Efficacy of Once-Daily Ophthalmic Bilastine for the Treatment of Allergic Conjunctivitis: A Dose-Finding Study.

BACKGROUND AND OBJECTIVE: Bilastine is a nonsedating second-generation antihistamine for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. Our study aimed to evaluate the optimal dose, efficacy, and safety of a newly developed once-daily preservative-free ophthalmic formulation of bilastine for allergic conjunctivitis. METHODS: Our phase 2, single-center, double-masked, randomized trial compared the efficacy of 3 doses of a bilastine ophthalmic formulation (0.2%, 0.4%, and 0.6%) with that of vehicle for the treatment of allergic conjunctivitis. The primary efficacy endpoint was the reduction in ocular itching. The Ora-CAC Conjunctival Allergen Challenge model was used to assess ocular and nasal symptoms at the onset of action (15 minutes) and at 8- and 16-hours after treatment. Tolerance and safety were also evaluated. RESULTS: A total of 121 adults with seasonal and/or perennial ocular allergy were randomized. Bilastine ophthalmic formulations 0.2%, 0.4%, and 0.6% were significantly superior (P>.001) to vehicle for the treatment of ocular itching at 3, 5, and 7 minutes after challenge at onset of action (15 minutes) and at 8 hours after treatment. Bilastine 0.6% was also effective at 16 hours after treatment. Treatment differences for bilastine 0.6% were statistically significant (P<.001) compared to vehicle at all timepoints for tearing, eyelid swelling, and nasal symptoms. No relevant adverse events were observed. CONCLUSION: All the tested ophthalmic bilastine doses were efficacious for rapid reduction of ocular itching. The 0.6% formulation was effective up to 16 hours after treatment, making it suitable for once-daily administration. The new formulation was safe and well tolerated.

Bilastine 0.6% preservative-free eye drops, a once-daily treatment for allergic conjunctivitis.

BACKGROUND: Bilastine is a second-generation antihistamine approved for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. This trial evaluated the efficacy and safety of a new bilastine 0.6% preservative-free eye-drops formulation for the symptomatic treatment of allergic conjunctivitis. METHODS: This phase 3, multicenter, double-masked, randomized study evaluated the efficacy, safety and tolerability of bilastine 0.6% ophthalmic solution compared to ketotifen 0.025% and vehicle. The primary efficacy endpoint was ocular itching reduction. The Ora-CAC® Allergen Challenge Model was used to assess ocular and nasal symptoms at 15 minutes (onset of action) and 16 hours post-treatment. RESULTS: Subjects (N=228) were 59.6% male, and the mean (SD) age was 44.1 (13.4) years. Bilastine demonstrated efficacy in reducing ocular itching compared to vehicle at both onset of action and 16 hours post-treatment (P <0.001). Ketotifen showed improvement compared to vehicle 15 minutes post-treatment (P <0.001). Bilastine demonstrated statistical non-inferiority to ketotifen for all 3 post-CAC timepoints at 15 minutes post-instillation, based on an inferiority margin of 0.4. Bilastine demonstrated improvement over vehicle (P <0.05) for conjunctival redness, ciliary redness, episcleral redness, chemosis, eyelid swelling, tearing, rhinorrhea, ear and palate pruritus and nasal congestion at 15 minutes post-treatment. Ophthalmic bilastine was safe and well tolerated. Mean drop comfort scores were significantly better (P <0.05) for bilastine compared with ketotifen immediately upon instillation, and similar compared with vehicle. CONCLUSIONS: Ophthalmic bilastine effectively reduced ocular itching for 16 hours post-treatment, suggesting that it could be used as a once-daily treatment for the signs and symptoms of allergic conjunctivitis. ClinicalTrials.gov identifier: NCT03479307.

Bilastine 0.6% preservative-free eye drops, an effective once-daily treatment to reduce signs and symptoms of allergic conjunctivitis: A pooled analysis of two randomized clinical trials.

