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This study aimed to evaluate biomarkers of oxidative stress (2-thiobarbituric acid reactive substances, aldehyde and ketone derivatives of oxidatively modified proteins and total antioxidant capacity), the activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase), that of lysosomal enzymes (alanyl aminopeptidase, leucyl aminopeptidase, β-N-acetylglucosaminidase and acid phosphatase) and changes in biochemical parameters (alanine aminotransferase, aspartate aminotransferase, de Ritis ratio, lactate dehydrogenase activity, lactate and pyruvate levels and their ratio) in the liver tissue of fish that were vaccinated against enteric redmouth disease and challenged with its causative agent, the bacterium Yersinia ruckeri.

This study analyzed time-dependent effects of vaccination against Y. ruckeri on the oxidative mechanism underlying those effects by detecting relevant lipid peroxidation (2-thiobarbituric acid reactive substances, TBARS) and protein oxidation biomarkers [aldehydic and ketonic derivatives of oxidatively modified proteins (OMP)], antioxidant defenses [activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), total antioxidant capacity (TAC)], as well as activities of lysosomal functioning [alanyl aminopeptidase (AAP), leucyl aminopeptidase (LAP), acid phosphatase (AcP), and â-N-acetylglucosaminidase (NAG)] in hepatic tissue of rainbow trout, Oncorhynchus mykiss (Walbaum) following anti-Y. ruckeri vaccination in the first, second, and sixth months. A concentrated vaccine with Y. ruckeri strains was enclosed in fish feed and was administered three times every other day. Rainbow trout from each group were euthanized 31, 61, and 181 days following vaccination, and hepatic tissue was sampled for analysis. In the current study, vaccination against Y. ruckeri resulted in a no statistically significant change in TBARS levels, while aldehydic and ketonic derivatives of OMP in hepatic tissue decreased, especially after the first and second months following immunization. Moreover, the activities of glutathione-dependent enzymes increased, especially after the first and sixth months. The highest TAC levels were observed two and six months after vaccination. It has been shown that vaccination-related oxidative stress in hepatic tissue is involved in adaptive responses through the temporary mobilization of antioxidant and lysosomal enzymes in rainbow trout. The present study showed the effect of vaccination on lysosome membrane permeability for carbohydrate cleavage after the development of immunity against Yersinia, whereas antioxidant defence was reduced. Our results confirmed that the concept of preserving antioxidant enzyme function after vaccination was also evident when CAT, GR, and GPx activities either increased or were unchanged following vaccination.

Juvenile sterlet (Acipenser ruthenus) were fed commercial feed (group C) and experimental feed supplemented with papain in doses of 10 g kg−1 feed (P1) and 20 g kg−1 feed (P2) for eight weeks. Growth, digestive enzyme activity, immunity parameters, pathological changes of the liver and intestine, proximate body composition, and oxidative response were assayed. A challenge test with Yersinia ruckeri was also performed. The final body weights of groups P1 (107.07 ± 7.66 g) and P2 (111.98 ± 1.93 g) were significantly (P

The objective of this study was to investigate the effect of trans-resveratrol, a potent antioxidant with anti-inflammatory and chemopreventive properties, naturally occurring in many fruits and plants on lymphocytes proliferation and also on macrophages metabolic and phagocytic activity. The aim of this study was to demonstrate the immunomodulatory effects of the compound on fish immunocompetent cells and determine the type of this interaction (immunosuppression or immunostimulation). Proliferative activity of lymphocytes was studied by MTT assay, and the respiratory burst was evaluated using the respiratory burst activity (RBA) test. Phagocytic killing was tested using the PKA test. The experiment have shown that trans-resveratrol suppressed blood B cells, while there was no significant influence on blood T lymphocytes. However, insignificant stimulatory effect occurred at the lowest concentration. In addition, the compound inhibited proliferation of T and B lymphocytes isolated from the organs. Importantly, trans-resveratrol caused stimulation of blood and organs macrophages phagocytic killing, and also increased the respiratory burst of macrophages isolated from organ. These results suggest a potential use of trans-resveratrol as an immunomodulator of innate immunity in fish. This is particularly important, as this kind of resistance plays leading role in protecting the body against infection. In comparison, adaptive immunity is slower and also much less precise.

