ABSTRACT The urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) reduces NH3 losses from urea (UR) surface-applied to soils, but its efficacy may be lower in acidic soils. The period when urease inhibition occurs efficaciously may change with soil pH. This needs to be clarified in tropical soils which are commonly acidic. This study evaluated the effectiveness of NBPT-treated urea to delay and reduce ammonia volatilization in two soils at three pH levels. Two experiments were conducted under laboratory conditions in soils with different textures (sandy-clay and clay). The treatments consisted of three soil pH levels and two N sources (UR and UR + NBPT), with five replicates. The soil pH values were adjusted and reached values of 4.5, 5.6, and 6.4 in the sandy-clay, and 4.5, 5.4, and 6.1 in the clay soil. Ammonia volatilization was measured using glass chambers (1.5 L). In the sandy-clay soil, NH3 losses were 40-47 % of the UR-N. In the clay soil, losses were 26-32 %. The addition of NBPT to UR reduced the NH3 volatilization by 18-53 %; the inhibitor decreased the N losses under all soil pH conditions but was significantly less efficient in acidic soils (pH 4.5). The lower efficiency of the inhibitor under acidic conditions was more evident in the first few days: 50 % of the total NH3 losses occurred in less than four days in soils with pH 4.5, but in 8-11 days in soils with pH above 5.4. The rapid loss in efficiency in more acidic soils is a drawback. Using NBPT in severely acidic soils showed a relatively small advantage over untreated UR as the inhibitor did not provide extra time for fertilizer incorporation and further reduction of NH3 losses.

Thermo-responsive copolymers grafted with N-isopropylacrylamide (NIPAm) are excellent candidates for drug release. Dextran sulfate (DS) acts as a specific ligand in inflamed regions, turning it highly useful as a target for drug delivery. DS was associated with NIPAm to produce amphiphilic graft copolymers prepared via free radicals. The molar ratio of feed reagents NIPAm/DS varied from 1 (DS-g-PNIPAm) to 4 (DS-g-4PNIPAm). The synthesis was confirmed by spectroscopic techniques (Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR)). All copolymers showed self-organization capacity in an aqueous medium in temperatures higher than 34 °C, and sizes less than 300 nm. DS-g-3PNIPAm exhibited stability in water and in phosphate buffer at pH 7.4. Scanning electron microscopy confirmed their spherical shape. This copolymer showed specificity to leukemic cells, and normal cells’ proliferation. Methotrexate (MTX) is a very low water-soluble drug used for rheumatoid arthritis and cancer. Unfortunately, MTX have severe collateral effects. MTX-loaded nanoparticles can overcome such issues as well as enhance bioactivity and stability. The MTX was encapsulated and delivered from the DS-g-3PNIPAm with potential target delivery due to the presence of DS. Comparison with MTX encapsulated in other nanoparticles reveals that the DS-g-PNIPam presents the best performance among the thermo-responsive and the second among the target MTX nanocarriers.

RESUMEN Objetivo. Desarrollar y evaluar un método de bajo costo basado en celulosa para la purificación rápida y amplificación directa de ADN de Bordetella pertussis de hisopados nasofaríngeos. Materiales y métodos. Se prepararon discos de celulosa y se evaluaron diferentes parámetros (buffers de lisis/lavado, número de discos y elución de ADN). El método se acopló a una amplificación directa por PCR en tiempo real (qPCR) y se estimó el rendimiento utilizando hisopados nasofaríngeos que fueron positivos (n=100) y negativos (n=50) para ADN B. pertussis por qPCR, comparado con el método basado en columnas de sílice. Se calculó el grado de concordancia, sensibilidad, especificidad, valor predictivo positivo (VPP) y valor predictivo negativo (VPN). Se evaluó la factibilidad del método rápido para ser acoplado a un ensayo colorimétrico de amplificación isotérmica mediada por lazo (LAMP). Resultados. El método rápido con un disco de celulosa y buffer de lisis y lavado conteniendo PVP-40 y Tween 20, respectivamente, mostró una mayor capacidad para purificar ADN amplificable de B. pertussis. El método tuvo una sensibilidad de 89,0% (IC95%, 80,2%-94,9%) y una especificidad de 98,5% (IC95%, 92,1%-100,0%), con un buen grado de concordancia (Kappa=0,867; IC95% 0,788 - 0,946), respecto al método referencial. Los VPP y VPN fueron 98,6% (IC95%, 92,7,2%-100,0%) y 88,2% (IC95%, 78,7%-94,4%), respectivamente. Se evidenció una amplificación exitosa por LAMP, y se obtuvieron resultados comparables con el método por columnas de sílice. Conclusión. El método desarrollado es simple, de bajo costo y libre de equipos para la obtención rápida (60 segundos) de ADN en el punto de atención, y puede ser implementado en diversas técnicas moleculares orientados al diagnóstico oportuno y al estudio epidemiológico de tos ferina.

