Zeolites synthesis from phyllosilicates and their performance for CO2 adsorption.

Five phyllosilicates (kaolinite, montmorillonite, saponite, sepiolite and palygorskite) have been selected as starting materials for the synthesis of zeolites. Among them, kaolinite and montmorillonite display the lowest Si/Al molar ratio leading to aluminosilicates with high crystallinity. Thus, the hydrothermal treatment under basic conditions forms 4A zeolite when kaolinite is used as starting material while 13X zeolite is obtained when montmorillonite is used as starting material. The microporosity and CO2-adsorption capacity of the prepared zeolites are directly related to its crystallinity. Thus, in order to improve it, raw phyllosilicates were subjected to a microwave-assisted treatment to remove undesired Mg or Fe-species, which have a negative effect in the assembling of the zeolites by hydrothermal basic conditions in a second step. The highest adsorption value was 3.85 mmol/g at 25 °C and 760 mm of Hg for Mont-A-B sample after the consecutive treatments.

Small Molecule Antagonists of the DNA Repair ERCC1/XPA Protein-Protein Interaction.

The DNA excision repair protein ERCC1 and the DNA damage sensor protein, XPA are highly overexpressed in patient samples of cisplatin-resistant solid tumors including lung, bladder, ovarian, and testicular cancer. The repair of cisplatin-DNA crosslinks is dependent upon nucleotide excision repair (NER) that is modulated by protein-protein binding interactions of ERCC1, the endonuclease, XPF, and XPA. Thus, inhibition of their function is a potential therapeutic strategy for the selective sensitization of tumors to DNA-damaging platinum-based cancer therapy. Here, we report on new small-molecule antagonists of the ERCC1/XPA protein-protein interaction (PPI) discovered using a high-throughput competitive fluorescence polarization binding assay. We discovered a unique structural class of thiopyridine-3-carbonitrile PPI antagonists that block a truncated XPA polypeptide from binding to ERCC1. Preliminary hit-to-lead studies from compound 1 reveal structure-activity relationships (SAR) and identify lead compound 27 o with an EC50 of 4.7 µM. Furthermore, chemical shift perturbation mapping by NMR confirms that 1 binds within the same site as the truncated XPA67-80 peptide. These novel ERCC1 antagonists are useful chemical biology tools for investigating DNA damage repair pathways and provide a good starting point for medicinal chemistry optimization as therapeutics for sensitizing tumors to DNA damaging agents and overcoming resistance to platinum-based chemotherapy.

Use of computed tomography coronary calcium score for prediction of cardiovascular events in cancer patients: a retrospective cohort analysis.

BACKGROUND: CT- coronary calcium score, is one of the most studied and widely available modalities in cardiovascular medicine. Coronary artery calcium score (CACS) is an established predictor of coronary artery disease. The 'standard of care' diagnostic modality to measure CACS is ECG-gated Cardiac Multi-Detector Computed Tomography. There is convincing evidence of a strong association between CACS and major cardiovascular (CV) events in asymptomatic individuals. Cancer patients (C) may have a higher risk for CV disease than non-cancer patients (NC) related not only to cancer treatments but also to shared biological factors and pathways. Thus, identifying tools for early detection of CV disease in this population is of utmost importance. METHODS: A retrospective cohort analysis was performed with patients from Cleveland Clinic Florida and Ohio who had CACS from 2017 to 2021. Patients who had cancer diagnosis prior to CACS were matched to NC for age and sex. CV events after their index CACS events were compared between C and NC, and matched control and propensity analysis were conducted. RESULTS: Ten thousand seven hundred forty-two patients had CACS; 703 cancer patients had CACS and were eligible. Extensive CACS (> 400) were significantly higher in cancer, 94 (13.37%) vs non-cancer patients, 76 (10.83%), P = 0.011. Furthermore, after propensity matched analysis, CACS > 400 was 14.8% in C vs 9.6% in NC, P = < 0.05. CV events were similar in both cohorts (p = NS), despite less CV risk factors in cancer patients (P = < 0.05). For the combined moderate (101-400) & extensive (> 400) CACS, the prevalence of stroke and peripheral arterial disease, a marker of systemic atherosclerosis, was significantly higher in patients with cancer (P < 0.01). CONCLUSIONS: Despite having fewer CV risk factors in our study, similar CACS in cancer patients are suggestive of a higher prevalence of CV disease independent of traditional risk factors. High CACS and the overall prevalence of vascular events were more frequent in patients with cancer. Higher prevalence of peripheral arterial disease and cerebrovascular accident further suggests the increased atherosclerotic burden in C.

