Economic evaluations in cataract surgery: a narrative review.

Economic evaluations are tools for assessing emerging technologies and a complement for decision-making in healthcare systems. However, this topic may not be familiar for doctors and academics, who may be confused when interpreting the results of studies using these tools. Cataract is a disease which has received special attention in healthcare systems due to its high incidence, the great impact that it could have on patients' quality of life, and the fact that it can be definitively solved in almost all cases through cataract surgery. Historically, economic evaluations in cataract surgery have been conducted for many purposes by simply assessing whether the surgery is cost-effective for specific questions related to the implantation of multifocal intraocular lenses, surgical techniques, optimizing assessments, preventing diseases or complications, etc. Moreover, although there are systematic reviews about cataract surgery and narrative reviews introducing the concept of economic evaluations, as far as we know, no previous study has been conducted that synthesizes and integrates evidence coming from both fields. Thus, the purpose of this narrative review is to introduce doctors and academics to economic evaluation tools, to describe how these have been historically applied to cataract surgery, and to provide special considerations for the correct interpretation of economic studies.

Experiencing short heat waves early in development changes thermal responsiveness of turtle embryos to later heat waves.

Although physiological responses to the thermal environment are most frequently investigated using constant temperatures, the incorporation of thermal variability can allow for a more accurate prediction of how thermally sensitive species respond to a rapidly changing climate. In species with temperature-dependent sex determination (TSD), developmental responses to incubation temperature are mediated by several genes involved in gonadal differentiation. Kdm6b and Dmrt1 respond to cool incubation temperatures and are associated with testis development, while FoxL2 and Cyp19A1 respond to warm incubation temperatures and are associated with ovary development. Using fluctuating incubation temperatures, we designed two studies, one investigating how conflicting thermal cues affect the timing of commitment to gonadal development, and another investigating the rapid molecular responses to conflicting thermal cues in the red-eared slider turtle (Trachemys scripta). Using gene expression as a proxy of timing of commitment to gonadal fate, results from the first study show that exposure to high amounts of conflicting thermal cues during development delays commitment to gonadal fate. Results from the second study show that Kdm6b splice variants exhibit differential responses to early heat wave exposure, but rapidly (within 2 days) recover to pre-exposure levels after the heat wave. Despite changes in the expression of Kdm6b splice variants, there was no effect on Dmrt1 expression. Collectively, these findings demonstrate how short exposures to heat early in development can change how embryos respond to heat later in development.

Temporal Changes in Racial and Ethnic Disparities in the Utilization of Left Atrial Appendage Occlusion in the United States.

Racial and ethnic disparities in the access to left atrial appendage occlusion (LAAO) have been previously described. However, it remains unclear if there have been any changes in these disparities over the years and if the disparities include other racial and ethnic groups not previously studied. We aimed to determine the temporal evolution of the racial and ethnic disparities in the utilization of LAAO from 2016 to 2019. We conducted a retrospective cohort study using the National Inpatient Sample from 2016 to 2019. International Classification of Diseases, 10th edition codes were used to identify all adult admissions with atrial fibrillation (AF) and those who underwent LAAO. The sample was divided into Asian American and Pacific Islander, Black, Hispanic, White, and other races/ethnicities. Our primary outcome was the utilization of LAAO in patients admitted with a diagnosis of AF. The Cochran-Armitage test was conducted to evaluate the yearly trend in LAAO utilization stratified by race/ethnicity. Multivariable regression analysis was conducted to assess the association of race/ethnicity with multiple end points. A total of 59,415 patients underwent LAAO. The highest yearly increase in LAAO utilization was seen in White patients (trend: 0.16%, p <0.001). Furthermore, compared with White patients, the yearly increase in LAAO utilization was lower in all other racial/ethnic groups. Black patients had the lowest odds of who underwent LAAO (odds ratio = 0.45, 95% confidence interval 0.40 to 0.50, p <0.001). In conclusion, significant gaps exist in the utilization of LAAO between racial and ethnic groups, and they appear to continue worsening from 2016 to 2019.

The uncharacterized Pseudomonas aeruginosa PA4189 is a novel and efficient aminoacetaldehyde dehydrogenase.

