Energy Resolution from a Silicon Detector's Interstrip Regions.

In this work, we present a novel approach for improving the energy resolution from particles impinging on the interstrip regions of silicon strip detectors. We employed three double-sided strip detectors from the GRIT array and a triple α-source under laboratory conditions. The results showed that the interstrip resolution depends not only on the impinging side but also on whether it is a P- or an N-interstrip. We obtained the interstrip energy resolution down to 0.4%, and, depending on the scenario, the resolution was enhanced by a factor of 2. We believe that this new rotation method allows for the possibility of applying particle identification methods on interstrip events, which in most cases are dismissed during data recording.

Microplastic fibres affect soil fungal communities depending on drought conditions with consequences for ecosystem functions.

Microplastics affect soil functions depending on drought conditions. However, how their combined effect influences soil fungi and their linkages with ecosystem functions is still unknown. To address this, we used rhizosphere soil from a previous experiment in which we employed microplastic fibres addition and drought in a factorial design, and evaluated their effects on soil fungal communities. Microplastics decreased soil fungal richness under well-watered conditions, likely linked to microplastics leaching toxic substances into the soil, and microplastic effects on root fineness. Under drought, by contrast, microplastics increased pathogen and total fungal richness, likely related to microplastic positive effects on soil properties, such as water holding capacity, porosity or aggregation. Soil fungal richness was the attribute most affected by microplastics and drought. Microplastics altered the relationships between soil fungi and ecosystem functions to the point that many of them flipped from positive to negative or disappeared. The combined effect of microplastics and drought on fungal richness mitigated their individual negative effect (antagonism), suggesting that changes in soil water conditions may alter the action mode of microplastics in soil. Microplastic leaching of harmful substances can be mitigated under drought, while the improvement of soil properties by microplastics may alleviate such drought conditions.

Rate-induced tracking for concave or d-concave transitions in a time-dependent environment with application in ecology.

This paper investigates biological models that represent the transition equation from a system in the past to a system in the future. It is shown that finite-time Lyapunov exponents calculated along a locally pullback attractive solution are efficient indicators (early-warning signals) of the presence of a tipping point. Precise time-dependent transitions with concave or d-concave variation in the state variable giving rise to scenarios of rate-induced tracking are shown. They are classified depending on the internal dynamics of the set of bounded solutions. Based on this classification, some representative features of these models are investigated by means of a careful numerical analysis.

Test Bench for Highly Segmented GRIT Double-Sided Silicon Strip Detectors: A Detector Quality Control Protocol.

This work deals with the characteristics of highly segmented double-sided silicon detectors. These are fundamental parts in many new state-of-the-art particle detection systems, and therefore they must perform optimally. We propose a test bench that can handle 256 electronic channels with off-the-shelf equipment, as well as a detector quality control protocol to ensure that the detectors meet the requirements. Detectors with a large number of strips bring new technological challenges and issues that need to be carefully monitored and understood. One of the standard 500 µm thick detectors of the GRIT array was investigated, undergoing studies that revealed its IV curve, charge collection efficiency, and energy resolution. From the data obtained, we calculated, among other things, the depletion voltage (110 V), the resistivity of the bulk material (9 kΩ·cm), and the electronic noise contribution (8 keV). We present, for the first time, a methodology called "the energy triangle'' to visualize the effect of charge sharing between two adjacent strips and to study the hit distribution with the interstrip-to-strip hit ratio (ISR).

Discrimination of residents during neurosurgical training in Mexico: Results of a survey prior to SARS-CoV-2.

BACKGROUND: Recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic represents an important negative impact on global training of neurosurgery residents. Even before the pandemic, discrimination is a challenge that neurosurgical residents have consistently faced. In the present study, we evaluated discriminatory conditions experienced by residents during their neurosurgical training in Mexico before the SARS-CoV-2 pandemic. METHODS: An electronic survey of 18 questions was sent among residents registered in the Mexican Society of Neurological Surgery (MSNS), between October 2019 and July 2020. Statistical analysis was made in IBM SPSS Statistics 25. The survey focused on demographic characteristics, discrimination, personal satisfaction, and expectations of residents. RESULTS: A response rate of 50% (132 of 264 residents' members of MSNS) was obtained and considered for analysis. Median age was 30.06 ± 2.48 years, 5.3% (n = 7) were female and 16.7% (n = 22) were foreigners undergoing neurosurgical training in Mexico. Approximately 27% of respondents suffered any form of discrimination, mainly by place of origin (9.1%), by gender (8.3%) or by physical appearance (6.1%). About 42.9% (n = 3) of female residents were discriminated by gender versus 6.4% (n = 8) of male residents (P = 0.001); while foreign residents mentioned having suffered 10 times more an event of discrimination by place of origin compared to native Mexican residents (36.4% vs. 3.6%, P < 0.001). CONCLUSION: This manuscript represents the first approximation to determine the impact of discrimination suffered by residents undergoing neurosurgical training in Mexico before the SARS-CoV-2 pandemic.

