Adsorption of Denaturated Lysozyme at the Air-Water Interface: Structure and Morphology

The application of protein deuteration and high flux neutron reflectometry has allowed a comparison of the adsorption properties of lysozyme at the air-water interface from dilute solutions in the absence and presence of high concentrations of two strong denaturants: urea and guanidine hydrochloride (GuHCl). The surface excess and adsorption layer thickness were resolved and complemented by images of the mesoscopic lateral morphology from Brewster angle microscopy. It was revealed that the thickness of the adsorption layer in the absence of added denaturants is less than the short axial length of the lysozyme molecule, which indicates deformation of the globules at the interface. Two-dimensional elongated aggregates in the surface layer merge over time to form an extensive network at the approach to steady state. Addition of denaturants in the bulk results in an acceleration of adsorption and an increase of the adsorption layer thickness. These results are attributed to incomplete collapse of the globules in the bulk from the effects of the denaturants as a result of interactions between remote amino acid residues. Both effects may be connected to an increase of the effective total volume of macromolecules due to the changes of their tertiary structure, that is, the formation of molten globules under the influence of urea and the partial unfolding of globules under the influence of GuHCl. In the former case, the increase of globule hydrophobicity leads to cooperative aggregation in the surface layer during adsorption. Unlike in the case of solutions without denaturants, the surface aggregates are short and wormlike, their size does not change with time, and they do not merge to form an extensive network at the approach to steady state. To the best of our knowledge, these are the first observations of cooperative aggregation in lysozyme adsorption layers.

Effects of Aggregate Charge and Subphase Ionic Strength on the Properties of Spread Polyelectrolyte/Surfactant Films at the Air/Water Interface under Static and Dynamic Conditions

We demonstrate the ability to tune the formation of extended structures in films of poly(sodium styrenesulfonate)/dodecyltrimethylammonium bromide at the air/water interface through control over the charge/structure of aggregates as well as the ionic strength of the subphase. Our methodology to prepare loaded polyelectrolyte/surfactant films from self-assembled liquid crystalline aggregates exploits their fast dissociation and Marangoni spreading of material upon contact with an aqueous subphase. This process is proposed as a potential new route to prepare cheap biocompatible films for transfer applications. We show that films spread on water from swollen aggregates of low/negative charge have 1:1 charge binding and can be compressed only to a monolayer, beyond which material is lost to the bulk. For films spread on water from compact aggregates of positive charge, however, extended structures of the two components are created upon spreading or upon compression of the film beyond a monolayer. The application of ellipsometry, Brewster angle microscopy, and neutron reflectometry as well as measurements of surface pressure isotherms allow us to reason that formation of extended structures is activated by aggregates embedded in the film. The situation upon spreading on 0.1 M NaCl is different as there is a high concentration of small ions that stabilize loops of the polyelectrolyte upon film compression, yet extended structures of both components are only transient. Analogy of the controlled formation of extended structures in fluid monolayers is made to reservoir dynamics in lung surfactant. The work opens up the possibility to control such film dynamics in related systems through the rational design of particles in the future.

Terpyridine-functionalized stimuli-responsive microgels and their assembly through metal–ligand interactions

We developed a terpyridine-functionalized microgel (tpy-mG) for its supramolecular assembly.

General Physical Description of the Behavior of Oppositely Charged Polyelectrolyte/Surfactant Mixtures at the Air/Water Interface

This work reports a unifying general physical description of the behavior of oppositely charged polyelectrolyte/surfactant mixtures at the air/water interface in terms of equilibrium vs nonequilibrium extremes. The poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate system with added NaCl at two different bulk polyelectrolyte concentrations and the poly(sodium styrenesulfonate)/dodecyltrimethylammonium bromide system have been systematically examined using a variety of bulk and surface techniques. Similarities in the general behavior are observed for all the investigated systems. Following the slow precipitation of aggregates in the equilibrium two-phase region, which can take several days or even weeks, depletion of surface-active material can result in a surface tension peak. The limiting time scale in the equilibration of the samples is discussed in terms of a balance between those of aggregate growth and settling. Bulk aggregates may spontaneously dissociate and spread material in the form of a kinetically trapped film if they interact with the interface, and a low surface tension then results out of equilibrium conditions. These interactions can occur prior to bulk equilibration while there remains a suspension of aggregates that can diffuse to the interface and following bulk equilibration if the settled precipitate is disturbed. Two clear differences in the behavior of the systems are the position in the isotherm of the surface tension peak and the time it takes to evolve. These features are both rationalized in terms of the nature of the bulk binding interactions.