The goal of the research was to select measures of regional competitiveness and analyze if in the considered period changes in value of these measures were in line with changes in the debt level of different forms of municipalities (communes). The survey was conducted for the Lower Silesia region and the municipalities located there. Data covered the period 2005-2015. The main measure of regional competitiveness selected by the author was regional GDP per capita. The additional measures were: labour productivity, employment rate, average monthly salary and business density. The survey indicated that the value of communes debt in Lower Silesia increased, even if in some years for particular forms of communes the level of debt was decreasing. At the same time generally an increase of competitiveness measures in the region was observed. In most of the analyzed years the direction of changes in municipalities debt was the same as that of changes of regional competitiveness measures.

Bacterial diseases are a significant problem in the controlled rearing of fish. Furunculosis (Aeromonas sp.), flavobacteriosis (Flavobacterium sp.), and pseudomonadosis (Pseudomonas sp.) are currently the most frequently identified diseases in recirculating aquaculture systems of various fish species. Such a situation is also observed in pikeperch rearing. Due to the emerging difficulties of effective prophylaxis using commercial vaccines, interest in the use of autovaccinations is increasing, not only in ichthyopathology but also in other veterinary fields. Our research aimed to assess the effect of the vaccination method on the overall condition of the fish and survival after the experimental infection with Aeromonas salmonicida. Pikeperch were vaccinated by (1) bath, (2) a single i.p. injection, or (3) feed. The fish were measured and weighed on day 0 and after 28 and 56 days of the experiment. Specific growth rate, daily growth rate, condition factor, and feed conversion ratio were calculated. On days 7, 14, 21, and 28 of the experiment, ceruloplasmin and lysozyme levels were rated. In addition, a challenge test was performed. The obtained results showed that the method of vaccination is important and affects the growth of fish, the overall condition of fish, and survival after experimental infection.

This study analysed the effect of the type of production on the nutritional and health value of common carp muscle tissue, especially lipid-related indexes. The muscle tissue of common carps originating from three types of fish farms with different technological levels (i.e., intensive, low-intensive, and semiextensive) was studied. The type of production technology, especially the intensive breeding technique, has been shown to have a significant effect on dry weight, total protein, and total fat content in the common carp muscle tissue under study. The muscles of fish originating from these farms were characterised by the highest values of the mentioned indicators, which amounted to 24.6%, 18.74%, and 1.58%, respectively, for dry matter, protein content, and total fat content. The type of feed used in intensive, low-intensive, and semiextensive common carp breeding has been proven to have a highly significant effect on the fatty acid profile. As regards unsaturated fatty acids, monounsaturated fatty acids were dominant in all cases. The muscle tissue of fish cultured in farms with a semiextensive technological level was characterised by the highest content of unsaturated fatty acids. Moreover, the ratio of polyunsaturated fatty acids to saturated fatty acids was, in this case, the most favourable. Dietary indices of atherogenicity (AI) and thrombogenicity (TI) were studied as well. In all analysed cases, the values of these indices were very favourable and several times lower than for other animal fats.

Objective. To examine general mental health in adult males and females, who in adolescence participated in a scoliosis-specific therapeutic exercise program or were under observation due to diagnosis of scoliosis. Design. Registry-based, cross-sectional study with retrospective data collection. Methods. Sixty-eight subjects (43 women) aged 30.10 (25–39) years, with mild or moderate scoliosis (11–36° Cobb angle), and 76 (38 women) nonscoliotic subjects, aged 30.11 (24–38) years, participated. The time period since the end of the exercise or observation regimes was 16.5 (12-26) years. Beck Depression Inventory (BDI) and General Health Questionnaire (GHQ-28) scores were analyzed with the χ2 and U tests. Multiple regression analyses for confounders were also performed. Results. Intergroup differences of demographic characteristics were nonsignificant. Scoliosis, gender, participation in the exercise program, employment, and marital status were associated with BDI scores. The presence of scoliosis and participation in the exercise program manifested association with the symptoms. Higher GHQ-28 “somatic symptoms” subscale scores interacted with the education level. Conclusions. Our findings correspond to the reports of a negative impact of the diagnosis of scoliosis and treatment on mental health. The decision to introduce a therapeutic program in children with mild deformities should be made with judgment of potential benefits, risks, and harm.

