Reacciones adversas a montelukast: de la teoría a la práctica. Serie de casos / Adverse drug reactions of montelukast: from theory to practice. Case report

El montelukast se utiliza ampliamente en el tratamiento de sibilancias recurrentes y/o asma. Están descritas numerosas reacciones adversas medicamentosas (RAM) en niños relacionadas con montelukast; se destacan las neuropsiquiátricas. Realizamos un estudio observacional, retrospectivo, descriptivo, sobre RAM relacionadas con montelukast. Entre enero de 2012 y diciembre de 2017, en la Unidad de Neumonología Pediátrica se trataron con Montelukast 348 pacientes; de ellos, 20 presentaron RAM. Los síntomas más frecuentes fueron insomnio (n = 7), hiperactividad (n = 4), pesadillas (n = 3), dolor abdominal (n = 2) y parestesias en extremidades (n = 2). Se presentaron desde días hasta meses tras iniciar el tratamiento, y desaparecieron tras su suspensión. Se destacan dos pacientes con parestesias en extremidades, síntoma no descrito antes en niños. El 5,7 % de los pacientes tratados con montelukast presentaron RAM que requirieron suspender el tratamiento. Los trastornos del sueño fueron los más frecuentes.

Montelukast is widely used in recurrent wheezing and/or asthma treatment. Several adverse drug reactions (ADRs) have been described in children related to montelukast. Neuropsychiatric reactions are one of the most important. We designed an observational, retrospective, descriptive study on ADRs related to montelukast in the Pediatric Pulmonology Unit, Hospital Universitario Miguel Servet, Zaragoza, Spain. Between January 2012 and December 2017, in the Pediatric Pulmonology Unit, 348 patients were treated with Montelukast; of them, 20 presented RAM. The main symptoms described were insomnia (n = 7), hyperactivity (n = 4), nightmares (n = 3), abdominal pain (n = 2) and paraesthesia in extremities (n = 2). They appeared from the first days to months after the start of treatment and disappeared after stopping it. Two patients presented limb paresthesia, not described previously in children. The 5.7 % of our patients treated with montelukast had ADRs that required treatment discontinuation. Sleep disorders were the most frequent.

The oil of garlic, Allium sativum L. (Amaryllidaceae), as a potential protectant against Anisakis spp. Type II (L3) (Nematoda) infection in Wistar rats / O óleo de alho, Allium sativum L. (Amaryllidaceae), como potencial protetor contra Anisakis spp. Infecção tipo II (L3) (Nematoda) em ratos Wistar

Abstract The consumption of inadequately thermally treated fish is a public health risk due to the possible propagation of Anisakis larvae. The present study demonstrated the physiological and histopathological changes that accompanied an oral inoculation of crude extracts from fresh and thermally treated Anisakis Type II (L3) in rats. Worms were isolated from a marine fish and examined and identified using light and scanning electron microscopy. The study was performed in 6 rat groups: control (I), garlic oil (GO) inoculated (II), fresh L3 inoculated (III), thermally treated L3 inoculated (IV), fresh L3 + GO inoculated (V), and a thermally treated L3 + GO inoculated (VI) groups. Rats inoculated with fresh and thermally treated L3 showed abnormal liver and kidney functions associated with the destruction of normal architecture. GO produced a protective effect in rat groups inoculated with L3 extracts + GO via the amelioration of liver and kidney functions, which was confirmed by the marked normal structure on histology. Cooking of L3-infected fish induced severe alterations compared to uncooked fish. The administration of garlic before and after fish eating is recommended to avoid the dangerous effect of anisakids, even if they are cooked.

