Cellulose films: designing template-free nanoporous cellulose films on semiconducting surfaces.

In this work, we report the preparation of ultrathin submicro- and nanoporous cellulose films onto Si (100). The effect of different experimental conditions of preparation on the film surface morphology was studied, namely the role of the film casting method (spin- versus dip-coating), solvent (toluene or tetrahydrofuran), substrate pretreatment (hydrophilicity degree), and regeneration procedure with HCl vapors (two consecutive dips followed by regeneration or regeneration after each dip). The surface morphological structures presented in this work were never obtained before without the use of templates. A rather regular two-dimensional pore network was obtained onto the less hydrophilic Si substrate (contact angle≅68°), after two consecutive dips (with an intercalary rotation of 180º) in trimethylsilyl cellulose diluted in toluene and regeneration at the end. All the surfaces were characterized by atomic force microscopy.

Antibody response against selected epitopes in the HIV-1 envelope gp41 ectodomain contributes to reduce viral burden in HIV-1 infected patients.

The ectodomain of gp41 is the target of potent binding and neutralizing antibodies (NAbs) and is being explored in new strategies for antibody-based HIV vaccines. Previous studies have suggested that the W164A-3S (3S) and EC26-2A4 (EC26) peptides located in the gp41 ectodomain may be potential HIV vaccine candidates. We assessed 3S- and EC26-specific binding antibody responses and related neutralizing activity in a large panel of chronic HIV-1-infected Portuguese individuals on ART. A similar proportion of participants had antibodies binding to 3S (9.6%) and EC26 (9.9%) peptides but the level of reactivity against 3S was significantly higher compared to EC26, except in the rare patients with double peptide reactivity. The higher antigenicity of 3S was unrelated with disease stage, as assessed by CD4+ T cell counts, but it was directly related with plasma viral load. Most patients that were tested (89.9%, N = 268) showed tier 1 neutralizing activity, the potency being inversely associated with plasma viral load. In the subset of patients that were tested for neutralization of tier 2 isolates, neutralization breadth was inversely correlated with plasma viral load and directly correlated with CD4+ T cell counts. These results are consistent with a role for neutralizing antibodies in controlling viral replication and preventing the decline of CD4+ T lymphocytes. Importantly, in patients with 3S-specific antibodies, neutralizing titers were inversely correlated with viral RNA levels and proviral DNA levels. Moreover, patients with 3S and/or EC26-specific antibodies showed a 1.9-fold higher tier 2 neutralization score than patients without antibodies suggesting that 3S and/or EC26-specific antibodies contribute to neutralization breadth and potency in HIV-1 infected patients. Overall, these results suggest that antibodies targeting the S3 and EC26 epitopes may contribute to reduce viral burden and provide further support for the inclusion of 3S and EC26 epitopes in HIV-1 vaccine candidates.

Phase behaviour of binary mixtures involving tristearin, stearyl stearate and stearic acid: thermodynamic study and BAM observation at the air-water interface and AFM analysis of LB films.

The binary mixtures involving tristearin (TS), stearyl stearate (SS) and stearic acid (SA) were studied by surface pressure-area (pi-A) measurements and by Brewster angle microscopy (BAM), at the air-water interface, and the Langmuir-Blodgett (LB) monolayers, transferred onto mica substrates, were analysed by AFM. The thermodynamic analysis indicated miscibility in the whole composition range for the system SA/TS, and partial miscibility for systems SA/SS and TS/SS. This behaviour was further confirmed by BAM observation and AFM analysis of LB films. The AFM imaging of collapsed monolayers revealed domains with a multilayered structure varying with system and composition. The layers thickness determined by cross section analysis are consistent with estimated molecular lengths and conformations proposed for the molecules, assuming nearly perpendicular or tilted orientations of the hydrocarbon chains to the interface.

When the Diagnosis is a Victim of the Circumstances.