The crystallographic structure of a steroid derivative molecule, 17,17-di-n-propyl-17a-aza-D-homo-5alpha-androstan-3beta-ol is obtained from a single crystal by laboratory X-ray and from a polycrystalline powder by high-resolution synchrotron powder diffraction. The molecule crystallizes in the orthorhombic space group P[2.sub.1][2.sub.1][2.sub.1] (a = 6.5346, b = 17.6006 and C = 19.6978 Angstrom) and the hydrogen bonds from infinite chains of molecules parallel to the c axis.

In contrast to terrestrial animals, fish can ingest minerals from food or directly from water. Although micro- and macro-elements are needed in small quantities, they play a key role in many metabolic processes. Trace mineral and macromineral deficiencies may go unnoticed due to an absence of clear clinical symptoms in fish. Absorption processes are determined by various factors, mostly mineral concentrations in water but also other water parameters. The required dietary supplementation of macronutrients and micronutrients is very difficult to determine, and the amount of nutrients absorbed by fish from water is equally difficult to measure. Interactions between elements should also be taken into consideration. Many authors emphasize that phosphates may reduce the absorption of most micronutrients. Also, the current parameters of the water can affect the bioavailability. Some elements such as calcium, chlorine and sodium can be absorbed from ambient water in a quantity sufficient to meet the demand for this element. Other elements, however, require supplementation in a diet. For example, studies indicate the need for supplementation of phosphorus, zinc, copper and manganese. Most research concentrates on feedstuff as a source of micro- and macronutrients. Meanwhile, information concerning bioavailability of minerals directly from water is scarce. The aim of this study was to analyse literature from a different perspective, and concentrate on water as a source of minerals in fish nutrition. Measurements of water parameters such as temperature, pH, nitrate and nitrite levels and the amount of dissolved oxygen are a regular component of environmental control in fish farming. Determination of micro- and macro-element levels, however, remains uncommon in aquaculture. Measurements of these parameters could suggest which elements need to be supplemented and which are found in water in amounts that satisfy the needs of the fish. [ABSTRACT FROM AUTHOR]

Since 2007 in Poland, skin lesions have been observed in salmon (Salmo salar L.) and sea trout (Salmo trutta L.) entering Pomeranian rivers to spawn. The clinical picture of affected fish resembled ulcerative dermal necrosis (UDN), a disease of unknown etiology affecting mainly the scalps of wild salmonids. The aim of the 2009-2012 study was to determine with microbiological tests the etiological agent of the skin lesions observed in salmonids entering the Pomeranian rivers. During the study, a total of 13 species of Gram-negative bacteria belonging mainly to the Yersiniaceae, Enterobacteriaceae, and Pseudomonadaceae families were isolated and identified from the skin and kidneys of diseased fish. The Gram-positive bacteria isolated were aerobic, hemolytic granules of the genus Streptococcus. Mycological examinations on damaged fish body surfaces revealed yeasts of the genus Rhodotorula and fungi of the family Saprolegniaceae. The results of our study did not permit us to identify unequivocally the direct cause of the fish diseases analyzed since all the bacteria isolated during the study are normally found in aquatic environments. Some of the isolated bacteria identified were assumed to be potentially pathogenic to fish. The fungal infections observed were probably secondary and only exacerbated ongoing disease processes.