ABSTRACT Objective. To develop and evaluate a low-cost cellulose-based method for rapid purification and direct amplification of Bordetella pertussis DNA from nasopharyngeal swabs. Materials and methods. We prepared cellulose discs and evaluated different parameters (lysis/wash buffers, number of discs and DNA elution). The method was coupled to a direct real-time PCR (qPCR) amplification and the performance was estimated using nasopharyngeal swabs that were positive (n=100) and negative (n=50) for B. pertussis DNA by qPCR, compared to the silica column-based method. We calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and the degree of agreement. The feasibility of the rapid method to be coupled to a loop-mediated isothermal amplification colorimetric assay (LAMP) was evaluated. Results. The rapid method, with a cellulose disk and lysis and wash buffer containing PVP-40 and Tween 20, respectively, showed a greater capacity to purify amplifiable DNA from B. pertussis. The method had a sensitivity of 89.0% (95%CI: 80.2%-94.9%) and a specificity of 98.5% (95%CI: 92.1%-100.0%), with a good degree of agreement (Kappa=0.867; 95%CI: 0.788 - 0.946), compared to the reference method. The PPV and NPV were 98.6% (95%CI: 92.7.2%-100.0%) and 88.2% (95%CI: 78.7%-94.4%), respectively. Successful amplification by LAMP was evident, and comparable results were obtained with the silica column method. Conclusion. The developed method is simple, low-cost and equipment-free for rapid (60 seconds) DNA collection at the point of care, and can be implemented in various molecular techniques aimed at the timely diagnosis and epidemiological study of pertussis.

ABSTRACT Objective. To develop and evaluate a low-cost cellulose-based method for rapid purification and direct amplification of Bordetella pertussis DNA from nasopharyngeal swabs. Materials and methods. We prepared cellulose discs and evaluated different parameters (lysis/wash buffers, number of discs and DNA elution). The method was coupled to a direct real-time PCR (qPCR) amplification and the performance was estimated using nasopharyngeal swabs that were positive (n=100) and negative (n=50) for B. pertussis DNA by qPCR, compared to the silica column-based method. We calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and the degree of agreement. The feasibility of the rapid method to be coupled to a loop-mediated isothermal amplification colorimetric assay (LAMP) was evaluated. Results. The rapid method, with a cellulose disk and lysis and wash buffer containing PVP-40 and Tween 20, respectively, showed a greater capacity to purify amplifiable DNA from B. pertussis. The method had a sensitivity of 89.0% (95%CI: 80.2%-94.9%) and a specificity of 98.5% (95%CI: 92.1%-100.0%), with a good degree of agreement (Kappa=0.867; 95%CI: 0.788 - 0.946), compared to the reference method. The PPV and NPV were 98.6% (95%CI: 92.7.2%-100.0%) and 88.2% (95%CI: 78.7%-94.4%), respectively. Successful amplification by LAMP was evident, and comparable results were obtained with the silica column method. Conclusion. The developed method is simple, low-cost and equipment-free for rapid (60 seconds) DNA collection at the point of care, and can be implemented in various molecular techniques aimed at the timely diagnosis and epidemiological study of pertussis.

