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The dynamic surface properties of aqueous dispersions of α-lactalbumin (ALA) amyloid fibrils differ noticeably from the properties of the fibril dispersions of other globular proteins. As a result, the protocol of the application of ALA fibrils to form stable foams and emulsions has to be deviate from that of other protein fibrils. Unlike the fibrils of β-lactoglobulin and lysozyme, ALA fibrils can be easily purified from hydrolyzed peptides and native protein molecules. The application of the oscillating barrier method shows that the dynamic surface elasticity of ALA fibril dispersions exceeds the surface elasticity of native protein solutions at pH 2. ALA fibrils proved to be stable at this pH, but the stability breaks at higher pH levels when the fibrils start to release small peptides of high surface activity. As a result, the dynamic surface properties of ALA coincide with those of native protein solutions. The ionic strength strongly influences the adsorption kinetics of both fibril dispersions and native protein solutions but have almost no impact on the structure of the adsorption layers. [ABSTRACT FROM AUTHOR]

Summary: Background: Long‐term administration of TDF/ETV in patients with HBV‐related compensated cirrhosis reduces HCC and decompensation events but the effect of this regimen on development/regression of oesophageal varices (EV) is currently unknown. Aim: To assess the risk of EV development/progression in this population. Methods: A total of 186 Caucasian HBV‐monoinfected compensated cirrhotics were enrolled in a long‐term cohort study from TDF/ETV introduction. Upper GI endoscopies were performed according to Baveno recommendations. Primary endpoint was development/progression of oesophageal/gastric varices over time. Results: At TDF/ETV start, median age was 61 years, 80% males, 60% HBV‐DNA undetectable, 63% NUCs previously exposed, 73% normal ALT, 40% platelets <150,000/mmc and 25 (13%) with low‐risk varices (LRV). During 11 years of antiviral therapy and 666 endoscopies performed, 9 patients either developed or had a progression of oesophageal or gastric varices with an 11‐year cumulative probability of 5.1% (95% CI 3–10%); no patient bled. Out of 161 patients without EV at baseline, the 11‐year probably was 4.5% with all varices developing within the first six years of treatment. In 25 patients with LRV at baseline, the 11‐year probability of progression or regression was 9.3% and 58%, respectively. Only baseline platelet count (HR 0.96, p = 0.028) was associated with LRV development at multivariate analysis: platelet ≤90,000/mmc (AUROC 0.70) had 98.1% specificity, 42.9% sensitivity, 50% PPV for LRV onset. Conclusions: In compensated cirrhotic patients under long‐term effective TDF/ETV treatment, the 11‐year risk of developing/progressing EV is negligible, thus challenging the current endoscopic surveillance recommendations in patients without EV at baseline. [ABSTRACT FROM AUTHOR]

Dynamic dilational viscoelasticity is an important physical characteristic of interfacial layers because it influences the dynamics and stability of multiphase systems, such as thin liquid films, foams and emulsions. Dilational viscoelasticity depends on many factors. Less studied, but very important, factors are the solubility of the solution components in two contacting liquids, the simultaneous presence of two solution components within a mixed adsorption layer and the curvature of the interface. In this review, we considered several new developments of previously proposed models, which can be used for the analysis of new experimental data. In the presence of such effects, the behaviour of the dilational viscoelasticity becomes more complicated and requires more parameters for its description. An alternative way is to use phenomenological models, which do not identify the particular relaxation processes but propose a description of the dilational viscoelasticity in general terms. [Display omitted] [ABSTRACT FROM AUTHOR]

The entry inhibitor bulevirtide (BLV) received conditional approval from the EMA in July 2020 for the treatment of adult patients with compensated chronic hepatitis delta. However, the effectiveness and safety of BLV administered as monotherapy beyond 48 weeks in difficult-to-treat patients with HDV-related cirrhosis is presently unknown. Herein, we describe the first patients with HDV-related compensated cirrhosis who were treated with BLV (10 mg/day as a starting dose) for up to 3 years on a compassionate use program. Patients were also monitored for HBcrAg and HBV RNA levels, and HDV- and HBV-specific T-cell markers. In the patient who stopped BLV at week 48, after achieving a virological and biochemical response, the initial virological and biochemical rebound was followed by alanine aminotransferase normalization coupled with low HDV RNA and HBsAg levels. In the 2 patients treated continuously for 3 years, virological and biochemical responses were maintained throughout the treatment period even after dose reduction. In a patient with advanced compensated cirrhosis, liver function tests significantly improved, esophageal varices disappeared, and histological/laboratory features of autoimmune hepatitis resolved. Overall, no safety issues were recorded, as bile salt increase was asymptomatic. While serum HBV RNA levels remained undetectable in all patients, HBV core-related antigen levels showed a progressive, yet modest decline during long-term BLV treatment. No HDV-specific interferon-γ-producing T cells were detected, neither after HDV reactivation (after BLV withdrawn in Patient 1) nor during 3 years of BLV treatment. In conclusion, this report shows that continuous administration of BLV monotherapy for 3 years leads to excellent virological and clinical responses in patients with HDV-related cirrhosis who had contraindications to interferon-based therapies. [ABSTRACT FROM AUTHOR]