This 56-day experiment examined the effect of actinidin added to commercial feed at concentrations of 0 g (control group C), 10 g (A1 group) and 20 g (A2 group) kg−1 diet on growth, feed utilization, intestinal morphology, digestive enzyme and immune response of juvenile sterlet (Acipenser ruthenus). A total of 270 juvenile sterlet with an average body weight of (46.21 ± 0.37 g) were divided into nine tanks (280 L for each), with 30 fish per tank (three replicates each) under a recirculating aquaculture system (RAS). At the end of the experiment, distinct differences in the mean body weights of the fish were observed, with the greatest differences (P

Abstract Aims and objectives Analysis of factors determining acceptance of disease and satisfaction with life in patients with peripheral artery disease. Background Peripheral artery disease is more common in older patients and is associated with increased morbidity and mortality due to cardiovascular diseases and the risk of amputation. The acceptance of disease is one of the most important factors for adjusting to life with a chronic disease. Design A cross‐sectional survey study. Patients’ questionnaires. Method The participants were patients with peripheral artery disease (N = 72). The study included the use the standardized research tools the Acceptance of Illness Scale (AIS) and the Satisfaction with Life Scale (SWLS). Results The highest acceptance of disease was observed for patients with higher education, while the lowest was found for patients with the greatest limitation of physical mobility. Conclusions The education level and physical fitness of patients had significant impact on disease acceptance.

Introduction: The thyroid and parathyroid glands play a major role in maintaining physiological homeostasis in all vertebrates. Reptiles have plasma concentrations of thyroid hormones far lower than mammals. Low levels of these hormones in reptiles impede thyroid hormone detection with assays designed for the higher levels of mammals. The aim of this study was to explore teaming this with ultrasound imaging of the thyroid to appraise glandular function. Material and Methods: Thyroid function of four pond sliders was evaluated based on the results of T4 analyses and ultrasound. Results: The concentrations of T4 varied considerably between the examined animals from 167.3 nmol/L. Ultrasound examination revealed uniform echogenicity and a smooth outline of the thyroid gland in all animals. Conclusion: Monitoring of thyroid function based on T4 and electrolyte concentrations is helpful in assessing the health and living conditions of reptiles, which is important in veterinary practice but problematic. Ultrasound examinations are useful in diagnosing changes in gland structure, such as tumours and goitres, and a combination of both methods supports comprehensive assessments of the anatomy and function of the thyroid gland.

Background: The IPNV is one of the most common viral pathogens of rainbow trout (Oncorhynchus mykiss), while Y. ruckeri infections are widespread among bacterial agents. The current study aimed to determine the influence of IPNV and Y. ruckeri co-infection on a non-specific immune response. Methods: Two experiments were conducted. The first experiment determined the changes in non-specific immunity parameters upon the simultaneous occurrence of IPNV and Y. ruckeri infection. In the second experiment, infection with the IPNV was performed two weeks before Y. ruckeri infection. The level of total protein, gamma globulins, the activity of lysozyme and ceruloplasmin, as well as the metabolic activity and potential killing activity of phagocytes were measured: 0, 24 h, 72 h, 7 days, 14 days, and 21 days after co-infection. Results: A differentiated effect on the parameters of the non-specific immune response was shown between single infections with the IPNV and Y. ruckeri as well as co-infection with these pathogens. Conclusions: The immune response in the course of a co-infection depended on the time between infections. IPNV infection causes lysozyme activity suppression, which may lead to secondary bacterial infections.

The main goal of this study was to determine in vitro antimicrobial activity of ethanolic extracts obtained from the leaves of various Ficus species against Aeromonas hydrophila isolated locally from infected rainbow trout (Oncorhynchus mykiss Walbaum) with the aim of providing scientific rationale for the use of the plant in the treatment of bacterial infections induced by Aeromonas spp. in fish. Antimicrobial susceptibility testing was done on Muller-Hinton agar with the disc diffusion method. In the present study, most ethanolic extracts proved effective against the A. hydrophila tested, with 10-12 mm inhibition zones observed. A. hydrophila demonstrated the highest susceptibility to F. pumila. Among various species of Ficus with moderate activity against A. hydrophila, the highest antibacterial activities were noted for F. benghalensis, F. benjamina, F. deltoidea, F. hispida, and F. lyrata. Thus, Ficus can be used as a natural antiseptic and antimicrobial agent in veterinary practice. Further investigations need to be conducted to isolate and identify the bioactive compounds that can then be subjected to detailed pharmacological studies and the development of clinical applications. The alarming rate of increasing resistance in bacterial pathogens in aquaculture environments means that medicinal plants with antibacterial properties are very important as natural resources of new active compounds.

