Minimal Exposure Research Articles

The Pronunciation Problems among Kurdish Learners of English

The goal of this study was to examine the pronunciation issues of different speakers of English and especially Kurdish speakers, and various perspectives on native vs foreign pronunciations. The research showed that Kurdish speakers had difficulties pronouncing several English vowels and some English consonants. The research results demonstrate that Kurdish English speakers understand the value of pronunciation compared to native and non-native English speakers. Kurdish speakers may hesitate to speak in a manner that seems natural to a native speaker, and their last consonants in words are almost always unaspirated and unvoiced. Given that Kurdish learners of English have difficulty pronouncing some English words, some suggested solutions include providing pronunciation instruction classes to language instructors, having educators speak in English, and giving students examples of native tongue sounds compared and contrasted with the target language sounds. With minimal exposure to cooperation with native speakers and variations in L1's phonological organization compared to English, the difficulty posed by pronunciation is evident. All the updated studies clearly show that these issues affect English speakers in general and rely less and less on their original tongue.

Introduction of a Novel Sequential Approach to the Ponte Osteotomy to Minimize Spinal Canal Exposure

Ponte osteotomy is an increasingly popular technique for multiplanar correction of adolescent idiopathic scoliosis. Prior cadaveric studies have suggested that sequential posterior spinal releases increase spinal flexibility. Here we introduce a novel technique involving a sequential approach to the Ponte osteotomy that minimizes spinal canal exposure. One fresh-frozen adult human cadaveric thoracic spine specimen with 4 cm of ribs was divided into three sections (T1-T5, T6-T9, T10-L1) and mounted for biomechanical testing. Each segment was loaded with five Newton meters under four conditions: baseline inferior facetectomy with supra/interspinous ligament release, superior articular process (SAP) osteotomy in situ, spinous process (SP) osteotomy in situ, and complete posterior column osteotomy with SP/SAP excision and ligamentum flavum release (PCO). Compared to baseline, in situ SAP osteotomy alone provided 3.5%, 7.6%, and 7.2% increase in flexion/extension, lateral bending, and axial rotation, respectively. In situ SP osteotomy increased flexion/extension, lateral bending, and axial rotation by 15%, 18%, and 10.3%, respectively. PCO increased flexion/extension, lateral bending, and axial rotation by 19.6%, 28.3%, and 12.2%, respectively. Our report introduces a novel approach where incremental increases in range of motion can be achieved with minimal spinal canal exposure and demonstrates feasibility in a cadaveric model.

Peripheral sensory function in non-freezing cold injury patients and matched controls.

What is the central question of this study? Is peripheral sensory function impaired in the chronic phase of non-freezing cold injury (NFCI)? What is the main finding and its importance? Warm and mechanical detection thresholds are elevated and intraepidermal nerve fibre density is reduced in individuals with NFCI in their feet when compared to matched controls. This indicates impaired sensory function in individuals with NFCI. Interindividual variation was observed in all groups, and therefore a diagnostic cut-off for NFCI has yet to be established. Longitudinal studies are required to follow NFCI progression from formation to resolution ABSTRACT: The aim of this study was to compare peripheral sensory neural function of individuals with non-freezing cold injury (NFCI) with matched controls (without NFCI) with either similar (COLD) or minimal previous cold exposure (CON). Thirteen individuals with chronic NFCI in their feet were matched with the control groups for sex, age, race, fitness, body mass index and foot volume. All undertook quantitative sensory testing (QST) on the foot. Intraepidermal nerve fibre density (IENFD) was assessed 10cm above the lateral malleolus in nine NFCI and 12 COLD participants. Warm detection threshold was higher at the great toe in NFCI than COLD (NFCI 45.93 (4.71)°C vs. COLD 43.44 (2.72)°C, P=0.046), but was non-significantly different from CON (CON 43.92 (5.01)°C, P=0.295). Mechanical detection threshold on the dorsum of the foot was higher in NFCI (23.61 (33.59) mN) than in CON (3.83 (3.69) mN, P=0.003), but was non-significantly different from COLD (10.49 (5.76) mN, P>0.999). Remaining QST measures did not differ significantly between groups. IENFD was lower in NFCI than COLD (NFCI 8.47 (2.36) fibre/mm2 vs. COLD 11.93 (4.04) fibre/mm2 , P=0.020). Elevated warm and mechanical detection thresholds may indicate hyposensitivity to sensory stimuli in the injured foot for individuals with NFCI and may be due to reduced innervation given the reduction in IENFD. Longitudinal studies are required to identify the progression of sensory neuropathy from the formation of injury to its resolution, with appropriate control groups employed.

