Nanoscale pores introduced into paper via mesoporous silica coatings using sol-gel chemistry.

Mesopores, with diameters between 2 and 50 nm, not only increase the specific surface area, but also generate hierarchically porous materials with specific properties such as capillary fluid transport, ion specific pore accessibility, or size exclusion. Paper is a strongly hierarchical, porous material with specific properties, such as capillary force-driven fluid transport. However, paper fibers change their morphology during the initial step of wood disintegration. This results in changes of the porous fiber structure. In particular paper fibers loose their mesopores during the final drying step in the fabrication process. Here, we investigate silica mesopore formation in paper by sol-gel chemistry and evaporation induced self-assembly to specifically introduce and rationally design mesopore formation and distribution in cotton linter and eucalyptus sulfate paper sheets. We demonstrate the importance of synchronizing the solvent evaporation rate and capillary fluid velocity to ensure mesopore formation as well as the influence of the fiber type and sol-gel solution composition. The combination of argon and krypton sorption, SAXS, TEM and CLSM provides systematic analysis of the porous structure and the silica distribution along the cellulose paper fiber length and cross-section. These results provide a deeper understanding of mesopore formation in paper and how the latter is influenced by paper fluidic properties.

Controlling the generation of bilayer and multilayer vesicles in block copolymer/epoxy blends by a slow photopolymerization process.

Vesicles are a highly attractive morphology to achieve in micellar dispersions of block copolymers (BCP) in epoxy thermosets due to the fact that small amounts can affect a large volume fraction of the matrix, a fact that is important for toughening purposes. However, generating vesicles in epoxy matrices requires operating in a narrow range of formulations and processing conditions. In this report, we show that block-copolymer vesicles dispersed in an epoxy matrix could be obtained through a sphere-to-cylinder-to-vesicle micellar transition induced by visible-light photopolymerization at room temperature. A 10 wt% colloidal solution of poly(ethylene-co-butene)-block-poly(ethylene oxide) (PEB-b-PEO) block copolymer (BCP) in an epoxy monomer (DGEBA) self-assembled into spherical micelles as shown by small-angle X-ray scattering (SAXS). During a slow photopolymerization of the epoxy monomer carried out at room temperature, a sphere-to-cylinder-to-vesicle transition took place as revealed by in situ SAXS and TEM images. This was driven by the tendency of the system to reduce the local interfacial curvature as a response to a decrease in the miscibility of PEO blocks in the polymerizing epoxy matrix. When the BCP concentration was increased from 10 to 20 and 40 wt%, the final structure evolved from bilayer vesicles to multilayer vesicles and to lamellae, respectively. In particular, for 20 wt% PEB-b-PEO, transient structures such as partially fused multilayered vesicles were observed by TEM, giving insight into the growth mechanism of multilayer vesicles. On the contrary, when a relatively fast thermal polymerization was performed at 80 °C, the final morphology consisted of kinetically trapped spherical and cylindrical micelles. Hopefully, this study will lead to new protocols for the preparation of vesicles dispersed in epoxy matrices in a controlled way.

ESTES guidelines: acute mesenteric ischaemia.

PURPOSE: Acute mesenteric ischaemia (AMI) accounts for about 1:1000 acute hospital admissions. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can halt and reverse this process leading to a full recovery, but the diagnosis of AMI is difficult and failure to recognize AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Early diagnosis and prompt treatment are the goals of modern therapy, but there are no randomized controlled trials to guide treatment and the published literature contains a high ratio of reviews to original data. Much of that data comes from case reports and often small, retrospective series with no clearly defined treatment criteria. METHODS: A study group of the European Society for Trauma and Emergency Surgery (ESTES) was formed in 2013 with the aim of developing guidelines for the management of AMI. A comprehensive literature search was performed using the Medical Subject Heading (MeSH) thesaurus keywords "mesenteric ischaemia", "bowel ischaemia" and "bowel infarction". The bibliographies of relevant articles were screened for additional publications. After an initial systematic review of the literature by the whole group, a steering group formulated questions using a modified Delphi process. The evidence was then reviewed to answer these questions, and recommendations formulated and agreed by the whole group. RESULTS: The resultant recommendations are presented in this paper. CONCLUSIONS: The aim of these guidelines is to provide recommendations for practice that will lead to improved outcomes for patients.

Isolation and characterization of a novel perivitellin from the eggs of Pomacea scalaris (Mollusca, Ampullariidae).