Background & Aims: Protein induced by vitamin K absence or antagonist‐II (PIVKA‐II) has been suggested as a serum biomarker for hepatocellular carcinoma (HCC) in Asian hepatitis B virus (HBV)‐treated subjects but no studies tested it in Caucasian cirrhotics long‐term nucleos(t)ide analogues (NUCs)‐treated. We assessed the detection accuracy of PIVKA‐II alone or in combination with alpha‐foetoprotein (AFP) in patients under surveillance. Methods: This cross‐sectional, single centre case‐control study was conducted in 212 NUC‐treated cirrhotics: 64 HCC and 148 HCC‐free controls for 84 (60‐107) months. PIVKA‐II was determined by a CMIA immunoassay (Abbott; limit of quantification: 8.2 mAU/mL). Results: Protein induced by vitamin K absence or agonist II (PIVKA‐II) and AFP levels were significantly higher in HCC patients [Barcelona Clinic Liver Cancer staging system stage 0/A in 91%, diameter 20 (6‐50) mm] compared to controls: 109 (17‐12 157) vs 31 (13‐82) mAU/mL and 5 (1‐1163) vs 2 (1‐7) ng/mL (P <.001 for both markers), with a cut‐off of 48 mAU/mL and 4.2 ng/mL by AUROC analysis. The PIVKA‐II 82 mAU/mL and AFP 7 ng/mL cut‐offs showed 100% specificity, with the former more sensitive (54% vs 42%), accurate (86% vs 83%), with higher negative predictive value (80% vs 76%) compared to AFP for HCC detection. PIVKA‐II more frequently than AFP levels exceeded the cut‐off 6‐18 months before HCC diagnosis. Combining PIVKA‐II with AFP increased sensitivity, accuracy and negative predictive values to 67%, 90% and 85%, preserving 100% specificity. PIVKA‐II was associated with lesions >20 mm or neoplastic thrombosis. Conclusions: Combination of PIVKA‐II and AFP increases the detection rate for HCC in NUC‐treated HBV Caucasian cirrhotics, a potential new approach for surveillance. [ABSTRACT FROM AUTHOR]

Short-term administration of the entry inhibitor myrcludex-B (MyrB) has been shown to be safe and effective in phase II studies in patients coinfected with hepatitis B virus (HBV) and hepatitis delta virus (HDV). However, its effectiveness and safety are unknown during long-term and high-dose treatment of patients with compensated cirrhosis in real-life settings. Herein, we describe the first 3 European patients with HDV-related compensated cirrhosis who were treated with MyrB 10 mg/day for 48 weeks as a compassionate therapy. Liver function tests, bile acids, and virological markers were monitored every 4 weeks. HBV/HDV-specific T cell quantity (up to 48 and 36 weeks) and HBV RNA levels were also assessed in 2 cases. During MyrB treatment, HDV RNA levels progressively declined from 4.4 and 5.6 logs IU/ml to undetectability in 2 cases, and from 6.8 log copies/ml to 500 copies/ml for the other patient. Alanine aminotransferase normalised after 20, 12 and 28 weeks, respectively. A significant improvement in features of portal hypertension, liver function tests and alpha-fetoprotein levels were documented in 2 cases. In the male patient with histological and clinical stigmata of autoimmune hepatitis, IgG and immunoglobulins rapidly normalised. No significant changes in HBV surface antigen levels and circulating HBV/HDV-specific T cells were demonstrated; HBV DNA and HBV RNA levels remained undetectable throughout the study period. MyrB was well tolerated; patients remained fully asymptomatic despite a significant increase of bile acids. In conclusion, this report shows excellent safety and effectiveness of a 48-week course of MyrB 10 mg/day, combined with tenofovir disoproxil fumarate, for the treatment of HDV-related compensated cirrhosis. [ABSTRACT FROM AUTHOR]

Background & Aims: In Caucasian patients with compensated cirrhosis caused by hepatitis B virus (HBV), the risk of hepatocellular carcinoma (HCC) developing persist despite long‐term nucleos(t)ide analogs (NUC) treatment. In the surveillance of this population with persistently normal transaminases because of NUCs, the added value of serum alpha‐foetoprotein (AFP) monitoring is poorly defined. Methods: Two hundred and fifty‐eight Caucasian HCC‐free patients with HBV‐compensated cirrhosis who started tenofovir or entecavir while having normal serum AFP levels (≤7 ng/mL) at baseline or within the first year of treatment underwent HCC surveillance by semiannual ultrasound evaluation and serum AFP determination. Results: During 96 (18‐120) months of antiviral therapy, 3947 AFP values were collected, median AFP level was 2 ng/mL. Thirty‐five patients developed an HCC at an overall 8‐year crude cumulative incidence of 14% (annual incidence of 2%). HCC incidence increased in parallel with increasing AFP thresholds: 24%, 36%, 64% and 92% for AFP levels after exceeding 2, 4, 6 and 7 ng/mL for the first‐time. Of the 12 patients who experienced an AFP rise > 7 ng/mL, 11 developed an HCC and one had liver metastases of lung cancer. Overall, an AFP > 7 ng/mL had 99.6% specificity, 31.4% sensitivity, 91.7% PPV, 90.2% NPV, LR+ 70.1 and LR− 0.69 for HCC; this excellent specificity was maintained up to 18 months before HCC detection. Conclusions: In Caucasian patients with HBV‐compensated cirrhosis on long‐term NUC, an increase in AFP over 7 ng/mL shows excellent specificity, heralding HCC development within 1 year. [ABSTRACT FROM AUTHOR]

In this work, dynamic surface properties of spread monolayers of DPPC and adsorbed layers of PS solutions were investigated in a broad range of surface pressure. Application of a modified Langmuir trough and a recently developed approach for the analysis of a non-linear response of the adsorption layer to large surface deformations gives a possibility to determine the dilational surface elasticity in the region of high surface pressures corresponding to the physiological state of the lung alveoli surface. Although DPPC is the main component of the complex pulmonary surfactant (PS) mixture, the dynamic surface properties of the adsorption layers of these two compounds are different. Other components in the PS adsorption layer lead to a decrease of the dynamic surface elasticity due to a looser packing of the layer, as confirmed by ellipsometry and infrared reflection absorption spectroscopy. Moreover, in the region of high surface pressures the main relaxation time of the surface stresses is much lower than that for spread DPPC monolayers. The fast relaxation in the adsorption layer can be connected with the redistribution of molecules between the surface and the subsurface layer in the course of compression. The acceleration of the relaxation processes can lead to a decrease of the number and size of collapsed parts of the layer and thereby to a decrease of the number of molecules with lost functional properties. This effect can be one of the reasons for the lower efficiency of synthetic pharmaceutical drugs, which do not have proteins in their composition, as compared with the natural PS extracted from animal lungs. [ABSTRACT FROM AUTHOR]