Effect of long-term culture on the biological and morphological characteristics of human adipose tissue-derived stem Cells

Mesenchymal stem cells (MSCs) are multipotent cells that can be obtained from different tissues, including bone marrow, adipose tissue, umbilical blood, Wharton's jelly, and dental pulp. Due to their differentiation potential, regenerative and immunosuppressive properties, as well as ability to expand under in vitro conditions, these cells represent a promising therapeutic tool for regenerative medicine. However, the basic prerequisite for the therapeutic utilization of MSCs is obtaining a sufficient amount. While this may be achieved by prolonged cultivation, long-term culture of MSCs is associated with accumulation of morphological and functional changes. In our study, we focused on analyzing morphological and biological changes of cultured adipose tissue-derived stem cells over 30 passages. We performed morphological analysis using light and electron microscopy, as well as analysis of selected biological properties (expression of surface antigens and selected genes involved in cell regulation and apoptosis, cell cycle, and cell senescence) every 5 passages. Our results showed that long-term expansion leads to significant changes in morphology and affects proliferation kinetics and the cell cycle. On the other hand, the MSCs maintained a prototypical immunophenotype, normal cell cycle and apoptosis regulator function, and maintained a low level of telomerase activity during later passages.

Telocytes (interstitial Cajal-like cells) in human Fallopian tubes

BACKGROUND

Telocytes represent a relatively newly discovered population of cells found within the various tissues and organs, including Fallopian tubes. It is presumed that telocytes could serve as a sensor of hormone levels or regulate activity of muscle peristaltic movement.

METHODS

Tissue sections from anatomically different parts of Fallopian tubes of 48 women (age 48.8±9.1) were stained for the expression of five different antigens: c-kit (CD117), CD34, vimentin, podoplanin (D2-40) and Dog-1.

RESULTS

Telocytes form a network associated with the smooth muscle cells. From the mentioned antibodies, only anti-c-kit (CD117) seems to be relatively selective specific to the telocytes, others react also with numerous other cells and tissue structures. Our results when using antibodies against podoplanin and Dog-1 are in dissonance with recent literature - with regards to our results, they are not suitable for detection of telocytes.

CONCLUSION

Methods of immunohistochemistry are suitable for identification of telocytes in Fallopian tubes. C-kit (CD117) antigens are useful for routine identification of telocytes in histological sections. This antigen can be combined with CD34 or vimentin in cases of double staining immunohistochemistry.

Polyelectrolyte/surfactant films spread from neutral aggregates

We describe a new methodology to prepare loaded polyelectrolyte/surfactant films at the air/water interface by exploiting Marangoni spreading resulting from the dynamic dissociation of hydrophobic neutral aggregates dispensed from an aqueous dispersion. The system studied is mixtures of poly(sodium styrene sulfonate) with dodecyl trimethylammonium bromide. Our approach results in the interfacial confinement of more than one third of the macromolecules in the system even though they are not even surface-active without the surfactant. The interfacial stoichiometry of the films was resolved during measurements of surface pressure isotherms in situ for the first time using a new implementation of neutron reflectometry. The interfacial coverage is determined by the minimum surface area reached when the films are compressed beyond a single complete surface layer. The films exhibit linear ripples on a length scale of hundreds of micrometers during the squeezing out of material, after which they behave as perfectly insoluble membranes with consistent stoichiometric charge binding. We discuss our findings in terms of scope for the preparation of loaded membranes for encapsulation applications and in deposition-based technologies.

Lloyd-model generalization: Conductance fluctuations in one-dimensional disordered systems

We perform a detailed numerical study of the conductance G through one-dimensional (1D) tight-binding wires with on-site disorder. The random configurations of the on-site energies ε of the tight-binding Hamiltonian are characterized by long-tailed distributions: For large ε, P(ε)∼1/ε^{1+α} with α∈(0,2). Our model serves as a generalization of the 1D Lloyd model, which corresponds to α=1. First, we verify that the ensemble average 〈-lnG〉 is proportional to the length of the wire L for all values of α, providing the localization length ξ from 〈-lnG〉=2L/ξ. Then, we show that the probability distribution function P(G) is fully determined by the exponent α and 〈-lnG〉. In contrast to 1D wires with standard white-noise disorder, our wire model exhibits bimodal distributions of the conductance with peaks at G=0 and 1. In addition, we show that P(lnG) is proportional to G^{β}, for G→0, with β≤α/2, in agreement with previous studies.

An embryological point of view on associated congenital anomalies of children with Hirschsprung disease

The most common congenital gut motility disorder is the Hirschsprung disease (HSCR). This anomaly is characterized by absence of neural crest-derived enteric neuronal ganglia. The aim of our study was to analyze the relationship between HSCR and other congenital anomalies or malfunctions. We examined 130 patients with Hirschsprung disease from Slovakia for last 10 years. During patients examination we focused not only on morphological abnormalities, but also functional anomalies. The incidence of associated congenital anomalies in our patients with HSCR was 26.1 %. But if we add functional defects (hypothyroidism, malfunction in cellular immunity, neurological deficit) to the morphological congenital abnormalities, the rate of the patients with HSCR with additional defects achieves 50.1 %. Nine of our patients (6.9 %) had syndromic HSCR. The most frequent disorder (13.6 % of patients) was primary deficiency in cellular immunity. More than 12.3 % of patients with HSCR had genitourinary abnormalities, in 10.0 % of patients variable degree of psychomotor retardation was observed, and skeletal, muscle and limb anomalies involved 7.7 % of patients. In 7.6 % cases of patients we found congenital hypothyroidism (including 2 cases of agenesis of thyroid gland). More than 6.1 % of patients presented with an associated anomaly in gastrointestinal tract (mostly anorectal malformations). Up to 5.5 % patients had congenital anomaly of heart, 3.8 % had ophthalmic and 3.1 % had craniofacial anomalies. Down syndrome was the main diagnosis in 3.8 % patients. We discussed  the relationship between HSCR and other anomalies, which are probably caused by abnormal migration, proliferation, or differentiation, of neural crest cells during embryogenesis (Tab. 1, Fig. 2, Ref. 75).