Comparative effectiveness of virtual reality (VR) vs 3D printed models of congenital heart disease in resident and nurse practitioner educational experience

BackgroundMedical trainees frequently note that cardiac anatomy is difficult to conceive within a two dimensional framework. The specific anatomic defects and the subsequent pathophysiology in flow dynamics may become more apparent when framed in three dimensional models. Given the evidence of improved comprehension using such modeling, this study aimed to contribute further to that understanding by comparing Virtual Reality (VR) and 3D printed models (3DP) in medical education.ObjectivesWe sought to systematically compare the perceived subjective effectiveness of Virtual Reality (VR) and 3D printed models (3DP) in the educational experience of residents and nurse practitioners.MethodsTrainees and practitioners underwent individual 15-minute teaching sessions in which features of a developmentally typical heart as well as a congenitally diseased heart were demonstrated using both Virtual Reality (VR) and 3D printed models (3DP). Participants then briefly explored each modality before filling out a short survey in which they identified which model (3DP or VR) they felt was more effective in enhancing their understanding of cardiac anatomy and associated pathophysiology. The survey included a binary summative assessment and a series of Likert scale questions addressing usefulness of each model type and degree of comfort with each modality.ResultsTwenty-seven pediatric residents and 3 nurse practitioners explored models of a developmentally typical heart and tetralogy of Fallot pathology. Most participants had minimal prior exposure to VR (1.1 ± 0.4) or 3D printed models (2.1 ± 1.5). Participants endorsed a greater degree of understanding with VR models (8.5 ± 1) compared with 3D Printed models (6.3 ± 1.8) or traditional models of instruction (5.5 ± 1.5) p < 0.001. Most participants felt comfortable with modern technology (7.6 ± 2.1). 87% of participants preferred VR over 3DP.ConclusionsOur study shows that, overall, VR was preferred over 3DP models by pediatric residents and nurse practitioners for understanding cardiac anatomy and pathophysiology.

A prospective investigation of protective factors for moral injury and psychiatric symptomatology among Israeli combatants: A Latent Class Analysis approach.

In this prospective study, we examined pre-enlistment characteristics and pre-deployment protective factors of exposure to potentially morally injurious events (PMIEs) among Israeli active-duty combatants, as well as psychiatric symptomatology outcomes of exposure. A sample of 335 active-duty Israeli combatants participated in a 2.5-year prospective study with three waves of measurements (T1: 12 months before enlistment, T2: 6 months following enlistment- pre deployment, and T3: 18 months following enlistment- post deployment). Participants' characteristics were assessed via semi-structured interviews (T1) and validated self-report measures (T2-T3) between 2019 and 2021. Latent Class Analysis (LCA) was used to identify three classes characterized by unique patterns of exposure to PMIEs (T2): Minimal Exposure (56.6%), Betrayal-Only (25.5%), and High Exposure (17.8%). Higher levels of pre-deployment psychological flexibility (T1) were associated with higher odds for inclusion in the high exposure class (T2). As compared to the minimal exposure class, both high exposure and betrayal-only classes were associated with higher levels of mental health symptoms and MI-related psychological outcomes (T2). This is the first prospective study of antecedents and outcomes of exposure to PMIEs among active-duty combatants. Clinicians treating combatants should be aware of the different types of exposure to PMIEs and their possible psychiatric outcomes.