Summary: Background: Long‐term oral nucleos(t)ide analogue (NUC) therapy in hepatitis B virus (HBV)‐related compensated cirrhotics prevents clinical decompensation but not hepatocellular carcinoma (HCC) development. Aims: To define the clinical features and outcomes of HCC in long‐term NUC‐treated HBV patients. Methods: All HCCs developing between 2005 and 2016 in NUC‐treated HBV patients under surveillance were studied, excluding those that occurred within the first 6 months of therapy. Clinical features of HCC, alpha faetoprotein (AFP) patterns and patients' outcome were studied. Results: Seventy‐six HCC patients were included. Median age was 67 (40‐83) years, 84% males, 96% Caucasian, 95% HBeAg‐negative, 96% with undetectable HBV DNA, 83% with normal ALT levels, and 92% with compensated cirrhosis. Median serum AFP levels were 4 (1‐3615) ng/mL (>7 ng/mL in 36%). HCC was monofocal in 78%, had a median diameter of 20 (6‐57) mm and was in its early stage in 92% which allowed potentially curative treatments in 78% (39% ablation, 28% surgical resection, 11% liver transplantation). Overall, a complete response was obtained in 61 (80%) patients: in 40 after a first‐line treatment, in 3 after the second–line treatment, in 2 after the third‐line treatment, while 16 underwent liver transplantation (8 as second line). During 45 (7‐144) months after HCC diagnosis, 19 patients died, 84% from HCC progression. The median time to recurrence was 20.2 (3‐53) months, and the cumulative 5‐year liver‐related survival was 74%. Conclusions: HCCs developing in patients under long‐term NUC treatment were single, small tumours, amenable to curative therapies able to confer excellent 5‐year survival rates. [ABSTRACT FROM AUTHOR]

A new approach to the analysis of nonlinear surface dilational rheological properties was developed with the aim to enlarge the accessible range of surface pressures. The dilational surface elasticity of spread monolayers of DPPC, cholesterol, DMEA and their mixtures was determined in the region of low surface tensions (less than 10 mN/m) corresponding to the state of pulmonary surfactants at the lung interface. The dilational surface elasticity of pure DPPC monolayer proved to be high (∼200 mN/m) up to the collapse. The addition of cholesterol, DMEA or their mixture to the DPPC monolayer increased the dynamic surface elasticity, but could decrease significantly the surface pressure of the monolayer collapse if the concentration of additions exceeds an optimal value. [ABSTRACT FROM AUTHOR]

Tenofovir disoproxil fumarate (TDF) is a recommended first-line therapy for both naïve and experienced patients with chronic hepatitis B (CHB), although reduced estimated glomerular filtration rate (eGFR), hypophosphatemia, hyperphosphaturia and Fanconi syndrome have been reported in some patients. Entecavir (ETV) could be considered as a rescue therapy for TDF-treated patients developing renal dysfunction, though patients with prior history of treatment with lamivudine (LAM) can develop ETV resistance strains, which can lead to potentially severe hepatitis flares. Tenofovir alafenamide (TAF), a new prodrug of tenofovir, has recently been developed to improve the renal and bone safety profile compared to TDF, while maintaining the same virologic efficacy. The recently published 48-week phase III TAF registration studies confirmed the superior safety profile. Here we describe a case of a 75-year-old woman with HBV mono-infection and compensated cirrhosis who developed ETV resistant strains and grade 3 chronic kidney disease after many years of LAM and adefovir (ADV) treatment and a TDF-induced Fanconi syndrome. The administration of 25 mg/day of TAF, granted as part of a compassionate use program, rapidly suppressed viral replication to undetectable levels without worsening renal function or side effects. [ABSTRACT FROM AUTHOR]

Measurements by capillary pressure tensiometry, under microgravity conditions aboard the International Space Station, supplied a consistent set of reliable results for the dynamic interfacial tension and for the interfacial dilational viscoelastic modulus, quantitatively characterizing the dynamics of Span-80 adsorbed layers at the paraffin-oil/water interface. The experiments were executed at three different temperatures, i.e., 20, 30 and 40 °C, according to a pre-established built-in time-line in the orbiting facility. The interfacial area was subjected to perturbations with various functional forms (square pulses, ramps and harmonic oscillations), at three consecutive amplitudes (5%, 10% and 20%). Each experiment was performed in three successive repetitions, in view of an advantageous telemetered data redundancy. The interfacial responses to imposed perturbations, for the studied minimal surfactant concentration of Span-80 in paraffin-oil (that is (2 ÷ 3) × 10 −5 mol/dm 3 ) revealed a diffusion-controlled adsorption mechanism, definitely matching the Lucassen & Van den Tempel model in the frequency-domain representation. The interfacial responses also showed a linearity range up to the 20% amplitude. Interfacial relaxation responses to transient interfacial perturbations substantially validated the diffusion-controlled model for the adsorption mechanism, in the time-domain representation. [ABSTRACT FROM AUTHOR]

The goal of antiviral therapy is to improve the quality of life and survival of patients with chronic hepatitis B ( CHB) by halting the progression to cirrhosis, end-stage liver disease or hepatocellular carcinoma ( HCC), thus preventing anticipated liver-related death. Oral administration of potent and less resistance-prone nucleot(s)ide analogues ( NUCs), such as entecavir ( ETV) and tenofovir disoproxil fumarate ( TDF) has become the most popular treatment strategy worldwide because of their excellent efficacy and safety profile as well as easy management confirmed in both registration trials and in clinical practice studies. Long-term administration of ETV or TDF suppresses HBV replication in >95% of patients, resulting in biochemical remission, histological improvement including the regression of cirrhosis and prevention or reversal of clinical decompensation but not the development of HCC, particularly in patients with cirrhosis. Moreover, NUCs can be administered to all patients including those with severe liver disease, the elderly and in those who do not respond, are unwilling to take or have contraindications to interferon. The need for long-term, perhaps indefinite, treatment is the main limitation of NUCs therapy with the associated costs, unknown long-term safety and the low rates of hepatitis B surface antigen ( HBsAg) seroclearance, which is still the best stopping rule for NUCs-treated patients with cirrhosis. [ABSTRACT FROM AUTHOR]

