Size at sexual maturity, seasonal variation by maturity stages, and fecundity of the spotted round ray (Urobatis maculatus) and the thorny stingray (Urotrygon rogersi) from the northern tropical eastern Pacific.

Round rays (family: Urotrygonidae) are commonly caught as by-catch by shrimp trawl fisheries in the tropical eastern Pacific (TEP). However, little information on their life history and catch species composition exists for most round ray species, preventing the evaluation of the impact of fishing on their populations. The mean size at sexual maturity (DW50), seasonal variation by maturity stages, and fecundity for two round ray species caught during shrimp trawl research cruises in the south-eastern Gulf of California (northern TEP) were estimated using a multi-model approach and inference for the first time, to determine the part of the population of each species that is being affected by shrimp trawling. Disc width (DW) ranged from 7.0 to 30.9 cm for the spotted round ray (Urobatis maculatus), and 7.2-33.5 cm for the thorny stingray (Urotrygon rogersi), with females reaching larger sizes than males in both species. The DW50 was estimated at 12.8 and 11.8 cm DW for the males and females of U. maculatus, respectively, whereas for U.rogersi, it was 15.0 and 18.4 cm DW for males and females, respectively. Embryos were found in females ≥14.5 cm DW in both species. The maximum fecundity was five embryos for U. maculatus (mean = 3.1 ± 0.2 S.E., mode = 4), and six embryos for U. rogersi (mean = 3.0 ± 0.3 S.E., mode = 2). Fecundity and embryo size did not vary with maternal size. Male and female immature and mature individuals for both species, including pregnant females, were found in the catches in all seasons of the year. Our results can help determine the vulnerability of the studied species populations to fishing pressure from shrimp trawling in the northern TEP and guide the development of future monitoring strategies and conservation actions for these species, if necessary.

Frequency Tunable, Cavity-Enhanced Single Erbium Quantum Emitter in the Telecom Band.

Single quantum emitters embedded in solid-state hosts are an ideal platform for realizing quantum information processors and quantum network nodes. Among the currently investigated candidates, Er^{3+} ions are particularly appealing due to their 1.5 µm optical transition in the telecom band as well as their long spin coherence times. However, the long lifetimes of the excited state-generally in excess of 1 ms-along with the inhomogeneous broadening of the optical transition result in significant challenges. Photon emission rates are prohibitively small, and different emitters generally create photons with distinct spectra, thereby preventing multiphoton interference-a requirement for building large-scale, multinode quantum networks. Here we solve this challenge by demonstrating for the first time linear Stark tuning of the emission frequency of a single Er^{3+} ion. Our ions are embedded in a lithium niobate crystal and couple evanescently to a silicon nanophotonic crystal cavity that provides a strong increase of the measured decay rate. By applying an electric field along the crystal c axis, we achieve a Stark tuning greater than the ion's linewidth without changing the single-photon emission statistics of the ion. These results are a key step towards rare earth ion-based quantum networks.

Principios éticos en la investigación en pacientes críticos

El paciente en estado crítico reviste una especial importancia al desarrollar investigaciones, debido a que ha perdido o visto reducida su autonomía. El objetivo del presente estudio fue identificar el uso de los principios éticos de Ezequiel J. Emanuel, como guía en el desarrollo de investigaciones en pacientes críticos. Se realizó una revisión integrativa en las bases de datos WoS, PUBMED, SCOPUS y SciELO, y se encontraron 545 artículos de los cuales ocho cumplieron con los criterios previamente definidos. En estos se identificó la descripción de los ocho principios de Emanuel, los cuales demostraron constituir un marco integral y sistemático de utilidad para orientar la conducta ética en la población analizada, siendo la 'validez científica' el principio más descrito en la investigación del paciente crítico, seguido del principio de 'consentimiento informado'.

The critically ill patient is of special importance in the development of research, due to the fact that he/she has lost or had his/her autonomy reduced. The aim of the present study was to identify the ethical principles of Ezekiel Emanuel, as a guide in the development of research in critically ill patients. An integrative review was carried out in the WoS, PUBMED, SCOPUS, SciELO databases, 545 articles were identified, of which eight met the previously defined criteria. The description of Emanuel's eight principles was identified, which proved to be a comprehensive and systematic framework to guide ethical conduct in the population analyzed, with scientific validity being the most described principle in critical patient research, followed by the principle of informed consent.