Resumo O consumo de peixe inadequadamente tratado termicamente representa um risco para a saúde pública, com a possibilidade da propagação de larvas de Anisakis. O presente estudo demonstrou as alterações fisiológicas e histopatológicas acompanhadas de inoculação oral de extractos brutos de Anisakis tipo II (L3) frescos e termicamente tratados em ratos. Os vermes foram isolados de um peixe marinho, examinados e identificados por microscopia de luz e eletrônica de varredura. O estudo foi conduzido em 6 grupos de ratos: controle (I), óleo de alho (GO) inoculado (II), L3 fresco inoculado (III), L3 tratado termicamente inoculado (IV), L3 fresco + GO inoculado (V), e um grupo L3 + GO tratado termicamente inoculado (VI). Observou-se que ratos inoculados com L3 fresco e tratados termicamente mostraram funções hepáticas e renais anormais, associadas à destruição da sua arquitetura normal. GO produziu um efeito protector em grupos de ratos inoculados com extractos L3 + GO através da melhoria das funções do fígado e dos rins, o que foi confirmado pela estrutura normal marcada da sua histologia. A cozedura de peixes infectados com L3 induziu alterações mais graves do que os peixes não cozidos. Recomenda-se a administração de alho antes e depois do consumo de peixe, para evitar o efeito perigoso dos anisakids, mesmo que sejam cozidos.

The examination of the nephroprotective effect of montelukast sodium and N-acetylcysteine in renal ischemia with dimercaptosuccinic acid imaging in a placebo-controlled rat model

Abstract Purpose To determine the nephroprotective effect of NAC and Montelukast Sodium administration against the development of renal damage associated with long warm renal ischemia. Methods Twenty-seven rats were randomly divided into 3 study groups, which received NAC, montelukast and placebo, and 3 rats were included in the sham-treated control group. Medications were given 3 days before the procedure. DMSA renal scintigraphy was performed before and after surgery. The right renal pedicle was occluded for 45 min to induce ischemia and then subjected to reperfusion for 6 h (I/R groups). Results On pathological examination, the mean pathological scores of the montelukast and NAC groups were significantly lower than those of the placebo group. (p <0.05). In biochemical examination, significant differences were found in all parameter levels between the placebo group and the montelukast and NAC groups. (p <0.05) When postoperative DMSA renal scintigraphy measurements and renal function levels were compared, significant differences were found between the montelukast and NAC groups and the placebo and sham groups. Conclusion The administration of NAC and montelukast sodium was seen to have a nephroprotective effect against the development of renal damage associated with warm renal ischemia.

Percepção sensorial do off-odor em carnes bovinas irradiadas em embalagens á vácuo contendo carvão ativado / Off-odor perception in irradiated beef vacuum packaged with charcoal

Objetivou-se avaliar a utilização de carvão ativo na redução de compostos voláteis responsáveis pelo off-odor de carnes bovinas irradiadas. Para tal, contrafilés bovinos, embalados a vácuo, com e sem carvão ativo, e irradiados (1, 2 e 3 kGy), foram analisados quanto a formação de compostos de enxofre e quanto a percepção sensorial de off-odor. O único composto de enxofre identificado nas amostras foi o dimetil sulfeto (DMS), sendo encontrado em menor concentração nas amostras irradiadas com carvão ativo na embalagem. Independentemente da utilização do carvão, os painelistas perceberam o off-odor das carnes irradiadas em qualquer dose quando comparado à carne não-irradiada. Quando foi comparado as carnes irradiadas com carvão em relação àquelas irradiadas sem carvão, os painelistas foram capazes de identificar o off-odor apenas nas amostras irradiadas com 1 kGy. Conclui-se que o carvão ativo reduziu a concentração de DMS na embalagem de carnes irradiadas.

