Site-directed conjugation of single-stranded DNA to affinity proteins: quantifying the importance of conjugation strategy.

Affinity protein-oligonucleotide conjugates are increasingly being explored as diagnostic and therapeutic tools. Despite growing interest, these probes are typically constructed using outdated, non-selective chemistries, and little has been done to investigate how conjugation to oligonucleotides influences the function of affinity proteins. Herein, we report a novel site-selective conjugation method for furnishing affinity protein-oligonucleotide conjugates in a 93% yield within fifteen minutes. Using SPR, we explore how the choice of affinity protein, conjugation strategy, and DNA length impact target binding and reveal the deleterious effects of non-specific conjugation methods. Furthermore, we show that these adverse effects can be minimised by employing our site-selective conjugation strategy, leading to improved performance in an immuno-PCR assay. Finally, we investigate the interactions between affinity protein-oligonucleotide conjugates and live cells, demonstrating the benefits of site-selective conjugation. This work provides critical insight into the importance of conjugation strategy when constructing affinity protein-oligonucleotide conjugates.

Correction: Real-time, smartphone-based processing of lateral flow assays for early failure detection and rapid testing workflows.

[This corrects the article DOI: 10.1039/D2SD00197G.].

The role of organic cations as additives in photovoltaic perovskites.

The design of additives for perovskite-based solar cells seeks to improve the balance between stability and power conversion efficiency. Organic molecules such as theophylline, theobromine and caffeine (xanthines) have proved to be a good engineering solution. As an alternative, we present a first-principles study of the use of organic cations as additives. These cations are obtained when the free nitrogen of the imidazole unit of the aforementioned molecules is quaternized. We have found that the interaction between the organic cations and the MAPbI3 perovskite surface is stronger compared to the organic molecules. The Pb-O and I-H bonds of the interface dominated these interactions. In addition, organic cations showed higher charge transfer through the interface and shallow states that are harmless and could improve the charge carrier mobility. These characteristics show that quaternized xanthines should be a promising additive for perovskite materials in photovoltaic applications.

Real-time, smartphone-based processing of lateral flow assays for early failure detection and rapid testing workflows.

Despite their simplicity, lateral flow immunoassays (LFIAs) remain a crucial weapon in the diagnostic arsenal, particularly at the point-of-need. However, methods for analysing LFIAs still rely heavily on sub-optimal human readout and rudimentary end-point analysis. This negatively impacts both testing accuracy and testing times, ultimately lowering diagnostic throughput. Herein, we present an automated computational imaging method for processing and analysing multiple LFIAs in real-time and in parallel. This method relies on the automated detection of signal intensity at the test line, control line, and background, and employs statistical comparison of these values to predictively categorise tests as "positive", "negative", or "failed". We show that such a computational methodology can be transferred to a smartphone and detail how real-time analysis of LFIAs can be leveraged to decrease the time-to-result and increase testing throughput. We compare our method to naked-eye readout and demonstrate a shorter time-to-result across a range of target antigen concentrations and fewer false negatives compared to human subjects at low antigen concentrations.

Enhancing the stability and efficiency of MAPbI3 perovskite solar cells by theophylline-BF4 - alkaloid derivatives, a theoretical-experimental approach.

Perovskite solar cells (PSCs) are an evolving photovoltaic field with the potential to disrupt the established silicon solar cell market. However, the presence of many transport barriers and defect trap states at the interfaces and grain boundaries has negative effects on PSCs; it decreases their efficiency and stability. The purpose of this work was to investigate the effects on efficiency and stability achieved by quaternary theophylline additives in MAPbI3 PSCs with the structure FTO/TiO2/perovskite/spiro-OMeTAD/Ag. The X-ray photoelectron spectroscopy (XPS) and theoretical calculation strategies were applied to study the additive's interaction in the layer. The tetrafluoroborinated additive results in an increase in device current density (J SC) (23.99 mA cm-1), fill factor (FF) (65.7%), and open-circuit voltage (V OC) (0.95 V), leading to significant improvement of the power conversion efficiency (PCE) to 15.04% compared to control devices (13.6%). Notably, films exposed to controlled humidity of 30% using the tetrafluoroborinated additive maintained their stability for more than 600 hours (h), while the control films were stable for less than 240 hours (h).