Measurements of the dilational dynamic surface elasticity allow determination of some distinctions between the properties of monolayers of charged polystyrene nano- and microparticles at the water/air and water/oil interfaces. For example, the surface elasticity at the water/oil interface is lower and does not depend on the solution’s ionic strength unlike the case of water/air interface. The obtained results at relatively low surface pressures (<15 mN/m) and homogeneous surface compression agree with a recent theory taking into account the residual charges at the particle/oil interfaces. At higher surface pressures, the behavior has some similarities with the properties of the monolayers of silica nanoparticles but differs strongly from the behavior of monolayers of soft microgel particles. [ABSTRACT FROM AUTHOR]

Abstract: A new methodology, based on fundamental optical principles relevant to the evanescent wave properties, is developed to evaluate the thinning behavior and the local thickness in different positions for curved aqueous emulsion films, generated in a hydrocarbon matrix. This methodology is applied to test data obtained by a specially-designed bread-board cell. The generated films, constituted by an aqueous sodium dodecylsulfate solution at concentration c =2.5 times the critical micellar concentration, remain stable during several hours. The results show a slow evolution of the film thickness as a function of time starting from micrometric dimension, at the initial film formation, to a few nanometres prior to film breakage. The action of the gravitational drainage is furthermore assessed by the local thickness values in different positions of the film profile. The illustrated examples demonstrate that the evanescent wave effect can be advantageously adopted as a complementary measurement technique, additional to the usual interferometric technique. [Copyright &y& Elsevier]

Abstract: Recent application of the methods of surface dilational rheology to solutions of the complexes between synthetic polyelectrolytes and oppositely charged surfactants (PSC) gave a possibility to determine some steps of the adsorption layer formation and to discover an abrupt transition connected with the formation of microaggregates at the liquid surface. The kinetic dependencies of the dynamic surface elasticity are always monotonous at low surfactant concentrations but can have one or two local maxima in the range beyond the critical aggregation concentration. The first maximum is accompanied by the generation of higher harmonics of induced surface tension oscillations and caused by heterogeneities in the adsorption layer. The formation of a multilayered structure at the surface for some systems leads to the second maximum in the dynamic surface elasticity. The hydrophobicity and charge density of a polymer chain influence strongly the surface structure, resulting in a variety of dynamic surface properties of PSC solutions. Optical methods and atomic force microscopy give additional information for the systems under consideration. Experimental results and existing theoretical frameworks are reviewed with emphasis on the general features of all studied PSC systems. [Copyright &y& Elsevier]

Underpotential (UPD) deposition of sulfur from Na2S solution in 0.1 M NaOH was studied on Ag(100) and Ag(110) using in situ scanning tunneling microscopy (STM). The cyclic voltammogram on Ag(100) presents two broad peaks, whereas three partial overlapping peaks and a sharper one are observed on Ag(110). STM measurements carried out during the whole UPD process show that progressively more compact structures are formed as the applied potential is scanned toward more positive potentials. More precisely, p(2×2), c(2×6), and c(2×2) were found on Ag(100) at E= −1.25, −1.0, and −0.9 V, respectively. Less definite conclusions can be drawn for the structures of S overlayers on Ag(110). However, the experimental findings are consistent with an incomplete p(2×1) at potentials preceding the sharp peak, and with a c(2×2) structure at E= −0.9 V vs Ag/AgCl, KClsat. The coverage values calculated on the basis of the hypothesized structures have been compared with the values obtained from chronocoulometric measurements at the most positive potentials investigated. Thus, the experimental coverage θ = 0.5 coincides with the coverage calculated for the c(2×2) structure found on Ag(110) at E= −0.9 V by STM, whereas the experimental coverage θ = 0.42 suggests that a mixture of structures c(2×6) and c(2×2) is formed on Ag(100). [ABSTRACT FROM AUTHOR]

Abstract: The Capillary Pressure Tensiometry is an effective technique for dilational rheological investigations when it is used according to the oscillating drop/bubble method. This method allows for an indirect determination of the dilational viscoelasticity versus frequency through the acquisition of the pressure signal obtained as response to harmonic perturbations of the drop/bubble interfacial area. A critical aspect of this technique concerns the calculation of the real and imaginary part of the dilational viscoelasticity from the directly acquired experimental data. Such calculation requires a specific experiment theory accounting also for the compressibility of the closed part of the experimental cell and for the fact that the acquired pressure is a superposition of different fluid dynamic contributions. Here we present an extension of previously proposed approaches, considering two different CPT configurations which refer to some already in use. The pressure inside the measurement cell is theoretically calculated considering the contributions, not only of the capillary pressure, but also of the Poiseuille pressure due to the fluid motion through the capillary and of hydrodynamic inertial terms. Simulations of experimental pressure signal are calculated as a function of specific experimental parameters in order to evaluate their influence on the measurement and to improve the effectiveness of the apparatus and the experimental methodology. Moreover in order to validate the assumptions of this approach, specifically acquired experimental data are analysed. [Copyright &y& Elsevier]

Abstract: Dilational rheology represents a powerful tool to investigate equilibrium and dynamic properties of simple and more complex interfacial layers containing surfactants, proteins, polymers or micro–nano sized particles. Concerning the experimental techniques for dilational rheology, drop/bubble tensiometers based on the acquisition of the drop/bubble profile and capillary pressure tensiometers are especially effective. This article focuses on oscillating drop/bubble methodologies where harmonic variations of the interfacial area are utilized for the measurement of the dilational viscoelasticity in the frequency domain. The increasing efficiency of these techniques of the last ten years is due, from one side, to the implementation of advanced instrumentations which make faster the drop/bubble control and the data acquisition and, on the other side, to the application of new theoretical approaches for data acquisition and interpretation. A critical analysis of such drop/bubble instruments is presented where their potentialities and limitations are underlined. Moreover, recent improvements in the definition of calculation methods based on the modelling of the experimental set up are reviewed together with some examples of experimental studies based on the utilisation of such methodologies. [Copyright &y& Elsevier]

