Amyl acetate: an alternative technique to dry mount Chalcidoidea (Hymenoptera) from alcohol, faster and inexpensively.

Ethanol (EtOH) 70% is commonly used in collections to preserve and store many unprepared soft-bodied Chalcidoidea. Specimens air-dried directly from alcohol, however, often suffer from collapse of some body parts, making subsequent observation of their morphology difficult or even impossible. We propose an inexpensive method for processing and dry-mounting specimens of Chalcidoidea, using a chemical process including amyl acetate. Four treatments using amyl acetate at different concentrations and exposure times were evaluated for specimens of Eulophidae, Mymaridae, Encyrtidae, Aphelinidae, Pteromalidae, and Trichogrammatidae. Treatment with amyl acetate resulted in specimens of consistently higher quality. Based on our results, treatment of specimens for 1 h with 50:50 amyl acetate and ethanol mixture, followed by treatment for 1 h with 100% amyl acetate, yielded specimens adequate for morphological observations for most of the families. Further experiments are required, however, to optimize this approach for Trichogrammatidae and Eulophidae. This method is a relatively simple, inexpensive, and safe alternative to other methods commonly used for restoring Chalcidoidea preserved in alcohol.

The liquidus temperature curve of aqueous methanol mixtures: A numerical simulation study.

The liquidus temperature curve that characterizes the boundary between the liquid methanol/water mixture and its coexistence with ice Ih is determined using the direct-coexistence method. Several methanol concentrations and pressures of 0.1, 50, and 100 MPa are considered. In this study, we used the TIP4P/Ice model for water and two different models for methanol: OPLS and OPLS/2016, using the geometric rule for the Lennard-Jones cross interactions. We compared our simulation results with available experimental data and found that this combination of models reproduces the liquidus curve for methanol mole fractions reasonably well, up to xm = 0.3 at p = 0.1 MPa. The freezing point depression of these mixtures is calculated and compared to experimental results. We also analyzed the effect of pressure on the liquidus curve and found that both models also reproduce the experimental decrease of the liquidus temperatures as the pressure increases qualitatively well.

Molecular dynamics study of nanoconfined TIP4P/2005 water: how confinement and temperature affect diffusion and viscosity.

In the past few decades great effort has been devoted to the study of water confined in hydrophobic geometries at the nanoscale (tubes and slit pores) due to the multiple technological applications of such systems, ranging from drug delivery to water desalination devices. To our knowledge, neither numerical/theoretical nor experimental approaches have so far reached a consensual understanding of structural and transport properties of water under these conditions. In this work, we present molecular dynamics simulations of TIP4P/2005 water under different nanoconfinements (slit pores or nanotubes, with two degrees of hydrophobicity) within a wide temperature range. It has been found that water is more structured near the less hydrophobic walls, independently of the confining geometries. Meanwhile, we observe an enhanced diffusion coefficient of water in both hydrophobic nanotubes. Finally, we propose a confined Stokes-Einstein relation to obtain the viscosity from diffusivity, whose result strongly differs from the Green-Kubo expression that has been used in previous works. While viscosity computed with the Green-Kubo formula (applied for anisotropic and confined systems) strongly differs from that of the bulk, viscosity computed with the confined Stokes-Einstein relation is not so much affected by the confinement, independently of its geometry. We discuss the shortcomings of both approaches, which could explain this discrepancy.

Water phase transitions from the perspective of hydrogen-bond network analysis.

We analyze the water vapour-liquid and solid-liquid phase transitions from the perspective of hydrogen bond networks. Using molecular dynamics simulation data for the TIP4P/2005 and TIP4P/ice water models, we built hydrogen bond networks in the neighbourhood of the transitions. We studied the behaviour of some topological network properties: the average degree, clustering coefficient, and average path length. We found that these properties exhibit a discontinuity while approaching a phase transition region, similar to those that appear for some thermodynamic properties in the same region. This approach can be extended to characterize other water phase transitions. Besides, it can also be applied to study the phase transitions of other hydrogen-bonded substances or to other scenarios whose relevant "interaction" could be identified together with a "proper criterion" defined in an analogous way as in the case of hydrogen bonded systems.