Neither the Pseudomonas aeruginosa aldehyde dehydrogenase encoded by the PA4189 gene nor its ortholog proteins have been biochemically or structurally characterized and their physiological function is unknown. We cloned the PA4189 gene, obtained the PA4189 recombinant protein, and studied its structure-function relationships. PA4189 is an NAD+-dependent aminoaldehyde dehydrogenase highly efficient with protonated aminoacetaldehyde and 3-aminopropionaldehyde, which are much more preferred to the non-protonated species as indicated by pH studies. Based on the higher activity with aminoacetaldehyde than with 3-aminopropionaldehyde, we propose that aminoacetaldehyde might be the PA4189 physiological substrate. Even though at the physiological pH of P. aeruginosa cells the non-protonated aminoacetaldehyde species will be predominant, and despite the competition of these species with the protonated ones, PA4189 would very efficiently oxidize ACTAL in vivo, producing glycine. To our knowledge, PA4189 is the first reported enzyme that might metabolize ACTAL, which is considered a dead-end metabolite because its consuming reactions are unknown. The PA4189 crystal structure reported here suggested that the charge and size of the active-site residue Glu457, which narrows the aldehyde-entrance tunnel, greatly define the specificity for small positively charged aldehydes, as confirmed by the kinetics of the E457G and E457Q variants. Glu457 and the residues that determine Glu457 conformation inside the active site are conserved in the PA4189 orthologs, which we only found in proteobacteria species. Also is conserved the PA4189 genomic neighborhood, which suggests that PA4189 participates in an uncharacterized metabolic pathway. Our results open the door to future efforts to characterize this pathway.

Trends and In-Hospital Outcomes of Patients With Baseline Right Bundle Branch Block Who Underwent Transcatheter Aortic Valve Implantation.

This study aimed to explore contemporary in-hospital outcomes and trends of transcatheter aortic valve implantation (TAVI) outcomes in patients with baseline right bundle branch block (RBBB) using data collected from a nationwide sample. Using the National Inpatient Sample, we identified patients hospitalized for an index TAVI procedure from 2016 to 2019. Primary outcomes included in-hospital all-cause mortality, complete heart block, and permanent pacemaker (PPM) implantation. A total of 199,895 hospitalizations for TAVI were identified. RBBB was present in 10,495 cases (5.3%). Patients with RBBB were older (median age 81 vs 80 years, p <0.001) and less likely to be female (35% vs 47.4%, p <0.001). After adjusting for differences in baseline characteristics and elective versus nonelective admission, patients with RBBB had a higher incidence of complete heart block (adjusted odds ratio [aOR] 4.77, confidence interval [CI] 4.55 to 5.01, p <0.001) and PPM implantation (aOR 4.15, CI 3.95 to 4.35, p <0.001) and no difference in-hospital mortality rate (aOR 0.85, CI 0.69 to 1.05, p = 0.137). Between 2016 and 2019, there was a 3.5% and 2.9% decrease in in-hospital PPM implantation in patients with and without RBBB, respectively. In conclusion, from 2016 to 2019, the rate of in-hospital PPM implantation decreased during index TAVI hospitalization in both patients with and without RBBB. However, in those with baseline RBBB, complete heart block complication rates requiring PPM implantation remain relatively high. Further research and advances are needed to continue to reduce complication rates and the need for PPM implantation.

Impact of left bundle branch block in Takotsubo Syndrome.

Background: Left bundle branch block (LBBB) causes left ventricular dyssynchrony, and its presence with concomitant left ventricular dysfunction has been proven to play a synergistic role, worsening ventricular function. Our study seeks to further explore the association between LBBB and various in-hospital outcomes in patients with takotsubo syndrome (TTS). Methods: The national inpatient sample was queried from 2016 to 2019 to identify all admissions with a primary diagnosis of TTS. International classification of diseases, tenth revision codes were used to divide patients based on the presence or absence of LBBB. Multivariate regression analysis was performed to assess the effect of LBBB among all the pre-specified outcomes. Results: A total of 26,615 admissions were included in the analysis. Admissions with LBBB were more likely to be older (72.2 vs. 66.2 years) and have a higher burden of comorbidities. The presence of a LBBB was associated with ventricular arrhythmias (OR = 1.97, 95% CI 1.08-3.61, p = 0.028) but not with sudden cardiac arrest (SCA), acute heart failure, cardiogenic shock, and all-cause intra-hospital mortality. Conclusions: Intraventricular dyssynchrony appears to play a significant role in ventricular arrhythmogenesis and SCA, as several trials have demonstrated that cardiac resynchronization therapy alone without defibrillator function reduces the rate of ventricular arrhythmias and SCA in patients with heart failure with systolic dysfunction and a widened QRS complex. The most likely mechanism of arrhythmia development in TTS is related to the elevated plasma levels of catecholamines and their proarrhythmic effects in the ventricular myocardium.