Effects of a cardiopulmonary telerehabilitation using functional exercises in individuals after COVID-19 hospital discharge: A randomized controlled trial.

INTRODUCTION: Individuals with severe coronavirus disease 2019 (COVID-19) may present respiratory and motor complications, requiring rehabilitation programs (RP) for long periods. However, access to cardiopulmonary rehabilitation is poor. Cardiopulmonary telerehabilitation is an alternative for cardiopulmonary dysfunction, improving functional capacity, dyspnea, and quality of life. Moreover, few clinical trials verified the effectiveness of telerehabilitation using functional exercise for post-COVID symptoms. Thus, the present study aimed to verify the effects of cardiopulmonary telerehabilitation using functional and accessible exercises in individuals after COVID-19 hospital discharge. METHODS: This blinded, randomized, and controlled clinical trial and included 67 adult individuals after COVID-19 hospital discharge. Participants were randomized into the groups of telerehabilitation (TG; n = 33) and control (CG; n = 34). TG underwent an individualized exercise program (functional and accessible exercises) supervised by a physical therapist (videoconference), and CG received guidance on general care and self-monitoring of vital signs (videoconference). The primary outcome was performance and physiological responses on the 6-minute step test (6MST). Secondary outcomes were performance on the 2-minute stationary walk test (2MSWT), 30-second chair stand test (30CST), and quality of life using the 36-Item Short Form Health Survey (SF-36) questionnaire physical functioning concept (PF). RESULTS: Functional capacity (6MST) improved by 28 ± 17 steps in TG and 15 ± 26 in CG (p = 0.04). For secondary outcomes, performance on 2MSWT increased by 39 ± 6 steps in TG and 10 ± 6 in CG (p = 0.00); 30CST by 3 ± 1 repetitions in TG and 1.5 ± 0.5 in CG (p = 0.05); and PF (SF-36) by 17 ± 4 points in TG and 12 ± 4 in CG (p = 0.00). Also, peak oxygen uptake VO2peak (6MST) improved by 3.8 ± 1 mL min-1 kg-1 in TG and 4.1 ± 1 in CG (p = 0.6), and heart rate demand (6MST) by 11 ± 37% in TG and -4 ± 19% in CG (p = 0.04). CONCLUSIONS: Cardiopulmonary telerehabilitation using functional exercises improved the exercise and functional capacity assessed using 6MST, 30CST, and 2MSWT and the quality of life of individuals after COVID-19 hospital discharge.

Effects of a cardiopulmonary telerehabilitation using functional exercises in individuals after COVID-19 hospital discharge: A randomized controlled trial

Individuals with severe coronavirus disease 2019 (COVID-19) may present respiratory and motor complications, requiring rehabilitation programs (RP) for long periods. However, access to cardiopulmonary rehabilitation is poor. Cardiopulmonary telerehabilitation is an alternative for cardiopulmonary dysfunction, improving functional capacity, dyspnea, and quality of life. Moreover, few clinical trials verified the effectiveness of telerehabilitation using functional exercise for post-COVID symptoms. Thus, the present study aimed to verify the effects of cardiopulmonary telerehabilitation using functional and accessible exercises in individuals after COVID-19 hospital discharge. This blinded, randomized, and controlled clinical trial and included 67 adult individuals after COVID-19 hospital discharge. Participants were randomized into the groups of telerehabilitation (TG; n = 33) and control (CG; n = 34). TG underwent an individualized exercise program (functional and accessible exercises) supervised by a physical therapist (videoconference), and CG received guidance on general care and self-monitoring of vital signs (videoconference). The primary outcome was performance and physiological responses on the 6-minute step test (6MST). Secondary outcomes were performance on the 2-minute stationary walk test (2MSWT), 30-second chair stand test (30CST), and quality of life using the 36-Item Short Form Health Survey (SF-36) questionnaire physical functioning concept (PF). Functional capacity (6MST) improved by 28 ± 17 steps in TG and 15 ± 26 in CG (p = 0.04). For secondary outcomes, performance on 2MSWT increased by 39 ± 6 steps in TG and 10 ± 6 in CG (p = 0.00); 30CST by 3 ± 1 repetitions in TG and 1.5 ± 0.5 in CG (p = 0.05); and PF (SF-36) by 17 ± 4 points in TG and 12 ± 4 in CG (p = 0.00). Also, peak oxygen uptake VO2peak (6MST) improved by 3.8 ± 1 mL min−1 kg−1 in TG and 4.1 ± 1 in CG (p = 0.6), and heart rate demand (6MST) by 11 ± 37% in TG and −4 ± 19% in CG (p = 0.04). Cardiopulmonary telerehabilitation using functional exercises improved the exercise and functional capacity assessed using 6MST, 30CST, and 2MSWT and the quality of life of individuals after COVID-19 hospital discharge.