[Functional morphology of recently discovered telocytes inside the female reproductive system]

Discovery of telocytes has become an important and key challenge in past few years. These cells are interstitial cells extending very long cytoplasmic processes named telopodes, by which they create functional networks in the interstitium of different organs. Telocytes are considered to be connective tissue elements that create contacts among each other, but they also function as intercellular structures, functionally connected with cells of the immune system, neurons and smooth muscle cells. Telocytes can be found also in the different parts of female reproductive system with functions and purpose, which is summarized in our overview. Telocytes regulate for example peristaltic movements in fallopian tubes. The decrease of their number (due to inflammatory disease or endometriosis) causes impairment in transport through fallopian tubes which may result in sterility or tubal gravidity. In uterus they regulate contraction of myometrial smooth muscle (blood expulsion in menstrual phase, childbirth) as well as they contribute in immunological care during embryo implantation. Telocytes probably control also the involution of uterus after delivery. Their function in vagina has not been yet clearly defined; they probably take part in slow muscle contraction movement during sexual intercourse. In mammary glands some scientists suppose their function in control of cell proliferation and apoptosis, that is why, they may play a role in carcinogenesis. In placenta they probably monitor and regulate flow of blood in vessels of chorionic villi and they may be responsible also for etiopathogenesis of pre-eclampsy. All these mentioned functions of telocytes are only in the level of hypothesis and have been published recently. New research and studies will try to answer the questions whether telocytes play a key role in these processes. Our review we completed with some original microphotographs of telocytes in different organs of female reproductive system.

Ultrastructural analysis of different human mesenchymal stem cells after in vitro expansion: a technical review

Transmission electron microscopy reveals ultrastructural details of cells, and it is a valuable method for studying cell organelles. That is why we used this method for detailed morphological description of different adult tissuederived stem cells, focusing on the morphological signs of their functions (proteosynthetic activity, exchange with external environment, etc.) and their comparison. Preparing a specimen from the cell culture suitable for transmission electron microscopy is, however, much more challenging than routine tissue processing for normal histological examination. There are several issues that need to be solved while working with cell pellets instead of solid tissue. Here we describe a simple protocol for the isolation and culture of mesenchymal stem cells from different adult tissues, with applications to stem cell biology and regenerative medicine. Since we are working with population of cells that was obtained after many days of passaging, very efficient and gentle procedures are highly necessary. We demonstrated that our semi-conservative approach regarding to histological techniques and processing of cells for transmission electron microscopy is a well reproducible procedure which results in quality pictures and images of cell populations with minimum distortions and artifacts. We also commented about riskiest steps and histochemical issues (e.g., precise pH, temperature) while preparing the specimen. We bring full and detailed procedures of fixation, post-fixation, infiltration, embedding, polymerization and contrasting of cell obtained from in vitro cell and tissue cultures, with modifications according to our experience. All this steps are essential for us to know more about adult stem cells derived from different sources or about other random cell populations. The knowledge about detailed ultra-structure of adult stem cells cultured in vitro are also essential for their using in regenerative medicine and tissue engineering.

Cardiovascular Screening and Management Among Kidney Transplant Candidates in Hungary

INTRODUCTION

Cardiovascular disease is a major cause of morbidity and mortality in end-stage renal disease patients on dialysis and the most common cause of death in the immediate post-transplantation period. The aim of our study was to describe a novel approach of cardiovascular screening and management of dialysis patients evaluated for the transplant waiting list.

METHODS

Twenty-eight patients with end-stage renal disease put on the waiting list between July 2013 and July 2014 were subjected to a prespecified cardiovascular screening protocol utilizing noninvasive and/or invasive tests. Patients were subsequently divided into 3 strata in terms of their estimated cardiovascular risk. Each of these groups were then prescribed interventions aiming to improve their cardiovascular condition.

RESULTS

According to our prespecified protocol of cardiovascular screening studies, 15 (54%) patients were identified as low, 5 (18%) as intermediate, and 8 (28%) as high risk. Four (14%) patients were current smokers. In the low-risk group, we initiated a patient education program involving counseling on regular exercise such as swimming or cycling to improve their functional capacity. In the high-risk group revascularization was done in 5 cases (63%), including 3 percutaneous transluminal coronary angioplasties (PTCA) with stents for single-vessel disease, and coronary artery bypass graft surgeries (CABG) for triple-vessel disease in 2 cases. In the medium-risk group medical management was opted for, including introduction of beta-blockers, inhibitors, statins, and ezetimibe, as well as efforts to optimize anemia management, indices of bone-mineral disease, and fluid status.