RESUMEN Objetivo. Desarrollar y evaluar un método de bajo costo basado en celulosa para la purificación rápida y amplificación directa de ADN de Bordetella pertussis de hisopados nasofaríngeos. Materiales y métodos. Se prepararon discos de celulosa y se evaluaron diferentes parámetros (buffers de lisis/lavado, número de discos y elución de ADN). El método se acopló a una amplificación directa por PCR en tiempo real (qPCR) y se estimó el rendimiento utilizando hisopados nasofaríngeos que fueron positivos (n=100) y negativos (n=50) para ADN B. pertussis por qPCR, comparado con el método basado en columnas de sílice. Se calculó el grado de concordancia, sensibilidad, especificidad, valor predictivo positivo (VPP) y valor predictivo negativo (VPN). Se evaluó la factibilidad del método rápido para ser acoplado a un ensayo colorimétrico de amplificación isotérmica mediada por lazo (LAMP). Resultados. El método rápido con un disco de celulosa y buffer de lisis y lavado conteniendo PVP-40 y Tween 20, respectivamente, mostró una mayor capacidad para purificar ADN amplificable de B. pertussis. El método tuvo una sensibilidad de 89,0% (IC95%, 80,2%-94,9%) y una especificidad de 98,5% (IC95%, 92,1%-100,0%), con un buen grado de concordancia (Kappa=0,867; IC95% 0,788 - 0,946), respecto al método referencial. Los VPP y VPN fueron 98,6% (IC95%, 92,7,2%-100,0%) y 88,2% (IC95%, 78,7%-94,4%), respectivamente. Se evidenció una amplificación exitosa por LAMP, y se obtuvieron resultados comparables con el método por columnas de sílice. Conclusión. El método desarrollado es simple, de bajo costo y libre de equipos para la obtención rápida (60 segundos) de ADN en el punto de atención, y puede ser implementado en diversas técnicas moleculares orientados al diagnóstico oportuno y al estudio epidemiológico de tos ferina.

The ternary amorphous CuSeP2 was designed and prepared as the anode material of potassium ion battery for the first time, and its electrochemical performance was also investigated. After ball-milling with commercial graphene powder, it is used as the anode material for potassium ion battery with reversible specific capacity up to 300 mAh g-1, and the corresponding initial coulombic efficiency is close to 60%. What’s more, the specific capacity remains above 150 mAh g-1 after 100 cycles at 200 mA g-1. When increasing the current density to 1000 mA g-1, the CuSeP2/graphene composites still has a potassium storage specific capacity of 100 mAh g-1. Our results show that the potassium storage mechanism of the ternary CuSeP2 anode material is a typical conversion reaction and the introduction of Cu can not only buffer the volume expansion during the subsequent electrochemical reaction, but also effectively enhance the electrochemical reversibility of potassium ion.

Plant composition, diversity and structure of riparian forests of Central Brazil are well known. However, little is known about soil physical properties under these forests. This knowledge is important as a baseline for biodiversity restoration and ecosystem services that occur in riparian zones. In order to bridge this gap, here we assessed the infiltration capacity and soil penetration resistance in a plinthic soil under gallery forest in Planaltina, Distrito Federal, Brazil. We measured infiltration capacity (Mini-Disk infiltrometer) and soil penetration resistance (Stof penetrometer) following linear transects. The plinthic soil had high infiltration capacity and low penetration resistance. Our infiltration estimate is in the middle range when compared to other permeability studies in tropical forests. Like their counterparts, high biological activity along with the lack of disturbance are the likely explanations for such high topsoil permeability to water.