More than meets no eyes: taxonomic status of a Liotyphlops (Serpentes: Anomalepididae) blindsnake from the atlantic rainforest

Liotyphlops Peters, 1881 is an anomalepidid blindsnake genus that encompasses 12 species, widely distributed in Central and South America. In this study, we evaluate the taxonomic status of Liotyphlops sousai Santos & Reis, 2018, a species described based on a single specimen from the Atlantic Rainforest of southern Brazil, and after analyzing evidences based upon molecular systematics, external morphology and osteology, we propose its synonymy with Liotyphlops beui (Amaral, 1924), a common and widely distributed Anomalepidid species. We also provide comments and recommendations on the taxonomy of Liotyphlops, assessing the risks associated with describing a new species based on small type series.

Health-Related Quality of Life and Daily Physical Activity Level in Patients with COPD- a Cluster Analysis.

Patients with chronic obstructive pulmonary disease (COPD) may have a limited level of physical activity in daily life (PADL) and health-related quality of life (HRQOL). The interrelationships of these variables should be measure by cluster analysis to characterize this population and enable rehabilitation programs to target each patient profile identified. This study investigates different phenotypes in COPD according to PADL and HRQOL. A cross-sectional study with cluster analysis was done, in which 76 people with COPD were submitted to measurements to characterize the sample on first day, followed by used of physical activity monitor, which was worn for 7 days. After 7 days, the six-minute walk test (6MWT) and HRQOL questionnaires were applied (St. George's Respiratory Questionnaire). The main results: three phenotypes were identified (A, B and C), with phenotype A who exhibited an inactive physical activity level and HRQOL scores above the value deemed satisfactory, phenotype B those with active physical activity level and poor HRQOL scores, and phenotype C subjects with inactive physical activity level and HRQOL scores but the value is close to cutoff point. To conclude, three phenotypes were found, with one indicating disproportionality between PADL and HRQOL.

El consentimiento informado como un continuo narrativo / El consentiment informat com un continu narratiu / Informed consent as a narrative continuum

Informed consent (IC) is generally understood as a statement, usually written, by which a person freely and informedly agrees to undergo a certain medical procedure. Recently, Tunzi et al. (2021) have proposed a new model of IC for primary medical care, which they call "the consent continuum" (CC), which offers an alternative to the current state of how IC is obtained. They argue that their model "honors patient autonomy, meets legal obligations, and improves patient care and satisfaction in a manner that is both transparent and pragmatic" (Tunzi et al. 2021:35). I propose to critically review their proposal and argue that this continuum model can be strengthened by framing it within a narrative approach and conceiving of the physician-patient relationship (PMR) under such an approach.(AU)

El consentimiento informado (CI) suele entenderse como una declaración, comúnmente escrita, con la que una persona acepta, de manera libre e informada, someterse a un cierto procedimiento médico. Recientemente, Tunziet al.(2021)han propuesto un nuevo modelo de CI para la atención médica primaria, al que llaman “el consentimiento continuo” (CC), el cual ofrece una alternativa al estado actual del modo en que se obtiene el CI. Ellos sostienen que su modelo “honra la autonomía del paciente, satisface las obligaciones legales [del personal médico] y mejora el cuidado del paciente de una manera que es tanto transparente como pragmática” (Tunzi et al.2021:35). Me propongo hacer una revisión crítica de su propuesta y argumentar que estemodelo continuo puede reforzarse enmarcándolo dentro de un enfoque narrativo y concibiendo a la relación médico paciente (RMP) bajo dicho enfoque.(AU)

