred. CONCLUSIONS: Pancreatoscopy is of diagnostic value in addition to CT, transabdominal ultrasound and ERCP in the differential diagnosis of poorly defined pancreatic lesions, particularly when assessing alterations of the ductal caliber without parenchymatous lesions.