The aim of the work was to evaluate long-term results of studies focusing on improving methods for preventing and treating fish diseases using selected natural and syntetic immunomodulators and vaccines in fish culture. Simultaneously, attention is drawn to infectious or environmental threats against which appropriately composed immunoprophylaxis can be used in production cycles. Fish culture is intensifying in Poland and globally, which means that the role of prevention and well-designed prophylaxis is of increasing significance to the prevention and treatment of fish diseases. Currently, 33 fish species are cultured in Poland as stocking material or for production. The primary methods for preventing diseases in controlled fish culture are ensuring the welfare of fish and other prophylactic methods, including immunoprophylaxis. Many infectious and non-infectious threats that can cause direct losses and limit fish culture are present in the aquatic environment. Fish diseases generally stem from the simultaneous action of many factors that coincide and are difficult to distinguish. Pesticides (organochlorine insecticides, organophosphorus herbicides), aromatic hydrocarbons, pentachlorophenol, heavy metals, and chemotherapeutics are particularly toxic to fish. Biodegradation, which is continual in aquatic environments, is a process by which toxic and other substances that negatively affect fish become bioavailable and impact the immune system, the functioning of which is a specific bioindicator of environmental quality. Innate immunity plays a key role in the defense against disadvantageous factors, which also include pathogens. Immunomodulation methods can protect resistance mechanisms, thereby increasing disease prevention and treatment in controlled fish culture.

Introduction: The goal of this study was to assess the influence of vaccination against enteric redmouth disease on oxidative stress biomarkers and antioxidant defence in the muscle tissue of rainbow trout (Oncorhynchus mykiss Walbaum) vaccinated against Yersinia ruckeri in the first and second month after immunisation. Material and Methods: Healthy fish were vaccinated orally with inactivated whole cells of a virulent strain of Y. ruckeri. One and two months after immunisation the muscle samples were collected. Results: No significant difference was noted in lipid peroxidation level in either the first or second month after vaccination, while aldehydic and ketonic derivatives of oxidatively modified proteins (OMB) in the vaccinated group were significantly lower in the second month compared to those in the first month after vaccination (P < 0.05). The content of ketonic derivatives of OMB in muscles in the first month after immunisation was higher compared to untreated control. All these culminated in a depletion of glutathione peroxidase (GPx) activity and low level of total antioxidant capacity (TAC). Conclusion: Correlations between catalase activity and lipid peroxidation and TAC confirmed the pivotal role of catalase in antioxidant defence during immunisation. From a broader perspective, it is suggested that immunisation of fish with Yersinia vaccine is associated with induced free radical formation and oxidative stress. Free radicals would therefore be at least partially responsible for the induction of both humoral and cellular elements of the immunity and increased protective immunity against Y. ruckeri infection.

The impact of applying NuPro® (40 g/kg feed) and levamisole (300 mg/kg feed) in European pikeperch (Sander lucioperca) diets with vegetable oils on growth, immunological, hematological, and blood chemical parameters was assayed. The fish were fed the feed containing sunflower and linseed oils (48 and 21 g/kg feed) (group VO) or this feed with levamisole (group VOL) or NuPro® (group VON). The fourth group was fed the feed with fish oil added in the amount of 69 g/kg feed (group FO). The pikeperch were reared for 56 days. Feeding the fish feed supplemented with levamisole or NuPro® increased the immunological responses of the phagocytes and lymphocytes, lysozyme activity, and total gamma-globulin levels. The feed supplemented with NuPro® resulted in decreased aspartate and alanine aminotransferase and alkaline phosphatase activity. Vegetable oils in the feed were linked to increased contents of linoleic acid in fish bodies. The quantity of eicosapentaenoic and docosahexaenoic acids was significantly the highest in group FO. The immunological index obtained in group VON indicated that the diet supplemented with brewer's yeast extract (NuPro®) was the most advantageous when feeding juvenile pikeperch feeds with vegetable oils.