BACKGROUND AND OBJECTIVE: Allergic conjunctivitis is the most common type of ocular allergy. The objective of this study was to evaluate the efficacy of a new once-daily, preservative-free, bilastine 0.6% eye drop formulation for the treatment of allergic conjunctivitis. METHODS: Two double-masked, vehicle controlled, clinical studies (a Phase 2 Dose Ranging Study and a Phase 3 Efficacy Study) were conducted to assess the efficacy of bilastine ophthalmic solution for the treatment of signs and symptoms of allergic conjunctivitis. Both studies used the Ora-CAC® Conjunctival Allergen Challenge (CAC) Model to allow observations of allergic responses under controlled conditions. Each study was analyzed separately and then combined to create an integrated dataset. RESULTS: Efficacy was achieved for the primary efficacy endpoint of ocular itching for three bilastine concentrations (0.2%, 0.4%, and 0.6%) at 15 minutes and 8 hours post-instillation and bilastine 0.6% ophthalmic solution was also efficacious at 16 hours post-instillation. Bilastine 0.6% ophthalmic solution demonstrated non-inferiority to ketotifen 0.025% at the onset of action. From the integrated data set, differences between vehicle and bilastine 0.6% were significant at all time points both at onset (15 minutes) and at a prolonged duration (16 hours) after instillation. CONCLUSION: This multi-trial assessment suggests that bilastine 0.6% ophthalmic solution is efficacious for the treatment of the signs and symptoms of allergic conjunctivitis, with a rapid and prolonged duration of action, and has a favorable safety profile. The added convenience of a once-a-day dosing regimen may contribute to patient adherence and improve their quality of life.

Salivary biomarkers present in patients with periodontitis without clinical distinction: findings from a meta-analysis.

BACKGROUND: A new classification for periodontitis has been adopted in clinical practice. However, there are still discussions regarding this new classification and difficulties in its adoption, both by professionals and researchers. Thus, this study aimed to evaluate which salivary biomarkers are present in periodontitis, following the new classification of periodontal diseases through meta-analysis. MATERIAL AND METHODS: A literature search was carried out in the scientific databases: PubMed, Scielo and Google scholar to select studies. The selection of studies was followed by two authors upon reading of the title, abstract and full text. The necessary data were collected and statistical analyses were performed using the Review Manager statistical software version 5.4, with calculation of Mean Difference, heterogeneity (I²) and funnel plot with P < 0.05. RESULTS: After following the selection criteria, 9 articles were selected for comparison. The studies address the presence of biomarkers in the saliva of patients with periodontitis and their possible use in the monitoring and diagnosis of the disease. For the meta-analytic comparison, a sample size of 1,983 individuals was used. Statistical analyses showed that nitric oxide, IL-6, IL-1B and osteoprotegerin are substances that are significantly present in patients with periodontitis (P < 0.05). CONCLUSIONS: IL-6, nitric oxide, IL-1B, TNF-α and osteoprotegerin are among the most present biomarkers in patients with periodontitis, and may be used in the future as a monitoring of periodontal disease. The present study also revealed that there was no statistically significant difference in the concentration of these biomarkers for clinical distinction from periodontitis.

Isomorphic diffuse glioma is a morphologically and molecularly distinct tumour entity with recurrent gene fusions of MYBL1 or MYB and a benign disease course.