El consentiment informat (CI) sol entendre's com una declaració, comunament escrita, amb la qual una persona accepta, de manera lliure i informada, sotmetre's a un cert procediment mèdic. Recentment, Tunzi et al. (2021) han proposat un nou model de CI per a l'atenció mèdica primària, al qual anomenen “el consentiment continu” (CC), el qual ofereix una alternativa a l'estat actual de la manera en què s'obté el CI. Ells sostenen que el seu model “honra l'autonomia del pacient, satisfà les obligacions legals [del personal mèdic] i millora la cura del pacient d'una manera que és tant transparent com pragmàtica” (Tunzi et al. 2021:35). Em proposo fer una revisió crítica de la seva proposta i argumentar que aquest model continu pot reforçar-se emmarcant-lo dins d'un enfocament narratiu i concebent a la relació metge pacient (RMP) baix dit enfocament.(AU)

Speciation process on brazilian continental islands, with the description of a new insular lancehead of the genus Bothrops (Serpentes, Viperidae)

Brazilian continental islands represent a natural laboratory to study speciation driven by recent phenotypic and genotypic divergence. The Bothrops jararaca species group is distributed in the Brazilian Atlantic Forest and on most of the Brazilian continental islands. The group is currently composed of the mainland common lancehead (B. jararaca) and four insular species (B. alcatraz, B. insularis, B. otavioi, and B. sazimai). Here, we evaluate mitochondrial DNA and morphological diversity of the B. jararaca species group and aim to provide additional evidence to understand insularization processes on the Brazilian coast. Our results, interpreted together with a comprehensive review of geomorphological data, provide a new conceptual framework for understanding the colonization process of the Brazilian continental islands. This framework suggests a history of multiple rounds of periodic isolation and reconnection between insular populations and their mainland relatives throughout the last 420,000 years. Furthermore, although some insular populations may have speciated prior to the last glacial maximum, other species likely diverged within the last 11,000 years. Additionally, the repeated evolution of size and dietary shift in the B. jararaca species group suggests a remarkable case of convergent adaptation. Our study provides evidence that the Bothrops from Ilha da Moela (Brazilian state of São Paulo) represents an undescribed species, presenting a distinct phenotype, and an exclusive history of isolation and adaptation. We describe this unique lancehead as a new species and we suggest it should be listed as critically endangered based on its endemicity to a small island that is severely impacted by constant and longstanding human presence.

Growing emergence of drug-resistant Pseudomonas aeruginosa and attenuation of its virulence using quorum sensing inhibitors: A critical review.

A perilous increase in the number of bacterial infections has led to developing throngs of antibiotics for increasing the quality and expectancy of life. Pseudomonas aeruginosa is becoming resistant to all known conventional antimicrobial agents thereby posing a deadly threat to the human population. Nowadays, targeting virulence traits of infectious agents is an alternative approach to antimicrobials that is gaining much popularity to fight antimicrobial resistance. Quorum sensing (QS) involves interspecies communication via a chemical signaling pathway. Under this mechanism, cells work in a concerted manner, communicate with each other with the help of signaling molecules called auto-inducers (AI). The virulence of these strains is driven by genes, whose expression is regulated by AI, which in turn acts as transcriptional activators. Moreover, the problem of antibiotic-resistance in case of infections caused by P. aeruginosa becomes more alarming among immune-compromised patients, where the infectious agents easily take over the cellular machinery of the host while hidden in the QS mediated biofilms. Inhibition of the QS circuit of P. aeruginosa by targeting various signaling pathways such as LasR, RhlR, Pqs, and QScR transcriptional proteins will help in blocking downstream signal transducers which could result in reducing the bacterial virulence. The anti-virulence agent does not pose an immediate selective pressure on growing bacterium and thus reduces the pathogenicity without harming the target species. Here, we review exclusively, the growing emergence of multi-drug resistant (MDR) P. aeruginosa and the critical literature survey of QS inhibitors with their potential application of blocking P. aeruginosa infections.