Kidney transplantation reduces the risk of chronic limb threatening ischemia and amputation among patients with end-stage renal disease on hemodialysis.

OBJECTIVE: This study aimed to analyze the risk of chronic limb threatening ischemia (CLTI) or amputation among patients with end-stage renal disease (ESRD) entering a hemodialysis (HD) program and to evaluate the protective effect associated with kidney transplantation (KT). DESIGN, MATERIAL AND METHODS: Retrospective cohort of all consecutive ESRD patients entering into a HD program at our institution between 2000 and 2010. Collected variables included baseline characteristics (pre-entry in hemodialysis), time on HD program, KT and the composite outcome of chronic limb threatening ischemia or need for any amputation (CLTI/AMP). Patients with previous symptomatic peripheral arterial disease or amputation were excluded. RESULTS: The study group included 336 patients (mean age 63 years, 66% male). The mean follow up was 6.7 years with an average time on HD of 4.2 years. Ninety two patients (27.4 %) underwent transplantation. CLTI free survival rates were 90.3 % and 82.6 % at 5 and 10 years, respectively. The episodes of CLT involved 28 revascularization procedures (17 endovascular and 11 open surgeries), 18 minor amputations and 20 major amputations. KT was associated with a protective effect over the development of CLTI (HR: 0.065; CI 95% 0.02-0.21) after adjustment for confounding factors. The long-term survival of non-transplanted patients was 45 % and 15 % at 5 and 10 years, respectively and the long-term survival in transplanted patients was 89% and 80% at 5 and 10 years, respectively; but decreased to 47 % at 1 year and 18.2 % at 5 years once CLTI occurred. CONCLUSION: Patients on HD program show a notorious risk of chronic limb threatening ischemia or amputation over time. Once this complication occurs, patient's survival is markedly reduced. Transplantation confers an independent protective effect over the development of chronic limb threatening ischemia or amputation.

Indigenous sovereignty, data sourcing, and knowledge sharing for health.

In this article, we consider the impacts of the COVID-19 pandemic on Indigenous Peoples (IPs) by reporting on information-gathering work across two non-governmental and Indigenous organisations to compensate where federal systems failed. Strategies IPs have employed to understand and respond to the pandemic, and described here, include: collaborative efforts across communities intra- and inter-nationally; open-source data platforms; and small-scale epidemiological research. Our review exposes the informational politics faced by Indigenous organisations and communities, and their struggle to pursue needed resources or protections while avoiding the critiques of 'post-neoliberal' and 'science denialism'. We conclude by suggesting ways that Indigenous communities improve our understanding of their needs during public health crises, and maintain both informational and medical self-governance.

Outcome of elective endovascular repair of abdominal aortic aneurysms in octogenarians.

