150 research outputs found
Upregulation of the Nifhdken Operon in Leptospirillum Species Subjected to Soluble Nitrogen Starvation
Background: Members of the genus Leptospirillum routinely dominate bioleaching systems. Understanding their metabolic complexity is necessary for the improvement of bioleaching technologies. Nitrogen is an essential element required for the cellular growth of all microorganisms. In this study Leptospirillum species were assessed for their nitrogen fixation capabilities under aerobic and anaerobic conditions, in the absence of soluble ammonia
Bioprospecting for and the applications of halophilic acidophiles in bioleaching operations
The economic recovery of metals from sulfide ores has become a topic of increasing interest due to the escalating demand for critical minerals and the reducing grade of available ores. Bioleaching is the use of acidophilic iron and sulfur-oxidising microorganisms to facilitate the extraction of base metals from primary sulfide ores and tailings. One significant issue limiting the use of bioleaching is the availability of freshwater due to the sensitivity of these microbes to chloride. The use of saline tolerant acidophilic iron- and-sulfur oxidising microorganisms will go a long way to addressing this issue. There are three possible means of sourcing suitable microorganisms; adaptation, genetic engineering and bioprospecting, with bioprospecting showing the greatest possibilities. Bioprospecting in search of native organisms for bioleaching operations has led researchers to numerous locations around the world and the isolation of iron- and sulfur-oxidising acidophiles that are capable of tolerating high levels of salinity has been of particular interest in these investigations
Analysis of element yield, bacterial community structure and the impact of carbon sources for bioleaching rare earth elements from high grade monazite
Rare earth element (REE) recovery from waste streams, mine tailings or recyclable components using bioleaching is gaining traction due to the shortage and security of REE supply as well as the environmental problems that occur from processing and refining. Four heterotrophic microbial species with known phosphate solubilizing capabilities were evaluated for their ability to leach REE from a high-grade monazite when provided with either galactose, fructose or maltose. Supplying fructose resulted in the greatest amount of REE leached from the ore due to the largest amount of organic acid produced. Gluconic acid was the dominant organic acid identified produced by the cultures, followed by acetic acid. The monazite proved difficult to leach with the different carbon sources, with preferential release of Ce over La, Nd and Pr
Draft Genome Sequence of the Iron-Oxidizing, Acidophilic, and Halotolerant “Thiobacillus prosperus” Type Strain DSM 5130
“Thiobacillus prosperus” is a halotolerant mesophilic acidophile that gains energy through iron and sulfur oxidation. Its physiology is poorly understood. Here, we describe the principal genomic features of the type strain of T. prosperus, DSM 5130. This is the first public genome sequence of an acidophilic halotolerant bacterium
La atención y la satisfacción del cliente en la discoteca Magno, en la ciudad de Chiclayo, 2016
Hoy en día las empresas de entretenimiento que quieran mejorar su rentabilidad y crecer cada día más y ser mejores que sus competidores, tienen que mejorar sus productos y servicios, ofrecer mayor calidad, en definitiva, satisfacer las necesidades del cliente, de este modo captarlos y mantenerlos, ya que es una oportunidad para crecer rápidamente a través del “boca a boca”. Es dentro de este contexto, que el objetivo de esta investigación fue conocer el nivel de satisfacción del cliente, en la Discoteca Magno S.A.C a través del método o modelo SERVPERF. El enfoque fue cuantitativo y la investigación fue tipo de descriptiva. La población estuvo conformada, por 6600 personas que asistieron los fines de semana (viernes y sábados) a la referida Discoteca. Este es el número de clientes mensuales, al aplicar la fórmula se obtuvo un total de 363 personas encuestadas. En este trabajo se utilizó como instrumento de recolección de datos, el cuestionario de ítem cerrado, basándose en las preguntas planteadas por el método SERVPERF, para su posterior análisis, se utilizaron los programas microsoft word, microsoft excel 2016 y IBM SPSS Statistics 25. Se comprobó que el nivel de satisfacción en la calidad de servicio al cliente, en la Discoteca Mango fue satisfactorio.Tesi
Klebsiella aerogenes adhesion behaviour during biofilm formation on monazite
The adsorption behaviour of micro-organisms during the initial attachment stage of biofilm formation affects subsequent stages. The available area for attachment and the chemophysical properties of a surface affect microbial attachment performance. This study focused on the initial attachment behaviour of Klebsiella aerogenes on monazite by measuring the ratio of planktonic against sessile subpopulations (P:S ratio), and the potential role of extracellular DNA (eDNA). eDNA production, effects of physicochemical properties of the surface, particle size, total available area for attachment, and the initial inoculation size on the attachment behaviour were tested. K. aerogenes attached to monazite immediately after exposure to the ore; however, the P:S ratio significantly (p = 0.05) changed in response to the particle size, available area, and inoculation size. Attachment occurred preferentially on larger-sized (~50 µm) particles, and either decreasing the inoculation size or increasing the available area further promoted attachment. Nevertheless, a portion of the inoculated cells always remained in a planktonic state. K. aerogenes produced lower eDNA in response to the changed surface chemical properties when monazite was replaced by xenotime. Using pure eDNA to cover the monazite surface significantly (p ≤ 0.05) hindered bacterial attachment due to the repulsive interaction between the eDNA layer and bacteria
Treatment of extravasation injuries in infants and young children : a scoping review and survey