We present the preparation and characterization of novel metallosupramolecular thin films on solid substrates. These films incorporate metallosupramolecular polymers based on a tritopic cyclam bis-terpyridine ligand and are formed using different deposition techniques. From layer-by-layer (LBL) method, alternate thin multilayers of this metallosupramolecule along with oppositely charged polyelectrolyte are constructed by electrostatic self-assembly. Using dip-coating method, homogenous monolayers are deposited. The monolayer thickness is controlled by withdraw velocity of substrate. In a direct-assembly approach: Langmuir-Blodgett (LB), well-ordered metallosupramolecular monolayer is achieved by using a Metallosupramolecular Polyelectrolyte Amphiphile Complex (MPAC). The structures of these metallosupramolecular thin films are characterized by X-ray reflectivity (XRR), Atomic Force Microscopy (AFM), Langmuir isotherms, and UV/Vis absorption. The results open access to fabricate novel molecular materials such as sensors and memory devices., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The formation of self-assembled nanotubes is usually accounted for by anisotropic elastic properties of membranelike precursors. We present experimental data as evidence of the role played by electrostatics in the formation of self-assembled tubes in alkaline aqueous suspensions of lithocholic acid (LCA). Striking salt effects are characterized by comparing the rheological, dynamical, and scattering properties of systems prepared either in stoichiometric neutralization conditions (SC) of LCA or in a large excess of sodium hydroxide (EOC, experimentally optimized conditions) and finally, in two steps: stoichiometric neutralization followed by an appropriate addition of NaCl (AISC). The SC liquid system is originally made up of loose helical ribbons (previous transmission electron microscopy data), and upon aging they exhibit both intra- and interordering processes. Initially, the helical ribbons are loose and progressively wind around a cylinder (R = 330 Å) with their edges exposed to the solvent. They can be temporarily organized in a centered rectangular two-dimensional lattice (pgg, a = 224 Å, b = 687 Å). Upon further aging, the ribbons wind into more compact helical ribbons (or tubes with helical grooves): their edges are less-exposed and their ordering vanishes. Upon addition of NaCl salt (as in the AISC systems), the specific screening of the intra-aggregate electrostatic repulsions induces the closure of the ribbons into tubes (R(ext) = 260 Å, R(int) = 245 Å as in the EOC systems). Simultaneously with the closure of the ribbons into plain tubes, a drastic enhancement of their interconnectivity through van der Waals attractions develops. Eventually, gels are obtained with networks having hexagonal bundles of tubes.

The self-assembly and gelating ability of a set of N-alkyl-(R)-12-hydroxyoctadecylammonium chlorides (NCl-n, where n = 0-6, 18 is the length of the alkyl chain on nitrogen) are described. Several are found to be ambidextrous (gelating both water and a variety of organic liquids) and very efficient (needing less than ca. 0.5 wt % at room temperature). Structure-property correlations at different distance scales of the NCl-n in their hydro- and organo-gels and neat, solid states have been made using X-ray diffraction, neutron scattering, thermal, optical, cryo-SEM and rheological techniques. The self-assembled fibrillar networks consist of spherulitic objects with fibers whose diameters and degrees of twisting differ in the hydro- and organo-gels. Increasing n (and, thus, the molecular length) increases the width of the fibers in their hydrogels; an irregular, less pronounced trend between n and fiber width is observed in the corresponding toluene gels. Time-dependent, small angle neutron scattering data for the isothermal sol-to-gel transformation of sols of NCl-18/toluene to their gels, treated according to Avrami theory, indicate heterogeneous nucleation involving rodlike growth. Rheological studies of gels of NCl-3 in water and toluene confirm their viscoelastic nature and show that the hydrogel is mechanically stronger than the toluene gel. Models for the different molecular packing arrangements within the fibrillar gel networks of the hydro- and organogels have been inferred from X-ray diffraction. The variations in the fibrillar networks provide a comprehensive picture and detailed insights into why seemingly very similar NCl-n behave very differently during their self-assembly processes in water and organic liquids. It is shown that the NCl-n provide a versatile platform for interrogating fundamental questions regarding the links between molecular structure and one-dimensional self-aggregation, leading to gelation.