CONCLUSION

In our regional transplant program, we introduced a comprehensive multidisciplinary approach to treat potential transplant candidates according to cardiovascular risk stratification based on a prespecified screening protocol. Further studies are needed to correlate this novel strategy with post-transplantation outcomes.

Synergetic effect of sodium polystyrene sulfonate and guanidine hydrochloride on the surface properties of lysozyme solutions

A study of the dilational surface viscoelastic properties of mixed solutions of lysozyme and denaturants allows us to characterize the changes of protein tertiary structure in the surface layer upon adsorption at the liquid–gas interface.

Emergence of energy dependence in the fragmentation of heterogeneous materials

The most important characteristics of the fragmentation of heterogeneous solids is that the mass (size) distribution of pieces is described by a power law functional form. The exponent of the distribution displays a high degree of universality depending mainly on the dimensionality and on the brittle-ductile mechanical response of the system. Recently, experiments and computer simulations have reported an energy dependence of the exponent increasing with the imparted energy. These novel findings question the phase transition picture of fragmentation phenomena, and have also practical importance for industrial applications. Based on large scale computer simulations here we uncover a robust mechanism which leads to the emergence of energy dependence in fragmentation processes resolving controversial issues on the problem: studying the impact induced breakup of platelike objects with varying thickness in three dimensions we show that energy dependence occurs when a lower dimensional fragmenting object is embedded into a higher dimensional space. The reason is an underlying transition between two distinct fragmentation mechanisms controlled by the impact velocity at low plate thicknesses, while it is hindered for three-dimensional bulk systems. The mass distributions of the subsets of fragments dominated by the two cracking mechanisms proved to have an astonishing robustness at all plate thicknesses, which implies that the nonuniversality of the complete mass distribution is the consequence of blending the contributions of universal partial processes.

Direct impact of nonequilibrium aggregates on the structure and morphology of Pdadmac/SDS layers at the air/water interface

We discuss different nonequilibrium mechanisms by which bulk aggregates directly modify, and can even control, the interfacial structure and morphology of an oppositely charged polyelectrolyte/surfactant (P/S) mixture. Samples are categorized at the air/water interface with respect to the dynamic changes in the bulk phase behavior, the bulk composition, and the sample history using complementary surface-sensitive techniques. First, we show that bulk aggregates can spontaneously interact with the adsorption layer and are retained in it and that this process occurs most readily for positively charged aggregates with an expanded structure. In this case, key nonequilibrium issues of aggregate dissociation and spreading of surface-active material at the interface have a marked influence on the macroscopic interfacial properties. In a second distinct mechanism, aggregates inherently become trapped at the interface during its creation and lateral flocculation occurs. This irreversible process is most pronounced for aggregates with the lowest charge. A third mechanism involves the deposition of aggregates at interfaces due to their transport under gravity. The specificity of this process at an interface depends on its location and is mediated by density effects in the bulk. The prevalence of each mechanism critically depends on a number of different factors, which are outlined systematically here for the first time. This study highlights the sheer complexity by which aggregates can directly impact the interfacial properties of a P/S mixture. Our findings offer scope for understanding seemingly mysterious irreproducible effects which can compromise the performance of formulations in wide-ranging applications from foams to emulsions and lubricants.

Removal of Ni (II) from Aqueous Solution by Adsorption onto Activated Carbon Prepared from Lapsi (Choerospondias axillaris) Seed Stone

Activated carbons were prepared from Lapsi seed stone by the treatment with H2SO4 and HNO3 for the removal of Ni (II) ions from aqueous solution. Two activated carbon have been prepared from Lapsi seed stones by treating with conc.H2SO4 and a mixture of H2SO4 and HNO3 in the ratio of 1:1 by weight for removal of Ni(II) ions. Chemical characterization of the resultant activated carbons was studied by Fourier Transform Infrared Spectroscopy and Boehm titration which revealed the presence of oxygen containing surface functional groups like carboxyl, lactones and phenols in the carbons. The optimum pH for nickel adsorption is found to be 5. The adsorption data were better fitted with the Langmuir equations than Freundlich adsorption equation to describe the equilibrium isotherms. The maximum adsorption capacity of Ni (II) on the resultant activated carbons was 28.25.8 mg g-1 with H2SO4 and 69.49 mg g-1 with a mixture of H2SO4 and HNO3. The waste material used in the preparation of the activated carbons is inexpensive and readily available. Hence the carbons prepared from Lapsi seed stones can act as potential low cost adsorbents for the removal of Ni (II) from water. DOI: http://dx.doi.org/10.3126/jie.v9i1.10680Journal of the Institute of Engineering, Vol. 9, No. 1, pp. 166–174

Effects of ionic strength on the surface tension and nonequilibrium interfacial characteristics of poly(sodium styrenesulfonate)/dodecyltrimethylammonium bromide mixtures