INTRODUCTION: Haemoptysis is a common symptom which can sometimes mimic gastrointestinal bleeding. CASE DESCRIPTION: We describe the case of a 31-year-old man who presented to the emergency department after an episode of sudden nausea and presumed massive haematemesis. The situation was interpreted as gastrointestinal bleeding but clinical evolution and greater attention to the anamnesis resulted in a diagnosis of pulmonary tuberculosis and the provision of appropriate care. DISCUSSION: This report emphasizes the difficulty of differentiating between haemoptysis and haematemesis and the importance of a careful anamnesis and attention to all clinical circumstances for an accurate diagnosis. LEARNING POINTS: Haematemesis and haemoptysis are not always distinguished from each other when a patient's history is being collected.Despite being a rare manifestation of tuberculosis, in the correct epidemiological context, haemoptysis should raise the suspicion of pulmonary tuberculosis.The clinical setting and the need for immediate care should not limit clinical investigation or the differential diagnosis.

Characterization of NS5A and NS5B Resistance-Associated Substitutions from Genotype 1 Hepatitis C Virus Infected Patients in a Portuguese Cohort.

This study is focused on the prevalent NS5 coding region resistance-associated substitutions (RASs) in DAA-naive genotype (GT)1 HCV-infected patients and their potential impact on success rates. Plasma RNA from 81 GT1 HCV-infected patients was extracted prior to an in-house nested RT-PCR of the NS5 coding region, which is followed by Sanger population sequencing. NS5A RASs were present in 28.4% (23/81) of all GT1-infected patients with 9.9% (8/81) having the Y93C/H mutation. NS5B RASs showed a prevalence of 14.8% (12/81) and were only detected in GT1b. Overall 38.3% (31/81) of all GT1 HCV-infected patients presented baseline RASs. The obtained data supports the usefulness of resistance testing prior to treatment since a statistically significant association was found between treatment failure and the baseline presence of specific NS5 RASs known as Y93C/H (p = 0.04).

Microdomains in mixed monolayers of oleanolic and stearic acids: thermodynamic study and BAM observation at the air-water interface and AFM and FTIR analysis of LB monolayers.

Monolayers of oleanolic acid (OLA) mixed with stearic acid (SA) were studied at the air-water interface. The surface pressure-area (pi-A) isotherms, measured over the whole composition range, and BAM observations were used to investigate the phase behaviour and self-organization of these components in a two-dimensional structure. Pure OLA forms a very compressible monolayer, and BAM observation revealed the coexistence of large and irregular solid domains of different thickness dispersed in a gas matrix, compatible with the two most probable orientations of the OLA molecule at the interface. Mixtures of OLA/SA form condensed monolayers from low surface pressures and the thermodynamic analysis indicates that OLA molecules, in the presence of the long-chain SA, orient with the major axis almost perpendicular to the interface. Langmuir-Blodgett (LB) monolayers of pure SA and mixtures were further characterized by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). AFM images of LB mixed monolayers evidenced microphase separation, not observable by BAM. The SA rich domains are 4-6A thicker than those rich in OLA. The FTIR spectra of mixed LB films on CaF2 substrates showed that OLA does not perturb the all-trans conformation of the SA long alkyl chains, up to a mole fraction of 0.4. The carbonyl-stretching band of OLA suggests that the carboxylic groups of neighbour OLA molecules are involved in hydrogen bonds, forming dimers, as in pure solid phase OLA. These interactions seem to prevail over the OLA-water hydrogen bonds.

Improve screening of HCV infection by targeting high prevalence aged groups: analysis of a cohort of HCV and HIV co-infected patients.