As florestas de galeria são bem descritas em termos de composição, diversidade e estrutura da vegetação. No entanto, pouco se sabe sobre as propriedades físicas do solo sob essas florestas que são importantes para a restauração de zonas ripárias. A fim de preencher essa lacuna, no presente trabalho, avaliou-se a capacidade de infiltração e a resistência do solo à penetração em um solo plíntico sob floresta ripária em Planaltina, Distrito Federal, Brasil. Mediu-se a capacidade de infiltração (infiltrômetro de Mini-Disk) e a resistência à penetração no solo (penetrômetro de Stolf) seguindo transectos lineares. O solo plíntico apresentou alta capacidade de infiltração e baixa resistência à penetração. Nossa estimativa de infiltração está na faixa intermediária em comparação com outros estudos de permeabilidade em florestas tropicais. Mesmo assim, a mediana da capacidade de infiltração foi superior à intensidade de chuva de alto período de retorno o que descarta a possibilidade de escoamento superficial Hortoniano. Como em outras florestas tropicais, a alta atividade biológica junto com a ausência de perturbação do solo são as razões prováveis para essa alta permeabilidade do solo à água.

ABSTRACT. Phosphorus (P) is one of the most important elements used in fertilizing soils in tropical regions due to the low efficiency of phosphate fertilization. This work aimed to fractionate inorganic P (Pi) in tropical soils of different mineralogical compositions and to relate these fractions with their respective phosphate buffer capacity (PBC) indicators. The soils were characterized physically, chemically and mineralogically. Additionally, we evaluated the P concentration that remained in solution of soil after equilibrium was met; this was termed P remaining (P-rem). In general, the Pi fractions of soils did not correlate with the PBC indicators. The P-H2O fraction showed a negative correlation with the P-Al fraction. Ferric minerals did not influence P fixation. P-rem showed a strong correlation with the maximum P adsorption capacity, adsorption energy, and the amorphous and crystalline forms of Fe. The minerals of aluminum contributed the most to P fixation. P-rem was the best estimator of PBC. The soils with high, moderate and low rates of P fixation showed high amounts of the fractions P-Al, P-Ca, and P-Fe, respectively. The results showed that P fixation was influenced by the fractions of P in the soil, suggesting that the efficiency of phosphate fertilizers in tropical soils depends on the mineralogy of the clay fraction within those soils.

RESUMO As florestas de galeria são bem descritas em termos de composição, diversidade e estrutura da vegetação. No entanto, pouco se sabe sobre as propriedades físicas do solo sob essas florestas que são importantes para a restauração de zonas ripárias. A fim de preencher essa lacuna, no presente trabalho, avaliou-se a capacidade de infiltração e a resistência do solo à penetração em um solo plíntico sob floresta ripária em Planaltina, Distrito Federal, Brasil. Mediu-se a capacidade de infiltração (infiltrômetro de Mini-Disk) e a resistência à penetração no solo (penetrômetro de Stolf) seguindo transectos lineares. O solo plíntico apresentou alta capacidade de infiltração e baixa resistência à penetração. Nossa estimativa de infiltração está na faixa intermediária em comparação com outros estudos de permeabilidade em florestas tropicais. Mesmo assim, a mediana da capacidade de infiltração foi superior à intensidade de chuva de alto período de retorno o que descarta a possibilidade de escoamento superficial Hortoniano. Como em outras florestas tropicais, a alta atividade biológica junto com a ausência de perturbação do solo são as razões prováveis para essa alta permeabilidade do solo à água.

ABSTRACT Plant composition, diversity and structure of riparian forests of Central Brazil are well known. However, little is known about soil physical properties under these forests. This knowledge is important as a baseline for biodiversity restoration and ecosystem services that occur in riparian zones. In order to bridge this gap, here we assessed the infiltration capacity and soil penetration resistance in a plinthic soil under gallery forest in Planaltina, Distrito Federal, Brazil. We measured infiltration capacity (Mini-Disk infiltrometer) and soil penetration resistance (Stolf penetrometer) following linear transects. The plinthic soil had high infiltration capacity and low penetration resistance. Our infiltration estimate is in the middle range when compared to other permeability studies in tropical forests. Like their counterparts, high biological activity along with the lack of disturbance are the likely explanations for such high topsoil permeability to water.