Tumor de cavum: quiste de thornwaldt. Reporte de un caso / Cavum tumor: thornwaldt's cyst. Case report

El quiste de Thornwaldt es un tumor benigno de cavum, poco frecuente, generalmente asintomático, pero puede llegar a causar sintomatología significativa según su tamaño. Se genera a partir de un resto embrionario de la notocorda. Suele ser un hallazgo incidental en los estudios endoscópicos e imagenológicos y su tratamiento depende de su sintomatología. Presentamos el caso de una paciente de 27 años de edad quien acudió a nuestro servicio con sintomatología caracterizada por obstrucción nasal, rinolalia y disfagia de dos años de evolución, secundarios a una tumoración de cavum hallada en la faringoscopía, la cual requirió tratamiento quirúrgico para su resolución

Thornwaldt's cyst is a rare benign cavum tumor usually asymptomatic, but it can cause significant symptoms depending on its size. Its generated from an embryological rest of the notochord. It is usually an incidental finding in endoscopic and imaging studies and its treatment depends on the symptoms. We present the case of a 27-year-old female patient who came to our service with symp-toms characterized by nasal obstruction, rhinolalia and dysphagia of two years of evolution secondary to a cavum tumor found in pharyngoscopy, which required surgical treatment for resolution

Towards the Limits of Existence of Nuclear Structure: Observation and First Spectroscopy of the Isotope

The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: ^{31}K. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of ^{28}S+3p and the respective decay vertices. The energies of the previously unknown ground and excited states of ^{31}K have been determined. This provides its 3p separation energy value S_{3p} of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed ^{31}K states have been derived from distributions of the measured decay vertices.

An innovative bioresorbable gelatin based 3D scaffold that maintains the stemness of adipose tissue derived stem cells and the plasticity of differentiated neurons.

Neural tissue engineering aims at producing a simulated environment using a matrix that is suitable to grow specialized neurons/glial cells pertaining to CNS/PNS which replace damaged or lost tissues. The primary goal of this study is to design a compatible scaffold that supports the development of neural-lineage cells which aids in neural regeneration. The fabricated, freeze-dried scaffolds consisted of biocompatible, natural and synthetic polymers: gelatin and polyvinyl pyrrolidone. Physiochemical characterization was carried out using Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) imaging. The 3D construct retains good swelling proficiency and holds the integrated structure that supports cell adhesion and proliferation. The composite of PVP-gelatin is blended in such a way that it matches the mechanical strength of the brain tissue. The cytocompatibility analysis shows that the scaffolds are compatible and permissible for the growth of both stem cells as well as differentiated neurons. A change in the ratios of the scaffold components resulted in varied sizes of pores giving diverse surface morphology, greatly influencing the properties of the neurons. However, there is no change in stem cell properties. Different types of neurons are characterized by the type of gene associated with the neurotransmitter secreted by them. The change in the neuron properties could be attributed to neuroplasticity. The plasticity of the neurons was analyzed using quantitative gene expression studies. It has been observed that the gelatin-rich construct supports the prolonged proliferation of stem cells and multiple neurons along with their plasticity.

Fluctuations of conformational mobility of macromolecules around the glass transition.

The heterogeneity of local dynamics in disordered systems is behind some key features of glass transition. In order to improve our understanding of the molecular dynamics in disordered systems in the vicinity of the glass transition, different parameters have been proposed to quantitatively describe dynamical heterogeneity. In the case of polymers, free volume models relate the macromolecular mobility to the free or accessible volume. The relationship between dynamic heterogeneity and fluctuations of accessible volume seems straightforward. In the present work, the heterogeneity of local dynamics in polymeric systems is analyzed by computer simulation with the bond fluctuation model. The value of the accessible volume around each polymer chain is evaluated from a snapshot or static structure at each system state, resulting in a distribution of accessible volume that reflects system heterogeneity. The relationship between the average value and the standard deviation of free volume distributions at different temperatures fits a master curve for different systems, regardless of the specific inter- and intramolecular interaction potentials that define each material. The dynamic slowdown around the glass transition is accompanied by a clear evolution of the mean value and shape of the accessible free volume distribution. The relative fluctuation of the dynamically accessible volume has been used as a parameter to quantitatively describe heterogeneity. The fluctuation varies with temperature with remarkable differences between the liquid and glassy states of the systems studied, presenting a peak at the glass transition temperature, which can be interpreted as a reflection of the distribution of local glass transition temperatures.