The constant force continuous molecular dynamics for potentials with multiple discontinuities.

In this work, we present an extension of the constant force approach [P. Orea and G. Odriozola, J. Chem. Phys. 138, 214105 (2013)] to the case of potentials with multiple discontinuities. To illustrate the method, we selected the square well potential of range λ=1.5 that exhibits two discontinuities. Square well single phase properties, vapor-liquid phase diagram, and surface tension were calculated and compared with available simulation data. Besides, we analyzed the internal energies of a square well plus a square shoulder potential having three discontinuities. For both potentials, a good agreement has been found when compared with results of other simulation techniques (discontinuous molecular dynamics and Monte Carlo methods). This extension can be easily implemented to more general and efficient continuous molecular dynamics packages (HOOMD, GROMACS, NAMD, etc.).

A potential model for sodium chloride solutions based on the TIP4P/2005 water model.

Despite considerable efforts over more than two decades, our knowledge of the interactions in electrolyte solutions is not yet satisfactory. Not even one of the most simple and important aqueous solutions, NaCl(aq), escapes this assertion. A requisite for the development of a force field for any water solution is the availability of a good model for water. Despite the fact that TIP4P/2005 seems to fulfill the requirement, little work has been devoted to build a force field based on TIP4P/2005. In this work, we try to fill this gap for NaCl(aq). After unsuccessful attempts to produce accurate predictions for a wide range of properties using unity ionic charges, we decided to follow recent suggestions indicating that the charges should be scaled in the ionic solution. In this way, we have been able to develop a satisfactory non-polarizable force field for NaCl(aq). We evaluate a number of thermodynamic properties of the solution (equation of state, maximum in density, enthalpies of solution, activity coefficients, radial distribution functions, solubility, surface tension, diffusion coefficients, and viscosity). Overall the results for the solution are very good. An important achievement of our model is that it also accounts for the dynamical properties of the solution, a test for which the force fields so far proposed failed. The same is true for the solubility and for the maximum in density where the model describes the experimental results almost quantitatively. The price to pay is that the model is not so good at describing NaCl in the solid phase, although the results for several properties (density and melting temperature) are still acceptable. We conclude that the scaling of the charges improves the overall description of NaCl aqueous solutions when the polarization is not included.

Consensus on the solubility of NaCl in water from computer simulations using the chemical potential route.

The solubility of NaCl in water is evaluated by using three force field models: Joung-Cheatham for NaCl dissolved in two different water models (SPC/E and TIP4P/2005) and Smith Dang NaCl model in SPC/E water. The methodology based on free-energy calculations [E. Sanz and C. Vega, J. Chem. Phys. 126, 014507 (2007)] and [J. L. Aragones et al., J. Chem. Phys. 136, 244508 (2012)] has been used, except, that all calculations for the NaCl in solution were obtained by using molecular dynamics simulations with the GROMACS package instead of homemade MC programs. We have explored new lower molalities and made longer runs to improve the accuracy of the calculations. Exploring the low molality region allowed us to obtain an analytical expression for the chemical potential of the ions in solution as a function of molality valid for a wider range of molalities, including the infinite dilute case. These new results are in better agreement with recent estimations of the solubility obtained with other methodologies. Besides, two empirical simple rules have been obtained to have a rough estimate of the solubility of a certain model, by analyzing the ionic pairs formation as a function of molality and/or by calculating the difference between the NaCl solid chemical potential and the standard chemical potential of the salt in solution.

Discrete perturbation theory for continuous soft-core potential fluids.

In this work, we present an equation of state for an interesting soft-core continuous potential [G. Franzese, J. Mol. Liq. 136, 267 (2007)] which has been successfully used to model the behavior of single component fluids that show some water-type anomalies. This equation has been obtained using discrete perturbation theory. It is an analytical expression given in terms of density, temperature, and the set of parameters that characterize the intermolecular interaction. Theoretical results for the vapor-liquid phase diagram and for supercritical pressures are compared with previous and new simulation data and a good agreement is found. This work also clarifies discrepancies between previous Monte Carlo and molecular dynamics simulation results for this potential.