Resumen Introducción y Objetivo: La saliva cumple una importante función en la homeostasis oral, aunque no es evaluada rutinariamente en pacientes con labio con/sin paladar hendido (LH±PH). Este estudio pretendió comparar las características salivares de niños con LH±PH no sindrómico vs. niños sin esta diferencia craneofacial. Materiales y métodos: Se incluyeron 17 niños con LH±PH no sindrómico y 25 niños sin LH±PH, de los cuales se colectaron muestras de saliva estimulada (SE) y no estimulada (SNE). Se realizaron pruebas fisicoquímicas, cuantificación de iones (Ca, Mg y P), proteína total y recuento de streptococcus mutans en ambos grupos para ambas muestras de saliva. Para establecer comparaciones entre grupos se realizó la prueba no paramétrica de Mann-Whitney. Resultados: Hubo diferencias estadísticamente significativas en el pH de SE y SNE, así como en proteína total y capacidad amortiguadora de SNE. El pH (p=0,002) y capacidad amortiguadora (p=0,023) de SNE de los niños con LH±PH fueron menores, mientras que la concentración de proteína total (p=0,003) fue mayor con respecto al grupo control. Se encontró mayor proporción de estreptococo mutans en SNE de niños con LH±PH (6,39x104 UFC mL-1) respecto al grupo control (2,21x104 UFC mL-1), aunque sin detectar diferencias estadísticamente significativas (p=0,243). Conclusiones: Estos hallazgos sugieren una alteración en la función y composición de la SNE en pacientes con LH±PH no sindrómico, que correspondería a una alteración en la formación y función de las glándulas salivales en estos individuos que requiere ser investigada.

Abstract Introduction and objective: Saliva plays an important role in oral homeostasis, although it is not routinely evaluated in patients with CL±P. This study aimed to compare these characteristics in children with non-syndromic CL±P vs. children without this craniofacial difference. Materials and methods: This descriptive study included 17 children with non-syndromic CL±P from Fundación Clínica Noel and 25 children without CL±P. Stimulated (SS) and non-stimulated saliva (NSS) from both groups were collected for physicochemical tests, quantification of ions (Ca, Mg and P), total protein and streptococcus mutans count. Results: There were statistically significant differences in pH of SS and NSS, as well as in total protein concentration and buffer capacity in NSS. The pH (p = 0.002) and buffering capacity (p = 0.023) of NSS of CL±P children decreased, while total protein concentration (p = 0.003) increased compared to the control group. A higher streptococcus mutans count was found in NSS of CL±P children (6.39x104 CFU UFC mL-1) compared to the control group (2.21x104 UFC mL-1), although without detecting statistically significant differences (p = 0.243). Conclusions: These findings suggest an alteration in the function and composition of NSS in patients with non-syndromic CL±P; which could possibly be explained from the genetic/biological point of view by an alteration in the salivary glands formation and function in these individuals that requires further investigation.

Resumo Introdução e objetivo: A saliva desempenha um papel fundamental na homeostase oral, não é avaliada rotineiramente em pacientes com FL/P. Portanto, este estudo objetivou indagar essas características em crianças com FL/P não sindrômico. Materiais e métodos: 17 crianças com FL/P não sindrômico da Fundación Clínica Noel, e 25 crianças sem FL/P foram incluídas neste estudo. Amostras de saliva estimulada (SE) e saliva não estimulada (SNE) foram coletadas para realização de testes físico-químicos, quantificação de íons (Ca, Mg e P), proteína total e contagem de streptococcus mutans. Resultados: Houve diferenças estatisticamente significativas no pH de SE e SNE, bem como na concentração de proteína total e capacidade tampão de SNE. O pH (p=0,002) e a capacidade tampão (p=0,023) de SNE de crianças com FL/P foram menores, enquanto a concentração de proteína total (p=0,003) foi maior, quando comparado ao grupo controle. Um contagem maior de streptococcus mutans foi encontrada na saliva não estimulada de crianças com FL/P (6,39x104 UFC mL-1) em comparação ao grupo controle (2,21x104 UFC mL-1), embora sem detectar diferenças estatisticamente significativas (p=0,243). Conclusão: Esses achados sugerem uma alteração na função e composição da SNE em pacientes com FL/P não sindrômico; isso possivelmente poderia ser explicado do ponto de vista genético/biológico por uma alteração na formação e função das glândulas salivares nesses indivíduos que requer investigação.