Relación entre los niveles basales de fructosamina y glucosa en adultos mayores / Relationship between basal levels of fructosamine and glucose in older adults

INTRODUCCIÓN: los cambios fisiológicos a los que están expuestos los adultos mayores, son muchas veces factores negativos en su calidad de vida, sobre todo en aquellos que se encuentran en residencias geriátricas, existen parámetros como la glicemia y hemoglobina glucosilada que podrían ser útiles en el control metabólico. OBJETIVO: relacionar los niveles basales de Fructosamina y Glucosa en adultos mayores institucionalizados en residencias geriátricas del municipio de Tiquipaya, septiembre 2019. METODOLOGÍA: estudio no experimental, observacional, prospectivo, transversal, con enfoque de análisis positivista cuantitativo, con un universo de 97 adultos mayores de 65 años, con una muestra de 79 que cumplen con los criterios de inclusión y exclusión, con un 4,77% de error máximo aceptable. RESULTADOS: el 71% (n=56) de los pacientes fueron mujeres. Los ancianos predominaron como grupo etario. Se evidenció que no hay una buena concordancia entre los niveles basales de Glicemia y Fructosamina, mediante el cálculo estadístico del índice de Kappa que fue de 0,023; Test de Wilcoxon 0.081; Test correlación Pearson r=0.281. Los niveles basales de Fructosamina tienen una sensibilidad y especificidad altas del 82,14% (L.I. 62,42% -L.S. 93,23%) y 56.92% (L.I. 47,95% - L.S. 65,48%), respectivamente. CONCLUSIONES: no existe relación entre los niveles basales de Glucosa y la Fructosamina puesto que son parámetros de evaluación metabólica en diferente tiempo y una no remplaza la otra, por lo tanto, se debería implementar adicionalmente a la Glucosa la determinación de la Fructosamina para monitorizar a los pacientes adultos a mediano plazo.

INTRODUCTION: the physiological changes to which older adults are exposed; are many times negative factors in their quality of life, especially in those who are in geriatric residences. Glycemia and glycosylated hemoglobin are useful as metabolic control parameters. OBJECTIVE: to relate the basal levels of Fructosamine and Glucose in institutionalized older adults in geriatric residences in the municipality of Tiquipaya, September 2019. METHODOLOGY: non-experimental, observational, prospective, cross-sectional study, with a quantitative positivist analysis approach, with a universe of 97 adults over 65 years of age, with a sample of 79 that met the inclusion and exclusion criteria, with a maximum acceptable error of 4.77%. RESULTS: 71% (n=56) of the patients were female. The elderly dominated as an age group. It was evidenced that there is not a good agreement between basal levels of Glycemia and Fructosamine, through the statistical calculation of the Kappa index which was 0.023; Wilcoxon test 0.081; Pearson correlation test r= 0.281. The basal levels of Fructosamine have a high sensitivity and specificity of 82.14% (L.I. 62.42% - L.S. 93.23%) and 56.92% (L.I.47.95% - L.S. 65.48%), respectively. CONCLUSIONS: there is no relationship between basal levels of Glucose and Fructosamine since they are parameters of metabolic evaluation in different time and one does not replace the other, therefore, the determination of Fructosamine should be implemented in addition to Glucose to monitor adult patients in the medium term.

Temperature fluctuations and estrone sulfate affect gene expression via different mechanisms to promote female development in a species with temperature-dependent sex determination.