We rationalize the surface tension behavior and nonequilibrium interfacial characteristics of high molecular weight poly(sodium styrenesulfonate)/dodecyltrimethylammonium bromide (NaPSS/DTAB) mixtures with respect to the ionic strength. Excellent agreement is achieved between experimental data and our recent empirical model [Langmuir 2013, 29, 11554], which is based on the lack of colloidal stability of bulk aggregates in the phase separation region and has no free fitting parameters. We show that the size of a surface tension peak positioned at the edge of the phase separation region can be suppressed by the addition of inert electrolyte, which lowers the critical micelle concentration in relation to the phase separation region. Such manipulation of the peak is possible for the 100 ppm NaPSS/DTAB system because there is a high free surfactant concentration in the phase separation region. The close agreement of our model with the experimental data of samples in the phase separation region with respect to the ionic strength indicates that the surface tension behavior can be rationalized in terms of comprehensive precipitation regardless of whether there is a peak or not. The time scale of precipitation for the investigated system is on the order of one month, which emphasizes the need to understand the dynamic changes in the state of bulk aggregation in order to rationalize the surface properties of strongly interacting mixtures; steady state surface properties measured in the interim period will represent samples far from equilibrium. We show also that the surface properties of samples of low ionic strength outside the equilibrium phase separation region can be extreme opposites depending on the sample history, which is attributed to the generation of trapped nonequilibrium states. This work highlights the need to validate the underlying nature of oppositely charged polyelectrolyte/surfactant systems prior to the interpretation of experimental data within an equilibrium framework.

[New views on the functional morphology of human clitoris]

The clitoris is the female external sexual organ and is composed of erectile bodies. The distal portion of the vagina, clitoris and urethra form an integrated entity sui generis. All these components share a common vasculature and nerve supply and during sexual stimulation they respond as one functional unit. The clitoris is closely linked to the mechanism of sexual arousal in women. Glans has a dense network of receptors, innervated often with a several nerves at the same time - taking care of tactile sensitivity, thus, standing on the beginning of the journey, which culminates in orgasm. Nervus dorsalis clitoridis, which is a branch of n. pudendus, takes care of sensitive innervation. For blood supply is responsible a. clitoridis, which is a branch of a. pudenda interna. The most common congenital developmental anomalies of the clitoris include: clitoromegaly, penis-like clitoris and bifid clitoris. All, however, are among the relatively rare birth defects. Mechanism of orgasm gets attention between both laic and scientific community, although to this date there are speculations about its exact mechanism. There is relevant opinion, influenced by Freuds doctrine, which strictly recognizes two kinds of female orgasms - vaginal and clitoral, and, according to proponents of this theory, only the second mentioned is caused by stimulation of the clitoris. The second school unifies the term orgasm and claims that only clitoral stimulation (digital, penile, cunnilingus) and contraction of striated perineal muscle are responsible for orgasm, whether the glans (external part) or the body of the clitoris from the vaginal approach is stimulated. Therewithal, special term for mythical and still undocumented (despite many attempts and bold claims about its finding) G spot (named after Ernst Gräfenberg, a German doctor who predicted the existence of this place) is redundant. Important role in the regulation of female sexuality and responsiveness play a hormonal influences and varying concentrations of neurotransmitters.

The normal human newborns thymus

The thymic microenvironment constitutes a unique cell environment composed of thymic epithelial cells, myoid cells, and bone marrow-derived accessory cells for the differentiation, maturation and selection of T lymphocytes. The histological feature of thymus is markedly dependent on the age of individual and on various negative stimuli. Our study group consisted of fourteen newborns whose thymuses were removed during surgery performed for various congenital heart defects. We used a palette of seven monoclonal antibodies for exact localization of different cells creating the thymic microenvironment (cytokeratin AE1/AE3, desmin, actin, S100 protein, CD68, CD20, and CD45RO) as well as three monoclonal antibodies against proteins regulating the process of apoptosis (bcl2 oncoprotein, p53 protein, and survivin). We described and microphotographically illustrated the localization of thymic cytokeratin AE1/AE3-positive epithelial cells (subcapsular part of the cortex and medulla, especially Hassall's corpuscles), dendritic cells (medulla, often inside the Hassall's corpuscles), thymic myoid cells (medulla, often in close contact with Hassall's corpuscles), macrophages (mostly cortex, but also medulla and inside the Hassall's corpuscles), B lymphocytes (thymic medulla) and CD45RO-positive T lymphocytes (mostly thymic cortex). We found p53-positive thymic epithelial cell nuclei in subcapsular part of cortex and in outer epithelial cell layer of Hassall's corpuscles (very similar to the basal layer of epidermis). Bcl2 positive lymphocytes were mostly localized in thymic medulla, especially nearby Hassall's corpuscles. The thymuses were mostly survivin-negative with exception of round cells in border between cortex and connective tissue septa (probably migrating progenitor cells) (Tab. 1, Fig. 14, Ref. 66).

The long-term response to treatment with calcium channel blockers in a patient with idiopathic pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a disease characterised by a gradual increase in resistance of pulmonary circulation leading to right ventricular failure and death. In only 10 % of cases, there is a response to acute vasoreactivity testing with a significant reduction in mean pulmonary artery pressure (PAP), while in this group of patients, less than one half of cases benefit from long-term treatment with calcium channel blockers (CCB). This paper describes a case report of a young patient with dyspnoea and suspicion of pulmonary hypertension who was referred to a specialised centre. The complex evaluation of her clinical state led to confirmed diagnosis of idiopathic pulmonary arterial hypertension (IPAH). Because there was a positive response to vasoreactivity testing, the treatment for IPAH was initiated with a high dose of CCB. This treatment markedly improved her clinical state as well as echocardiographic and hemodynamic findings.In this study, the authors present a diagnostic algorithm in pulmonary hypertension and emphasise the role of CCB in treatment of PAH in carefully selected patients (Tab. 1, Fig. 5, Ref. 7).