Origin of enhancement in Raman scattering from Ag-dressed carbon-nanotube antennas: experiment and modelling.

The D- and G-band Raman signals from random arrays of vertically aligned, multi-walled carbon nanotubes are significantly enhanced (up to ∼14×) while the signal from the underlying Si substrate is simultaneously attenuated (up to ∼6×) when the nanotubes are dressed, either capped or coated, with Ag. These Ag-induced counter-changes originate with the difference in geometry of the nanotubes and planar Si substrate and contrast in the Ag depositions on the substrate (essentially thin film) and the nanotube (nano-particulate). The surface integral equation technique is used to perform detailed modelling of the electromagnetic response of the system in a computationally efficient manner. Within the modelling the overall antenna response of the Ag-dressed nanotubes is shown to underpin the main contribution to enhancement of the nanotube Raman signal with hot-spots between the Ag nanoparticles making a subsidiary contribution on account of their relatively weak penetration into the nanotube walls. Although additional hot-spot activity likely accounts for a shortfall in modelling relative to experiment it is nonetheless the case that the significant antenna-driven enhancement stands in marked contrast to the hot-spot dominated enhancement of the Raman spectra from molecules adsorbed on the same Ag-dressed structures. The Ag-dressing procedure for amplifying the nanotube Raman output not only allows for ready characterisation of individual nanotubes, but also evidences a small peak at ∼1150 cm-1 (not visible for the bare, undressed nanotube) which is suggested to be due to the presence of trans-polyacetylene in the structures.

Haemosporidian prevalence and parasitaemia in the Black-throated sparrow (Amphispiza bilineata) in central-Mexican dryland habitats.

To date it is not well-understood how seasonality and human-induced habitat change may affect haemosporidian prevalence and parasitaemia in bird hosts in dryland habitats. We compared haemosporidian prevalence and parasitaemia between habitat types, including Yucca-dominated scrublands (closed habitat) and creosotebush scrublands (open habitat), and between seasons, including non-breeding (dry) and breeding (wet) in the Black-throated sparrow (Amphispiza bilineata) at semi-arid scrublands of Central Mexico. This bird species has different habitat preferences in comparison to other, previously studied species in the region; it shows higher abundances in open than in closed habitats and avoids urban areas. Overall haemosporidian prevalence was 22.1%. Prevalence and parasitaemia were higher for Haemoproteus sp. (Parahaemoproteus sp.) than Plasmodium. Variation in haemoparasitism was not associated with habitat type. This response differs from the previously recorded response in other bird species in the region for which haemoparasitism increases with increasing habitat degradation. Seasonality seems to be the most important driver of parasite infection for this sparrow as prevalence and parasitaemia were higher during the breeding than the non-breeding season. Two new lineages of Haemoproteus sp. that had not been reported before in any avian species were found through molecular diagnosis. A high diversity of haemosporidian lineages is shared among sites. More study is needed to understand the mechanisms that associate parasitaemia, prevalence, and specific environmental factors.

Surface stiffening and enhanced photoluminescence of ion implanted cellulose - polyvinyl alcohol - silica composite.

Novel Cellulose (Cel) reinforced polyvinyl alcohol (PVA)-Silica (Si) composite which has good stability and in vitro degradation was prepared by lyophilization technique and implanted using N(3+) ions of energy 24keV in the fluences of 1×10(15), 5×10(15) and 1×10(16)ions/cm(2). SEM analysis revealed the formation of microstructures, and improved the surface roughness on ion implantation. In addition to these structural changes, the implantation significantly modified the luminescent, thermal and mechanical properties of the samples. The elastic modulus of the implanted samples has increased by about 50 times compared to the pristine which confirms that the stiffness of the sample surface has increased remarkably on ion implantation. The photoluminescence of the native cellulose has improved greatly due to defect site, dangling bonds and hydrogen passivation. Electric conductivity of the ion implanted samples was improved by about 25%. Hence, low energy ion implantation tunes the mechanical property, surface roughness and further induces the formation of nano structures. MG63 cells seeded onto the scaffolds reveals that with the increase in implantation fluence, the cell attachment, viability and proliferation have improved greatly compared to pristine. The enhancement of cell growth of about 59% was observed in the implanted samples compared to pristine. These properties will enable the scaffolds to be ideal for bone tissue engineering and imaging applications.