Phase I study of PTM-101 as neoadjuvant therapy for borderline resectable or locally advanced pancreatic ductal adenocarcinoma: A trial in progress.

TPS775 Background: While there have been tremendous advances in cancer treatment, critical challenges remain including limited ability of drugs to successfully reach the tumor, short half-life, and low retention rate on site. Local control of non-metastatic pancreatic adenocarcinoma (PDAC) remains a major challenge. Up to 40% of patients present with locally advanced and borderline resectable anatomy, for whom enhanced local downsizing of disease could improve symptoms and increase overall survival (OS). Targeted therapies with reduced systemic toxicity are needed for the treatment of PDAC since current therapies have not provided meaningful advances. PTM-101 is a paclitaxel-impregnated absorbable product which is designed for direct, sustained release of the therapeutic agent at the tumor site. Preclinical animal studies demonstrate that PTM-101 results in enhanced drug levels in the tumor compared with comparable systemic paclitaxel dosing leading to tumor reduction, metastasis inhibition and survival benefit (Indolfi et al, 2016). Large animal (i.e. pigs) and human cadaver studies show that PTM-101 can successfully be deployed to the peritumoral pancreatic surface by a standard laparoscopic procedure. Further, large animal studies show no evidence of neutropenia, pancreatitis, severe fibrosis or scarring, or infection after placement of PTM-101. Methods: This Phase I trial will assess the addition of PTM-101 prior to mFOLFIRINOX in 6 subjects with newly diagnosed borderline resectable or locally advanced PDAC. The primary objective is to assess the safety, toxicity and feasibility of a single administration of PTM-101. It is hypothesized that PTM-101 will be readily implanted during diagnostic laparoscopy and will result in clinically meaningful delivery of paclitaxel directly towards the tumor area with good tolerance and minimal local systemic exposure of drug. Patients enrolled and treated on study will be monitored closely for local and systemic toxicities as well as preliminary signals of efficacy. Enrollment is in progress and 3 patients have been enrolled and completed prospective follow up at the time of abstract submission. Clinical trial information: ACTRN12621000881831 .

Moral injury and psychosocial functioning in health care workers during the COVID-19 pandemic.

Studies of moral injury among nonmilitary samples are scarce despite repeated calls to examine the prevalence and outcomes of moral injury among civilian frontline workers. The purpose of this study was to describe the prevalence of moral injury and to examine its association with psychosocial functioning among health care workers during the COVID-19 pandemic. We surveyed health care workers (N = 480), assessing exposure to potentially morally injurious events (PMIEs) and psychosocial functioning. Data were analyzed using latent class analysis (LCA) to explore patterns of PMIE exposure (i.e., classes) and corresponding psychosocial functioning. The minimal exposure class, who denied PMIE exposure, accounted for 22% of health care workers. The moral injury-other class included those who had witnessed PMIEs for which others were responsible and felt betrayed (26%). The moral injury-self class comprised those who felt they transgressed their own values in addition to witnessing others' transgressions and feeling betrayed (11%). The betrayal-only class included those who felt betrayed by government and community members but otherwise denied PMIE exposure (41%). Those assigned to the moral injury-self class were the most impaired on a psychosocial functioning composite, followed by those assigned to the moral injury-other and betrayal-only classes, and finally the minimal exposure class. Moral injury is prevalent and impairing for health care workers, which establishes a need for interventions with health care workers in organized care settings. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Minimal Exposure Paths in Time-Varying Fields: A Semi-Lagrangian Approach