The "isomorphic subtype of diffuse astrocytoma" was identified histologically in 2004 as a supratentorial, highly differentiated glioma with low cellularity, low proliferation and focal diffuse brain infiltration. Patients typically had seizures since childhood and all were operated on as adults. To define the position of these lesions among brain tumours, we histologically, molecularly and clinically analysed 26 histologically prototypical isomorphic diffuse gliomas. Immunohistochemically, they were GFAP-positive, MAP2-, OLIG2- and CD34-negative, nuclear ATRX-expression was retained and proliferation was low. All 24 cases sequenced were IDH-wildtype. In cluster analyses of DNA methylation data, isomorphic diffuse gliomas formed a group clearly distinct from other glial/glio-neuronal brain tumours and normal hemispheric tissue, most closely related to paediatric MYB/MYBL1-altered diffuse astrocytomas and angiocentric gliomas. Half of the isomorphic diffuse gliomas had copy number alterations of MYBL1 or MYB (13/25, 52%). Gene fusions of MYBL1 or MYB with various gene partners were identified in 11/22 (50%) and were associated with an increased RNA-expression of the respective MYB-family gene. Integrating copy number alterations and available RNA sequencing data, 20/26 (77%) of isomorphic diffuse gliomas demonstrated MYBL1 (54%) or MYB (23%) alterations. Clinically, 89% of patients were seizure-free after surgery and all had a good outcome. In summary, we here define a distinct benign tumour class belonging to the family of MYB/MYBL1-altered gliomas. Isomorphic diffuse glioma occurs both in children and adults, has a concise morphology, frequent MYBL1 and MYB alterations and a specific DNA methylation profile. As an exclusively histological diagnosis may be very challenging and as paediatric MYB/MYBL1-altered diffuse astrocytomas may have the same gene fusions, we consider DNA methylation profiling very helpful for their identification.

Design of a Multipoint Cost-Effective Optical Instrument for Continuous In-Situ Monitoring of Turbidity and Sediment.

A cost-effective optical instrument for continuous in-situ monitoring applications is presented. With a production cost in raw materials of 38 €, a power consumption of 300 A in sleep mode and 100 mA in active mode (5 ms reading), and a capacity to monitor turbidity and sedimentary displacement at eight different depths in the water column, the sensor was developed for sediment monitoring in coastal areas. Due to the extent and dynamics of the processes involved in these areas, observations require a wide spatial and temporal resolution. Each of the eight monitoring nodes uses one infrared backscatter channel, to estimate turbidity and sediment concentration, and one ultraviolet with one infrared transmitted light channels to distinguish organic/inorganic composition of the suspended material load. An in-lab calibration was conducted, using formazine to correlate turbidity with the electronic outputs of the instrument. An analysis of the influence of external light sources and correction techniques were performed. Moreover, an in-lab experiment was conducted to study the behaviour of the sensor-to-sediment transport, wash load and sediment accumulation. The device was deployed, with a water level sensor, in an estuarine area with high sediment dynamics. The monitoring data were analysed, showing the potential of the device to continuously monitor turbidity, sediment processes, and distinguish between organic and inorganic matter, at the different depths in the water column.

Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment.

A cost-effective optical sensor for continuous in-situ monitoring of turbidity and suspended particulate matter concentration (SPM), with a production cost in raw materials less than 20 €, is presented for marine or fluvial applications. The sensor uses an infrared LED and three photodetectors with three different positions related to the light source-135º, 90º and 0º-resulting in three different types of light detection: backscattering, nephelometry and transmitted light, respectively. This design allows monitoring in any type of environment, offering a wide dynamic range and accuracy for low and high turbidity or SPM values. An ultraviolet emitter-receiver pair is also used to differentiate organic and inorganic matter through the differences in absorption at different wavelengths. The optical transducers are built in a watertight structure with a radial configuration where a printed circuit board with the electronic signal coupling is assembled. An in-lab calibration of the sensor was made to establish a relation between suspended particulate matter (SPM) or the turbidity (NTU) to the photodetectors' electrical output value in Volts. Two different sizes of seashore sand were used (180 µm and 350 µm) to evaluate the particle size susceptibility. The sensor was tested in a fluvial environment to evaluate SPM change during sediment transport caused by rain, and a real test of 22 days continuous in-situ monitoring was realized to evaluate its performance in a tidal area. The monitoring results were analysed, showing the SPM change during tidal cycles as well as the influence of the external light and biofouling problems.