Increased Expression of Aquaporin 9 in Trophoblast From Gestational Diabetic Patients.

Gestational diabetes mellitus is the most frequent pathophysiological alteration in pregnancy, increasing the incidence of complications in both mother and fetus. The macrosomia that occurs in these fetuses may be related with some changes in nutrient transport mechanism in placenta. The presence of aquaporin 9, an aquaglyceroporin, has previously been demonstrated in placenta. We raised the question whether aquaporin 9 expression may be upregulated in placenta from gestational diabetes, thus providing a faster transport of glycerol and water through placenta. We studied 21 placentas (13 controls and 8 gestational diabetes) from cesarean delivery at term. The expression of aquaporin 9 was analyzed by quantitative PCR, immunoblot, and immunohistochemistry. The median values from quantitative PCR were compared by nonparametric tests for independent samples (Mann-Whitney U-test). We have found that trophoblast from gestational diabetes express higher amount of aquaporin 9, which was found statistically significant (p<0.05). The increase in aquaporin 9 expression was confirmed by immunoblot, and localization in the syncytiotrophoblast was checked by immunohistochemistry. The increase in aquaporin 9 expression in placenta from gestational diabetes may contribute to the higher transport rate in this pathology of pregnancy.

Validation in colorectal procedures of a useful novel approach for the use of C-reactive protein in postoperative infectious complications.

AIM: Our aim was to validate a novel use of C-reactive protein (CRP) measurement to identify postoperative infectious complications in patients undergoing colorectal surgery, and to compare the predictive value in this setting against white blood cell (WBC) count and neutrophil-to-lymphocyte ratio (NLR). METHOD: This was a retrospective study of CRP, NLR and WBC measurements in patients undergoing colorectal surgery. CRP, NLR and WBC were recorded on the second postoperative day and on the day of infectious complication (patients who developed infectious complications) or within 3 days prior to discharge (subjects with no complications). The test for detecting infectious complications consisted of comparing the value of the inflammatory marker on the day on which a complication was suspected against the value recorded on the second postoperative day. The test was considered positive if a given value was higher than the registered peak at postoperative day 2. Factors influencing the postoperative peak CRP were also studied. RESULTS: A total of 254 patients were retrospectively studied. Patients whose CRP value was higher than on the second postoperative day had a diagnostic accuracy for infectious complications of up to 94.4% and sensitivity, specificity, positive predictive value and negative predictive value of up to 97.4%, 93.4%, 85.7% and 99.1%, respectively. Poorer results were observed when WBC count and NLR were used rather than CRP measurement. Multiple linear regression analysis showed that surgical procedure and approach, as well as additional resections, were independent factors for 48 h peak CRP. CONCLUSION: C-reactive protein is a better parameter than WBC count and NLR for detecting infectious complications. Our proposed methodology presents good diagnostic accuracy and performance and could potentially be used for any surgical procedure.

Insulin and Leptin Signaling in Placenta from Gestational Diabetic Subjects.

Insulin and leptin receptors are known to share signaling pathways, such as JAK2/STAT-3 (Janus kinase2/signal transduction and activator of transcription3), MAPK (Mitogen activated protein kinase), and PI3K (phosphoinositide 3-kinase). Both positive and negative cross-talk have been previously found in different cellular systems. Gestational diabetes (GDM) is a pathophysiological state with high circulating levels of both insulin and leptin. We have previously found that these 3 signaling pathways are activated in placenta from GDM patients to promote translation, involving the activation of leptin receptor. Now, we have tested the hypothesis that both leptin and insulin receptors might contribute to this activation in a positive way that may become negative when the system is overactivated. We studied the activation of leptin and insulin receptors in placenta from GDM and healthy pregnancies. We have also performed in vitro studies with insulin and leptin stimulation of trophoblast explants from healthy placenta. We have found that both leptin and insulin receptors are activated in placenta from GDM. In vitro stimulation of trophoblast explants with both leptin and insulin at submaximal doses (0.1 nM) potentiated the activation of signaling, whereas preincubation with maximal concentrations of insulin (10 nM) and further stimulation with leptin showed negative effect. Trophoblastic explants from GDM placenta, which presented high signaling levels, had a negative signaling effect when further incubated in vitro with leptin. In conclusion, insulin and leptin receptors have positive effects on signaling, contributing to high signaling levels in GDM placenta, but insulin and leptin have negative effects upon overstimulation.