Surface tension and phase coexistence for fluids of molecules with extended dipoles.

Molecular dynamics simulations of fluids of molecules with extended dipoles were performed, with increasing distance between point charges but with a constant dipole moment, to obtain thermodynamic properties. It was found that the effect of varying the dipole length on the dielectric constant in the liquid phase, the vapor-liquid equilibria, and the surface tension was negligible for dipolar lengths up to half the particle diameter. By comparing thermodynamic properties of the predictions of the extended dipole model with those for the Stockmayer fluid of point dipoles, it was found that extended dipoles are equivalent to point dipoles over a wide range of dipole lengths, and not only near the point dipole limit, when the separation length is very small compared with the mean distance between particles. Finally, phase equilibrium results of extended dipoles were compared to those obtained from the discrete perturbation theory for a Stockmayer potential.

Imaging manifestations of pulmonary melioidosis: A case series.

Melioidosis is an endemic disease in Southeast Asia and Oceania caused by the gram-negative bacillus Burkholderia pseudomallei. We studied 15 adult patients from Colombia with microbiologically diagnosed pulmonary melioidosis. We reviewed 15 chest X-rays and 10 chest computed tomography (CT) studies. Of the 15 patients, 87% met the criteria for acute infection and 13% met the criteria for chronic infection. The most common findings on chest X-rays were consolidation (86%), nodules (26%), and cavitation (20%). On CT studies, consolidation and nodules were observed in 90% of cases; the areas of consolidation were predominantly located in the basal and central zones in 60%. Areas of cavitation were observed in 50%, pleural effusion in 60%, and mediastinal lymph nodes in 30%. In patients with acute pulmonary melioidosis (n=8), the findings observed were nodules (100%), mixed pattern with nodules and consolidation (87%), pleural effusion (88%), and mediastinal lymph nodes (25%). The two patients with chronic pulmonary melioidosis both had cavitation. Acute lung infection with B. Pseudomallei has radiologic manifestations similar to those of pneumonia due to other causes. In areas where the disease is endemic, it is essential to include acute melioidosis in the differential diagnosis of pulmonary nodules and chronic melioidosis in the differential diagnosis of cavitated chronic lung lesions.

Imaging manifestations of pulmonary melioidosis: a case series. / Manifestaciones radiológicas de la melioidosis pulmonar. Serie de casos.

Melioidosis is an endemic disease in Southeast Asia and Oceania caused by the gram-negative bacillus Burkholderia pseudomallei. We studied 15 adult patients from Colombia with microbiologically diagnosed pulmonary melioidosis. We reviewed 15 chest X-rays and 10 chest computed tomography (CT) studies. Of the 15 patients, 87% met the criteria for acute infection and 13% met the criteria for chronic infection. The most common findings on chest X-rays were consolidation (86%), nodules (26%), and cavitation (20%). On CT studies, consolidation and nodules were observed in 90% of cases; the areas of consolidation were predominantly located in the basal and central zones in 60%. Areas of cavitation were observed in 50%, pleural effusion in 60%, and mediastinal lymph nodes in 30%. In patients with acute pulmonary melioidosis (n=8), the findings observed were nodules (100%), mixed pattern with nodules and consolidation (87%), pleural effusion (88%), and mediastinal lymph nodes (25%). The two patients with chronic pulmonary melioidosis both had cavitation. Acute lung infection with B. Pseudomallei has radiologic manifestations similar to those of pneumonia due to other causes. In areas where the disease is endemic, it is essential to include acute melioidosis in the differential diagnosis of pulmonary nodules and chronic melioidosis in the differential diagnosis of cavitated chronic lung lesions.

Ecophysiological Performance of Proteaceae Species From Southern South America Growing on Substrates Derived From Young Volcanic Materials.