In the context of Wireless Sensor Networks (WSNs), the Minimal Exposure Path (MEP) represents an important metric to evaluate the quality of network services. Most of the current literature is concentrated on stationary sensors, while few works have addressed the existence of moving nodes. Mobile Wireless Sensor Networks (MWSNs) present a great potential for detecting invaders compared to static ones, but dealing with dynamic sensors significantly increases the coverage complexity since the overall exposure of the sensor field depends on time. Therefore, in this letter, we propose an approach to compute Minimal Exposure Paths in time-varying fields based on a control optimization method called semi-Lagrangian (SL) scheme, in such a way that an intruder will be able to penetrate the dynamic field with the lowest exposure. The SL has already been proven to reach the optimal Minimal Exposure Path (MEP) on static WSNs, but concerning dynamic nodes, the proof is much more complicated. Then, we propose a heuristics that provides convergence of the SL algorithm to a result we conjecture to be the optimal one. Results with different time-varying sensor models in obstacle-free and cluttered environments have been presented and discussed.

Dynamic, High-Fidelity, 3-Dimensional Pelvic Model Improves Education on Pelvic Organ Prolapse and the Pelvic Organ Prolapse Quantification System and Interest in Urogynecology.

Pelvic organ prolapse (POP) affects millions of women globally. Still, medical students and obstetrics and gynecology residents gain minimal exposure to POP during training. Our goal was to increase exposure to POP by creating a high-fidelity, dynamic, 3-dimensional pelvic model of prolapse and using it to teach through didactic learning sessions. This was a prospective cohort study from November 2021 to July 2022. Presession and postsession surveys were administered to assess for change in POP knowledge both subjectively and objectively. Statistical analysis was performed using the Wilcoxon signed-rank test with a P value of 0.05 denoting significance. Thirty-three learners participated in the study, including 18 residents and 15 medical students. Most participants had interacted with urogynecologists and had seen at least 1 patient with POP. Fewer participants had received prior education on POP and the Pelvic Organ Prolapse Quantification (POP-Q) examination, witnessed or performed a POP-Q examination, or participated in POP surgical procedures. After learning with the model, comfort with identifying POP doubled (P < 0.001), the ability to understand the POP-Q examination quadrupled (P < 0.001), the ability to perform a POP-Q examination tripled (P < 0.001), and the ability to teach a POP-Q examination doubled (P < 0.001). The median score on a multiple-choice knowledge assessment increased by 40% (P < 0.001). Learners felt that the pelvic model was an effective teaching tool that increased interest in the field of urogynecology. Using a high-fidelity, dynamic model in didactic sessions enhances education about POP and the POP-Q system and should be used to improve learner exposure and experience.

Determination of intensity and spread of light to the surrounding in conventional phototherapy and comparison with novel converging photo unit — an observational study

BackgroundBlue light phototherapy used extensively in the management of hyperbilirubinemia has many side effects like dry eyes, blurring, headache, and altered circadian rhythm. Healthcare providers working around the phototherapy are unduly exposed to these side effects. Altered circadian rhythm results in disruption in the sleep-wake cycle affecting healthcare providers particularly working during the night shift. The constant glare of the blue light interrupts in clinical observation of the baby on phototherapy. With the intent of providing effective phototherapy with minimal exposure of blue light to healthcare providers, a light source called the photo unit was designed and developed.The objective of this study was to estimate the intensity and spread of blue light to the surrounding in conventional phototherapy and to compare the same with newly developed converging photo unit.ResultsThe therapeutic range of irradiance was noted up to 22 inch in diameter with conventional phototherapy compared to only 7 inch with our photo unit. The light spread with a conventional phototherapy unit was seen beyond 50 inch in all directions whereas was confined to 19-inch diameter with photo unit.ConclusionPhoto unit developed by the authors has minimal divergence of light to the surrounding, thereby mitigating the side effects of blue light exposure to the people working in the vicinity. Multiple of these photo units can be used to make a phototherapy device.