Perivitellins are important components of the perivitelline fluid (PVF) that surrounds gastropod embryos. The glyco-lipo-carotenoprotein ovorubin (OR) from eggs of the snail Pomacea canaliculata has been the most studied to date. Here we report the characterization of scalarin (SC), a glyco-lipo-carotenoprotein from the PVF of P. scalaris. SC was purified by ultracentrifugation and exclusion chromatography. It is the major egg protein, representing 64% of the total soluble protein. The particle has a hydration density of 1.26 g/ml, an apparent molecular mass of 380 kDa and it is an elongated compact protein as estimated by small angle X-ray scattering (SAXS). It is composed of three subunits of ca. 35, 28, and 24 kDa noncovalently bonded. SC is highly glycosylated (carbohydrate content 20.1%, by wt.), with a low lipid content (0.7%), being esterified sterols, pigments and polar lipids the most abundant lipid classes. HPTLC and spectrophotometric analysis of the carotenoid fraction revealed the presence of free astaxanthin (ASX; 62.0%), and an unidentified carotenoid (38.0%). The carotenoid-apoprotein interaction was studied by spectrophotometry. Carotenoids do not seem to affect the structural characteristics of the oligomer. However, the carotenoid-protein association protected ASX against oxidation. The cross-reactivity between SC and perivitellins of P. canaliculata was tested using polyclonal antibodies (PAb) against SC, OR, and perivitellin PV2. The PAbs failed to cross-react with any egg proteins of either the same or other species. SC, among other functional similarities with OR, would be an antioxidant carrier, protecting at the same time carotenoids from oxidation in the perivitellin fluid of the egg.

Endoscopic ultrasonography (EUS) in portal hypertension.

UNLABELLED: Although the first studies on EUS in portal hypertension are by now dated approximately 20 years ago, this method still has not become a routine examination among the diagnostic and therapeutic examinations in this field. EUS has an important role in the following applications: early diagnosis of esophageal and gastric varices and of hypertensive gastropathy, screening of subjects to treat medically, endoscopically or surgically, and their follow-up, EUS-guided injection therapy of varices. Several papers have confirmed and/or added important clinical applications to the EUS use in such patients. In fact, if at the beginnig the studies were concentrated on the best way to show varices compared to the endoscopic examination, or on aspects still unknown such as the presence of periesophageal veins and collaterals increased in number and diameter, at present sophisticated instruments with several types of Doppler and therapeutic possibilities are available. The observation of perforating veins under the esophagogastric junction seems to have a particular clinical interest having a predictive value on the effectiveness of the sclerotherapy and therefore on the final eradication. Also the several instrumentations used can modify the RESULTS: Using the high frequencies EUS miniprobes, the sensibility in identifying even the minimal or initial varices increases. In the evaluation of the pharmacological therapy, EUS with the new instruments equipped with color Doppler can be very useful and can replace other diagnostic methods very invasive and dangerous and thus used only in highly specialized centers. As to the nursing aspect of EUS in portal hypertension, it must be underlined that such pathology is often the consequence of viral hepatitis infection. Therefore, beside a correct clinical evaluationl before endoscopic ultrasound examination, all devices, drugs and anything else could be be necessary to complete with success an intervention, e.g. sclerotherapy in emergency, should be prepared in advance.

The Veneto Region's Barrett's Oesophagus Registry: aims, methods, preliminary results.