Southern South American Proteaceae thrive on young volcanic substrates, which are extremely low in plant-available phosphorus (P). Most Proteaceae exhibit a nutrient-acquisition strategy based on the release of carboxylates from specialized roots, named cluster roots (CR). Some Proteaceae colonize young volcanic substrates which has been related to CR functioning. However, physiological functioning of other Proteaceae on recent volcanic substrates is unknown. We conducted an experiment with seedlings of five Proteaceae (Gevuina avellana, Embothrium coccineum, Lomatia hirsuta, L. ferruginea, and L. dentata) grown in three volcanic materials. Two of them are substrates with very low nutrient concentrations, collected from the most recent deposits of the volcanoes Choshuenco and Calbuco (Chile). The other volcanic material corresponds to a developed soil that exhibits a high nutrient availability. We assessed morphological responses (i.e., height, biomass, and CR formation), seed and leaf macronutrient and micronutrient concentrations and carboxylates exuded by roots. The results show that G. avellana was less affected by nutrient availability of the volcanic substrate, probably because it had a greater nutrient content in its seeds and produced large CR exuding carboxylates that supported their initial growth. Embothrium coccineum exhibited greater total plant height and leaf P concentration than Lomatia species. In general, in all species leaf macronutrient concentrations were reduced on nutrient-poor volcanic substrates, while leaf micronutrient concentrations were highly variable depending on species and volcanic material. We conclude that Proteaceae from temperate rainforests differ in their capacity to grow and acquire nutrients from young and nutrient-poor volcanic substrates. The greater seed nutrient content, low nutrient requirements (only for G. avellana) and ability to mobilize nutrients help explain why G. avellana and E. coccineum are better colonizers of recent volcanic substrates than Lomatia species.

Discrete perturbation theory for the hard-core attractive and repulsive Yukawa potentials.

In this work we apply the discrete perturbation theory [A. L. Benavides and A. Gil-Villegas, Mol. Phys. 97, 1225 (1999)] to obtain an equation of state for the case of two continuous potentials: the hard-core attractive Yukawa potential and the hard-core repulsive Yukawa potential. The main advantage of the presented equation of state is that it is an explicit analytical expression in the parameters that characterize the intermolecular interactions. With a suitable choice of their inverse screening length parameter one can model the behavior of different systems. This feature allows us to make a systematic study of the effect of the variation in the parameters on the thermodynamic properties of this system. We analyze single phase properties at different conditions of density and temperature, and vapor-liquid phase diagrams for several values of the reduced inverse screening length parameter within the interval kappa( *)=0.1-5.0. The theoretical predictions are compared with available and new Monte Carlo simulation data. Good agreement is found for most of the cases and better predictions are found for the long-range ones. The Yukawa potential is an example of a family of hard-core plus a tail (attractive or repulsive) function that asymptotically goes to zero as the separations between particles increase. We would expect that similar results could be found for other potentials with these characteristics.

Monitoring of fetuses with intrauterine growth restriction: longitudinal changes in ductus venosus and aortic isthmus flow.

OBJECTIVES: To explore in growth-restricted fetuses the sequence of changes in aortic isthmus and ductus venosus blood flow in relation to other arterial Doppler parameters commonly used to evaluate fetal wellbeing. METHODS: Umbilical and middle cerebral arteries, ductus venosus and aortic isthmus were explored serially by means of pulsed Doppler in a cohort of singleton small-for-gestational age fetuses requiring delivery before 34 weeks. Longitudinal changes in the last 30 days before delivery were modeled by multilevel analysis. Individual regression lines for each variable were calculated for each fetus and from these the regression lines for the whole group were derived, in order to estimate the mean time point at which each Doppler parameter became abnormal (outside the 5th-95th centile range). A survival analysis was performed during the monitoring period, in which the endpoint was an abnormal Doppler pulsatility index. RESULTS: A total of 162 observations were performed on 46 fetuses (median, 3; range, 2-10). The median gestational age at inclusion was 28.9 (range, 23.6-33.4) weeks and delivery occurred at a median gestational age of 30.5 (range, 25.9-33.9) weeks. Six (13%) cases of perinatal mortality occurred. Umbilical and middle cerebral artery Doppler showed an almost linear deterioration throughout monitoring, becoming abnormal on average 24 days and 20 days before delivery, respectively. Aortic isthmus Doppler became abnormal on average 13 days before delivery, while ductus venosus Doppler did so within the last week before delivery. CONCLUSIONS: In preterm growth-restricted fetuses, aortic isthmus blood flow becomes abnormal on average 1 week earlier than does that in the ductus venosus. This could provide a sound basis to better define management protocols aimed to improve intact fetal survival.