Impact of pNIPAM microgel size on its ability to stabilize Pickering emulsions

We study the influence of the particle size on the ability of poly(N-isoprolylacrylamide) microgels to stabilize direct oil-in-water Pickering emulsions. The microgel size is varied from 250 to 760 nm, the cross-linking density being kept constant. The emulsion properties strongly depend on the stabilizer size: increasing the particle size induces an evolution from dispersed drops and fluid emulsions toward strongly adhesive drops and flocculated emulsions. In order to get insight into this dependency, we study how particles adsorb at the interface and we determine the extent of their deformation. We propose a correlation between microgel ability to deform and emulsion macroscopic behavior. Indeed, as the microgels size increases, their internal structure becomes more heterogeneous and so does the polymeric interfacial layer they form. The loss of a uniform dense layer favors bridging between neighboring drops, leading to flocculated and therefore less handleable emulsions.

Rupture cascades in a discrete element model of a porous sedimentary rock

We investigate the scaling properties of the sources of crackling noise in a fully dynamic numerical model of sedimentary rocks subject to uniaxial compression. The model is initiated by filling a cylindrical container with randomly sized spherical particles that are then connected by breakable beams. Loading at a constant strain rate the cohesive elements fail, and the resulting stress transfer produces sudden bursts of correlated failures, directly analogous to the sources of acoustic emissions in real experiments. The source size, energy, and duration can all be quantified for an individual event, and the population can be analyzed for its scaling properties, including the distribution of waiting times between consecutive events. Despite the nonstationary loading, the results are all characterized by power-law distributions over a broad range of scales in agreement with experiments. As failure is approached, temporal correlation of events emerges accompanied by spatial clustering.

Approach to failure in porous granular materials under compression

We investigate the approach to catastrophic failure in a model porous granular material undergoing uniaxial compression. A discrete element computational model is used to simulate both the microstructure of the material and the complex dynamics and feedbacks involved in local fracturing and the production of crackling noise. Under strain-controlled loading, microcracks initially nucleate in an uncorrelated way all over the sample. As loading proceeds the damage localizes into a narrow damage band inclined at 30°-45° to the load direction. Inside the damage band the material is crushed into a poorly sorted mixture of mainly fine powder hosting some larger fragments. The mass probability density distribution of particles in the damage zone is a power law of exponent 2.1, similar to a value of 1.87 inferred from observations of the length distribution of wear products (gouge) in natural and laboratory faults. Dynamic bursts of radiated energy, analogous to acoustic emissions observed in laboratory experiments on porous sedimentary rocks, are identified as correlated trails or cascades of local ruptures that emerge from the stress redistribution process. As the system approaches macroscopic failure consecutive bursts become progressively more correlated. Their size distribution is also a power law, with an equivalent Gutenberg-Richter b value of 1.22 averaged over the whole test, ranging from 3 to 0.5 at the time of failure, all similar to those observed in laboratory tests on granular sandstone samples. The formation of the damage band itself is marked by a decrease in the average distance between consecutive bursts and an emergent power-law correlation integral of event locations with a correlation dimension of 2.55, also similar to those observed in the laboratory (between 2.75 and 2.25).

New method to predict the surface tension of complex synthetic and biological polyelectrolyte/surfactant mixtures

Although the surface tension of complex mixtures determines the fate of many important natural processes, the property is notoriously difficult to interpret. Here we announce a new method that successfully predicts the surface tension of two synthetic and one biological polyelectrolyte/surfactant mixtures in the phase-separation region after dynamic changes in the bulk phase behavior have reached completion. The approach is based on the nonequilibrium framework of a lack of colloidal stability of bulk complexes in compositions around the charge match point of the oppositely charged components and requires as input parameters only the surface tension isotherm of the pure surfactant and some bulk measurements of the mixtures; no surface measurements of the mixtures are required. The complexity of the problem is reduced to a single empirical equation. This simplification in our understanding of the surface properties of strongly interacting mixtures involving macromolecules can lead to the optimization of applications involving synthetic polymers and biomacromolecules such as DNA at surfaces.

[The structural basis for transport through the Fallopian tube]

The Fallopian tube has until recently been a neglected structure, bypassed by in vitro fertilization and seen only as a tube that transports the oocyte or early embryo to the uterus. More recently, its role is even more undervalued after the introduction of techniques of assisted reproduction, in which the Fallopian tubes become like unnecessary. The Fallopian tube performs several important functions. It captures the oocyte after ovulation, maintains and controls the migration of spermatozoa to the site of fertilization. It provides the special microenvironment for fertilization; nourishes the early embryo while it is being carried to the uterus and amplifies signals from embryo to the mother. In our article we conducted a systematic review of relevant articles found in PubMed, Scopus and ISI Web of Knowledge, focused on the new insights into the functional morphology of Fallopian tube. We described the possible function of muscle layer motility, ciliary activity and tubal fluid movement on transport of gamets / embryo, as well as we mentioned the negative factors (such as smoking, chlamydial infection or endometriosis) affecting the transport through the Fallopian tube.