Variation in developmental conditions can affect a variety of embryonic processes and shape a number of phenotypic characteristics that can affect offspring throughout their lives. This is particularly true of oviparous species where development typically occurs outside of the female, and studies have shown that traits such as survival and behavior can be altered by both temperature and exposure to steroid hormones during development. In species with temperature-dependent sex determination (TSD), the fate of gonadal development can be affected by temperature and by maternal estrogens present in the egg at oviposition, and there is evidence that these factors can affect gene expression patterns. Here, we explored how thermal fluctuations and exposure to an estrogen metabolite, estrone sulfate, affect the expression of several genes known to be involved in sexual differentiation: Kdm6b, Dmrt1, Sox9, FoxL2 and Cyp19A1. We found that most of the genes responded to both temperature and estrone sulfate exposure, but that the responses to these factors were not identical, in that estrone sulfate effects occur downstream of temperature effects. Our findings demonstrate that conjugated hormones such as estrone sulfate are capable of influencing temperature-dependent pathways to potentially alter how embryos respond to temperature, and highlight the importance of studying the interaction of maternal hormone and temperature effects.

Vascular aging in the young: New carotid stiffness centiles and association with general and abdominal obesity - The KIGGS cohort.

BACKGROUND AND AIMS: The evidence for an association between obesity and increased carotid intima-media thickness (CIMT) and carotid stiffness (CS) in the young has been limited by methodological challenges related to study populations, measurements, methods of percentile derivation and comprehensiveness of obesity markers investigated. This nationwide general population study developed new CS and CIMT centiles in the young and used them to study associations with body mass index, waist circumference, waist-to-height-ratio, bioimpedance-derived absolute and relative fat mass, fat-free mass, subscapular skinfold thickness and blood pressure. METHODS: In its 11-year follow-up, the KiGGS cohort, which is based on a nationally representative sample, included semi-automated state-of-the-art sonographic CIMT and CS measurements in 4,709 participants aged 14 to 28. Distensibility coefficient (DC), stiffness index ß, Young's elastic modulus (YEM) and Peterson's elastic modulus (Ep) centiles were modelled by sex, age and height simultaneously. RESULTS: CS increased with age in both sexes, and young men had stiffer arteries than young women at all ages. All obesity measures at baseline and at follow-up, except for subscapular skinfold thickness, were positively associated with several CS parameters with moderate relative risks (RR), e.g. cross-sectional RR 2.23 (95% CI 1.26-3.93) for DC ≥ 90th percentile when waist circumference ≥90th percentile; RR 5.98 (3.38-10.56) for elevated DC associated with simultaneously elevated waist circumference and BP. CONCLUSIONS: These new state-of-the-art CS percentiles show consistent associations of obesity with CS in the young and support primary prevention efforts starting at a young age.

Improvements in the radiochemical method for separating 226Ra in solid samples through coprecipitation with BaSO4.

The aim of this work was to improve the commonly used method for 226Ra determination in water and to establish its application in solid samples. This method is based on the coprecipitation of Ra with BaSO4 and gross alpha counting of the precipitate. An exhaustive study of the coprecipitation behaviour of the most abundant cations present in solid samples was performed to avoid incorrect radiochemical yields. As a result, it was considered necessary to introduce two new purification steps into the conventional method. Likewise, two nuclides, 241Am and 226Ra, were compared to obtain the mass efficiency curve given their different behaviour in the coprecipitation process. While Ra behaves similarly to Ba, Am coprecipitates, forming mixed crystals that may behave differently in the self-absorption process. The influence of the cations on the chemical yield with no precipitate purification was: Sr2+≫Fe3+>Mg2+≈Ca2+>K+≈Na+. The method was successfully applied to soil, sediment, and plant ash samples.

Noncompliance to iodine supplementation recommendation is a risk factor for iodine insufficiency in Portuguese pregnant women: results from the IoMum cohort.