Confined electrodeposition can be achieved through the use of suitable templates, by which the electrodeposition occurs in natural or artificial holes of an insulating layer on a conducting substrate. Here, we present the electrodeposition of CdS on the holes left by the selective desorption of 3-mercaptopropionic acid (MPA) from a binary self-assembled monolayer (SAM) formed on Ag(111) with 1-octanethiol (OT). The electrodeposition of a compound is quite demanding, since it requires the right stoichiometry. In addition, the surface underpotential deposition phenomena exploited by electrochemical atomic layer epitaxy (ECALE) technique ensures that the surface available for electrodeposition after the selective desorption is still Ag(111). Parallel electrochemical experiments show that the amount of compound electrodeposited is consistent with this free Ag(111) surface, and the morphological analysis performed both by atomic force microscopy (AFM) and by lateral force microscopy (LFM) confirm the electrochemical data. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on a study of the electrodeposition of nickel sulfide thin films on Ag(111) by the Electrochemical Atomic Layer Epitaxy (ECALE) technique. The multilayer growth of nickel sulfide has been studied by cyclic and stripping voltammetry. The composition of the films was studied by XPS analysis and the morphology was studied by Atomic Force Microscopy (AFM). The phenomenological observation of the hydrogen evolution reaction (HER) suggests the presence of electrocatalytic properties of the thin films obtained. [Copyright &y& Elsevier]

Image acquisition and subsampling of periodic high-frequency drop oscillations is presented as an advantageous metrological procedure in capillary pressure tensiometry (CPT). The observation of a finite sequence of single tone or of multiharmonic cycles, subsampled in an expanded time-scale interval, allows the characteristics of the real oscillations to be well-reconstructed in a frequency-compressed spectrum, where each component is translated toward lower frequencies. The introduced technique is applied to nanoliter-sized water drops, oscillating in a hydrocarbon matrix up to 150 Hz frequency, by using a standard PAL CCD camera provided with an electronic shutter. Application examples show the important role of this technique in data analysis and interpretation of typical high-frequency oscillating drop/bubble experiments. In particular, this technique is effective to check the onset of critical hydrodynamic effects and allows for the determination of the intrinsic elasticity of the liquid/cell system as a function of frequency by comparison of the liquid volume, as displaced by a piezo-actuator, and the actually observed drop volume-amplitude oscillation. The knowledge of this quantity is fundamental for the calculation of the dilational viscoelasticity from the acquired pressure data in the CPT. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the characterization of ternary II–VI semiconductor nanocrystals, deposited by the electrochemical atomic layer epitaxy (ECALE) technique. In particular, morphological and structural properties of the ternary compounds of formula Cd x Zn1−x Se deposited on Ag (111) have been characterized as a function of composition. The number of the attainable x values is limited by the necessity of using well-defined ZnSe/CdSe deposition sequences. However, the quantitative analysis carried out on the basis of both electrochemical and extended X-ray absorption fine structure (EXAFS) experiments indicates that the ECALE method is a successful way of controlling the composition of Cd x Zn1−x Se. In addition, the electrochemical measurements show that the amount of deposition is minimum in correspondence to the compound with x =0.5, thus corroborating the hypothesis of a higher degree of disorder suggested both by morphological and structural investigation. The morphology was studied by atomic force microscopy (AFM). The structure of the films is estimated by EXAFS which is a powerful technique for the analysis of the local structure around chosen atoms. [Copyright &y& Elsevier]

Abstract: Ultrathin films of well-ordered CdS on Ag(111) can be attained by electrochemical atomic layer epitaxy (ECALE) technique, which is based on self-limiting reactions, such as underpotential deposition. The layer-by-layer electrodeposition on single crystal faces allows a precise control of film thickness and yields semiconducting nanostructures of high crystallinity. In this paper, the ECALE method has been used to deposit CdS on Ag(111) covered by patterns of hexadecanethiol, C16SH. The patterned Ag(111) was obtained by using the microcontact printing technique of a polydimethylsiloxane (PDMS) stamp previously immersed in C16SH. The stamp used in this work produced thiol strips 320nm large, with an 850nm pitch. The deposition of CdS takes only place on the uncovered silver substrate whereas it is prevented on the thiols monolayers, yielding CdS patterned according to the used stamp. The deposit has been characterized by electrochemical techniques and AFM measurements. [Copyright &y& Elsevier]

In this article a technique that allows derivation of the conversion matrix of a two-port device using a measurement setup based on a nonlinear vector network analyzer (NVNA), which is capable of identifying the optimum local oscillator (LO) level and the corresponding RF and IF terminations for a microwave mixer, is discussed and validated. This technique is applied to extract the conversion matrix of gate-pumped 0.2-μm pseudomorphic high-electron-mobility transistors (PHEMTs) driven by a 4.8-GHz signal at different power levels and using an intermediate frequency of 600 MHz. Several experimental results provide a behavioral description of the up- and down-conversion mechanism in microwave mixers and highlight the dependency of the conversion-matrix coefficients on the pumping signal amplitude and phase. Detailed validation of this technique is provided by means of a circuit-level simulation and its consistency by vector network analyzer (VNA) measurements. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [ABSTRACT FROM AUTHOR]

Abstract: The complex dynamic surface elasticity of the solutions of copolymer of sodium 2-acrylamido-2-methyl-1-propansulfonate with N-isopropylacrylamide and dodecyltrimethylammonium bromide was measured as a function of the surfactant concentration and the surface age by the oscillating bubble and drop methods. The kinetic dependencies of the surface elasticity proved to be non-monotonic at low concentrations and the main features of the surface viscoelasticity differed from the results for other polyelectrolyte/surfactant solutions films studied so far. The observed peculiarities were connected with the properties of the copolymer chain. [Copyright &y& Elsevier]

This article considers an approach for the behavioral modeling of the conversion mechanism in a nonlinear device suitable for the analysis of RF/microwave mixers. The core of the model consists of the conversion matrix of the nonlinear cell under investigation, which represents its linearization around the large-signal state. This approach allows for a straightforward implementation in Computer-Aided Design (CAD) using the conversion matrix constructed from either simulation or measurements, of which the latter is considered here. Model order is significantly reduced due to the absence of the local oscillator signal in the frequency analysis plan. The intermodulation products are calculated in relative amplitude and phase and allocated in the spectrum on the basis of the conversion matrix coefficients. We illustrate the technique by implementing this model in commercial CAD software, which allows an in-depth insight into the conversion mechanism and illustrates the application to the design of a subharmonic mixer. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [ABSTRACT FROM AUTHOR]