O doente crítico é de particular importância no desenvolvimento da investigação devido à perda ou redução da autonomia do doente. O objectivo deste estudo era identificar os princípios éticos de Ezequiel Emanuel como guia no desenvolvimento da investigação em pacientes gravemente doentes. Foi realizada uma revisão integrativa nas bases de dados WoS, PUBMED, SCOPUS e SciELO, foram identificados 545 artigos, dos quais oito preenchiam os critérios previamente definidos. Foi identificada a descrição dos oito princípios de Emanuel, que provou ser um quadro abrangente e sistemático para orientar a conduta ética na população analisada, sendo a validade científica o princípio mais descrito na investigação crítica dos pacientes, seguido pelo princípio do consentimento informado.

Re-estimation of juvenile Isurus oxyrinchus growth in the Mexican Pacific through a multimodel inference approach and verification of growth band periodicity.

An update of the age and growth for juveniles of the short fin mako shark (I. oxyrinchus) from the Mexican Pacific is presented, based on the analysis of growth band counts from dorsal vertebrae of 198 individuals [110 females, 74-231 cm of total length (TL) and 88 males, 72-231 cm TL) caught during 2008-2018. New available information on vertebral growth band periodicity (biannual deposition in juveniles) and the convenience of using vertebrae form the dorsal region over the cervical region to count growth bands, as well as a multimodel approach, were used. The von Bertalanffy (VB) growth model, Gompertz, logistic and two parameters of VB (2-VB) were fitted to the length-at-age. Only ages ≤6 years were used for the fitting of the models and their performance was compared with the small-sample bias-corrected form of the Akaike information criterion (AICc), their differences ( ∆ i ) and weights ( w i ). Following a multimodel inference approach, the model averaged asymptotic length ( L ¯ inf ), length-at-age 0 ( L ¯ 0 ) and their unconditional standard error ( SE ¯ ), were estimated for each sex scenario using the three-parameter version of each model. The precision of growth band counts was acceptable for the different methods used and by two different readers. The centrum edge analysis (CEA) and marginal increment analysis (MIA) did not support the hypothesis of biannual band pair formation for juveniles, likewise for adults the periodicity could not be verified due to the small sample of large animals. Age was estimated assuming the formation of two pairs of growth bands per year during the first 5 years and one pair of bands per year afterwards considering direct validation information. The estimated ages in years ranged from 0-14 for females and 0-6 for males. The Kimura likelihood ratio test showed no differences in the growth curves of juveniles by sex (P > 0.05). According to the AICc, the 2-VB model better fitted the length-at-age data for combined sexes (Linf = 386.4 cm, k = 0.12 years-1 , L0 = 70 cm). The model averaged L ¯ inf and L ¯ 0 were 378.3 cm ( SE ¯ = 64.5 ) and 69.5 cm ( SE ¯ = 6.3 ), respectively. The growth parameters determined for juveniles of I. oxyrinchus are similar to those estimated in other regions, showing relatively fast growth rate as previously reported, medium longevity in comparison to other shark species and natural mortality close to that reported in the last stock assessment for the North Pacific Ocean. These life-history parameters should be considered to evaluate the population in the region and to develop better fishery management and conservation measures.

Adaptive neural PD controllers for mobile manipulator trajectory tracking.

Artificial intelligence techniques have been used in the industry to control complex systems; among these proposals, adaptive Proportional, Integrative, Derivative (PID) controllers are intelligent versions of the most used controller in the industry. This work presents an adaptive neuron PD controller and a multilayer neural PD controller for position tracking of a mobile manipulator. Both controllers are trained by an extended Kalman filter (EKF) algorithm. Neural networks trained with the EKF algorithm show faster learning speeds and convergence times than the training based on backpropagation. The integrative term in PID controllers eliminates the steady-state error, but it provokes oscillations and overshoot. Moreover, the cumulative error in the integral action may produce windup effects such as high settling time, poor performance, and instability. The proposed neural PD controllers adjust their gains dynamically, which eliminates the steady-state error. Then, the integrative term is not required, and oscillations and overshot are highly reduced. Removing the integral part also eliminates the need for anti-windup methodologies to deal with the windup effects. Mobile manipulators are popular due to their mobile capability combined with a dexterous manipulation capability, which gives them the potential for many industrial applications. Applicability of the proposed adaptive neural controllers is presented by simulating experimental results on a KUKA Youbot mobile manipulator, presenting different tests and comparisons with the conventional PID controller and an existing adaptive neuron PID controller.