INTRODUCTION: Hepatitis C constitutes a major public health burden. In Portugal, the prevalence is estimated at 1-1.5% (1). Of these, only 30% are presumed to be diagnosed, which reveals that most infections go unknown. The objective of this study is to identify the age-range distribution at HCV diagnosis and to identify the high-prevalence birth groups that could be targeted for screening, as a strategy to increase diagnosis and identify patients who would benefit most from treatment. METHODS: Retrospective observational study of a cohort of chronic HCV-infected and HIV co-infected patients followed at an Infectious Diseases Center, diagnosed between 1979 and 2014 (Figure 1). Hepatic fibrosis evaluation was performed by real time elastography using METAVIR score. Epidemiological, demographic, clinical, virological and therapeutic data was retrieved from clinical registries. Statistical analysis was performed using Microsoft Excel 2010®. Chi2, Student T were used for a significant p value of <0.05. RESULTS: Our study assessed a cohort of 665 patients: 442 (66.5%) HCV/HIV co-infected and 223 (33.5%) HCV monoinfected. There was a male predominance in both groups (74.9% vs 70.9%). The mean age was 47 HCV/HIV vs 49 years; Portuguese origin in 80% vs 83% and African in 14% vs 12%. The most frequently assumed transmission route was by intravenous drug use (IVDU) (81% vs 72%), followed by sexual contact (18% vs 20%). Mean age at diagnosis was 32 vs 40 years. Mean time since HCV diagnosis was 14, 6 vs 9, 6 years. Fibrosis stage evaluation by real time elastography was available for 133 (30%) and 99 (44.4%) patients (HCV/HIV vs HCV): 16% vs 13% F1; 32% vs 33% F2; 31% vs 35% F3; 21% vs 18% F4. The peak prevalence occurred between the birth intervals of 1960-1969 and 1970-1979 for both groups, corresponding to 81% vs 66,8% (p=0.003) (Figure 1). About three quarters of all patients (76%) were born between the year of 1960 and 1979, with a prevalence of 70% of IVDU. CONCLUSIONS: In our cohort we identify a high risk population for chronically HCV infection, which comprises people born between 1960 and 1979, findings common to those with mono or HIV co-infection. This finding is concordant with the epidemic of IVDU in Portugal around 1980-1990. These patients should be screened for diagnosis in order to be treated and to prevent further disease progression.

Evolution trends over three decades of HIV infection late diagnosis: the experience of a Portuguese cohort of 705 HIV-infected patients.

INTRODUCTION: Late HIV diagnosis is common and associated with an increased risk of clinical progression, blunted immune response on antiretroviral (ARV) therapy and higher risk of drug toxicity. Across Europe, more than a third of patients are diagnosed late and consequently delay medical care. European Consensus definition group identify as late presentation (LP) persons, presenting for care, with a CD4 count below 350 cell/mm(3) or presenting with AIDS-defining event, regardless of CD4 cell count. Additionally, advanced HIV disease (AD) is defined by a CD4 count below 200 cell/mm(3) or an AIDS defining condition in persons presenting to care. MATERIALS AND METHODS: Retrospective observational study of a cohort of 705 HIV-infected patients diagnosed between 1986 and 2014 and medically followed at an Infectious Diseases Service in Lisbon. OBJECTIVES: Evaluate LP rate evolution in the last three decades (10-year time intervals considered: 1986-1995; 1996-2005; 2006-2014); compare clinic, immunologic, virologic and therapeutic response over time. Identify main reasons responsible for late HIV diagnosis in order to promote optimized intervention strategies. SPSS version 20.0 was used for statistical analysis. RESULTS: Study included 705 patients HIV diagnosed during 3 time intervals: group A n=82 [1986-1995]; group B n=332 [1996-2005]; group C n=291 [2006-2014]. Demographic and epidemiological characterization revealed (A vs B vs C): male predominance of 79% vs 66% vs 66%; mean age at diagnosis 30 vs 36 vs 42 years; Portugal (82% vs 70% vs 58%) and Africa (13% vs 23% vs 29%) as the main places of birth; transmission by heterosexual contact in 21% vs 47% vs 62%, MSM in 21% vs 15% vs 23% and IVDU in 57% vs 35% vs 13%. Mean CD4 at diagnosis was 362 vs 344 vs 377 cell/mm(3). Considering the time intervals, LP was found in 52% vs 56% vs 52% of patients and AD in 31% vs 38% vs 35%, respectively. At first health care encounter, 46% vs 43% vs 39% of individuals presented with AIDS. Over follow up, the vast majority initiated ARV (95% vs 98% vs 84%) and mean CD4 at that time was 254 vs 282 vs 250 cell/mm(3). The last immunologic and virologic determination available registered mean CD4 of 657 vs 644 vs 584 cell/mm(3) and undetectable HIV plasma RNA in 92% vs 84% vs 82% of treated patients. CONCLUSIONS: This study evidenced a maintained LP rate, slightly above 50% in each of the three analyzed last decades, and one-third of patients presented AD at HIV diagnosis. At initial health care contact, nearly 40% of individuals met AIDS clinical or immunological criteria.