Lateral dynamics of surfactants at the free water surface: a computer simulation study

Molecular dynamics simulations of the adsorption layer of five different surfactant molecules, i.e., pentyl alcohol, octyl alcohol, dodecyl alcohol, sodium dodecyl sulfate, and dodecyl trimethyl ammonium chloride are performed at the free surface of their aqueous solution at two surface densities, namely 1 and 4 μmol/m(2) at 298 K. The results are analyzed in terms of the two-dimensional single molecule dynamics, in particlular, lateral diffusion of the surfactants at the liquid surface, in order to distinguish between two possible adsorption scenarios, namely the assumptions of localized and mobile surfactants. The obtained results, in accordance with the dynamical nature of the liquid phase and liquid surface, clearly support the latter scenario, as the time scale of lateral diffusion of the surfactant molecules is found to be comparable with that of the three-dimensional diffusion of water in the bulk liquid phase. The mechanism of this lateral diffusion is also investigated in detail by calculating binding energy distribution of the water molecules in the first hydration shell of the surfactant headgroups and that of the nonfirst shell surface waters, and by calculating the mean residence time of the water molecules in the first hydration shell of the surfactant headgroups. This time is found to be at least an order of magnitude smaller than the characteristic time of the lateral diffusion of the surfactants, revealing that surfactant molecules move without their first shell hydration water neighbors at the surface.

Adsorption and solution properties of bottle-brush polyelectrolyte complexes: effect of molecular weight and stoichiometry

Polyelectrolyte complexes (PECs) self-assembled from bottle-brush polyelectrolytes, having a cationic main chain and uncharged side chains, and linear anionic sodium polystyrenesulfonate (NaPSS) have been investigated with emphasis on (i) the charge density and side chain density of the bottle-brush polyelectrolyte, (ii) the molecular weight of NaPSS, and (iii) the charge stoichiometry of the mixture. Light scattering and electrophoretic mobility data demonstrate that small molecular complexes are formed when the PEO45 side chain density is sufficiently high to provide steric stabilization and prevent PEC aggregation. The adsorption of PECs on negatively charged silicon oxynitride was investigated using dual polarization interferometry, and the time evolution of the adsorbed amount and thickness was determined. Cationic, uncharged, and negatively charged complexes all adsorb to negatively charged silicon oxynitride, and maximum adsorption is achieved for positively charged complexes containing small amounts of PSS. The adsorbed amount and the kinetics of adsorption are reduced with increasing PSS content, and for any given stoichiometry with increasing PSS molecular weight. These findings are discussed in terms of the PEC structure and the ability of anionic polyelectrolytes to leave the PECs during adsorption.

Growth factors and chondrogenic differentiation of mesenchymal stem cells

The main purpose of the article is to review recent knowledge about growth factors and their effect on the chondrogenic differentiation of mesenchymal stem cells under in vitro conditions. Damaged or lost articular cartilage leads to progressive debilitation, which have major impact on the life quality of the affected individuals of both sexes in all age groups. Mature hyaline cartilage has a very low self-repair potential due to intrinsic properties - lack of innervation and vascular supply. Another limiting factor is low mitotic potential of chondrocytes. Small defects are healed by migration of chondrocytes, while large ones are healed by formation of inferior fibrocartilage. However, in many cases osteoarthritis develops. Recently, cellular therapy combining mesenchymal stem cells and proper differentiation factors seems to be promising tool for hyaline cartilage defects healing.

Quantum chaos in one dimension?

In this work we investigate the inverse of the celebrated Bohigas-Giannoni-Schmit conjecture. Using two inversion methods we compute a one-dimensional potential whose lowest N eigenvalues obey random matrix statistics. Our numerical results indicate that in the asymptotic limit N→∞ the solution is nowhere differentiable and most probably nowhere continuous. Thus such a counterexample does not exist.

Preparation of monodisperse poly(N-isopropylacrylamide) microgel particles with homogenous cross-link density distribution

Monodisperse microgel latex with homogeneous cross-link density distribution within the particles was prepared by feeding the monomer and cross-linker into the reaction mixture in a regulated way during the polymerization. To determine the appropriate monomer feeding parameters, the kinetics of the particle formation was investigated by HPLC. The swelling and optical characteristics of the prepared homogenously cross-linked microgel particles were compared to the properties of inhomogenously cross-linked microgels prepared by the normal precipitation polymerization method. The distribution of the cross-link density within the particles inserts a great influence on the characteristics of the system. The degree of swelling of the homogeneous particles is significantly higher than that of the heterogeneous microgel particles. Furthermore, at room temperature the pNIPAm latex containing the homogeneously cross-linked particles is transparent, while the heterogeneously cross-linked particles form a highly turbid system at the same 0.1 wt% concentration.