Updated taxonomic checklist of Chalcidoidea (Hymenoptera) associated with Bruchinae (Coleoptera: Chrysomelidae).

A taxonomic checklist of Chalcidoidea (Hymenoptera) associated with Bruchinae (Coleoptera: Chrysomelidae) is presented. A total of 139 species of Chalcidoidea or unidentified species to genus are reported as primary parasitoids. The valid name, primary host(s) (animal and plant taxa), distribution and references for each species are listed.

Umbrales auditivos en pacientes con enfermedad de Méniere manejados con corticoides transtimpánicos / Hearing thresholds in Ménière's disease patients managed with transtympanic dexametasone

Introducción: Pese a que el uso de corticoides transtimpánicos en pacientes con enfermedad de Méniere es habitual en muchos centros, la evidencia respecto de su efecto sobre los umbrales auditivos es aún controversial. Objetivo: Estudiar los umbrales auditivos de pacientes con enfermedad de Méniere que recibieron corticoides transtimpánicos en el Servicio de Otorrinolaringología del Hospital Clínico de la Universidad de Chile. Material y Método: Estudio retrospectivo de pacientes con enfermedad de Méniere que consultaron entre los años 2015 y 2021. Se estudiaron los umbrales auditivos, antes y después de 3 inyecciones de dexametasona transtimpánica. Resultados: Se obtuvieron datos completos de 27 pacientes. Al comparar el promedio tonal puro antes y después del tratamiento, no se observaron diferencias significativas. A nivel individual, la variación de cambio de los umbrales auditivos con dexametasona se correlaciona en forma significativa con los umbrales auditivos previos a las inyecciones y con el tiempo transcurrido desde la última inyección, pero no con la edad. Conclusión: La terapia con dexametasona transtimpánica en pacientes con enfermedad de Méniere no altera los umbrales auditivos. Sin embargo, se requieren más estudios, para comprobar, si existe un efecto transitorio en los umbrales auditivos de los primeros días posterior al procedimiento.

Introduction: Although transtympanic corticosteroids are proposed in Méniere's disease patients refractory to standard medical therapy, the evidence regarding the effect of transtympanic corticosteroids on hearing thresholds is still controversial. Aim: To study the hearing thresholds of patients with Méniere's disease who were administrated with transtympanic corticosteroids at the Otorhinolaryngology Service of the University of Chile's Clinical Hospital. Material and Method: Retrospective study of Méniere's disease patients who consulted between 2015 and 2021. Demographic variables and hearing thresholds were studied before and after three transtympanic injections of dexamethasone. Results: A total of 27 patients were studied. There were non-significant differences in pure-tone hearing threshold averages before and after the injections. Individual variation in hearing thresholds correlates significantly with the pre-injection hearing thresholds and the period since the last injection, but not with age. Conclusion: Transtympanic dexamethasone therapy in patients with Meniere's disease does not alter hearing thresholds. However, more studies are needed to verify whether there is a transitory effect on hearing thresholds in the first days after the procedure.

Differential regulation of calcium channel coding genes by prolonged depolarization.

Calcium channels must be subjected to a very precise regulation in order to preserve cell function and viability. Voltage gated calcium channels (VGCC) represent the main pathway for calcium entry in excitable cells. This explains why depolarization induces a rapid-onset and short-term inactivation of calcium currents. Contrarily to this well-documented mechanism to maintain calcium below toxic levels, the regulatory pathways inducing longer-lasting changes and cell surface expression of functional calcium channels are largely unknown. Since calcium is a main player in the activity-dependent regulation of many genes, we hypothesize that calcium channel coding genes could be also subjected to activity-dependent regulation. We have used prolonged depolarization to analyze the effects of sustained intracellular calcium elevation on the mRNAs coding for the different alpha(1) pore-forming subunits of the calcium channels expressed in chromaffin cells. Our findings reveal that persistent depolarization is accompanied by a prolonged intracellular calcium elevation and reduction of calcium current. This calcium current inhibition could be mediated, at least partially, by the downregulation of the mRNAs coding for several alpha(1) subunits. Thus, we show here that depolarization inhibits the expression of Ca(V)1.1, Ca(V)1.2, Ca(V)1.3, Ca(V)2.2 and Ca(V)2.3 mRNAs, while the Ca(V)2.1 mRNA remains unmodified. Moreover, such downregulation of channels depends on calcium entry through the L-type calcium channel, as both mRNA and calcium current changes induced by depolarization are abrogated by L-type channel specific blockers.