Sub-micron tailoring of bi-soft segment asymmetric polyurethane membrane surfaces with enhanced hemocompatibility properties.

Enhancement of membrane hemocompatibility is achieved through the control of the surface morphology. Bi-soft segment integrally skinned poly(ester urethane urea) (PEUU) membranes containing polycaprolactone (PCL) as a second soft segment are synthesized with PCL-diol ranging from 0% to 15% (w/w). Scanning electron microscopy and atomic force microscopy characterized membrane asymmetry and sub-micron roughnesses, R(a), of top dense surfaces as major assets to the development of platelet/membrane surface interactions. Here we show that the top dense surfaces of asymmetric PEUU membranes can be tailored with different morphologies when the ratio of the two soft segments PPO/PCL varies. A strong correlation between the top surface roughnesses, R(a) and platelet deposition is identified. The membrane with 15% (w/w) of PCL-diol, PEUU 85, shows the smoothest top dense layer with a R(a) as low as 1 nm which is 5 times below the characteristic value of the PEUU membrane with a single soft segment. The PEUU 85 asymmetric membrane displayed minimal platelet deposition and inhibition of extreme stages of platelet activation.

Interactions between DNA purines and ruthenium ammine complexes within nanostructured sol-gel silica matrixes.

The interactions between DNA purines (guanine and adenine) and three ruthenium ammine complexes (hexaammineruthenium(III) chloride, hexaammineruthenium(II) chloride, and ruthenium-red) were studied in a confined environment, within sol-gel silica matrixes. Two encapsulation methods were rehearsed (differing in temperature and condensation pH), in order to analyze the effects of the sol-gel processes on the purines and on the Ru complexes separately. The extent of decomposition of the Ru complexes, as well as the interactions established with the purine bases, proved to be determined by the coencapsulation method. Combined results by diffuse reflectance UV-vis and infrared spectroscopies showed that, when coencapsulation is carried out at 60 degrees C, specific H bonding interactions are established between the amine group of Ade and the ammine groups of the Ru complex or the hydroxo group of an early decomposition product. These are responsible for the important role of the purine in inhibiting the oxidation reactions of the Ru(II) and Ru(III) complexes. In contrast, Gua establishes preferential H bonds with the matrix (mainly due to the carbonyl group), leading to higher yields in the final oxidation products of the Ru complexes, namely, trimers and dimers. Direct covalent bonding of either purine to the metal was not observed.

Ultrasensitive microchip sensor based on boron-containing polyfluorene nanofilms.

A fluorene-based π-conjugated copolymer with on-chain dibenzoborole units was used in the development of a nanocoated gold interdigitated microelectrode array device which successfully detects fluoride in a broad range of concentrations (10(-11)-10(-4) M) in aqueous solution, upon impedance spectroscopy measurements. A calibration curve obtained over this range of concentrations and a new analytical method based on impedance spectroscopy measurements in aqueous solution is proposed. The sensor nanofilm was produced by spin-coating and diagnosed via spectroscopic ellipsometry, AFM, and electrically conductivity techniques. Changes in the conductivity due to the boron-fluoride complex formation seem to be the major mechanism behind the dependence of impedimetric results on the fluoride concentration.

Thermo-responsiveness of poly(N,N-diethylacrylamide) polymers at the air-water interface: The effect of a hydrophobic block.