Abstract: Fourier series analysis is utilised to quantitatively evaluate the linearity limits and characterise the non-linearity of the perturbation–response relationship, in the frequency domain, for dynamic surface properties of 2% (w/w) aqueous solutions of poly(sodium 4-styrenesulfonate). Under condition of periodic oscillations with different amplitudes at the same frequency (i.e., at single-line spectrum), the total harmonic distortion (THD) parameter shows the existence of a linearity range in the relationship between an imposed change of interfacial area and the ensuing surface tension response. Experiments at two-line spectrum, both with harmonic and with non-harmonic tones, also convey information about the linearity of the response. Under linearity approximation, results reveal that the magnitude of the surface dilational modulus can be determined even under periodic oscillations with a non-monochromatic spectrum, by taking just the proper components of the Fourier series. [Copyright &y& Elsevier]

Abstract: Electrochemical AFM technique has been used for the in situ study of the electrogeneration-deposition process of polybithiophene at varying the polymerisation conditions, such as supporting electrolyte, i.e., LiClO4 or tetrabutylammonium hexafluorophosphate, and polymerisation procedure, i.e., either potentiostatic or potentiodynamic method. In order to better follow the evolution of the morphology of the deposit, particularly during the early stages of the polymer film growth, a suitable home-made electrochemical cell has been used. [Copyright &y& Elsevier]

Abstract: The electrochemical atomic layer epitaxy methodology was employed for the growth of CdSe on Ag(111), for up to 50 deposition cycles. The voltammetric analysis of the first Cdupd peak indicates a mechanism of two-dimensional growth: this is consistent with layer-by-layer growth, which is a good prerequisite for epitaxial deposits. The amount of Cd and Se deposited in a given number of cycles, as determined by stripping the deposits first anodically and then cathodically, is a function of the number of cycles employed, again suggesting a layer-by-layer growth. The charges associated with each layer of Cd and Se, 75 μCcm−2, give the right 1:1 stoichiometric ratio between the elements, indicating the formation of a compound. Preliminary results from a structural analysis carried out by extended X-ray absorption spectroscopy (EXAFS) at the Se K edge confirm the presence of Cd neighbors around Se. [Copyright &y& Elsevier]

The present analysis shows that the introduction of intrinsic two-dimensional compressibility of a surfactant adsorption layer allows a much better interpretation of experimental data on the limiting (high-frequency) elasticity and characteristic frequency of diffusional relaxation than models using Frumkin''s or other adsorption isotherms. The proposed model describes experimental data on surface dilational elasticity, as well as on surface pressure, sufficiently well at low and high surfactant concentrations, assuming the Lucassen and van den Tempel model of surface dilational elasticity is realized. [Copyright &y& Elsevier]

Ternary compound semiconductors such as CdxZn1−xS (with 0.75>x>0.31) and CdxZn1−xSe (with 0.74>x>0.34) were grown on Ag (1 1 1) by the electrochemical atomic layer epitaxy (ECALE) method. The interest in ternary compounds arises from the possibility of varying the bandgap with composition. The elements forming the ternary cadmium and zinc sulfide were, at first, deposited in the sequence: S/Cd/S/Zn…, the order being one cycle of CdS and one cycle of ZnS. However, the quantitative analysis of the compound obtained revealed a very high percentage of Cd, roughly 75%. This means that the presence of cadmium somehow hinders Zn deposition. The most effective way to increase the amount of Zn is to deposit more cycles of ZnS. As an example, the compound with 50% of Cd and 50% of Zn is obtained by performing 3 deposition cycles of ZnS per deposition cycle of CdS. Therefore, the stoichiometry of the ternary sulfides depends on the ZnS/CdS deposition sequence. An analogous result was obtained for CdxZn1−xSe. The stoichiometry of the compounds obtained with different deposition sequences was determined by classical quantitative analysis after dissolving the deposits. The composition measurements were confirmed by ex situ X-ray photoelectron spectroscopy (XPS) in ultra-high vacuum. The right 1:1 ratio between cations and anions was found for all compounds examined, whatever the stoichiometry. A systematic electrochemical investigation was carried out with ZnS/CdS deposition sequences equal to 1, 2, 5. [Copyright &y& Elsevier]

A method is reported for verifying and controlling the accuracy of the calibration parameters, operating in image acquisition, for drop and bubble shape-analysis tensiometry. An error, impartially affecting the calibration parameters of both Cartesian axes, results in a squared error for the determined surface tension. Moreover, in the case where the calibration factors are affected by different errors, the determined value of surface tension is definitely unreliable, depending on the drop (or bubble) size and showing spurious in-phase or out-of-phase alterations. A procedure is illustrated for correcting the calibration parameters, on the basis of the observed results for a reference liquid. Method and procedure are validated by numerical examples. [Copyright &y& Elsevier]

The construction of a time-resolved surface viscoelastometer for the study of fluid/fluid interfaces is described in detail. Instrument design and operation are based on the formalism of systems theory. An interracial-area change (i.e., an external stimulus) is generated according to a given time function; the ensuing dynamic surface tension response is continuously recorded in synchronism with the stimulus. The principal characteristic of the equipment is a computercontrolled mechanical motion of the area-confining device (i.e., of a particular ring barrier, in place of the traditional linear barriers). The software allows a wide variety of oscillatory or transient experiments to be conducted. Instrument performance is illustrated by a typical experimental response, obtained under conditions of small-amplitude area perturbation, for a submicellar aqueous solution of surfactant. The recorded trace is fitted to a theoretical twoparameter model. Results show the effectiveness of the controlled-surface-deformation technique, allowed by the instrument, for determining static and dynamic interracial properties. [ABSTRACT FROM AUTHOR]