Supercritical carbon dioxide is used to prepare aerogels of two reference molecular organogelators, 2,3-bis-n-decyloxyanthracene (DDOA) (luminescent molecule) and 12-hydroxystearic acid (HSA). Electron microscopy reveals the fibrillar morphology of the aggregates generated by the protocol. SAXS and SANS measurements show that DDOA aerogels are crystalline materials exhibiting three morphs: (1) arrangements of the crystalline solid (2D p6m), (2) a second hexagonal morph slightly more compact, and (3) a packing specific of the fibers in the gel. Aggregates specific of the aerogel (volume fraction being typically phi approximately 0.60) are developed over larger distances (approximately 1000 A) and bear fewer defaults and residual strains than aggregates in the crystalline and gel phases. Porod, Scherrer and Debye-Bueche analyses of the scattering data have been performed. The first five diffraction peaks show small variations in position and intensity assigned to the variation of the number of fibers and their degree of vicinity within hexagonal bundles of the related SAFIN according to the Oster model. Conclusions are supported by the guidelines offered by the analysis of the situation in HSA aerogels for which the diffraction pattern can be described by two coexisting lamellar-like arrangements. The porosity of the aerogel, as measured by its specific surface extracted from the scattering invariant analysis, is only 1.8 times less than that of the swollen gel and is characteristic of a very porous material.

Structural and rheological features of a series of molecular hydrogels formed by synthetic bile salt analogues have been scrutinized. Among seven gelators, two are neutral compounds, while the others are cationic systems among which one is a tripodal steroid derivative. Despite the fact that the chemical structures are closely related, the variety of physical characteristics is extremely large in the structures of the connected fibers (either plain cylinders or ribbons), in the dynamical modes for stress relaxation of the associated SAFINs, in the scaling laws of the shear elasticity (typical of either cellular solids or fractal floc-like assemblies), in the micron-scale texture and the distribution of ordered domains (spherulites, crystallites) embedded in a random mesh, in the type of nodal zones (either crystalline-like, fiber entanglements, or bundles), in the evolution of the distribution and morphology of fibers and nodes, and in the sensitivity to added salt. SANS appears to be a suitable technique to infer all geometrical parameters defining the fibers, their interaction modes, and the volume fraction of nodes in a SAFIN. The tripodal system is particularly singular in the series and exhibits viscosity overshoots at the startup of shear flows, an "umbrella-like" molecular packing mode involving three molecules per cross section of fiber, and scattering correlation peaks revealing the ordering and overlap of 1d self-assembled polyelectrolyte species.

A tripodal cholic steroid ( TCS+) derivative forms hydrogels in acidic conditions that are studied by the small-angle neutron scattering and rheometry techniques. The self-assembled systems exhibit particular scattering and flow properties unusual in the class of molecular gels. The scattering data show separated form- and structure-factor features with, respectively, a low-Q correlation peak and a large-Q secondary oscillation. A probable aggregation model is deduced involving 3 TCS+ molecules per cross-section of fibrillar aggregates packed in a tail-to-tail fashion. The fibers have monodisperse cross-sections (40 A diameter) and result from a versatile mechanism taking advantage of the free articulation of the three hydrophobic steroid pods ("umbrella-like" packing) around the N+ charge. The N+ charges are distributed at the periphery of the cylinders and give rise to a moderate linear charge density (nu approximately 0.16 e/A). The variation with concentration of the static scattering structure factor peak S(Q) reveals ordering properties typical of 1d polyelectrolytes. The fibers further organize into fractal clusters characterized by their scattering signature at low-Q and also by the exponent of the scaling of the elastic shear modulus with the concentration. It is suggested that the TCS+ polyion fibers extend under shear (or in a concentrated environment) by varying the angle between the pods along the fiber axis. Viscosity overshoots appear at the startup of shear flow experiments. Analogies with the phenomenology observed with DNA solutions are discussed.