The poly(N,N-diethylacrylamide) (h-PDEA) homopolymer and the poly(N-decylacrylamide)-b-PDEA (PDcA(11)-b-PDEA(231)) diblock copolymer were studied in the range of 10 to 40 degrees C, at the air-water interface. The pi-A isotherms of h-PDEA appear nearly invariant with temperature while the pi-A isotherms of PDcA(11)-b-PDEA(231) deviate significantly to lower areas with the temperature increase evidencing the thermo-responsiveness of this diblock copolymer at the interface. For the copolymer, the limiting area per segment versus temperature shows a break point around 29 degrees C, slightly lower than the lower critical solution temperature (LCST) of h-PDEA in water (31-33 degrees C). AFM images of LB monolayers transferred at 40 degrees C revealed for both polymers the presence of hydrophobic aggregates due to the conformational changes (collapse) of chains that occur at the LCST. Differences in the morphology of these aggregates, flat irregular structures for h-PDEA and round-shaped domains for PDcA(11)-b-PDEA(231), were related with the condensing effect of the hydrophobic block. The PDcA(11) block, anchoring the polymer to the interface, ensures a better stability and cohesion to the film and preserves the thermo-sensitivity of the h-PDEA at the interface.

Interfacial behavior of poly(isoprene-b-methyl methacrylate) diblock copolymers and their blends with polystyrene at the air-water interface.

The interfacial behavior of poly(isoprene-b-methyl methacrylate) diblock copolymers (PI-b-PMMA), with similar PMMA blocks but differing in the percentage of PI segments, SP19 (5% PI) and SP38 (52% PI), was studied at the air-water interface. The surface pressure-area (pi-A) isotherms, compression-expansion cycles, and relaxation curves were compared with those of the PMMA homopolymer. The short hydrophobic PI block of SP19 does not contribute to the mean molecular area at low surface pressures and yet has a negative contribution (condensing effect) when the surface pressure increases. On the contrary, the long PI block of SP38 contributes considerably to the surface area from low to high surface pressures. The A-t relaxation curves compare well with those of PMMA at low surface pressures (pi = 2 mN.m-1), but not at intermediate and high pressures (pi = 10, 30 mN.m-1), where a clear dependence on the length of the PI block was observed. The quantitative analysis of the relaxation curves at high pressures shows both a fast and slow component, attributed mostly to the local and middle-to-long-range reorganization of PMMA chains, respectively. PI-b-PMMA diblocks and PMMA were further blended with PS. The PS and PMMA are immiscible at the air-water interface. The addition of PS does not change the pi-A isotherm of PMMA, but the copolymers blended with PS form films that are more condensed at low pressures. The Langmuir-Blodgett (LB) films transferred onto mica substrates were analyzed by atomic force microscopy (AFM). The LB films of single diblocks are uniform, while those of PI-b-PMMA and PMMA blended with PS show aggregates with variable patterns.

Subunits of the chaperonin CCT are associated with Tetrahymena microtubule structures and are involved in cilia biogenesis.

The cytosolic chaperonin CCT is a heterooligomeric complex of about 900 kDa that mediates the folding of cytoskeletal proteins. We observed by indirect immunofluorescence that the Tetrahymena TpCCTalpha, TpCCTdelta, TpCCTepsilon, and TpCCTeta-subunits colocalize with tubulin in cilia, basal bodies, oral apparatus, and contractile vacuole pores. TpCCT-subunits localization was affected during reciliation. These findings combined with atomic force microscopy measurements in reciliating cells indicate that these proteins play a role during cilia biogenesis related to microtubule nucleation, tubulin transport, and/or axoneme assembly. The TpCCT-subunits were also found to be associated with cortex and cytoplasmic microtubules suggesting that they can act as microtubule-associated proteins. The TpCCTdelta being the only subunit found associated with the macronuclear envelope indicates that it has functions outside of the 900 kDa complex. Tetrahymena cytoplasm contains granular/globular-structures of TpCCT-subunits in close association with microtubule arrays. Studies of reciliation and with cycloheximide suggest that these structures may be sites of translation and folding. Combined biochemical techniques revealed that reciliation affects the oligomeric state of TpCCT-subunits being tubulin preferentially associated with smaller CCT oligomeric species in early stages of reciliation. Collectively, these findings indicate that the oligomeric state of CCT-subunits reflects the translation capacity of the cell and microtubules integrity.