Abstract: The treatment of chronic hepatitis B (CHB) patients is based on monotherapy with pegylated‐interferon (Peg‐IFN) or with one of the three most potent nucleot(s)ide analogues (NUCs) with the best resistance profiles, i.e. entecavir (ETV), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF). Long‐term NUCs treatment can achieve virological suppression in almost all patients. However, this requires lifelong therapy, is costly and the rate of hepatitis B surface antigen (HBsAg) seroclearance is low. A one‐year course of Peg‐IFN has the advantage of providing immune‐mediated control of the hepatitis B virus (HBV) infection, the possibility of achieving a sustained off‐treatment response in nearly 30% of the patients and ultimately, HBsAg loss in approximately 30%‐50% of the latter patients during long‐term off treatment follow‐up. However, the major limitations to the extensive use of this treatment are the need for parenteral therapy and clinical and laboratory monitoring, the side‐effects profile and contraindications in certain patients and the limited effectiveness in a large proportion of patients. Nevertheless, the cost‐effectiveness of Peg‐IFN can be significantly increased by careful patient selection based upon baseline alanine aminotransferase (ALT), HBV DNA levels, viral genotype, host genetic variants and especially by applying early on‐treatment stopping rules based upon HBsAg kinetics. Recently, because of the different mechanisms of action of Peg‐IFN and NUCs, the strategy of “adding‐on” or “switching to” Peg‐IFN in patients being treated with NUCs to accelerate the decline in HBsAg and enhance HBsAg seroclearance rates, has provided interesting results. [ABSTRACT FROM AUTHOR]

The dynamic surface properties of mixed monolayers of 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC) and negatively charged polystyrene particles (PS) of different size were investigated with the aim to model the interactions of particles with biointerfaces. Special attention was paid to the aggregation of the particles at the water/air interface. The particle aggregates have a weaker influence on the dynamic properties of DPPC monolayers as compared with non-aggregated particles because of a shorter three phase contact line. The incorporation of particles into a DPPC monolayer leads to disordering of the monolayer structure, decreases the changes of surface properties in the course of two-dimensional phase transitions and the dynamic surface elasticity of the condensed lipid film. The influence of particles on the properties of mixed monolayers depends strongly on the ratio of lipid molecules and particles, and decreases with the decrease of particle surface concentration. The Brewster angle microscopy gives direct evidence of the PS particle aggregation in the course of compression of mixed monolayers. [ABSTRACT FROM AUTHOR]

In chronic HBV infection, elevated reactive oxygen species levels derived from dysfunctional mitochondria can cause increased protein oxidation and DNA damage in exhausted virus-specific CD8 T cells. The aim of this study was to understand how these defects are mechanistically interconnected to further elucidate T cell exhaustion pathogenesis and, doing so, to devise novel T cell-based therapies. DNA damage and repair mechanisms, including parylation, CD38 expression, and telomere length were studied in HBV-specific CD8 T cells from chronic HBV patients. Correction of intracellular signalling alterations and improvement of antiviral T cell functions by the NAD precursor nicotinamide mononucleotide and by CD38 inhibition was assessed. Elevated DNA damage was associated with defective DNA repair processes, including NAD-dependent parylation, in HBV-specific CD8 cells of chronic HBV patients. NAD depletion was indicated by the overexpression of CD38, the major NAD consumer, and by the significant improvement of DNA repair mechanisms, and mitochondrial and proteostasis functions by NAD supplementation, which could also improve the HBV-specific antiviral CD8 T cell function. Our study delineates a model of CD8 T cell exhaustion whereby multiple interconnected intracellular defects, including telomere shortening, are causally related to NAD depletion suggesting similarities between T cell exhaustion and cell senescence. Correction of these deregulated intracellular functions by NAD supplementation can also restore antiviral CD8 T cell activity and thus represents a promising potential therapeutic strategy for chronic HBV infection. Correction of HBV-specific CD8 T cell dysfunction is believed to represent a rational strategy to cure chronic HBV infection, which however requires a deep understanding of HBV immune pathogenesis to identify the most important targets for functional T cell reconstitution strategies. This study identifies a central role played by NAD depletion in the intracellular vicious circle that maintains CD8 T cell exhaustion, showing that its replenishment can correct impaired intracellular mechanisms and reconstitute efficient antiviral CD8 T cell function, with implications for the design of novel immune anti-HBV therapies. As these intracellular defects are likely shared with other chronic virus infections where CD8 exhaustion can affect virus clearance, these results can likely also be of pathogenetic relevance for other infection models. [Display omitted] • In chronic HBV infection elevated ROS production is associated with high DNA damage in HBV-specific CD8 T cells. • Response to DNA damage is dysfunctional. • Upregulation of CD38 and persistent activation of poly-ADP-ribose polymerases contribute to NAD consumption. • NAD depletion maintains and amplifies cellular dysfunction in exhausted HBV-specific T cells. • NAD replenishment can restore T-cell function. [ABSTRACT FROM AUTHOR]

Bulevirtide (BLV) has recently been conditionally approved for the treatment of chronic hepatitis delta (CHD) in Europe, but its effectiveness and safety in patients with compensated cirrhosis and clinically significant portal hypertension (CSPH) are unknown. Consecutive patients with HDV-related compensated cirrhosis and CSPH who started BLV 2 mg/day were enrolled in this single-center study. Clinical/virological characteristics were collected at baseline, weeks 4, 8 and every 8 weeks thereafter. HDV RNA was quantified by Robogene 2.0 (lower limit of detection 6 IU/ml). Eighteen Caucasian patients with compensated cirrhosis and CSPH under nucleos(t)ide analogue treatment were enrolled: median (IQR) age was 48 (29-77) years, and 67% were male. Median (IQR) platelet count was 70 (37-227) x103/μl, liver stiffness measurement (LSM) 16.4 (7.8-57.8) kPa, alanine aminotransferase (ALT) 106 (32-222) U/L, HBsAg 3.7 (2.5-4.3) log IU/ml, HDV RNA 4.9 (3.3-6.6) log IU/ml. During 48 weeks of BLV monotherapy, HDV RNA declined by 3.1 (0.2-4.3) log IU/ml (p < 0.001 vs. baseline), becoming undetectable in 5 patients (23%). A virological response was observed in 14 (78%) patients while a non-response was observed in 2 (11%). ALT decreased to 35 (15-86) U/L (p < 0.001 vs. baseline), normalizing in 83% of patients. A combined response was observed in 67% of patients. Aspartate aminotransferase and gamma-glutamyltransferase levels significantly improved. Concerning liver function parameters, albumin values significantly increased and bilirubin remained stable. LSM significantly improved in patients with virological response, while platelet count was unchanged. None of the patients developed decompensating events or hepatocellular carcinoma. BLV was well tolerated, no patient discontinued treatment and the increase in bile acids was fully asymptomatic. A 48-week course of BLV 2 mg/day monotherapy is safe and effective even for difficult-to treat patients with HDV-related compensated cirrhosis and CSPH. Hepatitis delta virus (HDV) is associated with the most severe form of viral hepatitis. A new treatment for HDV called bulevirtide has recently received conditional approval for patients with chronic HDV infection. However, its safety and effectiveness in patients with more advanced liver disease is not known. Herein, we show that it is safe and effective in patients with HDV-related cirrhosis and clinically significant portal hypertension. [Display omitted] • 48 weeks of bulevirtide 2 mg/day monotherapy was safe in patients with compensated cirrhosis and clinically significant portal hypertension. • Virological, biochemical, and combined responses were achieved in 78%, 83% and 67% of patients, respectively. • BLV treatment led to a significant improvement in most biochemical variables and an increase in liver function parameters. • Treatment was safe and well tolerated, an asymptomatic increase of bile acids was observed. [ABSTRACT FROM AUTHOR]