Bioleaching of realgar nanoparticles using the extremophilic bacterium Acidithiobacillus ferrooxidans DLC-5

BACKGROUND: This paper presents micro- and nano-fabrication techniques for leachable realgar using the extremophilic bacterium Acidithiobacillus ferrooxidans (A. ferrooxidans) DLC-5. RESULTS: Realgar nanoparticles of size ranging from 120 nm to 200 nm were successfully prepared using the highenergy ball mill instrument. A. ferrooxidans DLC-5 was then used to bioleach the particles. The arsenic concentration in the bioleaching system was found to be increased significantly when compared with that in the sterile control. Furthermore, in the comparison with the bioleaching of raw realgar, nanoparticles could achieve the same effect with only one fifth of the consumption. CONCLUSION: Emphasis was placed on improving the dissolvability of arsenic because of the great potential of leachable realgar drug delivery in both laboratory and industrial settings

Historia en tiempo real de las bacterias del siglo XXI: gigantes y marcianas / Real time history of 21st century bacteria: giants and martians

Resumen Hemos denominado bacterias del siglo XXI a dos tipos de extrañas y maravillosas criaturas del Reino Protista, descubiertas entre los últimos años del siglo pasado y los días que hoy vivimos: las bacterias gigantes y las de un posible origen marciano. En su búsqueda, audaces investigadores han viajado a tierras distantes y peligrosas, acampando en lugares desolados y descendiendo a las profundidades marinas, actividades que llamamos investigación aventura. Presentamos como ejemplos una expedición al Mar Rojo, buscando el gigantesco Epulopiscium; una temporada en el lago Mono, California, en pos de una bacteria con arsénico en su ADN; un patrullaje en el Ártico, para encontrar bacterias petrificadas en un meteorito marciano; sin olvidar que el tranquilo laboratorio también puede ser un lugar peligroso, porque toda investigación es una aventura.

We denominate "21st century bacteria" two types of strange and amazing creatures from the kingdom Protista, discovered between the last years of the twentieth and the present days: the giant bacteria and those with a possible Martian origin. Searching for them, bold investigators have travelled to distant and hostile lands, desolate places and deep waters, performing a kind of investigation that we only can describe as "investigation-adventure". This paper presents expeditions to the Red Sea, fishing the Epulopiscium; to Lake Mono, searching a bacteria able to growth with arsenic; to the Antarctic Circle, finding a meteorite with petrified alien microorganisms; and… to the quiet laboratory, a not less dangerous place.

Hydrogen sulfide protects H9c2 cardiomyoblasts against H2O2-induced apoptosis

Reactive oxygen species (ROS) are highly reactive chemical species that may cause irreversible tissue damage, and play a critical role in cardiovascular diseases. Hydrogen sulfide (H2S) is a gasotransmitter that acts as a ROS scavenger with cardio-protective effects. In this study, we investigated the cytoprotective effect of H2S against H2O2-induced apoptosis in cardiomyocytes. H9c2 rat cardiomyoblasts were treated with H2S (100 μM) 24 h before challenging with H2O2 (100 μM). Apoptosis was then assessed by annexin V and PI, and mitochondrial membrane potential was measured using a fluorescent probe, JC-1. Our results revealed that H2S improved cell viability, reduced the apoptotic rate, and preserved mitochondrial membrane potential. An increased Bcl-2 to Bax ratio was also seen in myocytes treated with H2S after H2O2-induced stress. Our findings indicated a therapeutic potential for H2S in preventing myocyte death following ischemia/reperfusion.

Investigation of Allium sativum's protective effect on ovarian reserve in an experimental ovarian injury model / Investigación del efecto protector de Allium sativum de la reserva ovárica en un modelo experimental de lesión ovárica

We aimed to evaluate the effects of detorsion and Allium sativum (garlic oil) treatment on the ovarian reserve in an ovarian torsion model. Ovarian torsion may lead to loss of ovarian tissue and infertility. It is an experimental rat study that was carried out on 16 sets of ovaries each, one for treatment group and a control group. In the control group, the procedure involved only the surgically opening and closing the abdomen. Bilateral adnexal torsion/detorsion was performed after a 3-hour ischemia period for the detorsion-only group. The detorsion + Allium sativum group received a 5 ml/kg dose of Allium sativum intraperitoneally, 2 hours before surgery. After the second surgery, removed ovarian samples were evaluated for follicle counts, damage scores and other parameters. Primordial, preantral, small antral and large antral follicle counts were significantly higher in the detorsion + Allium sativum group. Degeneration, congestion, hemorrhage ,inflammation and total damage scores were significantly elevated in the detorsion only group compared to those for the detorsion + Allium sativum group. Finally, there was a significant correlation between AMH alterations and postoperative, preantral follicle count (p<0.05). As a conclusion detorsion + Allium sativum treatment may be effective in protecting the ovarian reserve after torsion.