Electrochemical and quantum mechanical investigation of various small molecule organic compounds as corrosion inhibitors in mild steel.

The corrosion inhibition property of selected small organic compounds was investigated using electrochemical measurements, including potentiodynamic polarization (PDP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and density functional theory (DFT) calculations. The inhibition efficiency (IE %) of the inhibitor on mild steel (MS) in 1 M HCl was then determined. Results show that the presence of the inhibitors resulted in decreased corrosion current density (I corr) values and increased polarization resistance (R p). Furthermore, the use of higher concentrations of inhibitors led to an increased inhibition efficiency. Tafel slopes and shifts in the E corr values suggested that the inhibitors tested are mixed-type inhibitors that form a protective layer on the surface of the substrate. Of the organic compound inhibitors tested, the inhibitor 4-ethylpyridine (EP) exhibited the highest R p values and inhibition efficiency values from the PDP, LPR, and EIS analyses, respectively. DFT calculations showed negative adsorption energies and confirmed the chemisorption of the inhibitors allowing for the formation of a hydrophobic protective film against corrosion and correlations between the quantum chemical values and electrochemical data were demonstrated. The results show the influence of the presence of electronegative O, S, and N atoms, as well as the role of aromatic rings in the promotion of surface protection by preventing aggressive ionic species from binding onto MS.

Highly Sensitive and Selective Spiropyran-Based Sensor for Copper(II) Quantification.

The metal-binding capabilities of the spiropyran family of molecular switches have been explored for several purposes from sensing to optical circuits. Metal-selective sensing has been of great interest for applications ranging from environmental assays to industrial quality control, but sensitive metal detection for field-based assays has been elusive. In this work, we demonstrate colorimetric copper sensing at low micromolar levels. Dimethylamine-functionalized spiropyran (SP1) was synthesized and its metal-sensing properties were investigated using UV-vis spectrophotometry. The formation of a metal complex between SP1 and Cu2+ was associated with a color change that can be observed by the naked eye as low as ≈6 µM and the limit of detection was found to be 0.11 µM via UV-vis spectrometry. Colorimetric data showed linearity of response in a physiologically relevant range (0-20 µM Cu2+) with high selectivity for Cu2+ ions over biologically and environmentally relevant metals such as Na+, K+, Mn2+, Ca2+, Zn2+, Co2+, Mg2+, Ni2+, Fe3+, Cd2+, and Pb2+. Since the color change accompanying SP1-Cu2+ complex formation could be detected at low micromolar concentrations, SP1 could be viable for field testing of trace Cu2+ ions.

Complex formation of silver(I) ions with a glucosinolate derivative: structural and mechanistic insights into myrosinase-mimicking C-S bond cleavage.

The crystal structure of an unprecedented silver complex of O-acetylsinigrin has shown chelating bonds of the sulfated thiohydroximate and an η2-bond of the ethylene moiety with Ag(i). Mechanistic studies on the formation and decomposition of the complex by the 1H NMR measurements and theoretical calculations with the DFT method indicated relevance to the glucosinolate degradation in biological systems.

A new species of emThamnodynastes/em Wagler, 1830 from western Amazonia, with notes on morphology for members of the emThamnodynastes/em empallidus/em group (Serpentes, Dipsadidae, Tachymenini).

The genus Thamnodynastes is the most diverse within the tribe Tachymenini, with an extensive and complex taxonomic history. The brief descriptions and lack of robust diagnostic characters are the main sources for identification errors and for the difficulty to assess the diversity estimates of the genus. The Thamnodynastes pallidus group was briefly designated to encompass the most arboreal species of the genus, with thinner bodies and longer tails: T. pallidus, T. longicaudus, T. sertanejo, and a fourth undescribed species. After its designation, no other paper addressed this group and its morphological variation, especially for the hemipenis, is still undetermined. After the analysis of all species of Thamnodynastes we were able to corroborate the distinctiveness of the T. pallidus group and to accurately diagnose its fourth species from the western portion of the Amazonia lowlands. The new species is distinguishable from all congeners, except T. sertanejo, by the absence of ventral longitudinal stripes, 17/17/11 dorsal scale rows, and dorsal dark brown blotches on the anterior third of the body. The new species is distinguished from T. sertanejo by the higher number of subcaudals, lower number of ventrals, and smaller body and head sizes. We also provide additional diagnostic features for the Thamnodynastes pallidus group, including new data on hemipenial variation. Finally, we briefly discuss the defensive behavior and morphological characters associated with arboreality in members of the T. pallidus species group.