Role of plant volatiles and hetero-specific pheromone components in the wind tunnel response of male Grapholita molesta (Lepidoptera: Tortricidae) to modified sex pheromone blends.

Female Grapholita molesta (Busck) release a pheromone blend composed of two stereoisomeric acetates (Z8-12:Ac and E8-12:Ac), which in a 100:6 ratio stimulate maximum conspecific male approach. Z8-12:OH is described as a third pheromone component that increases responses to the acetate blend. Departures from the optimal pheromone blend ratio, or too high or low pheromone doses of the optimal blend ratio, result in lower male response. In a previous study, we show that plant volatiles synergize male response to a suboptimal-low pheromone concentration. In the present study, we show that the plant blend does not synergize male response to a suboptimal-high pheromone dose. The plant blend, however, synergized male response to pheromone blends containing unnatural Z:E-acetate isomer ratios. We revisited the role of alcohols in the pheromone response of G. molesta by replacing Z8-12:OH with conspecific and heterospecific pheromone alcohols or with plant odors. Codlemone, the alcohol sex pheromone of Cydia pomonella L., E8, E10-12:OH, did supplant the role of Z8-12:OH, and so did the plant volatile blend. Dodecenol (12:OH), which has been described as a fourth pheromone component of G. molesta, also increased responses, but not as much as Z8-12:OH, codlemone or the plant blend. Our results reveal new functions for plant volatiles on moth sex pheromone response under laboratory conditions, and shed new light on the role of alcohol ingredients in the pheromone blend of G. molesta.

RAPID-COMMUNICATION Genetic diversity and differentiation in natural populations of Arapaima gigas from lower Amazon revealed by microsatellites.

Genetic variability is one of the important criteria for species conservation decisions. This study aimed to analyze the genetic diversity and the population differentiation of two natural populations of Arapaima gigas, a species with a long history of being commercially exploited. We collected 87 samples of A. gigas from Grande Curuai Lake and Paru Lake, located in the Lower Amazon region of Amazônia, Brazil, and genotyped these samples using a multiplex panel of microsatellite markers. Our results showed that the populations of A. gigas analyzed had high levels of genetic variability, which were similar to those described in previous studies. These two populations had a significant population differentiation supported by the estimates of FST and RST (0.06), by Bayesian analysis (K = 2), and by population assignment tests, which revealed a moderate genetic distance.

First record of Cynoscion regalis (Pisces, Sciaenidae) in Portuguese continental waters.

The occurrence of Cynoscion regalis in Portuguese continental waters is reported for the first time, with six specimens collected in 2015 from three areas: Tagus Estuary, Sado Estuary and Praia da Vieira (central-west coast). Analyses of morphometric and meristic characteristics confirmed all six specimens as C. regalis; further validation was obtained by sequencing a 675 bp region of the mitochondrial cytochrome c oxidase I gene. These records constitute a range extension of C. regalis into the southern north-east Atlantic Ocean.

Hydrochemical characterization of a river affected by acid mine drainage in the Iberian Pyrite Belt.

This paper addresses the modelling of the processes associated with acid mine drainage affecting the Trimpancho River basin, chosen for this purpose because of its location and paradigmatic hydrological, geological, mining and environmental contexts. By using physical-chemical indicators it is possible to define the contamination degree of the system from the perspective of an entire river basin, due to its reduced dimension. This allows an exhaustive monitoring of the study area, considering the particularity that the stream flows directly into a water dam used for human supply. With such a perspective, and in order to find global solutions, the present study seeks to develop methodologies and tools for expeditious and accurate diagnosis of the pollution level of the affected stream that feeds the water reservoir. The implemented methodology can be applied to other water systems affected by similar problems, while the results will contribute to the development of the state of the art in a representative basin of the Iberian Pyrite Belt, whose pollutants' contributions are incorporated into the reservoir.

The Osteogenic Priming of Mesenchymal Stem Cells is Impaired in Experimental Diabetes.