[Actions that should not be taken with a paediatric patient who has been exposed to a potentially toxic substance]. / Acciones que no hay que hacer ante un paciente que ha contactado con un posible tóxico.

OBJECTIVE: To show the preparation process by the Poisoning Working Group of the Spanish Society of Paediatric Emergencies (GTI-SEUP), of the list of things «not to do¼ for a paediatric patient who has been exposed to a potentially toxic substance. METHOD: The preparation process of the list was carried out in three phases. First: «Brainstorming¼ that was open to all members of the GTI-SEUP. Second: Recommendations were selected by following modified-Delphi methodology. All participants were asked to rate the proposals (from 1 = strongly disagree to 9 = strongly agree). Those with an average score greater than 8 were accepted (provided that at least two-thirds of the participants had given them a score ≥ 7), and a second consultation was made for the recommendations with an average score between 6 and 8. Third: Writing and creating a consensus of the final document was done. RESULT: A total of 11 proposals were initially obtained. Thirty-two of the 57 GTI-SEUP participants completed the scoring questionnaire. In the first consultation, seven «not to do¼ recommendations were accepted, and four obtained a doubtful average score (between 6 and 8). After the second consultation, the list was made up of eight recommendations. Two refer to general management, four to gastrointestinal decontamination techniques, and two to the administration of antidotes. CONCLUSION: The list of actions that should not be taken with a child that has been exposed to a possible poison is a consensus tool, within the GTI-SEUP, to promote improvement in the quality of care offered to these patients. This improvement is based on avoiding unnecessary measures, which can sometimes be harmful to the child.

Biodiversity and conservation of sharks in Pacific Mexico.

Mexico is home to a broad biodiversity of shark species, and more than half of the sharks in Mexican waters are distributed in the Mexican Pacific, with over 62 species recorded. This high biodiversity is the result of numerous and diverse marine and coastal environments, including the dynamic Mexican seas, where circulation and spatial variation of oceanic currents is complex, and the seasonal variation of isotherms can be substantial. In the Mexican Pacific we can distinguish some patterns of species distribution, with temperate water and subtropical species found in the northern regions, and tropical conditions and species found in the south. Due to the blending of cold and warm waters, however, we can find a mixture of subtropical and tropical sharks in northern regions seasonally, off the west coast of the Baja California Peninsula and in the Gulf of California, and these areas contain the highest shark species richness. In this chapter we described the shark species biodiversity occurring in the Mexican Pacific, review their conservation status in a regional and global context, and summarize the main conservation measures and issues associated with their management.

Shark ecology, the role of the apex predator and current conservation status.

Feeding studies, since traditional stomach content analysis to stable isotopes analyses, provides insights into the trophic relationship among the apex predators and the ecosystems they inhabit. The Pacific Coast of Mexico (PCM) is inhabited by 62 known species (or 12%) of living sharks, which belong to 21 families and 34 genera. We divide the Pacific Coast of Mexico (PCM) into four regions for consideration: (1) the western coast of Baja California (WcBJ), (2) the Gulf of California (GC), (3) the Central Pacific Mexican (CPM), and (4) the Gulf of Tehuantepec (GT). Biodiversity is highest in the GC, with 48 shark species, followed by the WcBJ with 44 species, then the CPM with 28 species and the GT with 26 species. Few large species (>2m in total length) function as top predators in any region, with a greater number of smaller shark species (<1.5m total length). Information about the trophic ecology of different shark species is included to know the ecological role and position of each shark species within a food web to understand the dynamics of marine communities and the impact that each species has on trophic net, which is critical to effective resource conservation and responsible exploitation. The different shark species predate mainly on coastal or oceanic waters. The coastal sharks feed mainly on crustaceans and small fishes; whereas the oceanic species predate mainly on squids and fishes from mesopelagic to epipelagic habits. Also is included a summary of the IUCN Red List category assigned to all shark species from the Mexican Pacific. Thirty-one percent (19 species) of sharks in the Mexican Pacific are considered as threatened (Critically Endangered, Endangered or Vulnerable). Of these, 4.9% (3 species) are Endangered and 26.2% (15 species) are Vulnerable. In addition, since 2012 the fishing of shark and rays has been closed between 1 May and 31 July in the Mexican Pacific as a conservative management measure.