Reassessment of Tantilla boipiranga (Serpentes: Colubrinae) and a preliminary approach to the phylogenetic affinities within Tantilla

Tantilla is one of the most diverse genera among colubrids, with 67 species arranged in six phenotypically recognized species groups. Tantilla boipiranga is the most recently described species within the T. melanocephala group, and it was described based on a small type series, collected in the rupestrian grasslands of south-eastern Brazil. The morphological diversity and the phylogenetic affinity of this species remain poorly known. Here, based on the assessment of recently collected specimens in combination with results of a molecular phylogenetic analysis, we evaluate the morphological variation within T. boipiranga and its phylogenetic position. Our analyses confirm T. boipiranga as genetically distinct from its generic counterparts, and diagnosable based on a combination of colour pattern, meristic counts, and hemipenial morphology. However, contrary to its original description, the hemipenial ornamentation does not differen-tiate T. boipiranga from the highly variable T. melanocephala. In our phylogenetic analysis, T. boipiranga is retrieved as a monophyletic group, nested within the diversity of T. melanocephala and sister to a clade composed by specimens from south-eastern Brazil. Tantilla melanocephala is recovered as a highly diverse lineage, indicating the possible presence of undescribed species. Additionally, our analysis indicates that the T. coronata and T. planiceps species group are mono-phyletic, while the T. taeniata species group is paraphyletic and the only sampled species for the T. calamarina group is nested within the T. melanocephala group. Our results suggest that the phenotypic evolution within the genus is probably more complex than previously recognized, and some colouration patterns used to define the groups can in fact represent phenotypical convergences. Moreover, our phylogenetic analysis suggests a strong signal of geographical structure in the tree topology. Three main geographical lineages were found, a North American, a South American and a Central Ameri-can. The first two lineages were recovered as monophyletic, while the latter is paraphyletic, with Central American species positioned as sister groups of both, the North American and the South American clades. Although a more comprehensive phylogenetic analysis is needed, our study strongly indicates the existence of hidden diversity within the T. melanocephala group and that Tantilla represents an ideal model to evaluate the validity of phenotypical groups in snake systematics and to study the driven mechanisms of morphological evolution.

A new species of Thamnodynastes Wagler, 1830 from western Amazonia, with notes on morphology for members of the Thamnodynastes pallidus group (Serpentes, Dipsadidae, Tachymenini)

The genus Thamnodynastes is the most diverse within the tribe Tachymenini, with an extensive and complex taxonomic history. The brief descriptions and lack of robust diagnostic characters are the main sources for identification errors and for the difficulty to assess the diversity estimates of the genus. The Thamnodynastes pallidus group was briefly designated to encompass the most arboreal species of the genus, with thinner bodies and longer tails: T. pallidus, T. longicaudus, T. sertanejo, and a fourth undescribed species. After its designation, no other paper addressed this group and its morphological variation, especially for the hemipenis, is still undetermined. After the analysis of all species of Thamnodynastes we were able to corroborate the distinctiveness of the T. pallidus group and to accurately diagnose its fourth species from the western portion of the Amazonia lowlands. The new species is distinguishable from all congeners, except T. sertanejo, by the absence of ventral longitudinal stripes, 17/17/11 dorsal scale rows, and dorsal dark brown blotches on the anterior third of the body. The new species is distinguished from T. sertanejo by the higher number of subcaudals, lower number of ventrals, and smaller body and head sizes. We also provide additional diagnostic features for the Thamnodynastes pallidus group, including new data on hemipenial variation. Finally, we briefly discuss the defensive behavior and morphological characters associated with arboreality in members of the T. pallidus species group.

Submucosal Tunneling Endoscopic Resection.