[Meningoencephalomyelitis as the initial symptom of a brain tumour mimicking encephalitis due to herpes simplex virus: a case report]. / Meningoencefalomielitis como manifestacion inicial de un tumor cerebral que imita una encefalitis por virus del herpes simple: descripcion de un caso.

INTRODUCTION: Meningoencephalomyelitis can be due to a number of treatable causes. A tumoural aetiology is rare and they are generally malignant tumours with an ominous prognosis. We report a case of meningoencephalomyelitis that initially presented as encephalitis due to herpes simplex virus (HSV) and which was finally seen to be an anaplastic oligoastrocytoma. CASE REPORT: We describe the case of a 68-year-old male with a history of just strong low back pain during the previous month, who was admitted to hospital because of progressive clinical symptoms involving cognitive impairment and myoclonias. The polymerase chain reaction for the cerebrospinal fluid was positive for HSV and magnetic resonance imaging revealed diffuse compromise of right temporal lobe, the spinal cord and the cervical meninges. The progressive deterioration of the patient despite treatment with acyclovir, anti-tuberculosis agents and with corticoids made it necessary to perform a biopsy study of the cervical meninges, the results of which suggested non-specific macromonocytic meningoencephalitis. The patient's condition continued to deteriorate until he died. The post-mortem examination revealed a grade III oligoastrocytoma in both temporal lobes, which had extended into the adjacent subarachnoid space and the cerebral and cervical leptomeninges. CONCLUSIONS: Non-specific symptoms of low back pain can conceal a brain tumour. Attention is drawn to how infrequently it manifests clinically and in imaging studies as meningoencephalomyelitis due to direct tumoural invasion. This should be considered as a possibility when faced with a slowly progressing clinical picture that, despite the initial suspicion of encephalitis due to HSV, does not respond to the usual treatment.

[Comparison of clinical features and diagnosis between the A and B subgroups of respiratory syncytial virus.] / Comparación de las características clínicas y diagnósticas de los subgrupos A y B del virus respiratorio sincitial.

BACKGROUND: Lower respiratory tract infection by respiratory syncytial virus (RSV) is the most frequent cause of admission in children under 2 years old. The RSV subgroups A and B may circulate simultaneously. We aimed to determine whether clinical differences exist between RSV subgroups A and B. Additionally, we tested the sensitivity of the rapid antigen detection test (RADT) based on immunochromatography in diagnosing subgroups A and B, taking the polymerase chain reaction assay (RT-PCR) as reference. METHODS: A retrospective observational study was performed in a tertiary hospital from October 2013 to March 2014. Clinical records and analytical variables of all children under 5 admitted with lower respiratory tract infection and RT-PCR positive for RSV in nasal lavage were consulted. Previously, the RADT for RSV had been performed from the same sample. RESULTS: A total of 198 children under 5 were diagnosed with RSV by RT-PCR: 55 (28%) were RSV-A, 132 (67%) RSV-B and 11 (5%) were positive for both subgroups. No differences were observed between subgroups in medical history, symptoms, radiological and analytical findings, and severity. The sensitivity of RADT for RSV was 52%, higher for RSV-A (69%) than for RSV-B (44%, p=0.001). CONCLUSIONS: The two RSV subgroups were indistinguishable in symptoms and prognosis. The sensitivity of RADT compared to RT-PCR was low and limits its usefulness for clinical decision-making. Key words. Respiratory syncytial virus. RSV subgroups. Rapid antigen detection test. Reverse transcription polymerase chain reaction.