Periodicity of the growth-band formation in vertebrae of juvenile scalloped hammerhead shark Sphyrna lewini from the Mexican Pacific Ocean.

The age of 296 juvenile scalloped hammerhead sharks Sphyrna lewini caught by several fisheries in the Mexican Pacific Ocean from March 2007 to September 2017 were estimated from growth band counts in thin-sectioned vertebrae. Marginal-increment analysis (MIA) and centrum-edge analysis (CEA) were used to verify the periodicity of formation of the growth bands, whereas elemental profiles obtained from LA-ICP-MS transect scans in vertebrae of 15 juveniles were used as an alternative approach to verify the age of the species for the first time. Age estimates ranged from 0 to 10+ years (42-158.7 cm total length; LT ). The index of average percentage error (IAPE 3.6%), CV (5.2%), bias plots and Bowker's tests of symmetry showed precise and low-biased age estimation. Both MIA and CEA indicated that in the vertebrae of juveniles of S. lewini a single translucent growth band was formed during winter (November-March) and an opaque band during summer (July-September), a period of faster growth, apparently correlated with a higher sea surface temperature. Peaks in vertebral P and Mn content spatially corresponded with the annual banding pattern in most of the samples, displaying 1.19 and 0.88 peaks per opaque band, respectively, which closely matched the annual deposition rate observed in this study. Although the periodicity of growth band formation needs to be verified for all sizes and ages representing the population of the species in the region, this demonstration of the annual formation of the growth bands in the vertebrae of juveniles should lead to a re-estimation of the growth parameters and productivity of the population to ensure that it is harvested at sustainable levels.

Trichologist, Dermatotrichologist, or Trichiatrist? A Global Perspective on a Strictly Medical Discipline.

Few dermatologic problems carry as much emotional overtones as the complaint of hair loss. The best way to alleviate the distress related to hair loss is to effectively treat it. In fact, one of the oldest medical professions is the Egyptian physician who specialized on diseases of the head. And yet, from ancient Egypt down to modern times, human hair has been the object of superstition and mystery. Remarkably and despite the genuine advances in effective medical treatments, hair cosmetics, and surgical procedures, phony hair loss solutions continue to be marketed with an amazing success. In 1860, a quasi-scientific interest in hair loss and hair care originated in a London barbershop and became known as trichology, with the Institute of Trichologists being founded. Other corporations successively followed internationally, but it was only in 2010 that the term dermatotrichologist was proposed for board-certified dermatologists dealing with the scientific study of the hair and scalp, in contrast to the trichologist who is rather associated with laity and cosmetics than with medical professionalism, or - worse - offers opportunities to possible imposters with a primary commercial interest. The new term "trichiatrist" is proposed, literally meaning the "medical treatment of the hair," to designate the strictly medical professional dealing with the hair and scalp in health and disease. Trichiatrists differ from trichologists by virtue of being physicians. The quality and stringency of their graduate medical training is identical to that of other physicians.

Visual Servoing for an Autonomous Hexarotor Using a Neural Network Based PID Controller.

In recent years, unmanned aerial vehicles (UAVs) have gained significant attention. However, we face two major drawbacks when working with UAVs: high nonlinearities and unknown position in 3D space since it is not provided with on-board sensors that can measure its position with respect to a global coordinate system. In this paper, we present a real-time implementation of a servo control, integrating vision sensors, with a neural proportional integral derivative (PID), in order to develop an hexarotor image based visual servo control (IBVS) that knows the position of the robot by using a velocity vector as a reference to control the hexarotor position. This integration requires a tight coordination between control algorithms, models of the system to be controlled, sensors, hardware and software platforms and well-defined interfaces, to allow the real-time implementation, as well as the design of different processing stages with their respective communication architecture. All of these issues and others provoke the idea that real-time implementations can be considered as a difficult task. For the purpose of showing the effectiveness of the sensor integration and control algorithm to address these issues on a high nonlinear system with noisy sensors as cameras, experiments were performed on the Asctec Firefly on-board computer, including both simulation and experimenta results.