Intentamos evaluar los efectos de la detorsión y el tratamiento con Allium sativum (aceite de ajo) en la reserva ovárica en un modelo de torsión ovárica. La torsión ovárica puede ocasionar pérdida de tejido ovárico e infertilidad. Este es un estudio experimental en ratas que se llevó a cabo en 16 sets de ovarios para cada grupo: tratamiento y control. En el grupo control, el procedimiento involucró solamente la apertura y el cierre quirúrgicos del abdomen. La torsión / detorsión anexial bilateral se realizó después de un período de isquemia de 3 horas para el grupo de solo detorsión. El grupo de detorsión + Allium sativum recibió una dosis de 5 ml / kg de Allium sativum por vía intraperitoneal, 2 horas antes de la cirugía. Después de la segunda cirugía, las muestras ováricas eliminadas se evaluaron para recuentos de folículos, puntajes de daño y otros parámetros. Los recuentos de folículos antrales primordiales, preantrales, antrales pequeños y grandes fueron significativamente mayores en el grupo con detorsión + Allium sativum. Los puntajes de degeneración, congestión, hemorragia, inflamación y daño total fueron significativamente elevados en el grupo de solo detorsión, en comparación con los del grupo de detorsión + Allium sativum. Finalmente, hubo una correlación significativa entre las alteraciones de AMH y el recuento de folículos preantrales postoperatorios (p <0,05). Como conclusión, el tratamiento con detorsión + Allium sativum puede ser eficaz para proteger la reserva ovárica después de la torsión.

Characterization of a hyperthermophilic sulphur-oxidizing biofilm produced by archaea isolated from a hot spring

Background: Sulphur-oxidizing microorganisms are widely used in the biofiltration of total reduced sulphur compounds (odorous and neurotoxic) produced by industries such as the cellulose and petrochemical industries, which include high-temperature process steps. Some hyperthermophilic microorganisms have the capability to oxidize these compounds at high temperatures (N60°C), and archaea of this group, for example, Sulfolobus metallicus, are commonly used in biofiltration technology. Results: In this study, a hyperthermophilic sulphur-oxidizing strain of archaea was isolated from a hot spring (Chillán, Chile) and designated as M1. It was identified as archaea of the genus Sulfolobus (99% homology with S. solfataricus 16S rDNA). Biofilms of this culture grown on polyethylene rings showed an elemental sulphur oxidation rate of 95.15 ± 15.39 mg S l-1 d-1, higher than the rate exhibited by the biofilm of the sulphur-oxidizing archaea S. metallicus (56.8 ± 10.91 mg l-1 d-1). Conclusions: The results suggest that the culture M1 is useful for the biofiltration of total reduced sulphur gases at high temperatures and for other biotechnological applications.

Surface detail reproduction and dimensional accuracy of molds: influence of disinfectant solutions and elastomeric impression materials / Reprodução de detalhes da superfície e estabilidadedimensional de moldes: influência das soluçõesdesinfetantes e elastômeros