Attraction-driven aggregation of dipolar particles in an external magnetic field

We present a detailed experimental study of the aggregation of particles of permanent magnetic moment in an external magnetic field. The experiments are performed with millimeter-sized particles floating on the surface of water. Due to the large size of the particles, thermal noise does not have any relevance in the system; the particles undergo deterministic motion. Experiments are carried out varying the concentration which also controls the relative importance of the dipole-external field and the dipole-dipole interactions. We determined the exponents characterizing the aggregation process and found that the attraction driven aggregation of dipolar particles obeys the Vicsek-Family dynamic scaling. The exponents are found to have a concentration dependence which can be attributed to the change of mobility of clusters and their interaction at higher concentrations.

Adsorption characteristics of stoichiometric and nonstoichiometric molecular polyelectrolyte complexes on silicon oxynitride surfaces

Adsorption properties of stoichiometric and nonstoichiometric polyelectrolyte complexes (PECs) have been investigated by means of dual polarization interferometry (DPI) and X-ray photoelectron spectroscopy (XPS). Poly(sodium styrenesulfonate) (NaPSS) of molecular weight 4300 g/mol was used as polyanion, and two bottle-brush copolymers possessing different molar ratios of the cationic segment methacryloxyethyltrimethylammonium chloride (METAC) and the nonionic segment poly(ethylene oxide) methyl ether methacrylate (PEO(45)MEMA) were used as polycations. They are referred to as PEO(45)MEMA:METAC-25 and PEO(45)MEMA:METAC-50, where the last digits denote the mol % of charged main-chain segments. The time evolution of the adsorbed amount, thickness, and refractive index of the PEC layers were determined in aqueous solution using DPI. We demonstrate that cationic, uncharged, and negatively charged complexes adsorb to negatively charged silicon oxynitride and that maximum adsorption is achieved when small amounts of PSS are present in the complexes. The surface composition of the adsorbed PEC layers was estimated from XPS measurements that demonstrated very low content of NaPSS. On the basis of these data, the PEC adsorption mechanism is discussed and the competition between PSS and negative surface sites for association with the cationic polyelectrolyte is identified as a key issue.

Biological and morphological characterization of in vitro expanded human muscle-derived stem cells

Stem cells are generally characterised as clonogenic and undifferentiated cells with the capacity of self-renewal and plasticity. Over the past few years, the adult stem cells have been derived from various types of tissues including the skeletal muscle. The main goal of the present study was the isolation, in vitro expansion and characterisation of muscle-derived stem cells (MDSCs). Thereby obtained results showed that MDSCs have a fibroblast-like shape with a large nucleus having one to four nucleoli. The cytoplasm was transparent without any signs of vacuolisation. TEM analysis showed an ultrastructure of cells with high proteosynthetic activity. MDSCs had a large and irregular nucleus with variable number of nucleoli. The cytoplasm contained a richly developed and rough endoplasmic reticulum, prominent Golgi apparatus cisterns as well as transport vesicles containing glycogen granules and variable microvilli and filopodia. They expressed alpha-actin and desmin. Results of the phenotypic characterization showed that the analyzed cells were positive for CD29, CD34, CD44, CD90, CD105 and HLA Class I. They did not express CD14, CD45, CD235a, HLA Class II and human fibroblast surface protein. According to these results it should be emphasised that MDSCs after performing the detailed studies focused on their immunological properties and differentiation potential may be used in the cell therapy of many degenerative diseases.

The thymus: picture review of human thymus prenatal development

The thymus is derived from pharyngeal region; a region from which, in case of aquatic vertebrates, the gills develop. According to the classical hypothesis, the epithelial thymus stroma of human embryos is derived from the endodermal cells of the left and right ventral parts of the third pharyngeal pouches. But a close contact of the third pharyngeal pouch with its corresponding third pharyngeal clefts ectoderm plays an important role. Also an epithelial-mesenchymal interaction between the third pharyngeal pouch endoderm and surrounding neural crest derived-cells ectomesenchyme is necessary for the proliferation and differentiation of thymic epithelial cells. In our work we photographically presented the development of thymus from the 6th up to the 25th week of development. The first primordia of the thymus and parathyroid glands within the endoderm of third pharyngeal pouches can be seen in 8 to 9 mm stages. We found also an epithelial proliferation in the second pharyngeal pouches, but this "thymus secundus" stopped their differentiation. The thymus primordia at the 7th and 8th week of development contain almost exclusively epithelial cells. These cells are arranged at the periphery as a row of prismatic cells. The mesenchyme accumulates around the epithelial thymic primordium, and during 9th to 12th weeks of development, septa from mesenchyme fold between the epithelial cells and create the "openings" in the capsular surround. According to our observations, in the 13th week of development the differentiation of cortex and medulla becomes obvious and is completed from the 17th up to 18th week of development onward. The first developing Hassall's corpuscle was detected in the 13th week of development. The striking increase in the number of the Hassall's bodies was observed between the 16th and the 18th week of development, as well as between the 22nd and the 25th week of development (Fig. 14, Ref. 35).