RESUMEN En épocas de escasez, los ganaderos recurren a conservar el alimento mediante procesos de fermentación anaeróbica, conocidos como ensilajes. Una vez que el silo es abierto, el sustrato resulta aeróbicamente estable, cuando, al momento de la apertura, conserva su integridad nutricional. Esto es el resultado de un ambiente ácido que restringe los efectos deletéreos de la acción de microrganismos patógenos, expresado en indicadores de estabilidad a la exposición aeróbica. Uno de los problemas empíricos que enfrenta el productor es resolver la pregunta de cómo evitar el deterioro del ensilaje, una vez es abierto, por lo cual, esta investigación apunta a la resistencia en el periodo de exposición aeróbica (PEA) de un ensilaje de Pennisetum purpureum (PP), con diferentes niveles de sustitución de Tithonia diversifolia (TD). El estudio, se adelantó en el Centro Internacional de Agricultura Tropical en Colombia. Con un ensilaje de 90 días de fermentación, se realizó una prueba de estabilidad aeróbica de siete días, usando ensilajes de un kilogramo, a diferentes proporciones (%) de TD/PP: 100/0, 67/33, 33/67 y 0/100, enriquecidos con dos aditivos basados en Lactobacillus. Se midió el cambio de la materia seca, temperatura y el pH, encontrándose una estabilidad a la exposición aeróbica. El papel de TD es notable, una vez que el ensilado entra en el PEA, debido a la capacidad tampón que amortigua el cambio de pH, una vez que se abre el silo, generando mayor estabilidad aeróbica.

ABSTRACT In times of scarcity, farmers resort to preserving food through anaerobic fermentation processes, known as silage. Once the silo is opened, the substrate is aerobically stable if it retains its nutritional integrity when opening. This is the result of an acidic environment that restricts the deleterious effects of the action of pathogenic microorganisms, expressed as indicators of stability to aerobic exposure. One of the empirical problems faced by the producer is to solve the question of how to avoid deterioration of the silage once it is opened, for which this research points to the resistance in the period of aerobic exposure (PEA) of a silage of Pennisetum purpureum (PP) with different levels of substitution of Tithonia diversifolia (TD). The study was conducted at the International Center for Tropical Agriculture in Colombia. With a 90-day fermentation silage, a seven-day aerobic stability test was carried out, using a kilogram silage at different proportions (%) of TD/PP: 100/0, 67/33, 33/67 and 0/100 enriched with two Lactobacillus-based additives. The change in dry matter, temperature and pH was measured, finding stability to aerobic exposure. The role of TD is remarkable once the silage enters the PEA due to the buffer capacity that buffers the change in pH once the silo is opened, generating greater aerobic stability.

RESUMEN Introducción: La erosión dental es la pérdida patológica, crónica, localizada e indolora de los tejidos dentarios duros, producido por la acción química de ácidos, donde no está involucrada la acción de microorganismos. En los últimos años se ha observado un incremento significativo de la prevalencia de esta patología, especialmente en niños y adolescentes. El objetivo fue establecer la relación del flujo, el pH y la capacidad buffer de la saliva estimulada con el desarrollo de erosión dental en una muestra de 400 niños valencianos de edades comprendidas entre 6 y 14 años. Material y métodos: Se realizó un estudio transversal. Mediante una exploración clínica se determinó con el índice BEWE la presencia o no de erosión en cada paciente, así como la gravedad en caso de ser detectada. Además, se determinó el flujo de saliva estimulado, la capacidad buffer y el pH salival. Resultados: La prevalencia de erosión dental en la muestra estudiada fue del 22,3%. Se observó que los pacientes con un pH moderadamente ácido presentaron un mayor índice BEWE (p<0,001). Además, cuanto menor fue la capacidad buffer salival menor fue la gravedad de las lesiones erosivas presentes (p<0,001) en los pacientes. No se pudo establecer una relación positiva entre el flujo salival y el índice BEWE. Discusión: Una baja capacidad buffer, así como un pH moderadamente ácido salival parecen ser factores asociados positivamente con el desarrollo de lesiones erosivas.