[Outcome of posterior anorectal myectomy for the treatment of idiopathic chronic constipation]. / Resultados de la miectomía anorrectal posterior en el tratamiento del estreñimiento crónico idiopático.

OBJECIVES: The aim of this study is to assess the outcome of surgery (Lynn's myectomy) in patients with chronic persistent constipation and failure of medical treatment. MATERIAL AND METHODS: Descriptive study of patients with severe chronic constipation treated by posterior anorectal myectomy (Lynn's technique). We report data from the last 15 years, with a minimum postoperative follow-up of one year. Patients included in the study suffered from a long-term constipation refractory to medical management. Data regarding contrast enema, anorectal manometry and rectal biopsy were recorded. The procedure's outcome is classified following clinical criteria: Asymptomatic: >3 bowel movements per week, with no soiling/incontinence and with no medical treatment; Improvement: >3 bowel movements per week, with no soiling/incontinence but using laxatives occasionally. RESULTS: Nineteen myectomies were performed (median age of 8.47 years). Median time of constipation before surgery was 7.89 years. Rectal biopsy findings: 10 with ganglion cells, 4 without ganglion cells and other abnormalities in 5. Anorectal manometry was performed in 6 patients, 4 presented rectoanal inhibitory reflex. Four patients were diagnosed of Hirschsprung's disease (1 was asymptomatic after myectomy, 2 needed further surgery and 1 was lost in follow-up). Of the remaining 15 patients, 8 were asymptomatic (53.3%), 4 experienced improvement (26.6%) and 1 without clinical changes is on pelvic floor physiotherapy. Two were lost in follow-up. There were no other postoperative complications after long term follow-up. CONCLUSIONS: Lynn's myectomy is an effective and safe procedure in patients suffering from persistent chronic constipation despite of medical treatment. It is also the definitive treatment for patients with ultrashort-segment Hirschsprung's disease.

OBJETIVO: Evaluar los resultados clínicos del tratamiento quirúrgico de pacientes con estreñimiento crónico incontrolable con tratamiento médico. MATERIAL Y METODOS: Estudio descriptivo de pacientes con estreñimiento crónico severo tratados mediante miectomía anorrectal posterior (técnica de Lynn). Se recogen los resultados de los últimos 15 años, con periodo de seguimiento postoperatorio mínimo de 1 año. Se incluyen pacientes con larga historia de estreñimiento, refractarios a tratamiento médico. Pruebas complementarias: enema opaco, manometría anorrectal y biopsias rectales. El resultado clínico de la técnica se clasifica según los siguientes criterios: Curación: >3 movimientos intestinales por semana, sin incontinencia/encopresis y sin necesidad de tratamiento médico; Mejoría: >3 movimientos intestinales por semana, sin incontinencia/encopresis y con necesidad de laxante. RESULTADOS: Se realizaron 19 miectomías (edad media de 8,47 años). Tiempo medio de estreñimiento previo de 7,89 años. Los hallazgos en la anatomía patológica fueron: presencia de células ganglionares en 10, ausencia de células ganglionares en 4 y otras alteraciones en 5. Manometría en 6 pacientes, 4 presentaron reflejo inhibitorio anal. Cuatro pacientes se diagnosticaron de enfermedad de Hirschsprung (uno se curó con la miectomía, dos precisaron cirugía correctora y uno no acudió a revisiones). En los 15 restantes, cumplieron criterios de curación 8 pacientes (53,3%), 4 mejoraron (26,6%), 1 sin mejoría sigue tratamiento fisioterápico. Dos pacientes no continuaron las revisiones. No se registró incontinencia fecal ni otras complicaciones. CONCLUSIONES: La miectomía de Lynn es un procedimiento eficaz y seguro para los pacientes con estreñimiento crónico severo refractario al tratamiento médico. También resulta el tratamiento definitivo en la enfermedad de Hirschsprung de segmento ultracorto.

Diamond detector for alpha-particle spectrometry.

An artificially grown high purity diamond was used as a detector for alpha-particle spectrometry. Diamond detectors can match the performance of silicon detectors employed in standard continuous air monitoring systems. Its radiation hardness and electronic properties make them ideal to work under extreme condition such as high temperature and ambient lights. A 50 µm thickness single-crystal diamond detector has been compared with a 300 µm passivated implanted planar silicon detector, under ambient conditions.