Changes in air quality in Mexico City, London and Delhi in response to various stages and levels of lockdowns and easing of restrictions during COVID-19 pandemic.

The impacts of COVID-19 lockdown restrictions have provided a valuable global experiment into the extent of improvements in air quality possible with reductions in vehicle movements. Mexico City, London and Delhi all share the problem of air quality failing WHO guideline limits, each with unique situations and influencing factors. We determine, discuss and compare the air quality changes across these cities during the COVID-19, to understand how the findings may support future improvements in their air quality and associated health of citizens. We analysed ground-level PM10, PM2.5, NO2, O3 and CO changes in each city for the period 1st January to August 31, 2020 under different phases of lockdown, with respect to daily average concentrations over the same period for 2017 to 2019. We found major reductions in PM10, PM2.5, NO2 and CO across the three cities for the lockdown phases and increases in O3 in London and Mexico City but not Delhi. The differences were due to the O3 production criteria across the cities, for Delhi production depends on the VOC-limited photochemical regime. Levels of reductions were commensurate with the degree of lockdown. In Mexico City, the greatest reduction in measured concentration was in CO in the initial lockdown phase (40%), in London the greatest decrease was for NO2 in the later part of the lockdown (49%), and in Delhi the greatest decrease was in PM10, and PM2.5 in the initial lockdown phase (61% and 50%, respectively). Reduction in pollutant concentrations agreed with reductions in vehicle movements. In the initial lockdown phase vehicle movements reduced by up to 59% in Mexico City and 63% in London. The cities demonstrated a range of air quality changes in their differing geographical areas and land use types. Local meteorology and pollution events, such as forest fires, also impacted the results.

Therapy with ombitasvir/paritaprevir/ritonavir plus dasabuvir is effective and safe for the treatment of genotypes 1 and 4 hepatitis C virus (HCV) infection in patients with severe renal impairment: A multicentre experience.

Limited data are available on direct-acting antivirals for treating hepatitis C virus (HCV) infection in patients with severe renal impairment. The aim of this study was to evaluate the effectiveness and safety of ombitasvir/paritaprevir/ritonavir (OBV/PTV/r) ± dasabuvir (DSV) ± ribavirin (RBV) in patients with stage 4 or 5 chronic kidney disease (CKD) and HCV genotype 1 or 4 infection in real clinical practice, and to investigate pharmacological interactions. This retrospective study included patients treated with OBV/PTV/r+DSV±RBV or OBV/PTV/r+RBV with CKD stage 4 (eGFR: 15-29 mL/min/1.73m2 ) or 5 (eGFR<15 mL/min/1.73m2 or requiring dialysis) and HCV infection by genotypes 1 and 4 between April 2015 and October 2015 in nine Spanish centres. Sustained virological response at 12 weeks (SVR12) was assessed, and clinical and laboratory data, fibrosis stage, adverse events and pharmacological interactions were reported. Forty-six patients were included: 10 (21.7%) had CKD stage 4 and 36 (78.2%) CKD stage 5. Seventeen (36.9%) had cirrhosis. SVR12 rate in the intention-to-treat population was 95.7%. Twenty-one (45.6%) received RBV, which was discontinued in two (9.5%) patients. Anaemia (haemoglobin <10 g/dl) occurred in 12 patients (57.1%) with RBV vs 10 (40.0%) without RBV (P=.246). Renal function remained stable during antiviral therapy. Nine patients (19.5%) experienced serious adverse events unrelated to antiviral therapy. Concomitant medication was discontinued or modified in 41.3% of patients. In conclusion, the effectiveness of OBV/PTV/r±DSV±RBV in patients with CKD 4-5 was similar to that observed in those with normal renal function and was not associated with severe adverse events.

Hemorragia posparto y ascariasis: presentación de un caso / Postpartum hemorrhage and ascariasis: a case reporte

Resumen La hemorragia posparto es una de las principales complicaciones maternas que genera morbimortalidad. Se asocia diversas causas, como atonía uterina, retención de restos placentarios y coagulopatías. Una poco conocida es la infección por Ascarislumbricoides. Se realiza la revisión de un caso clínico de paciente de 16 años de edad, que evolucionó a histerectomía secundaria a ascariasis y muerte materna, que ingresó al Servicio de Urgencias Obstétricas del Hospital de la Universidad del Norte. Según nuestro conocimiento, es el primer caso descrito en nuestro país en el que se sospecha la asociación de hemorragia posparto y la infección por Ascarislumbricoides.