ABSTRACT Introduction: Dental erosion is the pathological, chronic, localized and painless loss of hard dental tissues, produced by the chemical action of acids, where the action of microorganisms is not involved. In recent years, a significant increase in the prevalence of this pathology has been observed, especially in children and adolescents. The objective was to establish the relationship between flow, pH and buffer capacity of stimulated saliva with the development of dental erosion in a sample of 400 Valencian children aged between 6 and 14 years. Material and methods: A cross-sectional study was carried out. A clinical examination was used to determine the presence or absence of erosion in each patient, as well as the severity of erosion, if detected. In addition, stimulated saliva flow, buffer capacity and salivary pH were determined. Results: The prevalence of dental erosion in the studied sample was 22.3%. It was observed that the patients with a moderately acid pH had a higher BEWE index (p <0.001). Furthermore, the lower the salivary buffer capacity was, the lower the severity of the erosive lesions present (p <0.001) in the patients. A positive relationship between salivary flow and BEWE index could not be established. Discussion: A low buffer capacity, as well as a moderately salivary acid pH seem to be factors positively associated with the development of erosive lesions.

Buffers are a widely used resource to keep solutions from abruptly change their pH when amounts of acids or bases are added or when dilution occurs. Considering this, buffer is a topic addressed in several university majors and due its relevance should be well known by students and by all professionals who eventually need to prepared a buffer. Mistakes during the procedure might bring unwanted effects depending on the purpose of the buffer. Even though the theory behind buffers is extensively covered in textbooks, the calculations required can sometimes be interpreted as difficult. Therefore, the aim of this work is to disseminate a tool to assist on these calculations. We provide a practical guide on how to prepare buffers of the user’s choice with or without ionic strength adjustment. Exploring the free software PeakMaster®, the user can calculate pH, ionic strength, buffer capacity and predict the precise concentration of each component involved to the proper preparation of the most common and several others buffer solutions. In addition, we hope this paper can be helpful for anyone who is interested in acquire deeper knowledge about buffers.

ABSTRACT Background Carica papaya Linn. has high nutraceutical and pharmacological values. The leaves possess antimicrobial, anti-tumor and antioxidant properties. They are used to treat thrombocytopenia during dengue fever and the leaf extract is commercially available as tablets under the name Caripill™ (MicroLabs, Bengaluru). Nevertheless, platelet transfusion is recommended in severe cases of thrombocytopenia, but the platelet storage is limited to 5-7 days at 22−24 °C. Reducing oxidative stress (OS) during platelet storage might help in prolonging the shelf-life, since the OS is known to cause platelet storage lesion. Hence, this study investigated the effects of Caripill™ as an additive in Tyrode's buffer during extended platelet storage. Methods Platelets isolated from 4 months old male Wistar rats were stored with Caripill™ (50 and 100 µg/ml) at 22 °C for 12 days. Platelet functional and metabolic markers and various OS markers were analyzed on days 0, 4, 8 and 12. Results Caripill™ (50 and 100 µg/ml) maintained platelet functions and lactate dehydrogenase, elevated nitrites, reduced glucose consumption, protected proteins and up-regulated the antioxidant enzymes. However, the CP100 up-regulated catalase from day 4, elevated nitrites from day 8, prevented the formation of secondary products of lipid peroxidation and increased the total antioxidant capacity on day 4. Conclusions Caripill™ reduced platelet storage lesion up to day 8 of storage. Results suggest that a higher concentration of Caripill™ was more effective in combating the oxidative damage during platelet storage. This study throws light on the beneficial effects of Caripill™ in combating oxidative stress during platelet storage.