BACKGROUND: The natural history of Barrett's Oeosphagus is not completely clarified and Barrett's Oeosphagus Registries are considered useful tools to expand our knowledge on this disease. A Barrett's Oeosphagus Registry has been therefore established in the Veneto Region and neighbouring provinces. AIMS: The aims of the Registry are to assess the demographical, endoscopical and histological characteristics of Barrett's Oeosphagus patients; the prevalence of non-invasive neoplasia and Barrett's Adenocarcinoma and the timing and incidence of Barrett's Oeosphagus progression to malignancy. METHODS: An interdisciplinary committee of endoscopists, pathologists and information technology experts was established in 2004 to design a website-based Barrett's Oesophagus Registry for the Veneto Region and neighbouring north-eastern Italian provinces. Protocols for endoscopies and biopsies and standard reports were carefully defined. RESULTS: In the first 18 months, 397 patients with endoscopically visible and histologically proven Barrett's Oeosphagus were enrolled in the Registry; the median age of these patients was 66 years (male:female=3:1). Most patients (75%) had a Short Segment of Barrett's Oesophagus (3 cm). Long Segment of Barrett's Oesophagus patients were 5 years older than the Short Segment of Barrett's Oesophagus patients (p<0.05), suggesting a progression from Short Segment of Barrett's Oesophagus to Long Segment of Barrett's Oesophagus. Though no data are available on the incidence of non-invasive neoplasia or Barrett's Adenocarcinoma (i.e., progression to cancer at least 12 months after enrolment), the prevalence of neoplastic lesions (found within 12 months of enrolment) was 5% for Short Segment of Barrett's Oesophagus and 19% for Long Segment of Barrett's Oesophagus, indicating that a careful multiple-biopsy endoscopic protocol is needed, especially when Long Segment of Barrett's Oesophagus are suspected at endoscopy. The prevalence of Barrett's Adenocarcinoma among patients with non-invasive neoplasia was 1/17 cases of low-grade non-invasive neoplasia and 2/3 cases of high-grade non-invasive neoplasia, indicating that these patients require strict endoscopic and bioptic follow-up. CONCLUSION: A regional Barrett's Oeosphagus Registry is feasible at a relatively low cost and enables significant data to be collected in a relatively short time. The use of a standardised endoscopic nomenclature and report form, a strict biopsy protocol, a standard report for pathologists improves the quality of endoscopic and histological diagnoses.

Head-to-tail and side-by-side oligomerization of human carbonic anhydrase II: a small angle X-ray scattering study.

Solvent-induced directional aggregation of human carbonic anhydrase II (hCA) was studied by small angle X-ray scattering and fluorescence and fourth-derivative ultraviolet absorption spectroscopy. We propose that hCA at 5 mg ml(-1) in pure water forms head-to-tail oligomers built up, on average, by four to five monomers. At higher protein concentrations, the oligomers associate pair-wise and side-by-side. Spectroscopic evidence suggests that the subunits forming the aggregates are tightly folded, but with a structure that differs, at least locally, from the native state. A more complex aggregation pattern was observed under solvent conditions that favor the removal of zinc from the enzyme-active site, conditions under which the subunits are significantly less compact than in water. hCA may provide a useful model to investigate the effects of additives and genetic manipulation on protein aggregation.

Perturbed angular correlation experiments on the pressure-induced structural modification of bovine serum albumin.

The hydrodynamic behaviour of the bovine serum albumin (BSA) was studied by means of the Perturbed Angular Correlation (PAC) technique as a function of the hydrostatic pressure (up to 4.1 kbar) applied to the sample. The results have clearly shown that at moderated pressures (around 1.5 kbar) the BSA molecule suffers structural modifications which produces an increase of the molecular volume and the rotational correlation time of the molecule. About the reversibility of the process, our results indicate that the changes are fully irreversible. Our experiments are the first devoted to the study of the high-pressure behaviour of biological molecules using the PAC technique.

Engineering a compact non-native state of intestinal fatty acid-binding protein.

The last three C-terminal residues (129-131) of intestinal fatty acid-binding protein (IFABP) participate in four main-chain hydrogen bonds and two electrostatic interactions to sequentially distant backbone and side-chain atoms. To assess if these interactions are involved in the final adjustment of the tertiary structure during folding, we engineered an IFABP variant truncated at residue 128. An additional mutation, Trp-6-->Phe, was introduced to simplify the conformational analysis by optical methods. Although the changes were limited to a small region of the protein surface, they resulted in an IFABP with altered secondary and tertiary structure. Truncated IFABP retains some cooperativity, is monomeric, highly compact, and has the molecular dimensions and shape of the native protein. Our results indicated that residues 129-131 are part of a crucial conformational determinant in which several long-range interactions, essential for the acquisition of the native state, are established. This work suggests that carefully controlled truncation can populate equilibrium non-native states under physiological conditions. These non-native states hold a great promise as experimental models for protein folding.

Time differential perturbed angular correlation of 111In-EDTA linked to the single free cysteine of bovine serum albumin.

By means of a facile chemical modification of the bovine serum albumin molecule, it was possible to measure its hydrodynamic radius with high accuracy (approximately 3%) using the TDPAC technique. The new approach presented here allows a wide use of the TDPAC technique to perform high precision studies of backbone dynamics of almost any protein.