Diabetes mellitus encompasses a group of metabolic conditions embracing the dysfunction and failure of various tissues and organs, including bone. Sustained bone alterations seem to result from anabolic, rather than catabolic processes, and suggest a decreased osteoblastic recruitment and activity. Current knowledge on the cellular and molecular mechanisms were provided by studies performed with osteogenic populations cultured in diabetic-simulated conditions, and osteogenic-induced precursor populations harvested from diabetic animals, sustaining an impaired cellular behavior in terms of osteogenic responsiveness and function. However, the reasons leaning to this impairment remain essentially unknown, as the priming capability and functionality of undifferentiated precursors, developed within the diabetic environment, have not been addressed. Accordingly, this work aims to evaluate the functionality and osteogenic priming capability of bone marrow-derived mesenchymal stem cells (MSCs), harvested from animals with experimental diabetes, and grown in the absence of any given differentiation factor. MSCs developed within a diabetic microenvironment displayed an impaired behavior, with diminished cell viability and proliferation, altered cytoskeleton organization, impaired osteogenic priming, and increased adipogenic activation. Further, the osteogenic induction of diabetic MSCs resulted in an impaired osteogenic commitment. The modified cell phenotype may be related, at least in part, with altered activity of ERK WNT and p38 signaling pathways in diabetic-derived cultures. Specific strategies, aiming the modulation of the verified hindrances, may be of therapeutic value to enhance the functionality of diabetic MSCs and sustain an improved outcome in the metabolism and regeneration of the bone tissue in diabetic conditions.

The biomaterial-mediated healing of critical size bone defects in the ovariectomized rat.

UNLABELLED: This study demonstrated an impaired biomaterial-mediated bone regeneration in a critical sized calvarial defect established within an ovariectomized rat model. Histological and microtomographic evidences were supported by an impaired osteoblastic gene expression and altered expression of estrogen receptors and adipogenic markers. INTRODUCTION: This work aims to address the bone regeneration process in the ovariectomized rat model, by assessing a calvarial critical size defect implanted with a biocompatible bovine bone mineral graft. METHODS: Animals were randomly divided into two groups: Ovx (bilateral ovariectomy) and Sham (control surgery). Following 8 weeks, all animals were submitted to a surgical bicortical craniotomy (5-mm circular critical size defect), which was filled with a biocompatible mineral graft. Animals were euthanized at 1, 3, and 6 months following graft implantation (n = 10), and results on the orthotopic bone regeneration process were blindly evaluated by radiographic, microtomographic, histological, histomorphometric, and gene expression techniques. RESULTS: In the attained model, in both Sham and Ovx groups, the bone regenerative process was found to occur in a slow-paced manner. Likewise, a qualitative evaluation of the microtomographic and histological analysis, as well as quantitative data from histomorphometric indexes, revealed reduced bone regeneration in Ovx animals, at the assayed time points. Significant differences were attained at the 3 and 6 months. Gene expression analysis revealed a reduced expression of osteoblastic-related genes and an altered expression of estrogen receptors and adipogenic markers, within the regenerating bone of Ovx animals. CONCLUSIONS: Due to the similarities between the osteoporotic animal model and the human condition of postmenopausal osteoporosis, it might be relevant to consider the potential clinical implication of the osteoporotic condition in the biomaterial-mediated bone tissue healing/regeneration process.

Processing strategies for smart electroconductive carbon nanotube-based bioceramic bone grafts.