This study compared the surface detail reproduction anddimensional accuracy of molds after disinfection using 2% sodium hypochlorite, 2% chlorhexidine digluconate or 0.2% peracetic acid to those of molds that were not disinfected, forfour elastomeric impression materials: polysulfide (Light Bodied Permlastic), polyether (Impregum Soft), polydimethylsiloxane(Oranwash L) and polyvinylsiloxane (Aquasil Ultra LV). Themolds were prepared on a matrix by applying pressure, using aperforated metal tray. The molds were removed followingpolymerization and either disinfected (by soaking in one of thesolutions for 15 minutes) or not disinfected. The samples werethus divided into 16 groups (n=5). Surface detail reproductionand dimensional accuracy were evaluated using opticalmicroscopy to assess the 20 ­µm line over its entire 25 mm length. The dimensional accuracy results (%) were subjectedto analysis of variance (ANOVA) and the means were comparedby Tukey’s test (α=5%). The 20 ­µm line was completelyreproduced by all elastomeric impression materials, regardlessof disinfection procedure. There was no significant difference between the control group and molds disinfected with peraceticacid for the elastomeric materials Impregum Soft (polyether)and Aquasil Ultra LV (polyvinylsiloxane). The high­leveldisinfectant peracetic acid would be the choice material for disinfection.

Este estudo comparou a reprodução de detalhes da superfície e estabilidade dimensional de moldes obtidos após desinfecção utilizando hipoclorito de sódio 2%, digluconato de clorexidina 2%, ou ácido peracético 0,2% a moldes que não foram desinfetados com quatro elastômeros: polissulfeto (Light Bodied Permlastic), polieter (Impregum Soft), silicona reação porcondensação (Oranwash L) e silicona reação por adição (Aquasil Ultra LV). Os moldes foram preparados sobre matriz conten dolinhas de 20, 50 e 75 µm realizado sob pressão com moldeirade metal perfurada. Os moldes foram removidos após a polimerização e desinfetados (utilizando uma das soluções porimersão, armazenados em frascos fechados durante 15 minutos)ou não desinfetados. Assim, as amostras foram divididas em 16grupos (n=5). A reprodução detalhes da superfície e a precisão dimensional foram avaliadas usando microscopia óptica na linha 20 µm com 25 mm de comprimento, de acordo com a norma ISO 4823. Os resultados de precisão dimensional (%) foram submetidos à análise de variância (A NOVA) e as médias comparadas pelo teste de Tukey com 5% de nível de significância. A linha de 20 µm foi completamente reproduzida por todos os elastômeros, independentemente do processo de desinfecção. Não houve diferença estatisticamente significativa entre o grupo controle e moldes desinfetados com acido peracético para os elastômeros Impregum Soft (polieter) e Aquasil Ultra LV (siliconareação por adição). O desinfetante de alto nível ácido peracético seria o material de escolha para a desinfecção.

Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent

Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetrasulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.

Síntese e funcionalização de compostos organoenxofre: sulfóxidos, sulfetos e N-sulfinil iminas / Synthesis and functionalization of organosulfur compounds: sulfoxides, sulfides and N-sulfinyl imines

Neste trabalho promovemos a síntese de sulfóxidos vinílicos ?-substituídos através da reação de acoplamento cruzado de Suzuki-Miyaura. Também foi feita a síntese de sulfóxidos enínicos inéditos, pela adição do nucleófilo no carbono ß-sulfóxido. Esses compostos eram passíveis de serem submetidos a reação de rearranjo de Pummerer aditivo e assim gerarem uma pequena biblioteca de compostos α-tioaldeídos. Um desses aldeídos sintetizados foi empregado na reação de formação de uma imina propargílica, com consequente reação de CuAAC formando iminas triazólicas. Outras iminas arílicas foram sintetizadas, passando por uma etapa de redução, com intuito de se obter a amina livre, para que fosse feita a reação de ciclização com auxílio de um agente eletrofílico. Outra classe de composto organoenxofre foi sintetizada, as N-sulfinil imina, que após a reação de acoplamento cruzado de Sonogashira, com consequente remoção de um grupo protetor e a formação do anel heterocíclico, foram obtidos compostos triazólicos N-sulfinil imínicos.