How do I look? Self-focused attention during a video chat of women with social anxiety (disorder).

We investigated the role of self-focused attention (SFA) in social anxiety (disorder) in an ecologically valid way. In Experiment 1 high (n = 26) versus low (n = 25) socially anxious single women between 18 and 30 years had a video ("Skype") conversation with an attractive male confederate, while seeing themselves and the confederate on-screen. The conversation was divided in four phases: (I) warm-up, (II) positive (confederate was friendly to the participant), (III) critical (confederate was critical to the participant), and (IV) active (participant was instructed to ask questions to the confederate). Participant's SFA was measured by eye-tracked gaze duration at their own image relative to the confederates' video image and other places at the computer screen. Results show that high socially anxious participants were more self-focused in the critical phase, but less self-focused in the active phase than low socially anxious participants. In Experiment 2 women diagnosed with SAD (n = 32) and controls (n = 30) between 18 and 30 years conducted the same experiment. Compared to controls participants with SAD showed increased SFA across all four phases of the conversation, and SFA predicted increased self-rated anxiety during the conversation. In conclusion, in subclinical social anxiety SFA is high only when the interaction partner is critical, whereas instructions to ask questions to the confederate reduces subclinical socially anxious' SFA, while clinical SAD is characterized by heightened self-focused attention throughout the interaction. Results support theories that social anxiety disorder is maintained by SFA, and imply that interventions that lower SFA may help prevent and treat social anxiety disorder, but that SFA can also be adaptive in certain types of interaction, such as when receiving compliments.

The Algal Meroterpene 11-Hydroxy-1'-O-Methylamentadione Ameloriates Dextran Sulfate Sodium-Induced Colitis in Mice.

Inflammatory bowel disease (IBD) is a complex class of immune disorders. Unfortunately, a treatment for total remission has not yet been found, while the use of natural product-based therapies has emerged as a promising intervention. The present study was aimed to investigate the anti-inflammatory effects of the algal meroterpene 11-hydroxy-1'-O-methylamentadione (AMT-E) in a murine model of dextran sodium sulphate (DSS)-induced colitis. AMT-E was orally administered daily (1, 10, and 20 mg/kg animal) to DSS treated mice (3% w/v) for 7 days. AMT-E prevented body weight loss and colon shortening and effectively attenuated the extent of the colonic damage. Similarly, AMT-E increased mucus production and reduced myeloperoxidase activity (marker for anti-inflammatory activity). Moreover, the algal meroterpene decreased the tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-10 levels, and caused a significant reduction of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Our results demonstrate the protective effects of AMT-E on experimental colitis, provide an insight of the underlying mechanisms of this compound, and suggest that this class of marine natural products might be an interesting candidate for further studies on the prevention/treatment of IBD.

Evaluation of the free, open source software WordPress as electronic portfolio system in undergraduate medical education.

BACKGROUND: Electronic portfolios (ePortfolios) are used to document and support learning activities. E-portfolios with mobile capabilities allow even more flexibility. However, the development or acquisition of ePortfolio software is often costly, and at the same time, commercially available systems may not sufficiently fit the institution's needs. The aim of this study was to design and evaluate an ePortfolio system with mobile capabilities using a commercially free and open source software solution. METHODS: We created an online ePortfolio environment using the blogging software WordPress based on reported capability features of such software by a qualitative weight and sum method. Technical implementation and usability were evaluated by 25 medical students during their clinical training by quantitative and qualitative means using online questionnaires and focus groups. RESULTS: The WordPress ePortfolio environment allowed students a broad spectrum of activities - often documented via mobile devices - like collection of multimedia evidences, posting reflections, messaging, web publishing, ePortfolio searches, collaborative learning, knowledge management in a content management system including a wiki and RSS feeds, and the use of aid tools for studying. The students' experience with WordPress revealed a few technical problems, and this report provides workarounds. The WordPress ePortfolio was rated positively by the students as a content management system (67 % of the students), for exchange with other students (74 %), as a note pad for reflections (53 %) and for its potential as an information source for assessment (48 %) and exchange with a mentor (68 %). On the negative side, 74 % of the students in this pilot study did not find it easy to get started with the system, and 63 % rated the ePortfolio as not being user-friendly. Qualitative analysis indicated a need for more introductory information and training. CONCLUSIONS: It is possible to build an advanced ePortfolio system with mobile capabilities with the free and open source software WordPress. This allows institutions without proprietary software to build a sophisticated ePortfolio system adapted to their needs with relatively few resources. The implementation of WordPress should be accompanied by introductory courses in the use of the software and its apps in order to facilitate its usability.