This research presents a fast, sensitive, and selective ultrasound-assisted dispersive solid phase microextraction technique for simultaneous preconcentration and determination of ultra-trace amount of carbamazepine and phenobarbital. Reduced graphene oxide sheets decorated with cadmium sulfide quantum dots was synthesized, characterized, and used as a high capacity adsorbent. A high performance liquid chromatography with UV detector (HPLC-UV) instrument with 58:42 composition of methanol:acetic acid/acetate buffer (pH = 5; 0.05 mol L-1) as the mobile phase and set on the wavelength of 230 nm was used to separate and quantify the analytes. In this regard, different parameters affecting adsorption and desorption of the analytes on the surface of the nanocomposite were studied and optimized to maximize the efficiency of the method. The method was linear in the ranges of 0.5-180 and 0.5-140 ng mL−1 (correlation coefficient (r) > 0.999) with limits of detection of 0.19 and 0.24 ng mL−1 for carbamazepine and phenobarbital, respectively. Eventually, to evaluate the efficiency of the proposed method for the determination of pharmaceuticals in biological samples, different real samples including breast milk, urine and human plasma were tested. Obtained recoveries values were within the range of 96.3 ± 2 to 103.7 ± 3.3% which showed satisfactory efficiency.

ABSTRACT Objetive: Investigation the application of niosome as a nanocarrier for sage (Salvia officinalis L.) extract by spectroscopy and chemometrics. Material and Method: In this study,niosome nanoparticles containing cholesterol and without cholesterol were prepared by thin film hydration method. Ethanol extract of sage was extracted by microwave and loaded inside the niosome nanoparticles. The size of the nanoparticles was determined by field imaging scanning electron microscopy (FE-SEM). The zeta potential of the niosomes was determined by Dynamic light scattering (DLS). to investigate the type of interactions between surfactants and cholesterol used in the niosome structure, Fourier transform infrared spectroscopy (FT-IR) was used. Drug release was investigated for 5 consecutive days in phosphate buffer salin (PBS) 0/01 M with pH=7.4 at T=370C. Results:The zeta potential of the niosomes with cholesterol and without cholesterol was -24/1&-15/6 mv . The loading capacity of the drug in the concentration range (1-3% w / w of niosum) for both types of niosome was between 61% and 93%. Conclusion: This results show that the release rate of niosme with cholesterol is significantly more regular and lower than of niosome without cholesterol. In general, it can be concluded that niosome can be a suitable nano-carrier for delivery of hydrophilic extract of the sage.

RESUMEN Objetivo: Investigar la aplicación del niosoma como nanoportador de extracto de salvia (Salvia officinalis L.) mediante espectroscopia y quimiometría. Material y método: En este estudio, se prepararon nanopartículas de niosoma que contienen colesterol y sin colesterol mediante el método de hidratación de película fina. El extracto etanólico de salvia se extrajo mediante microondas y se cargó dentro de las nanopartículas de niosoma. El tamaño de las nanopartículas se determinó mediante microscopía electrónica de barrido de imágenes de campo (FE-SEM). El potencial zeta de los niosomas se determinó mediante dispersión dinámica de luz (DLS). Para investigar el tipo de interacciones entre los tensioactivos y el colesterol utilizados en la estructura del niosoma, se utilizó la espectroscopia infrarroja por transformada de Fourier (FT-IR). Se investigó la liberación de fármaco durante 5 días consecutivos en tampón fosfato salina (PBS) 0/01 M con pH = 7,4 a T = 37ºC. Resultados: El potencial zeta de los niosomas con colesterol y sin colesterol fue de -24 / 1 y -15 / 6 mv. La capacidad de carga del fármaco en el rango de concentración (1-3% p / p de niosum) para ambos tipos de niosoma estuvo entre 61% y 93%. Conclusión: Estos resultados muestran que la tasa de liberación de niosma con colesterol es significativamente más regular y más baja que la de niosoma sin colesterol. En general, se puede concluir que el niosoma puede ser un nanoportador adecuado para el suministro de extracto hidrófilo de la salvia.