In this work we promote the synthesis of α-substituted vinylic sulfoxides through the Suzuki-Miyaura cross coupling reaction. Also the synthesis of unpublished enynic sulfoxides was made, by the addition of the nucleophile in the ß-sulfoxide carbon. These compounds were susceptible to additive Pummerer rearragement reaction and thus generated a small library of compounds. One of these aldehydes synthesized was used in the formation reaction of a propargyl imine, with consequent CuAAC reaction, forming triazol imines. Other aryl imines were synthesized, undergoing a reduction step, in order to obtain the free amine, so that the cyclization reaction was carried out with the aid of an electrophilic agent. Another class of organosulfur compound was synthesized, the N-sulfinyl imine, which after the Sonogashira cross-coupling reaction, with consequent removal of a protecting group and formation of the heterocyclic ring, N-sulfinyl imine triazolic compounds were obtained.

Enzymatic potential of heterotrophic bacteria from a neutral copper mine drainage

Abstract Copper mine drainages are restricted environments that have been overlooked as sources of new biocatalysts for bioremediation and organic syntheses. Therefore, this study aimed to determine the enzymatic activities (esterase, epoxide hydrolase and monooxygenase) of 56 heterotrophic bacteria isolated from a neutral copper mine drainage (Sossego Mine, Canaã dos Carajás, Brazil). Hydrolase and monooxygenase activities were detected in 75% and 20% of the evaluated bacteria, respectively. Bacterial strains with good oxidative performance were also evaluated for biotransformation of organic sulfides. Fourteen strains with good enzymatic activity were identified by 16S rRNA gene sequencing, revealing the presence of three genera: Bacillus, Pseudomonas and Stenotrophomonas. The bacterial strains B. megaterium (SO5-4 and SO6-2) and Pseudomonas sp. (SO5-9) efficiently oxidized three different organic sulfides to their corresponding sulfoxides. In conclusion, this study revealed that neutral copper mine drainages are a promising source of biocatalysts for ester hydrolysis and sulfide oxidation/bioremediation. Furthermore, this is a novel biotechnological overview of the heterotrophic bacteria from a copper mine drainage, and this report may support further microbiological monitoring of this type of mine environment.

Burnout syndrome among undergraduate nursing students at a public university / Síndrome de Burnout entre estudantes de graduação em enfermagem de uma universidade pública / Síndrome de Burnout entre estudiantes de pregrado en enfermería de una universidad pública

OBJECTIVE: to investigate the burnout syndrome and its relationship with demographic and academic variables among undergraduate nursing students at a public university in Southern Brazil. METHOD: a quantitative study with 168 students, by applying an adaptation of the Maslach Burnout Inventory - Student Survey, validated for this study. We used descriptive and variance analysis of the data analysis. RESULTS: we found that students do not have the burnout syndrome, manifesting high average scores in Emotional Exhaustion, low in Disbelief and high in Professional Effectiveness; that younger students who perform leisure activities have greater Professional Effectiveness, unlike students in early grades with no extracurricular activities; combining work and studies negatively influenced only the Professional Effectiveness factor, while the intention of giving up influenced negatively Disbelief and Professional Effectiveness factors. CONCLUSION: the situations that lead students to Emotional Exhaustion need to be recognized, considering the specificity of their study environments. .

OBJETIVO: investigar a síndrome de Burnout e sua relação com variáveis sociodemográficas e acadêmicas, entre estudantes de graduação em enfermagem de uma universidade pública do Sul do Brasil. MÉTODO: estudo quantitativo, realizado com 168 estudantes, mediante a aplicação de uma adaptação do Maslach Burnout Inventory - Student Survey, validada para este estudo. Utilizou-se a análise descritiva e de variância para análise dos dados. RESULTADOS: constatou-se que os estudantes não apresentam a síndrome de Burnout, manifestando médias altas em exaustão emocional, baixas em descrença e altas em eficácia profissional; que estudantes mais jovens e que realizam atividades de lazer apresentam maior eficácia profissional, diferentemente de estudantes das séries iniciais e que não realizam atividades extracurriculares; conciliar trabalho e estudos influenciou negativamente apenas o fator eficácia profissional, enquanto a intenção de desistir do curso influenciou negativamente os fatores descrença e eficácia profissional. CONCLUSÃO: faz-se necessário o reconhecimento das situações que levam os estudantes à exaustão emocional, considerando a especificidade de seus ambientes de formação. .