The convergence of medicine and neurotoxins: a focus on botulinum toxin type A and its application in aesthetic medicine--a global, evidence-based botulinum toxin consensus education initiative: part II: incorporating botulinum toxin into aesthetic clinical practice.

BACKGROUND: The new world of safe aesthetic injectables has become increasingly popular with patients. Not only is there less risk than with surgery, but there is also significantly less downtime to interfere with patients' normal work and social schedules. Botulinum toxin (BoNT) type A (BoNTA) is an indispensable tool used in aesthetic medicine, and its broad appeal has made it a hallmark of modern culture. The key to using BoNTA to its best effect is to understand patient-specific factors that will determine the treatment plan and the physician's ability to personalize injection strategies. OBJECTIVES: To present international expert viewpoints and consensus on some of the contemporary best practices in aesthetic BoNTA, so that beginner and advanced injectors may find pearls that provide practical benefits. METHODS AND MATERIALS: Expert aesthetic physicians convened to discuss their approaches to treatment with BoNT. The discussions and consensus from this meeting were used to provide an up-to-date review of treatment strategies to improve patient results. Information is presented on patient management and assessment, documentation and consent, aesthetic scales, injection strategies, dilution, dosing, and adverse events. CONCLUSION: A range of product- and patient-specific factors influence the treatment plan. Truly optimized outcomes are possible only when the treating physician has the requisite knowledge, experience, and vision to use BoNTA as part of a unique solution for each patient's specific needs.

Implantación de la norma de calidad UNE-EN ISO/IEC 17043 en el Programa de Control de Calidad Externo SEIMC / Implementation of quality standard UNE-EN ISO/IEC 17043 in the External Quality Control Program of the Spanish Society of Infectious Diseases and Clinical Microbiology

La norma UNE-EN–ISO 17043: 2010. Evaluación de la conformidad. Requisitos generales para los ensayos de aptitud, es de aplicación a los centros que organizan ejercicios de intercomparación en todos los ámbitos. En el caso de los laboratorios de microbiología clínica, estos ejercicios deben cumplir unos requisitos técnicos y de gestión concretos para alcanzar una calidad máxima en la realización de los análisis microbiológicos y en la preparación de los objetos de ensayo (muestra, producto, conjunto de datos u otra información utilizada en un ensayo de aptitud); esto permitirá obtener su acreditación y, de este modo, poder actuar como una herramienta útil para el control de calidad externo de los laboratorios de microbiología, así como para la evaluación de la competencia de éstos.En España, la entidad evaluadora es la Entidad Nacional de Acreditación (ENAC).El objetivo de esta revisión es comentar cómo aplicar los requisitos de la norma a los laboratorios proveedores de ejercicios intercomparativos (organización responsable de todas las tareas relacionadas con el desarrollo y la operación de un programa de ensayo de aptitud) en el ámbito de la microbiología clínica. Para ello es prioritario definir los alcances y especificar los requisitos técnicos (la gestión de personal, el control de equipos, instalaciones y ambiente, el diseño de los ensayos de aptitud y el análisis de datos para la evaluación de resultados, comunicación con los participantes y confidencialidad) y los requisitos de gestión (control de documentos, control de compras, control de quejas/reclamaciones, no conformidades, auditorías internas y revisiones por la dirección) (AU)

The quality standard “UNE-EN-ISO 17043: 2010. Conformity assessment. General requirements for proficiency testing” applies to centers that organize intercomparisons in all areas. In the case of clinical microbiology laboratories, these intercomparisons must meet the management and technical standards required to achieve maximum quality in the performance of microbiological analysis and the preparation of test items (sample, product, data or other information used in the proficiency test) to enable them to be accredited. Once accredited, these laboratories can operate as a tool for quality control laboratories and competency assessment.In Spain, accreditation is granted by the Spanish Accreditation Body [Entidad Nacional de Acreditación (ENAC)].The objective of this review is to explain how to apply the requirements of the standard to laboratories providing intercomparisons in the field of clinical microbiology (the organization responsible for all the tasks related to the development and operation of a proficiency testing program). This requires defining the scope and specifying the technical requirements (personnel management, control of equipment, facilities and environment, the design of the proficiency testing and data analysis for performance evaluation, communication with participants and confidentiality) and management requirements (document control, purchasing control, monitoring of complaints / claims, non-compliance, internal audits and management reviews)(AU)

Absolute configuration of 7,8-seco-7,8-oxacassane diterpenoids from Acacia schaffneri.