AIM: The need to adjust the indications of elective abdominal aortic aneurysm (AAA) repair among patients with a limited life-span deserves a specific evaluation for octogenarians. The aim of this study was to compare the postoperative results and the long-term survival after endovascular repair of abdominal aortic and/or iliac aneurysms (EVAR) in octogenarians compared with patients under 80 years of age. METHODS: Retrospective analysis of 241 consecutive patients who underwent an elective EVAR between 2000 and 2017. EVAR was not considered among patients with clear life-limiting conditions. Patients receiving other than commercially standard infra-renal endoprostheses were excluded. RESULTS: Seventy patients (29.0%) were octogenarians. They had a lower rate of active smoking (10.0% vs. 30.4%, P < 0.001) and a higher prevalence of previous cerebrovascular disease (21.4% vs. 11.7%, P = 0.055) than younger patients. Thirty-day/in-hospital complication and mortality rates were not significantly higher among octogenarians when compared with younger patients (24.3% vs. 16.9% and 2.9% vs. 2.4%, respectively). Octogenarians had a lower long-term survival at 1, 3 and 5 years (92.6% vs. 93.3%, 67.7% vs. 78.0% and 39.3% vs. 60.6%, P = 0.039) in the bivariate analysis. However, an age ≥ 80 years per se was not an independent predictor of survival after adjustment for confounding factors. CONCLUSION: An age above 80 years was not associated with an increased risk of postoperative complications or long-term mortality. Our results suggest that EVAR can be considered in elderly patients without a clear life-limiting condition and with a suitable aneurysm anatomy. Geriatr Gerontol Int 2021; 21: 392-397.

On the stability of Cu x Te polytypes: phase transitions, vibrational and electronic properties.

Based on the experimental structures reported for the Cu x Te (1 ⩽ x ⩽ 2) system, a theoretical study on stability and phase transitions has been performed. Three theoretical structures derived from rickardite (Cu1.5Te) were considered to represent different Cu/Te ratios (1, 1.5 and 2). The structural, electronic, and vibrational properties were calculated by density functional theory and compared to the experimental data available to date. This analysis showed that the proposed CuTe and Cu1.5Te structures are energetically and dynamically stable (unlike Cu2Te), and that their vibrational modes may play an important role in the reported Raman spectra for Cu x Te films. As well, it was found that being vulcanite the most stable phase for x = 1, the addition of Cu atoms to this structure induces a gradual flattening of the Cu planes, producing significant changes in the electronic band structure. A thorough review of the experimental reports on the electrical properties of the system was carried out. The experimental data showed that, in agreement with the calculations, the electrical conductivity is higher for phases with x ⩽ 1.5, decreasing as x gets closer to 2. Hence, the low-copper concentration phases are the best choice for solar cell applications due to their electrical properties and stability.

Magnetic Force Microscopy Study of Multiscale Ion-Implanted Platinum in Silica Glass, Recorded by an Ultrafast Two-Wave Mixing Configuration.

This study explores magnetization exhibited by nanoscale platinum-based structures embedded in pure silica plates. A superposition of laser pulses in the samples produced periodic linear arrangements of micro-sized structures. The samples were integrated by PtO2 microstructures (PtOΣs) with dispersed Pt oxide nanoparticles in their surroundings. The characterization of the materials was performed by high transmission electron microscopy studies. Furthermore, topographical and magnetic effects on the sample surfaces were analyzed by atomic force microscopy and magnetic force microscopy, respectively. The magnetic measurements indicated an enhancement in the gradient phase shift and in the gradient force related to the magnetic PtOΣs. The possibility of tuning the magnetic characteristics of the samples through contact with a Nd2Fe14B magnet was demonstrated. This process corresponds to an innovative method for obtaining magnetic PtOΣs induced by laser pulses. Moreover, an increase in the compactness of the silica with platinum-based structures was confirmed by an evaluation of the effective elastic modulus with reference to pure silica. The multimodal magnetic structures studied in this work seem to be candidates for developing high-density magnetic storage media.

Adipose tissue-derived mesenchymal stromal cells for treating chronic kidney disease: A pilot study assessing safety and clinical feasibility.