OBJETIVO: investigar la síndrome de burnout y su relación con variables sociodemográficas y académicas, entre estudiantes de pregrado en enfermería de una universidad pública del Sur de Brasil. MÉTODO: estudio cuantitativo, desarrollado con 168 estudiantes, mediante la aplicación de una adaptación del Maslach Burnout Inventory - Student Survey, validada para fines de ese estudio. Fueron utilizados los análisis descriptivo y de variancia para analizar los datos. RESULTADOS: se constató que los estudiantes no presentan la síndrome de burnout, manifestando altos promedios en Agotamiento Emocional, bajos en Descreencia y altos en Eficacia Profesional; que estudiantes más jóvenes y que practican actividades de ocio presentan mayor Eficacia Profesional, diferentemente de estudiantes de los años iniciales sin actividades extracurriculares; conciliar trabajo y estudios influyó negativamente apenas el factor Eficacia Profesional, mientras la intención de desistir del curso influyó negativamente los factores Descreencia y Eficacia Profesional. CONCLUSIÓN: es necesario reconocer las situaciones que llevan a los estudiantes al Agotamiento Emocional, considerando la especificidad de sus ambientes de formación. .

Bioaugmentation of latex rubber sheet wastewater treatment with stimulated indigenous purple nonsulfur bacteria by fermented pineapple extract

Background Treating latex rubber sheet wastewater often leads to the generation of a rotten-egg odor from toxic H2S. To increase the treatment efficiency and eliminate H2S, purple nonsulfur bacteria (PNSB), prepared by supplementing non-sterile rubber sheet wastewater (RAW) with fermented pineapple extract (FPE), were used to treat this wastewater under microaerobic light conditions. The following 3 independent variables: chemical oxygen demand (COD), initial pH and FPE dose were investigated using the Box-Behnken design to find optimal conditions for stimulating the growth of indigenous PNSB (PNSBsi). Results The addition of 2.0% FPE into RAW, which had a COD of 2000 mg L- 1 and an initial pH of 7.0, significantly decreased oxidation reduction potential (ORP) value and stimulated PNSBsi to reach a maximum of 7.8 log cfu mL- 1 within 2 d. Consequently, these PNSBsi, used as inoculants, were investigated for their ability to treat the wastewater under microaerobic light conditions. A central composite design was used to determine the optimal conditions for the wastewater treatment. These proved to be 7% PNSBsi, 0.8% FPE and 4 d retention time and this combination resulted in a reduction of 91% for COD, 75% for suspended solids, 61% for total sulfide while H2S was not detected. Results of abiotic control and treatment sets indicated that H2S was produced by heterotrophic bacteria and it was then effectively deactivated by PNSBsi. Conclusions The stimulation of PNSB growth by FPE under light condition was to lower ORP, and PNSBsi proved to be effective for treating the wastewater.

Modeling the kinetics of pyrite ash biodesulfurization by Saccharomyces cerevisiae and Acetobacter aceti in liquid state bioreactors