PURPOSE: After a recommendation for iodine supplementation in pregnancy has been issued in 2013 in Portugal, there were no studies covering iodine status in pregnancy in the country. The aim of this study was to assess iodine status in pregnant women in Porto region and its association with iodine supplementation. METHODS: A cross-sectional study was conducted at Centro Hospitalar Universitário São João, Porto, from April 2018 to April 2019. Pregnant women attending the 1st trimester ultrasound scan were invited to participate. Exclusion criteria were levothyroxine use, gestational age < 10 and ≥ 14 weeks, non-evolutive pregnancy at recruitment and non-signing of informed consent. Urinary iodine concentration (UIC) was measured in random spot urine by inductively coupled plasma-mass spectrometry. RESULTS: Median UIC was 104 µg/L (IQR 62-189) in the overall population (n = 481) of which 19% had UIC < 50 µg/L. Forty three percent (n = 206) were not taking an iodine-containing supplement (ICS) and median UIC values were 146 µg/L (IQR 81-260) and 74 µg/L (IQR 42-113) in ICS users and non-users, respectively (p < 0.001). Not using an ICS was an independent risk factor for iodine insufficiency [adjusted OR (95% CI) = 6.00 (2.74, 13.16); p < 0.001]. Iodised salt use was associated with increased median iodine-to-creatinine ratio (p < 0.014). CONCLUSIONS: A low compliance to iodine supplementation recommendation in pregnancy accounted for a mild-to-moderately iodine deficiency. Our results evidence the need to support iodine supplementation among pregnant women in countries with low household coverage of iodised salt. Trial registration number NCT04010708, registered on the 8th July 2019.

Understanding how variable thermal environments affect the molecular mechanisms underlying temperature-sensitive phenotypes: lessons from sex determination.

The thermal environment that organisms experience can affect many aspects of their phenotype. As global temperatures become more unpredictable, it is imperative that we understand the molecular mechanisms by which organisms respond to variable, and often transient, thermal environments. Beyond deciphering the mechanisms through which organisms respond to temperature, we must also appreciate the underlying variation in temperature-dependent processes, as this variation is essential for understanding the potential to adapt to changing climates. In this Commentary, we use temperature-dependent sex determination as an example to explore the mechanistic processes underlying the development of temperature-sensitive phenotypes. We synthesize the current literature on how variable thermal conditions affect these processes and address factors that may limit or allow organisms to respond to variable environments. From these examples, we posit a framework for how the field might move forward in a more systematic way to address three key questions: (1) which genes directly respond to temperature-sensitive changes in protein function and which genes are downstream, indirect responders?; (2) how long does it take different proteins and genes to respond to temperature?; and (3) are the experimental temperature manipulations relevant to the climate the organism experiences or to predicted climate change scenarios? This approach combines mechanistic questions (questions 1 and 2) with ecologically relevant conditions (question 3), allowing us to explore how organisms respond to transient thermal environments and, thus, cope with climate change.

The critical role of the aldehyde dehydrogenase PauC in spermine, spermidine, and diaminopropane toxicity in Pseudomonas aeruginosa: Its possible use as a drug target.

The opportunistic human pathogen Pseudomonas aeruginosa exhibits great resistance to antibiotics; so, new therapeutic agents are urgently needed. Since polyamines levels are incremented in infected tissues, we explored whether the formation of a toxic aldehyde in polyamines degradation can be exploited in combating infection. We cloned the gene encoding the only aminoaldehyde dehydrogenase involved in P. aeruginosa polyamines-degradation routes, PaPauC, overexpressed this enzyme, and found that it oxidizes 3-aminopropionaldehyde (APAL) and 3-glutamyl-3-aminopropionaldehyde (GluAPAL) - produced in spermine (Spm), spermidine (Spd), and diaminopropane (Dap) degradation, as well as 4-aminobutyraldehyde (ABAL) and 4-glutamyl-4-aminobutyraldehyde (GluABAL) - formed in putrescine (Put) degradation. As the catalytic efficiency of PaPauC with APAL was 30-times lower than with GluAPAL, and GluAPAL is predominantly formed, APAL will be poorly oxidized 'in vivo'. We found polyamines-induced increases in the PaPauC activity of cell crude-extracts and in the expression of the PapauC gene that were diminished by glucose. Spm, Spd, or Dap, but not Put, were toxic to P. aeruginosa even in the presence of other carbon and nitrogen sources, particularly to a strain with the PapauC gene disrupted. APAL, but not GluAPAL, was highly toxic even to wild-type cells, suggesting that its accumulation, particularly in the absence of, or low, PaPauC activity is responsible for the toxicity of Spm, Spd, and Dap. Our results shed light on the toxicity mechanism of these three polyamines and strongly support the critical role of PaPauC in this toxicity. Thus, PaPauC emerges as a novel potential drug target whose inhibition might help in combating infection by this important pathogen.