Minimally invasive endoscopic resection procedures continue to evolve, with submucosal tunneling endoscopic resection (STER) being a durable option for en bloc resection of submucosal tumors. Whether STER can be effectively used for larger (>3.5 cm) lesions remains to be seen. STER-ET is a novel approach for removal of extraluminal tumors, but data are currently limited to support its use.

Effect of Structure and Intramolecular Distances on Photoswitchable Magnetic Resonance Imaging Contrast Agents.

Light-activated sensors are of great interest for biological applications but are limited by the depth of penetration of light. We have been interested in transducing light activation to a magnetic signal that can be detected through noninvasive imaging by magnetic resonance imaging (MRI). We have previously developed agents incorporating spiropyran derivatives as the sensing moiety and characterized features that influence photoswitching; however, we found the MRI response to be unpredictable. In this work, we delve deeper into the potential mechanisms for the observed MRI responses in an effort to better understand the structural effects on controlling magnetic properties. A series of light-activatable MRI contrast agents were synthesized and characterized to assess the effect of spiropyran positioning on contrast agent functions and properties. These compounds are based on the same spiropyran skeleton, also named 1',3',3'-trimethyl-6-nitrospiro[chromene-2,2-indoline], which is linked with an MRI contrast agent, gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7-triacetate (DO3A). We investigated the photo-to-magnetic conversion properties of these novel compounds by adjusting linker lengths over a range from three to seven methylene groups. The primary results indicated that the contrast agent with a five-carbon linker (25) showed the highest light-sensing ability after irradiation with visible light. The results will aid in the design of future spiropyran-based MRI sensors.

Evaluation of Drosophila chromosomal segments proposed by means of simulations of possessing hybrid sterility genes from reproductive isolation.

In heterozygote state, we interogressed three chromosomal segments of Drosophila koepferae in D. buzzatii. The effect of each introgression was evaluated in the fertility of the segmental males, quantifying the amount of offspring produced. Through specific crosses method, we generated Drosophila segmental isolines carrying specific chromosomal introgression segments. The introgressions were monitored cytogenetically by the method of molecular markers of chromosomal asynapsis. The statistical analysis showed that none of the three segments evaluated, introgressed individually or in pairs, as well as cis or trans, do not produce sterility in the segmental males, as determined by the normal productions of offspring. Additional introgressions using other larger segments show that when the introgressions reach a minimum size of 31.15%, they produce sterility. It is concluded that the hybrid sterility genes present in the three segments evaluated did not act in strong epistasis, but show a pattern of gradual additive behaviour by requiring a minimum threshold size to produce sterility. Finally, we also isolated the smallest introgressing segment that has been reported for these species (2.19%), and for the first time we have managed to place it in homozygous state (data not shown), so we are now in the process of evaluating the ability to these segments in homozygous state.

Museums and cradles of diversity are geographically coincident for narrowly distributed neotropical snakes

Factors driving the spatial configuration of centres of endemism have long been a topic of broad interest and debate. Due to different eco-evolutionary processes, these highly biodiverse areas may harbour different amounts of ancient and recently diverged organisms (paleo- and neo-endemism, respectively). Patterns of endemism still need to be measured at distinct phylogenetic levels for most clades and, consequently, little is known about the distribution, the age and the causes of such patterns. Here we tested for the presence of centres with high phylogenetic endemism (PE) in the highly diverse Neotropical snakes, testing the age of these patterns (paleo- or neo-endemism), and the presence of PE centres with distinct phylogenetic composition. We then tested whether PE is predicted by topography, by climate (seasonality, stability, buffering and relictualness), or biome size. We found that most areas of high PE for Neotropical snakes present a combination of both ancient and recently diverged diversity, which is distributed mostly in the Caribbean region, Central America, the Andes, the Atlantic Forest and on scattered highlands in central Brazil. Turnover of lineages is higher across Central America, resulting in more phylogenetically distinct PE centres compared to South America, which presents a more phylogenetically uniform snake fauna. Finally, we found that elevational range (topographic roughness) is the main predictor of PE, especially for paleo-endemism, whereas low paleo-endemism levels coincide with areas of high climatic seasonality. Our study highlights the importance of mountain systems to both ancient and recent narrowly distributed diversity. Mountains are both museums and cradles of snake diversity in the Neotropics, which has important implications for conservation in this region.