Chemical investigations of Acacia schaffneri led to the isolation of the new diterpenoid (5S,7R,8R,9R,10S)-(-)-7,8-seco-7,8-oxacassa-13,15-diene-7,17-diol (1), together with the known (5S,7R,8R,9R,10S)-(-)-7,8-seco-7,8-oxacassa-13,15-dien-7-ol-17-al (2) and (5S,7R,8R,9R,10S)-(-)-7,8-seco-7,8-oxacassa-13,15-dien-7-ol (3). Compounds 2 and 3 were analyzed by single-crystal X-ray diffraction, while the structure of 1 was determined by 1D and 2D NMR experiments and by chemical correlation with 2. Oxidation of 3 afforded conformationally restricted (5S,8R,9R,10S)-(-)-8-hydroxy-7,8-seco-cassa-13,15-dien-7-oic acid ε-lactone (4), which was studied by vibrational circular dichroism spectroscopy. Comparison of the experimental VCD spectrum of 4 with the DFT//B3PW91/DGDZVP2 calculated spectrum assigned for the first time the absolute configuration of these seco-oxacassane diterpenes.

Absolute configuration of podophyllotoxin related lignans from Bursera fagaroides using vibrational circular dichroism.

The ethanol extract from the dried exudate of Bursera fagaroides (Burseraceae) showed significant cytotoxic activity in the HT-29 (human colon adenocarcinoma) test system. The extract provided four podophyllotoxin related lignans, identified as (7'R,8R,8'R)-(-)-deoxypodophyllotoxin (3), (7'R,8R,8'R)-(-)-morelensin (4), (8R,8'R)-(-)-yatein (5), and (8R,8'R)-(-)-5'-desmethoxyyatein (6), whose spectroscopic and chiroptical properties were compared with those of (7R,7'R,8R,8'R)-(-)-podophyllotoxin (1) and its acetyl derivative (2). Their absolute configurations were assigned by comparison of the vibrational circular dichroism spectra of 1 and 3 with those obtained by density functional theory calculations.

[Position paper about isotretinoin on acne vulgaris]. / Declaración de posición conjunta. Uso de isotretinoína en acné común.

Isotretinoin was authorized since 1982 for the treatment of acne vulgaris associated to severe cutaneous lesions. It has been used in others clinical conditions in various plans of prescription. Since the Isotretinoin was launched, it caused controversies in our country and around the world, especially in relation with the security. Isotretinoin is proscribed in pregnant patient. As a security rule we must measure serum lipids and hepatic enzymes. The aim of the consensus was to spread information worked by a group of Mexican experienced dermatologists to the health professionals about the use and the specific indications about isotretinoin.

Absolute configuration of labdanes and ent-clerodanes from Chromolaena pulchella by vibrational circular dichroism.

The aerial parts of Chromolaena pulchella biosynthesize two groups of diterpenes belonging to opposite enantiomeric series, specifically, the furanoid ent-clerodanes (5R,8R,9S,10R)-(-)-hardwikiic acid (1), methyl (5R,8R,9S,10R)-(-)-hardwikiate (2), (5S,8R,9S,10R)-(-)-hautriwaic acid lactone (3), methyl (5R,8R,9S,10R)-(-)-nidoresedate (4) and methyl (8R,9R)-(-)-strictate (5), as well as the labdanes (5S,8R,9R,10S)-(+)-(13E)-labd-13-ene-8,15-diol (6) and (5S,8R,9R,10S)-(+)-isoabienol (7). The absolute configuration of the two groups of diterpenes was unambiguously assigned by comparison of the vibrational circular dichroism spectra of 3 for ent-clerodanes, and of 7 for labdanes with their theoretical spectra obtained by density functional theory calculations. The results support a biogenetic proposal to diterpenes found in the studied botanical species.