BACKGROUND: Chronic kidney disease (CKD) is a growing public health concern, and available treatments are insufficient in limiting disease progression. New strategies, including regenerative cell-based therapies, have emerged as therapeutic alternatives. Results from several groups, including our own, have reported evidence of a supportive role for mesenchymal stromal cells (MSCs) in functional recovery and prevention of tissue damage in murine models of CKD. Prompted by these data, an open pilot study was conducted to assess the safety and efficacy of a single injection of autologous adipose tissue-derived MSCs (AT-MSCs) for treatment of CKD. METHODS: AT-MSCs were infused intravenously into six CKD patients at a dose of 1 million cells/kg. Patients were stabilized and followed for one year prior to MSC infusion and one year following infusion. RESULTS: No patients presented with adverse effects. Statistically significant improvement in urinary protein excretion was observed in AT-MSCs transplanted patients, from a median of 0.75 g/day (range, 0.15-9.57) at baseline to 0.54 g/day (range, 0.01-2.66) at month 12 (P = 0.046). The glomerular filtration rate was not significantly decreased post-infusion of AT-MSCs. CONCLUSION: Findings from this pilot study demonstrate that intravenous infusion of autologous expanded AT-MSCs into CKD patients was not associated with adverse effects and could benefit patients already undergoing standard medical treatment.

Crystalline structure, electronic and lattice-dynamics properties of NbTe2.

Layered-structure materials are currently relevant given their quasi-2D nature. Knowledge of their physical properties is currently of major interest. Niobium ditelluride possesses a monoclinic layered-structure with a distortion in the tellurium planes. This structural complexity has hindered the determination of its fundamental physical properties. In this work, NbTe2 crystals were used to elucidate its structural, compositional, electronic and vibrational properties. These findings have been compared with calculations based on density functional theory. The chemical composition and elemental distribution at the nanoscale were obtained through atom probe tomography. Ultraviolet photoelectron spectroscopy allowed the first determination of the work function of NbTe2. Its high value, 5.32 eV, and chemical stability allow foreseeing applications such as contact in optoelectronics. Raman spectra were obtained using different excitation laser lines: 488, 633, and 785 nm. The vibrational frequencies were in agreement with those determined through density functional theory. It was possible to detect a theoretically-predicted, low-frequency, low-intensity Raman active mode not previously observed. The dispersion curves and electronic band structure were calculated, along with their corresponding density of states. The electrical properties, as well as a pseudo-gap in the density of states around the Fermi energy are characteristics proper of a semi metal.

Segmentation and additive approach: A reliable technique to study noncovalent interactions of large molecules at the surface of single-wall carbon nanotubes.

This investigation explores a new protocol, named Segmentation and Additive approach (SAA), to study exohedral noncovalent functionalization of single-walled carbon nanotubes with large molecules, such as polymers and biomolecules, by segmenting the entire system into smaller units to reduce computational cost. A key criterion of the segmentation process is the preservation of the molecular structure responsible for stabilization of the entire system in smaller segments. Noncovalent interaction of linoleic acid (LA, C18 H32 O2 ), a fatty acid, at the surface of a (10,0) zigzag nanotube is considered for test purposes. Three smaller segmented models have been created from the full (10,0)-LA system and interaction energies were calculated for these models and compared with the full system at different levels of theory, namely ωB97XD, LDA. The success of this SAA is confirmed as the sum of the interaction energies is in very good agreement with the total interaction energy. Besides reducing computational cost, another merit of SAA is an estimation of the contributions from different sections of the large system to the total interaction energy which can be studied in-depth using a higher level of theory to estimate several properties of each segment. On the negative side, bulk properties, such as HOMO-LUMO (highest occupied molecular orbital - lowest occupied molecular orbital) gap, of the entire system cannot be estimated by adding results from segment models. © 2016 Wiley Periodicals, Inc.

Basic fibroblast growth factor reduces functional and structural damage in chronic kidney disease.