Relación de los niveles plasmáticos de homocisteína y apolipoproteína b-100 con el riesgo cardiovascular / Relationship of plasma levels of homocysteine and apolipoprotein b-100 with cardiovascular risk

INTRODUCCION: las enfermedades cardiovasculares son responsables del 31% de la mortalidad mundial, existen parámetros como la homocisteína y la Apolipoproteína B-100 que podrían tener utilidad en la predicción del riesgo. OBJETIVO: relacionar los niveles plasmáticos de Homocisteína y Apolipoproteína B-100 con el riesgo cardiovascular en pacientes que acuden a consulta externa del Hospital Univalle, durante julio-agosto del 2018 METODOLOGIA: el presente estudio es no experimental observacional, tipo prospectivo, transversal, con un enfoque de análisis positivista cuantitativo, con un universo de (N=133) que se redujo a una unidad de análisis de 81, que cumplieron con los criterios de inclusión y exclusión con un 6.83% de error máximo aceptable. RESULTADOS: el 52% de los pacientes fueron mujeres. La edad media de fue de 49,8 (Rango 25 a 83), el grupo etario predominante fueron los adultos mayores. Según el IMC los sujetos de estudio presentan sobre peso (n=31) y grado de obesidad 1 (n=24) más frecuentemente. Los niveles plasmáticos elevados de Apolipoproteína B en ambos sexos no muestran una diferencia significativa, mientras en que los de homocisteína la diferencia fue de 8:1. Se constato que los niveles séricos de la Apolipoproteína B-100 tienen una sensibilidad y especificidad bajas del 19.40% y 28.42%, mientas los de la homocisteína fueron del 14.29% y 27.27% respectivamente en comparación con la técnica convencional. CONCLUSIONES: los niveles plasmáticos de homocisteína y Apolipoproteína B-100 no son parámetros predictores de padecer riesgo cardiovascular

INTRODUCTION: cardiovascular diseases are responsible for 31% of world mortality, there are parameters such as homocysteine and Apolipoprotein B-100 that could be useful in predicting risk. OBJECTIVE: to relate the plasma levels of Homocysteine and Apolipoprotein B-100 with cardiovascular risk in patients who attend the outpatient clinic of the Univalle Hospital, during July-August 2018. METHODOLOGY: this study is non-experimental, observational, prospective, cross-sectional, with a quantitative positivist analysis approach, with a universe of (N=133) that was reduced to an analysis unit of 81, who met the inclusion criteria. and exclusion with a 6.83% maximum acceptable error. RESULTS: 52% of the patients were women. The mean age was 49.8 (range 25 to 83), the predominant age group was the elderly. According to the BMI, the study subjects are overweight (n=31) and obesity grade 1 (n=24) more frequently. The elevated plasmatic levels of Apolipoprotein B in both sexes do not show a significant difference, while in those of homocysteine the difference was 8:1. It was found that the serum levels of Apolipoprotein B-100 have a low sensitivity and specificity of 19.40% and 28.42%, while those of homocysteine were 14.29% and 27.27% respectively compared to the conventional technique. CONCLUSIONS: plasma levels of homocysteine and Apolipoprotein B-100 are not predictors of cardiovascular risk.

Multiple conformations in solution of the maize C4-phosphoenolpyruvate carboxylase isozyme.

The photosynthetic phosphoenolpyruvate carboxylase isozyme from C4 plants (PEPC-C4) has a complex allosteric regulation, involving positive cooperativity in binding the substrate phosphoenolpyruvate as well as positive and negative allosteric effectors. Besides the proposed R- and T-states, previous kinetic results suggested functionally relevant different R-states of the maize enzyme (ZmPEPC-C4) elicited by PEP or its two kinds of activators, glucose 6-phosphate or glycine. To detect these different R-state conformations, we used as conformational probes the fluorescence of 8-anilino-1-naphthalene sulfonate (ANS), near-UV circular dichroism (CD) spectroscopy, and limited proteolysis by trypsin. Phosphoenolpyruvate and malate binding caused distinct concentration-dependent fluorescence changes of ZmPEPC-C4/ANS, suggesting that they elicited conformational states different from that of the free enzyme, while glucose 6-phosphate or glycine binding did not produce fluorescence changes. Differences were also observed in the near UV CD spectra of the enzyme, free or complexed with its substrate or allosteric effectors. Additionally, differences in the trypsin-digestion fragmentation patterns, as well as in the susceptibility of the free and complexed enzyme to digestion and digestion-provoked loss of activity, provided evidence of several ZmPEPC-C4 conformations in solution elicited by the substrate and the allosteric effectors. Using the already reported ZmPEPC-C4 crystal structures and bioinformatics methods, we predicted that the most probable trypsin-cleavage sites are located in superficial flexible regions, which seems relevant for the protein dynamics underlying the function and allosteric regulation of this enzyme. Together, our findings agree with previous kinetic results, shed light on this enzyme's complex allosteric regulation, and place ZmPEPC-C4 in the growing list of allosteric enzymes possessing an ensemble of closely related R-state conformations.