Background: Modeling the kinetics of the biodesulphurization bioprocess for the refining of pyrite ash by Saccharomyces cerevisiae and Acetobacter aceti have been studied in batch-type liquid- state bioreactors. Results: The biodesulphurization experiments were performed at varying temperatures of 25ºC, 30ºC and 35ºC for eight weeks. Glucose, acetic acid and ethyl alcohol were used in the incubation media as substrates and acid sources. pH and oxidation reduction potential (ORP) observations have been determined weekly and the dissolved sulphur was measured at the end of the eight weeks trials. An equation calculating pH was derived from the iron oxidation reaction containing the ferric to ferrous iron [Fe+3/Fe+2] ratio as a variable. The Michaelis-Menten predictive specific growth rates (qFe+2), which were estimated from pH and ORP observations, were compared by plotting [qFe+²]pH vs. [qFe+2]mV. The highest ratio of dissolved sulphur over total sulphur (Sd/St) was found to be 0.5 in the biodesulphurization processes. Conclusions: The model provides predictions of ferric to ferrous iron rates and specific growth rates [qFe+²]pH vs. [qFe+2]mV and can be used for the determination of oxidized and reduced ions. The ratios of dissolved sulphur to total sulphur (Sd/St) have shown some promising results for S. cerevisiae to be used as a biodesulphurization and refining microorganism for pyrite ash and the other sulphide minerals.

Modelling of the biofiltration of reduced sulphur compounds through biotrickling filters connected in series: effect of H2S

Background: The behaviour of two biotrickling filters connected in serie (BTF) inoculated with Acidithiobacillus thiooxidans and Thiobacillus thioparus, biodegrading hydrogen sulphide (H2S) and dimethyl sulphide (DMS) simultaneously were studied. A model which considers gas to liquid mass transfer and biooxidation in the biofilm attached to the support is developed. Additionally, a fixed bed biotrickling filter where the microorganism is immobilized in a biofilm which degrades a mixture of H2S and DMS is implemented. Validation of the model was carried out using experimental data obtained at different H2S and DMS loads. Results: The inhibitory effect caused by the presence of H2S on the DMS is observed, which is evidenced by the decrease of the DMS removal efficiency from 80 to 27 percent, due to the preference that T. thioparus has by simple metabolism. H2S is not affected by the DMS, with removal efficiencies of 95 to 97 percent, but it decreases at high concentrations of the compound, due to the inhibition of metabolism by high H2S input loads. The model which describes the BFT fits successfully with the experimental results and it has a high sensitivity to inhibition parameters. Conclusion: It is shown that the microorganism has a high affinity for H2S, producing substrate inhibition when the concentration is high. The H2S is able to inhibit the DMS biooxidation, whereas the DMS does not affect the H2S biooxidation.

Composition of the essential oil of leaves and roots of Allium schoenoprasum L. (Alliaceae) / Composición del aceite esencial de hojas y raíces de Allium schoenoprasum L

Essential oil from leaves and roots of Allium schoenoprasum L. (Alliaceae) were analyzed by GC/MS. The oils extracted by hydrodistillation yielded 0.02 percent and 0.03 percent for leaves and roots, respectively. Five (99.12 percent leaves) and four (98.32 percent roots) components were identified being bis-(2-sulfhydryethyl)-disulfide (72.06 percent leaves, 56.47 percent roots) the major constituent on the two oil samples while 2,4,5-trithiahexane (5.45 percent leaves, 15.90 percent roots) and tris (methylthio)-methane (4.01 percent leaves, 12.81 percent roots) were detected in lower amounts.

Los aceites esenciales de hojas y raíces de Allium schoenoprasum L. (Alliaceae fueron analizados por CG/EM. La extracción por hidrodestilación mostró un rendimiento de 0.02 por ciento y 0.03 por ciento para las hojas y raíces, respectivamente. Cinco (99.12 por ciento hojas) y cuatro (98.32 por ciento raíces) compuestos fueron identificados siendo el bis-(2-sulfidietil)-disulfuro (72.06 por ciento hojas, 56.47 por ciento raíces) el compuesto mayoritario en los dos aceites mientras que 2,4,5-tritiahexano (5.45 por ciento hojas, 15.90 por ciento raíces) y tris (metilthio)-metano (4.01 por ciento hojas, 12.81 por ciento raíces) fueron observados en menores cantidades.