Chronic kidney disease (CKD) is characterized by loss of renal function. The pathological processes involved in the progression of this condition are already known, but the molecular mechanisms have not been completely explained. Recent reports have shown the intrinsic capacity of the kidney to undergo repair after acute injury through the reexpression of repairing proteins (Villanueva S, Cespedes C, Vio CP. Am J Physiol Regul Integr Comp Physiol 290: R861-R870, 2006). Stimulation with basic fibroblast growth factor (bFGF) could accelerate this process. However, it is not known whether bFGF can induce this phenomenon in kidney cells affected by CKD. Our aim was to study the evolution of renal damage in animals with CKD treated with bFGF and to relate the amount of repairing proteins with renal damage progression. Male Sprague-Dawley rats were subjected to 5/6 nephrectomy (NPX) and treated with bFGF (30 µg/kg, NPX+bFGF); a control NPX group was treated with saline (NPX+S). Animals were euthanized 35 days after bFGF administration. Functional effects were assessed based on serum creatinine levels; morphological damage was assessed by the presence of macrophages (ED-1), interstitial α-smooth muscle actin (α-SMA), and interstitial collagen through Sirius red staining. The angiogenic factors VEGF and Tie-2 and the epithelial/tubular factors Ncam, bFGF, Pax-2, bone morphogenic protein-7, Noggin, Lim-1, Wnt-4, and Smads were analyzed. Renal stem cells were evaluated by Oct-4. We observed a significant reduction in serum creatinine levels, ED-1, α-SMA, and Sirius red as well as an important induction of Oct-4, angiogenic factors, and repairing proteins in NPX+bFGF animals compared with NPX+S animals. These results open new perspectives toward reducing damage progression in CKD.

Mesenchymal stem cell injection ameliorates chronic renal failure in a rat model.

CKD (chronic kidney disease) has become a public health problem. The therapeutic approaches have been able to reduce proteinuria, but have not been successful in limiting disease progression. In this setting, cell therapies associated with regenerative effects are attracting increasing interest. We evaluated the effect of MSC (mesenchymal stem cells) on the progression of CKD and the expression of molecular biomarkers associated with regenerative effects. Adult male Sprague-Dawley rats subjected to 5/6 NPX (nephrectomy) received a single intravenous infusion of 0.5×106 MSC or culture medium. A sham group subjected to the same injection was used as the control. Rats were killed 5 weeks after MSC infusion. Dye tracking of MSC was followed by immunofluorescence analysis. Kidney function was evaluated using plasma creatinine. Structural damage was evaluated by H&E (haematoxylin and eosin) staining, ED-1 abundance (macrophages) and interstitial α-SMA (α-smooth muscle actin). Repairing processes were evaluated by functional and structural analyses and angiogenic/epitheliogenic protein expression. MSC could be detected in kidney tissues from NPX animals treated with intravenous cell infusion. This group presented a marked reduction in plasma creatinine levels and damage markers ED-1 and α-SMA (P<0.05). In addition, treated rats exhibited a significant induction in epitheliogenic [Pax-2, bFGF (basic fibroblast growth factor) and BMP-7 (bone morphogenetic protein-7)] and angiogenic [VEGF (vascular endothelial growth factor) and Tie-2] proteins. The expression of these biomarkers of regeneration was significantly related to the increase in renal function. Many aspects of the cell therapy in CKD remain to be investigated in more detail: for example, its safety, low cost and the possible need for repeated cell injections over time. Beyond the undeniable importance of these issues, what still needs to be clarified is whether MSC administration has a real effect on the treatment of this pathology. It is precisely to this point that the present study aims to contribute.

Population history, phylogeography, and conservation genetics of the last Neotropical mega-herbivore, the lowland tapir (Tapirus terrestris).