Electroconductive bone grafts have been designed to control bone regeneration. Contrary to polymeric matrices, the translation of the carbon nanotube (CNT) electroconductivity into oxide ceramics is challenging due to the CNT oxidation during sintering. Sintering strategies involving reactive-bed pressureless sintering (RB + P) and hot-pressing (HP) were optimized towards prevention of CNT oxidation in glass/hydroxyapatite (HA) matrices. Both showed CNT retentions up to 80%, even at 1300 °C, yielding an increase of the electroconductivity in ten orders of magnitude relative to the matrix. The RB + P CNT compacts showed higher electroconductivity by ∼170% than the HP ones due to the lower damage to CNTs of the former route. Even so, highly reproducible conductivities with statistical variation below 5% and dense compacts up to 96% were only obtained by HP. The hot-pressed CNT compacts possessed no acute toxicity in a human osteoblastic cell line. A normal cellular adhesion and a marked orientation of the cell growth were observed over the CNT composites, with a proliferation/differentiation relationship favouring osteoblastic functional activity. These sintering strategies offer new insights into the sintering of electroconductive CNT containing bioactive ceramics with unlimited geometries for electrotherapy of the bone tissue.

Analysis of a microbial community associated with polychlorinated biphenyl degradation in anaerobic batch reactors.

The degradation of polychlorinated biphenyls (PCBs) was investigated under fermentative-methanogenic conditions for up to 60 days in the presence of anaerobic biomass from a full-scale UASB reactor. The low methane yields in the PCBs-spiked batch reactors suggested that the biomass had an inhibitory effect on the methanogenic community. Reactors containing PCBs and co-substrates (ethanol/sodium formate) exhibited substantial PCB reductions from 0.7 to 0.2 mg mL(-1). For the Bacteria domain, the PCBs-spiked reactors were grouped with the PCB-free reactors with a similarity of 55 %, which suggested the selection of a specific population in the presence of PCBs. Three genera of bacteria were found exclusively in the PCB-spiked reactors and were identified using pyrosequencing analysis, Sedimentibacter, Tissierela and Fusibacter. Interestingly, the Sedimentibacter, which was previously correlated with the reductive dechlorination of PCBs, had the highest relative abundance in the RCS-PCB (7.4 %) and RCS-PCB-PF (12.4 %) reactors. Thus, the anaerobic sludge from the UASB reactor contains bacteria from the Firmicutes phylum that are capable of degrading PCBs.

Adverse events with arterial catheters in intensive care units: a scoping review.

INTRODUCTION: The installation of an arterial line is one of the invasive procedures performed for hemodynamic monitoring and, even with its clear importance in intensive care, it is still an invasive procedure and liable to cause harms to the patients. OBJECTIVE: To identify the adverse events associated with the use of arterial catheters in critically-ill patients in the world scientific production. METHODOLOGY: The present scoping review was conducted according to the JBI methodology for scoping reviews. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist was used for reporting. The research question was "Which adverse events related to the use of arterial catheters in patients admitted to intensive care are more evident in the literature?". Data collection took place in the following databases: LILACS; MEDLINE; EMBASE; CINAHL, EBSCOhost; and WEB OF SCIENCE. RESULTS: Through the search strategies, 491 articles were found in the databases. After exclusion of duplicates, peer analysis of titles and abstracts, full reading and screening of lists of references, the final sample of studies included was 38 articles. The main harms cited by the publications were as follows: limb ischemia, thrombosis, hemorrhage, accidental removal, inadvertent connection of inadequate infusion solution, pseudoaneurysm and bloodstream infection. CONCLUSIONS: It was evidenced that patients are subjected to risks of adverse events from the insertion moment to removal of the arterial catheter, focusing on the infusion solution used to fill the circuit, the type of securement and dressings chosen, as well as the Nursing care measures for the prevention of bloodstream infection.

Dhvar5-chitosan nanogels and their potential to improve antibiotics activity.