MENINGKATKAN ENGLISH AWARENESS DENGAN FUN LISTENING ACTIVITY

Language awareness is a term that can help students use and learn English better. Language awareness that is owned will help motivate when someone learns a language. However, English as EFL (English as Foreign Language) in Indonesia presents a challenge to students who have minimal exposure to English. This community service aims to promote language awareness by using activities such as the interactive Fun Listening Activity. Respondents in this activity were parents of school students. The evaluation of this activity was considered good and enthusiastic parents could get ideas for a fun way of learning English for their children. After the community service activities were completed in the form of counseling, it can be concluded that respondents who took part in the activities were able to get new and fun ideas while learning English.

Small molecule inhibitors of intestinal epithelial anion exchanger SLC26A3 (DRA) with a luminal, extracellular site of action

The anion exchanger protein SLC26A3 (down-regulated in adenoma, DRA) is expressed in the luminal membrane of intestinal epithelial cells in colon, where it facilitates the absorption of Cl− and oxalate. We previously identified a 4,8-dimethylcoumarin class of SLC26A3 inhibitors that act from the SLC26A3 cytoplasmic surface, and demonstrated their efficacy in mouse models of constipation and hyperoxaluria. Here, screening of 50,000 new compounds and 1740 chemical analogs of active compounds from the primary screen produced five novel classes of SLC26A3-selective inhibitors (1,3-dioxoisoindoline-amides; N-(5-sulfamoyl-1,3,4-thiadiazol-2-yl)acetamides; thiazolo-pyrimidin-5-ones; 3-carboxy-2-phenylbenzofurans and benzoxazin-4-ones) with IC50 down to 100 nM. Kinetic washout and onset of action studies revealed an extracellular site of action for the thiazolo-pyrimidin-5-one and 3-carboxy-2-phenylbenzofuran inhibitors. Molecular docking computations revealed putative binding sites for these inhibitors. In a loperamide model of constipation in mice, orally administered 7-(2-chloro-phenoxymethyl)-3-phenyl-thiazolo [3,2-a]pyrimidin-5-one (3a) significantly increased stool weight, pellet number and water content. SLC26A3 inhibitors with an extracellular site of action offer the possibility of creating non-absorbable, luminally acting inhibitors with minimal systemic exposure following oral administration. Our findings also suggest that inhibitors of related SLC26 anion transporters with an extracellular site of action might be identified for pharmacological modulation of selected epithelial ion transport processes.

Transmission of radiant light energy through the sides of fiber posts.

Resin cements are light polymerized, but the light may not reach all areas of root canals. The purpose of this study was to determine the best predictor of transmitted light radiant exposure (TLRE) from posts' sides. Fiber posts were placed in a custom-made apparatus and advanced by 1-mm increments. The LED curing probe tip was activated for 40 s on the coronal end of the post. The TLRE was measured with an LED radiometer detector positioned on the side of the post exposed by an opening in the apparatus. Hierarchical multiple linear regression analysis was performed. Post system explained an additional 23.62% of the variation in TRLE. Adding actual post diameter explained an additional 62.64% of the variation in TRLE. While adding post length explained an additional 0.67%. Changing post system from FiberKleer to Postec Plus will decrease the mean value of TRLE by 4.90 units on average. Also, a one-unit increase of actual post diameter and length will decrease the value of TRLE by 44.96 and 0.44 units respectively. The TLRE ranged from 46 to 290 mJ/cm2 , which was between 0.73% and 6.63% of the original emanating light. The changes in post system, posts' diameter and length can be used to predict the unit changes in TLRE on the side of a translucent fiber post. Emanating radiant exposure from the side of the post was lower than 6.63% of the exposure entering the post. Fiber post diameter and length and post system can influence light radiant exposure transmitted from posts' sides, transmitting minimal radiant exposure, which can be increased by increasing curing duration.