The spread layers of lysozyme (LYS) microgel particles were studied by surface dilational rheology, infrared reflection–absorption spectra, Brewster angle microscopy, atomic force microscopy, and scanning electron microscopy. It is shown that the properties of LYS microgel layers differ significantly from those of ß-lactoglobulin (BLG) microgel layers. In the latter case, the spread protein layer is mainly a monolayer, and the interactions between particles lead to the increase in the dynamic surface elasticity by up to 140 mN/m. In contrast, the dynamic elasticity of the LYS microgel layer does not exceed the values for pure protein layers. The compression isotherms also do not exhibit specific features of the layer collapse that are characteristic for the layers of BLG aggregates. LYS aggregates form trough three-dimensional clusters directly during the spreading process, and protein spherulites do not spread further along the interface. As a result, the liquid surface contains large, almost empty regions and some patches of high local concentration of the microgel particles. [ABSTRACT FROM AUTHOR]

X-ray micro-computer aided tomography (μ-CT), together with optical microscopy and imaging, have been applied to the study of six moldavite samples. These techniques enabled a complete characterization to be made of the textural features of both Muong Nong-type and common splashform moldavites. A detailed study of the size and distribution of pores or bubbles confirmed the marked variability in pore size among the samples, as well as within each sample, and indicated in the Muong Nong-type moldavites the presence of at least two deformation stages which occurred before and after pore formation. [ABSTRACT FROM AUTHOR]

Abstract: Chloride and iodide adsorption on Ag(111) was investigated from mixed c M KX+(0.02− c) M KPF6, with X=Cl, I, using the potential-step chronocoulometric technique. Measurements were carried out at potentials negative of –0.5V/SCE, where STM does not provide images of ordered adlayers of these halides. Their adsorption behavior was compared with that of bromide ion on Ag(111), reported in a previous work. The plot of the applied potential E, decreased by the potential difference ϕ d across the diffuse layer, shows a maximum when plotted against the specifically adsorbed charge density σ i of the halides, at constant charge density σ M on the metal. This behavior is explained by an appreciable contribution from reorientation and displacement of adsorbed water molecules by the adsorbing halides. The minimum of the E − ϕ d vs. σ i plot is much shallower for iodide than for chloride and bromide. The σ i vs. log c plots at σ M =0 are linear, thus satisfying the Temkin isotherm. The resulting interaction factor is appreciably less repulsive for iodide than for chloride and bromide. These results indicate that partial charge transfer from iodide to Ag(111) is appreciable even at negative potentials at which adsorption is random, as distinct from chloride and bromide. [ABSTRACT FROM AUTHOR]

Abstract: Measurements of the concentration and adsorption time dependencies of the dynamic surface elasticity of mixed polyethylenimine/sodium dodecyl sulfate (PEI/SDS) solutions show transitions between a few states of different surface elasticity. In the range of low surface pressures the elasticity is governed by the branched structure of the macromolecules, while at high surface pressures the elasticity exhibits a behaviour typical for other polyelectrolyte/surfactant surface layers. [ABSTRACT FROM AUTHOR]

Abstract: The dynamic surface properties of mixed solutions of polyacrylic acid (PAA) and alkyltrimethylammonium bromides (CnTAB) were measured by the oscillating ring method as a function of surface age and surfactant concentration. The concentration dependencies of the surface tension and dilational dynamic surface elasticity were similar to the corresponding results for other polyelectrolyte/surfactant solutions, which have been investigated earlier. The kinetic dependencies of the surface elasticity proved to be non-monotonic for all the investigated surfactants at n =8, 10, 12, 14, 16 and displayed two local maxima at surfactant concentrations close to the critical micellar concentration (CMC). The first maximum was caused by an aggregate formation in the surface layer while the second maximum occurred simultaneously with a multilayer formation at the gas–liquid interface. The surface tension corresponding to the beginning of the aggregate formation decreased and the surface elasticity in the region of the first local maximum increased with the hydrophobicity of CnTAB/PAA complexes caused by the increasing hydrocarbon chain length of the surfactant. The hydrophobic interactions influenced also the height and position of the second local elasticity maximum. These effects were connected with changes in the rate of adsorption layer and aggregate structure formation. Comparable values of the real and imaginary parts of the dynamic surface elasticity at concentrations for aggregate formation in the surface layer indicated that the relaxation time of the mass exchange between the aggregates and the surrounding adsorption layer is comparable with the period of oscillations, i.e. ≤10s. [Copyright &y& Elsevier]

Lead sulfide (PbS) thin films were grown on a single crystal Ag(111) substrate by Electrochemical Atomic Layer Epitaxy (ECALE) method, i.e., by alternated underpotential deposition (UPD) of lead and sulfur. The electrochemical analysis includes the investigation of the underpotential deposition processes of both Pb and S, and the characterization of deposits obtained with different deposition cycles to confirm the attainment of the right stoichiometric ratio between Pb and S. The morphological analysis has been performed by Atomic Force Microscopy (AFM) for deposits formed with 50 and 75 deposition cycles and at different times of exposition to the atmosphere. [ABSTRACT FROM AUTHOR]