Infection is one of the main causes of orthopedic implants failure, with antibiotic-resistant bacteria playing a crucial role in this outcome. In this work, antimicrobial nanogels were developed to be applied in situ as implant coating to prevent orthopedic-device-related infections. To that regard, a broad-spectrum antimicrobial peptide, Dhvar5, was grafted onto chitosan via thiol-norbornene "photoclick" chemistry. Dhvar5-chitosan nanogels (Dhvar5-NG) were then produced using a microfluidic system. Dhvar5-NG (1010 nanogels (NG)/mL) with a Dhvar5 concentration of 6 µg/mL reduced the burden of the most critical bacteria in orthopedic infections - methicillin-resistant Staphylococcus aureus (MRSA) - after 24 h in medium supplemented with human plasma proteins. Transmission electron microscopy showed that Dhvar5-NG killed bacteria by membrane disruption and cytoplasm release. No signs of cytotoxicity against a pre-osteoblast cell line were verified upon incubation with Dhvar5-NG. To further explore therapeutic alternatives, the potential synergistic effect of Dhvar5-NG with antibiotics was evaluated against MRSA. Dhvar5-NG at a sub-minimal inhibitory concentration (109 NG/mL) demonstrated synergistic effect with oxacillin (4-fold reduction: from 2 to 0.5 µg/mL) and piperacillin (2-fold reduction: from 2 to 1 µg/mL). This work supports the use of Dhvar5-NG as adjuvant of antibiotics to the prevention of orthopedic devices-related infections.

N-cinnamoylated aminoquinolines as promising antileishmanial agents.

A series of cinnamic acid conjugates of primaquine and chloroquine were evaluated for their in vitro antileishmanial activities. Although primaquine derivatives had modest activity, chloroquine conjugates exhibited potent activity against both promastigotes (50% inhibitory concentration [IC50] = 2.6 to 21.8 µM) and intramacrophagic amastigotes (IC50 = 1.2 to 9.3 µM) of Leishmania infantum. Both the high activity of these chloroquine analogues and their mild-to-low toxicity toward host cells make them promising leads for the discovery of new antileishmanial agents.

Determination of degree of ionization of poly(allylamine hydrochloride) (PAH) and poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) in layer-by-layer films using vacuum photoabsorption spectroscopy.

Electrostatic and hydrophobic interactions govern most of the properties of supramolecular systems, which is the reason determining the degree of ionization of macromolecules has become crucial for many applications. In this paper, we show that high-resolution ultraviolet spectroscopy (VUV) can be used to determine the degree of ionization and its effect on the electronic excitation energies of layer-by-layer (LbL) films of poly(allylamine hydrochloride) (PAH) and poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO). A full assignment of the VUV peaks of these polyelectrolytes in solution and in cast or LbL films could be made, with their pH dependence allowing us to determine the pK(a) using the Henderson-Hasselbach equation. The pK(a) for PAZO increased from ca. 6 in solution to ca. 7.3 in LbL films owing to the charge transfer from PAH. Significantly, even using solutions at a fixed pH for PAH, the amount adsorbed on the LbL films still varied with the pH of the PAZO solutions due to these molecular-level interactions. Therefore, the procedure based on a comparison of VUV spectra from solutions and films obtained under distinct conditions is useful to determine the degree of dissociation of macromolecules, in addition to permitting interrogation of interface effects in multilayer films.

Cassava interspecific hybrids with increased protein content and improved amino acid profiles.

Cassava (Manihot esculenta) is a principal food for large populations of poor people in the tropics and subtropics. Its edible roots are poor in protein and lack several essential amino acids. Interspecific hybrids may acquire high protein characteristics from wild species. We analyzed 19 hybrids of M. esculenta with its wild relative, M. oligantha, for crude protein, amino acid profile, and total cyanide. Some hybrids produced roots with high protein content of up to 5.7%, while the common cultivar that we examined had just 2.3% crude protein. The essential amino acids alanine, phenylalanine, and valine were detected in the hybrids. The sulfur-containing amino acids cysteine and methionine were found at relatively high concentrations in the roots of 4 hybrids. The proportion of lysine in one hybrid was 20 times higher than in the common cultivar. The levels of total cyanide ranged from 19.73 to 172.56 mg/kg and most of the roots analyzed were classified as "non-toxic" and "low toxic". Furthermore, 2 progenies showed reasonable levels of cyanide, but higher protein content and amino acid profile more advantageous than the common cassava.