A NOVEL GUT-RESTRICTED ARYL HYDROCARBON RECEPTOR AGONIST WITH ACTIVITY IN THE DEXTRAN SODIUM SULFATE COLITIS MURINE MODEL

Abstract BACKGROUND Patients with inflammatory bowel disease (ulcerative colitis, Crohn’s disease) have decreased production of endogenous aryl hydrocarbon receptor (AhR) ligands in colon tissue. Activation of the AhR is a potential novel therapeutic target for ulcerative colitis and may play an important role in promoting immune homeostasis through increased IL-22 production, downregulation of proinflammatory mediators, and improved epithelial barrier function. Indigo naturalis, a botanical extract containing potent AhR agonists, has been effective for the treatment of moderate-to-severe and treatment-refractory ulcerative colitis in multiple clinical studies. The most potent AhR agonist in indigo naturalis is indirubin. OBJECTIVE The objective was to develop novel indirubin prodrugs that maximize local colonic delivery and minimize systemic exposure to reduce the risk of potential systemic side effects. RESULTS We developed a novel synthetic small molecule prodrug of indirubin that maximizes colonic exposure and minimizes systemic exposure. In a dextran sodium sulfate (DSS)-induced colitis murine model, oral administration of our lead prodrug significantly reduced Disease Activity Index and weight loss similar in magnitude to indirubin. The prodrug resulted in colon concentrations of indirubin that were over 100-fold greater than plasma concentrations, and low systemic organ exposure. CONCLUSION Azora’s novel indirubin prodrug enhanced colonic delivery of indirubin while maintaining minimal systemic exposure in a DSS colitis murine model and may reduce the risk of systemic side effects. This compound may be suitable for development as a first-in-class oral AhR agonist for the treatment of ulcerative colitis.

Low levels of tenofovir in breast milk support breastfeeding in HBV-infected mothers treated with tenofovir disoproxil fumarate

ObjectiveTenofovir disoproxil fumarate (TDF) is recommended for the prevention of mother-to-infant transmission of the hepatitis B virus (HBV). This study investigated the safety of infants whose mothers continued to receive TDF while breastfeeding. Patients and methodThirty women taking TDF daily from the second or third trimester of pregnancy to three months postpartum were enrolled. Tenofovir (TFV) concentrations in breast milk were determined and compared with those in umbilical cord (UC) blood and amniotic fluid. Infant growth parameters were assessed at birth, and at 3, 6, and 12 months. TFV uptake experiments were conducted in vitro to elucidate the mechanisms of TFV exposure via breast milk. ResultsTFV concentrations in breast milk ranged from 1.4 to 11.7 ng/mL within 24 h after dosing in the third month postpartum. The median trough concentration of TFV in breast milk was 3.7 (interquartile range, 2.6–6.2) ng/mL, which is lower than that in UC blood (median = 53.5 ng/mL) and amniotic fluid (median = 531.0 ng/mL). The low permeability of TFV in MCF-10A cells may explain the minimal exposure to TFV in breast milk. Body weights, body lengths, and head circumferences of the breastfed infants were comparable to the national standards for physical development. ConclusionInfant exposure to TFV from breast milk is much lower than the exposure from placental transfer and swallowing from amniotic fluid. The physical growth parameters of all infants in this study were normal. The findings indicate that breastfeeding is safe for infants of HBV-infected mothers who continue to receive TDF through three months postpartum.

Hybrid reconstruction of the physical model with the deep learning that improves structured illumination microscopy

Structured illumination microscopy (SIM) has been widely used in live-cell superresolution (SR) imaging. However, conventional physical model-based SIM SR reconstruction algorithms are prone to artifacts in handling raw images with low signal-to-noise ratios (SNRs). Deep-learning (DL)-based methods can address this challenge but may lead to degradation and hallucinations. By combining the physical inversion model with a total deep variation (TDV) regularization, we propose a hybrid restoration method (TDV-SIM) that outperforms conventional or DL methods in suppressing artifacts and hallucinations while maintaining resolutions. We demonstrate the performance superiority of TDV-SIM in restoring actin filaments, endoplasmic reticulum, and mitochondrial cristae from extremely low SNR raw images. Thus TDV-SIM represents the ideal method for prolonged live-cell SR imaging with minimal exposure and photodamage. Overall, TDV-SIM proves the power of integrating model-based reconstruction methods with DL ones, possibly leading to the rapid exploration of similar strategies in high-fidelity reconstructions of other microscopy methods.