BACKGROUND: Extravasation injuries are caused by unintended leakages of fluids or medicines from intravenous lines, but there is no consensus on the best treatment approaches. OBJECTIVES: To identify which treatments may be best for treating extravasation injuries in infants and young children. DESIGN: Scoping review and survey of practice. POPULATION: Children aged < 18 years with extravasation injuries and NHS staff who treat children with extravasation injuries. INTERVENTIONS: Any treatment for extravasation injury. MAIN OUTCOME MEASURES: Wound healing time, infection, pain, scarring, functional impairment, requirement for surgery. DATA SOURCES: Twelve database searches were carried out in February 2017 without date restrictions, including MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature) Plus and EMBASE (Excerpta Medica dataBASE). METHODS: Scoping review - studies were screened in duplicate. Data were extracted by one researcher and checked by another. Studies were grouped by design, and then by intervention, with details summarised narratively and in tables. The survey questionnaire was distributed to NHS staff at neonatal units, paediatric intensive care units and principal oncology/haematology units. Summary results were presented narratively and in tables and figures. RESULTS: The evidence identified in the scoping review mostly comprised small, retrospective, uncontrolled group studies or case reports. The studies covered a wide range of interventions including conservative management approaches, saline flush-out techniques (with or without prior hyaluronidase), hyaluronidase (without flush-out), artificial skin treatments, debridement and plastic surgery. Few studies graded injury severity and the results sections and outcomes reported in most studies were limited. There was heterogeneity across study populations in age, types of infusate, injury severity, location of injury and the time gaps between injury identification and subsequent treatment. Some of the better evidence related to studies of flush-out techniques. The NHS survey yielded 63 responses from hospital units across the UK. Results indicated that, although most units had a written protocol or guideline for treating extravasation injuries, only one-third of documents included a staging system for grading injury severity. In neonatal units, parenteral nutrition caused most extravasation injuries. In principal oncology/haematology units, most injuries were due to vesicant chemotherapies. The most frequently used interventions were elevation of the affected area and analgesics. Warm or cold compresses were rarely used. Saline flush-out treatments, either with or without hyaluronidase, were regularly used in about half of all neonatal units. Most responders thought a randomised controlled trial might be a viable future research design, though opinions varied greatly by setting. LIMITATIONS: Paucity of good-quality studies. CONCLUSIONS: There is uncertainty about which treatments are most promising, particularly with respect to treating earlier-stage injuries. Saline flush-out techniques and conservative management approaches are commonly used and may be suitable for evaluation in trials. FUTURE WORK: Conventional randomised trials may be difficult to perform, although a randomised registry trial may be an appropriate alternative. FUNDING: The National Institute for Health Research Health Technology Assessment programme
Treating extravasation injuries in infants and young children : a scoping review and survey of UK NHS practice
BACKGROUND: Extravasation injuries are caused by unintended leakages of fluids or medicines from intravenous lines but there is no consensus on the best treatment approaches, particularly in infants and young children. METHODS: This paper presents a more succinct account of a study of treatments for extravasation injuries in infants and children which has also been reported in full as an NIHR HTA report. A systematic scoping review and survey of UK NHS practice were undertaken. Twelve databases - including MEDLINE and EMBASE - were searched for relevant studies in February 2017. Studies of children with extravasation injuries receiving any treatment for extravasation injury were eligible, providing they reported one of the following outcomes: wound healing time, infection, pain, scarring, functional impairment, and requirement for surgery. Studies were screened in duplicate. Data were extracted by one researcher and checked by another. Studies were summarised narratively. An online questionnaire was distributed to NHS staff at neonatal units, paediatric intensive care units and principal oncology/haematology units. RESULTS: The evidence identified in the scoping review was mostly comprised of small, retrospective, uncontrolled group studies or case reports. The studies covered a wide range of interventions including conservative management approaches, saline flush-out techniques (with or without prior hyaluronidase), hyaluronidase without flush-out, artificial skin treatments, debridement and plastic surgery. Few studies graded injury severity and the results sections and outcomes reported in most studies were limited. There was heterogeneity across study populations in many factors. The survey yielded 63 responses from hospital units across the UK. Results indicated that although most units had written documentation for treating extravasation injuries, only one-third of documents included a system for grading injury severity. The most frequently used interventions were elevation of the affected area and analgesics. Saline wash-out treatments, either with or without hyaluronidase, were regularly used in about half of all neonatal units. Most responders thought a randomised controlled trial might be a viable future research design. CONCLUSIONS: There is some uncertainty about which are most the promising treatments for extravasation injuries in infants and young children. Saline flush-out techniques and conservative management approaches are commonly used and may be suitable for evaluation in trials. Although conventional randomised trials may be difficult to perform a randomised registry trial may be an appropriate alternative design
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