Abstract Postpartum hemorrhage is one of the most important obstetrical complications, having a high morbidity and mortality rate. It is associated to different causes such as uterine atony, placental birth alterations, and coagulopathy. One not so well-known cause is the infestation with the parasite Ascarislumbricoides. We report a case of a 16-year-old patient who required an emergency postpartum hysterectomy until progressing to death due to ascariasis. To our current knowledge, this is the first reported case in Colombia where there is a suspected association between the infestation with Ascarislumbricoides and postpartum hemorrhage.

Live attenuated malaria vaccine designed to protect through hepatic CD8⁺ T cell immunity.

Our goal is to develop a vaccine that sustainably prevents Plasmodium falciparum (Pf) malaria in ≥80% of recipients. Pf sporozoites (PfSPZ) administered by mosquito bites are the only immunogens shown to induce such protection in humans. Such protection is thought to be mediated by CD8(+) T cells in the liver that secrete interferon-γ (IFN-γ). We report that purified irradiated PfSPZ administered to 80 volunteers by needle inoculation in the skin was safe, but suboptimally immunogenic and protective. Animal studies demonstrated that intravenous immunization was critical for inducing a high frequency of PfSPZ-specific CD8(+), IFN-γ-producing T cells in the liver (nonhuman primates, mice) and conferring protection (mice). Our results suggest that intravenous administration of this vaccine will lead to the prevention of infection with Pf malaria.

Discriminability measures for predicting readability of text on textured backgrounds.

Several discriminability measures were examined for their ability to predict reading search times for three levels of text contrast and a range of backgrounds (plain, a periodic texture, and four spatial-frequency-filtered textures created from the periodic texture). Search times indicate that these background variations only affect readability when the text contrast is low, and that spatial frequency content of the background affects readability. These results were not well predicted by the single variables of text contrast (Spearman rank correlation = -0.64) and background RMS contrast (0.08), but a global masking index and a spatial-frequency-selective masking index led to better predictions (-0.84 and -0.81, respectively).

Detection in fixed and random noise in foveal and parafoveal vision explained by template learning.

Foveal and parafoveal contrast detection thresholds for Gabor and checkerboard targets were measured in white noise by means of a two-interval forced-choice paradigm. Two white-noise conditions were used: fixed and twin. In the fixed noise condition a single noise sample was presented in both intervals of all the trials. In the twin noise condition the same noise sample was used in the two intervals of a trial, but a new sample was generated for each trial. Fixed noise conditions usually resulted in lower thresholds than twin noise. Template learning models are presented that attribute this advantage of fixed over twin noise either to fixed memory templates' reducing uncertainty by incorporation of the noise or to the introduction, by the learning process itself, of more variability in the twin noise condition. Quantitative predictions of the template learning process show that it contributes to the accelerating nonlinear increase in performance with signal amplitude at low signal-to-noise ratios.

The Zn(II) binding motifs of E. coli DNA topoisomerase I is part of a high-affinity DNA binding domain.

Escherichia coli DNA topoisomerase I binds three Zn(II) with three tetracysteine motifs. Three subclones containing these tetracysteine motifs were expressed and purified. Subclone ZD1 contained the minimal tetracysteine motifs sequence. A larger subclone ZD2 corresponded to a region bordered by two protease sensitive sites. Subclone ZD3 also included the 14-kDa C-terminal domain that has been shown to bind DNA. Subclones ZD1 and ZD2 were found to bind one and two Zn(II), respectively, and neither had detectable DNA binding activity. ZD3 could bind three Zn(II) and had higher DNA binding affinity than the 14-kDa C-terminal domain. The complex formed between ZD3 and a single-stranded 31mer could be detected by the gel shift assay while the complex formed by the 14-kDa C-terminal domain was not stable under gel electrophoresis conditions. The three Zn(II) binding motifs appeared to be part of a high-affinity DNA binding domain.

Devenir de embarazos expuestos inadvertidamente a análogos de GnRH durante programas de fertilización asistida / Background of inadvertently exposed pregnancies to GnRH analogs during assisted fertilization program

El embarazo precoz expuesto inadvertidamente a agonistas de GnRH constituye un cuadro clínico poco frecuente en la práctica ginecoobstétrica, su presentación corresponde a un 1 por ciento de los ciclos de pacientes tratadas por problemas de infertilidad mediante fertilización asistida. El objetivo de la presente comunicación es el relato de 4 casos de pacientes que participaron en el programa de fertilización asistida del Hospital Clínico San Borja Arriarán y que embarazaron en forma espontánea durante la fase lútea en la cual comenzó la desensibilización hipofisiaria con análogos de GnRH. De los casos observados, 2 presentaron un embarazo ectópico que fue corregido quirúrgicamente y dos cursaron con embarazos de evolución normal

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise.