Effect of frequent exposures of various indigenous sugars on cariogenicity of a biofilm caries model.

The aim of this study was to assess and compare the cariogenicity of indigenous sugars (palm sugar, jaggery, and brown sugar) and refined sugar at different frequencies of exposure through a biofilm caries model. This in vitro study was conducted on 60 extracted human premolar teeth which were randomly divided into four groups (refined sugar, jaggery, palm sugar, and brown sugar) with each group being exposed to their respective sugars at one, three, and five frequencies for 5 min at defined time periods with five sample teeth for each exposure (4 × 3 × 5 = 60). The acidogenicity of biofilm was found by a 5-day pH cycling model. After 5 days, enamel demineralization, protein content, and polysaccharide formation of the biofilm following exposure to various sugars at various frequencies were assessed and compared. Statistical analyses were done using a one-way analysis of variance for intergroup comparisons between various sugars at various levels of frequencies. The enamel demineralization was found to be least in palm sugar with mean percentage surface hardness loss of 8%, 17%, and 25% at one, three, and five frequencies of exposures and this was found to be statistically significant compared to other sugars (P < 0.001). The acidogenicity of biofilm increased with an increase in the frequency of exposures, but none of the indigenous sugars had a drop below 5.5 (critical pH) at a single frequency of exposure indicating less acid production at minimal exposure. The protein content of the biofilm exposed to palm sugar was less on comparison with other sugars and it was found to be statistically significant (P < 0.001). The polysaccharide formation of all sugars was similar at each frequency of exposure and was statistically nonsignificant. From the results obtained, it was concluded that though cariogenicity increased in all sugars with an increase in frequency of exposure, the level of cariogenicity was least in palm sugar compared to other sugars used in the study. Hence, it is recommended to use palm sugar as an alternative to refined sugar.

RIS-Aided mmWave Network Planning Toward Connectivity Enhancement and Minimal Electromagnetic Field Exposure

RIS-Aided mmWave Network Planning Toward Connectivity Enhancement and Minimal Electromagnetic Field Exposure

Development of low-loss minimal exposure technique for thallium foil fabrication

Despite its availability as a solid bead or ingot, non-isotopic thallium metal is no longer commercially produced as a foil because of its high toxicity. To conduct fundamental studies on the material, the Stable Isotope Materials and Chemistry Group (SIMC) at Oak Ridge National Laboratory (ORNL) was approached to develop a safe method to process thallium and produce 40 non-isotopic thallium foils. The commercially sourced metal was consolidated into an ingot by melting the material in a special tube furnace under a reducing atmosphere. The resulting ingot was cold rolled using a work-hardened, stainless-steel pack and oil lubricant before cutting the final foils to 2.5 × 2.5 cm2 area and thickness of 50–75 mg/cm2. The appropriate safeguards used at each step are outlined to ensure the safe and consistent production of high-quality foils. The low-loss process enables future requests for isotopic thallium and other hazardous and rare materials.

Some remarks on Spanish in the bilingual world

AbstractThe core goal of this article consists of raising new questions about the status of Spanish in bilingual contexts. The starting point is that we observe tremendous variance in the repertoire, competence, and use of Spanish by bilinguals across the globe: from very fluent bilinguals to subtractive bilinguals (also known as heritage speakers) to overhearers, who heard Spanish in the background growing up but did not actively speak it. Setting the overhearer type aside, I contend that the other types of bilinguals meet the criteria for native speakerhood, which is nowadays understood in a more flexible and nuanced way than in more traditional variants of sociolinguistics. The discussion centers around the issues of the baseline (the language that serves as input to the bilingual upbringing), minimal exposure required for the acquisition of a language as a native one, and sociolinguistic models that allow for discontinuity in a given language community.