BACKGROUND: Understanding the forces that shaped Neotropical diversity is central issue to explain tropical biodiversity and inform conservation action; yet few studies have examined large, widespread species. Lowland tapir (Tapirus terrrestris, Perissodactyla, Tapiridae) is the largest Neotropical herbivore whose ancestors arrived in South America during the Great American Biotic Interchange. A Pleistocene diversification is inferred for the genus Tapirus from the fossil record, but only two species survived the Pleistocene megafauna extinction. Here, we investigate the history of lowland tapir as revealed by variation at the mitochondrial gene Cytochrome b, compare it to the fossil data, and explore mechanisms that could have shaped the observed structure of current populations. RESULTS: Separate methodological approaches found mutually exclusive divergence times for lowland tapir, either in the late or in the early Pleistocene, although a late Pleistocene divergence is more in tune with the fossil record. Bayesian analysis favored mountain tapir (T. pinchaque) paraphyly in relation to lowland tapir over reciprocal monophyly, corroborating the inferences from the fossil data these species are sister taxa. A coalescent-based analysis rejected a null hypothesis of allopatric divergence, suggesting a complex history. Based on the geographic distribution of haplotypes we propose (i) a central role for western Amazonia in tapir diversification, with a key role of the ecological gradient along the transition between Andean subcloud forests and Amazon lowland forest, and (ii) that the Amazon river acted as an barrier to gene flow. Finally, the branching patterns and estimates based on nucleotide diversity indicate a population expansion after the Last Glacial Maximum. CONCLUSIONS: This study is the first examining lowland tapir phylogeography. Climatic events at the end of the Pleistocene, parapatric speciation, divergence along the Andean foothill, and role of the Amazon river, have similarly shaped the history of other taxa. Nevertheless further work with additional samples and loci is needed to improve our initial assessment. From a conservation perspective, we did not find a correspondence between genetic structure in lowland tapir and ecogeographic regions proposed to define conservation priorities in the Neotropics. This discrepancy sheds doubt into this scheme's ability to generate effective conservation planning for vagile species.

Building a culture of personal benefits responsibility.

Successfully having employees take personal responsibility for their benefits plans requires going beyond the rapid rollout of new benefit plan designs; it requires employers to invest in understanding the complexity of their workforce. This article reviews the evolution of benefit plans and what has arisen as the current state of employee benefits. It then discusses steps employers can take to build a successful total benefit strategy that recognizes the importance of the emerging workforce's racial, ethnic and cultural diversity.

Perfil epidemiológico de pacientes con baciloscopía positiva en el Hospital de Llanquihue entre enero de 2001 a junio de 2004 / Epidemiologic profile of patients with positive baciloscopy in Llanquihue's Hospital between january of 2001 to june of 2004

La tuberculosis pulmonar, enfermedad causada por la especie Mycobacterium tuberculosis, es una importante causa de muerte en Chile. Se notifican unos 3,8 millones de nuevos casos en el mundo, correspondiendo a unos 600000 casos en Latinoamérica. Objetivo: Identificar grupos de riesgo según sexo, edad y procedencia, para mejorar la salud local de Llanquihue. Se analizó el total de baciloscopías realizadas en el Hospital de Llanquihue, entre enero 2001 y junio 2004 de forma retrospectiva, utilizando el registro de estadística del laboratorio del Hospital. Las baciloscopías positivas se clasificaron según: edad, procedencia, año de diagnóstico y eficacia del tratamiento. Hubo 1662 baciloscopías, de las cuales 43 (2,6 por ciento) fueron positivas (32 pacientes); 56.2 por ciento correspondientes a hombres y 43,8 por ciento a mujeres. Más frecuentemente, los pacientes se afectaron entre los 40-59 años de edad. Casos curados: 78 por ciento. Entre 2001 y junio 2004, hubo cada año 6,17, 7 y 2 casos de baciloscopías positivas que correspondieron a un 18.8 por ciento, 53.1 por ciento, 21.9 por ciento y 6.2 por ciento, respectivamente; 75 por ciento de estos casos eran personas que vivían en Llanquihue, de los cuales un 50 por ciento residía en población Los Volcanes. Conclusiones: Grupo de riesgo: hombres, entre los 40 y 59 años de edad, domiciliados en un área común de Llanquihue, identificados como grupo de riesgo para detección precoz. El perfil epidemiológico coincide con el patrón hacia la eliminación, es decir, se afectan mayormente hombres mayores de 40 años y no se registra en menores de 15 años. La eficacia del tratamiento se encuentra dentro del promedio nacional.