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

Image discrimination models predict detection in fixed but not random noise.

By means of a two-interval forced-choice procedure, contrast detection thresholds for an aircraft positioned on a simulated airport runway scene were measured with fixed and random white-noise masks. The term fixed noise refers to a constant, or unchanging, noise pattern for each stimulus presentation. The random noise was either the same or different in the two intervals. Contrary to simple image discrimination model predictions, the same random noise condition produced greater masking than the fixed noise. This suggests that observers seem unable to hold a new noisy image for comparison. Also, performance appeared limited by internal process variability rather than by external noise variability, since similar masking was obtained for both random noise types.

Object detection in natural backgrounds predicted by discrimination performance and models.

Many models of visual performance predict image discriminability, the visibility of the difference between a pair of images. We compared the ability of three image discrimination models to predict the detectability of objects embedded in natural backgrounds. The three models were: a multiple channel Cortex transform model with within-channel masking; a single channel contrast sensitivity filter model; and a digital image difference metric. Each model used a Minkowski distance metric (generalized vector magnitude) to summate absolute differences between the background and object plus background images. For each model, this summation was implemented with three different exponents: 2, 4 and infinity. In addition, each combination of model and summation exponent was implemented with and without a simple contrast gain factor. The model outputs were compared to measures of object detectability obtained from 19 observers. Among the models without the contrast gain factor, the multiple channel model with a summation exponent of 4 performed best, predicting the pattern of observer d's with an RMS error of 2.3 dB. The contrast gain factor improved the predictions of all three models for all three exponents. With the factor, the best exponent was 4 for all three models, and their prediction errors were near 1 dB. These results demonstrate that image discrimination models can predict the relative detectability of objects in natural scenes.

Desarrollo y validación de una encuesta para evaluar la satisfacción de los pacientes con la consulta médica en consultorios de atención primaria / Development and validation of a survey to assess patients satisfaction with medical consultation in primary health care

Te aim of this work was to devise and assess the reliability of an instrument to measure satisfaction with medical consultation of primary care urban patients at public outpatients clinics. A model was elaborated, based on data collected from the literature and from focal groups of patients and physicians and an enquiry was developed and applied at four outpatient clinics. Fifty enquires were obtained and analyzed to discard questions of difficult understanding. Next, a second self administered questionnaire and with fewer questions was devised. Its reliability was assessed in 53 enquires, obtaining a Cronbach's of 0.904. Questions that decreased consistency were discared, finally obtaining a self administered instrument with analysis with varimax rotation, which separated three factors that explain 64 percent of the variance. It is concluded that a valid and reliable instrument was obtained

Expression and DNA-binding properties of the 14K carboxyl terminal fragment of Escherichia coli DNA topoisomerase I.

DNA sequence coding for the last 121 amino acids of Escherichia coli topoisomerase I was synthesized by PCR and cloned into a plasmid under the control of the T7 promoter. Induction of T7 RNA polymerase in E. coli carrying the plasmid clone resulted in over-expression of this C-terminal domain fragment previously shown to confer higher DNA binding affinity to the enzyme. Purification to homogeneity was achieved by phosphocellulose and single-stranded DNA agaraose chromatography. Direct interaction between this 14K domain and poly(dA) was demonstrated by UV spectroscopy. Noncovalent complexes formed between this fragment and oligo(dT) 8 and oligo(dT) 16 can also be trapped by photo-crosslinking.

A new microassay for the determination of alkaline phosphatase activity in early mouse concepti.

A new enzymatic assay for the determination of alkaline phosphatase (APase) activity in preimplantation mouse concepti is described. This method allows estimation of APase activity of concepti extracts using the fluorogenic substrate, 3,6-fluorescein diphosphate (FDP). For measuring APase activity, 0.1% Nonidet P-40 was used to solubilize the enzyme. Control assays showed that this procedure does not modify the enzyme activity. According to the Km obtained for APase from mouse concepti (between 1-2 microM), the initial concentration of FDP was 20 microM, which is 10 fold the Km. The assay sensitivity allows continuous recording of the product generated and a reliable determination in less than 20 min. Results show that APase activity in mouse concepti may be detected from the 2-cell stage, increasing exponentially towards the blastocyst stage.