Brief exposure to warm temperatures reduces intron retention in Kdm6b in a species with temperature-dependent sex determination.

Animals with temperature-dependent sex determination (TSD) respond to thermal cues during early embryonic development to trigger gonadal differentiation. TSD has primarily been studied using constant temperature incubations, where embryos are exposed to constant male- or female-producing temperatures, and these studies have identified genes that display sex-specific expression in response to incubation temperature. Kdm6b, a histone demethylase gene, has received specific attention as it is among the initial genes to respond to incubation temperature and is necessary for testis development. Interestingly, Kdm6b retains an intron when eggs are incubated at a constant male-producing temperature, but the role of thermal variability in this developmental process is relatively understudied. Species with TSD regularly experience thermal cues that fluctuate between male- and female-producing temperatures throughout development but it is unclear how Kdm6b responds to such variable temperatures. In this study, we investigate temperature-sensitive splicing in Kdm6b by exposing embryos to male- and female-producing thermal conditions. We show a rapid decrease in levels of the intron retaining transcript of Kdm6b upon exposure to female-producing conditions. These results demonstrate that, under ecologically relevant conditions, temperature-sensitive splicing can differentially regulate genes critical to TSD.

Detecting turnover among complex communities using null models: a case study with sky-island haemosporidian parasites.

Turnover in species composition between sites, or beta diversity, is a critical component of species diversity that is typically influenced by geography, environment, and biotic interactions. Quantifying turnover is particularly challenging, however, in multi-host, multi-parasite assemblages where undersampling is unavoidable, resulting in inflated estimates of turnover and uncertainty about its spatial scale. We developed and implemented a framework using null models to test for community turnover in avian haemosporidian communities of three sky islands in the southwestern United States. We screened 776 birds for haemosporidian parasites from three genera (Parahaemoproteus, Plasmodium, and Leucocytozoon) by amplifying and sequencing a mitochondrial DNA barcode. We detected infections in 280 birds (36.1%), sequenced 357 infections, and found a total of 99 parasite haplotypes. When compared to communities simulated from a regional pool, we observed more unique, single-mountain haplotypes and fewer haplotypes shared among three mountain ranges than expected, indicating that haemosporidian communities differ to some degree among adjacent mountain ranges. These results were robust even after pruning datasets to include only identical sets of host species, and they were consistent for two of the three haemosporidian genera. The two more distant mountain ranges were more similar to each other than the one located centrally, suggesting that the differences we detected were due to stochastic colonization-extirpation dynamics. These results demonstrate that avian haemosporidian communities of temperate-zone forests differ on relatively fine spatial scales between adjacent sky islands. Null models are essential tools for testing the spatial scale of turnover in complex, undersampled, and poorly known systems.

Electrodialytic treatment of secondary mining resources for raw materials extraction: Reactor design assessment.

The sustainability of mining activities is compromised due to the high amounts of mining residues generated that have to be disposed of, often in open dams, that may cause environmental deterioration, e.g. release of toxic elements to water supplies. These residues are, however, secondary resources of raw materials. In the case of Panasqueira mine, they even are a source of tungsten, considered a critical raw material. The present work aims to assess the electrodialytic process efficiency for raw materials extraction from Panasqueira mine residues. Experiments were performed with 2 and 3-compartment electrodialytic reactors, applying current intensities between 50 and 100 mA, from 4 to 14 days, and sample suspensions enhanced with NaCl or effluent. Additionally, control experiments with no current application were carried out. The results showed that a 3-compartment reactor operating at 100 mA, with NaCl as supporting electrolyte, presented the highest extraction of copper (13%), tin (10%), tungsten (13%) and arsenic (63%).