Microfabrication-based engineering of biomimetic dentin-like constructs to simulate dental aging.

Human dentin is a highly organized dental tissue displaying a complex microarchitecture consisting of micrometer-sized tubules encased in a mineralized type-I collagen matrix. As such, it serves as an important substrate for the adhesion of microbial colonizers and oral biofilm formation in the context of dental caries disease, including root caries in the elderly. Despite this issue, there remains a current lack of effective biomimetic in vitro dentin models that facilitate the study of oral microbial adhesion by considering the surface architecture at the micro- and nanoscales. Therefore, the aim of this study was to develop a novel in vitro microfabricated biomimetic dentin surface that simulates the complex surface microarchitecture of exposed dentin. For this, a combination of soft lithography microfabrication and biomaterial science approaches were employed to construct a micropitted PDMS substrate functionalized with mineralized type-I collagen. These dentin analogs were subsequently glycated with methylglyoxal (MGO) to simulate dentin matrix aging in vitro and analyzed utilizing an interdisciplinary array of techniques including atomic force microscopy (AFM), elemental analysis, and electron microscopy. AFM force-mapping demonstrated that the nanomechanical properties of the biomimetic constructs were within the expected biological parameters, and that mineralization was mostly predominated by hydroxyapatite deposition. Finally, dual-species biofilms of Streptococcus mutans and Candida albicans were grown and characterized on the biofunctionalized PDMS microchips, demonstrating biofilm-specific morphologic characteristics and confirming the suitability of this model for the study of early biofilm formation under controlled conditions. Overall, we expect that this novel biomimetic dentin model could serve as an in vitro platform to study oral biofilm formation or dentin-biomaterial bonding in the laboratory without the need for animal or human tooth samples in the future.

Spatial biology of Ising-like synthetic genetic networks.

BACKGROUND: Understanding how spatial patterns of gene expression emerge from the interaction of individual gene networks is a fundamental challenge in biology. Developing a synthetic experimental system with a common theoretical framework that captures the emergence of short- and long-range spatial correlations (and anti-correlations) from interacting gene networks could serve to uncover generic scaling properties of these ubiquitous phenomena. RESULTS: Here, we combine synthetic biology, statistical mechanics models, and computational simulations to study the spatial behavior of synthetic gene networks (SGNs) in Escherichia coli quasi-2D colonies growing on hard agar surfaces. Guided by the combined mechanisms of the contact process lattice simulation and two-dimensional Ising model (CPIM), we describe the spatial behavior of bi-stable and chemically coupled SGNs that self-organize into patterns of long-range correlations with power-law scaling or short-range anti-correlations. These patterns, resembling ferromagnetic and anti-ferromagnetic configurations of the Ising model near critical points, maintain their scaling properties upon changes in growth rate and cell shape. CONCLUSIONS: Our findings shed light on the spatial biology of coupled and bistable gene networks in growing cell populations. This emergent spatial behavior could provide insights into the study and engineering of self-organizing gene patterns in eukaryotic tissues and bacterial consortia.

Carrot DcALFIN4 and DcALFIN7 Transcription Factors Boost Carotenoid Levels and Participate Differentially in Salt Stress Tolerance When Expressed in Arabidopsis thaliana and Actinidia deliciosa.

ALFIN-like transcription factors (ALs) are involved in several physiological processes such as seed germination, root development and abiotic stress responses in plants. In carrot (Daucus carota), the expression of DcPSY2, a gene encoding phytoene synthase required for carotenoid biosynthesis, is induced after salt and abscisic acid (ABA) treatment. Interestingly, the DcPSY2 promoter contains multiple ALFIN response elements. By in silico analysis, we identified two putative genes with the molecular characteristics of ALs, DcAL4 and DcAL7, in the carrot transcriptome. These genes encode nuclear proteins that transactivate reporter genes and bind to the carrot DcPSY2 promoter in yeast. The expression of both genes is induced in carrot under salt stress, especially DcAL4 which also responds to ABA treatment. Transgenic homozygous T3 Arabidopsis thaliana lines that stably express DcAL4 and DcAL7 show a higher survival rate with respect to control plants after chronic salt stress. Of note is that DcAL4 lines present a better performance in salt treatments, correlating with the expression level of DcAL4, AtPSY and AtDXR and an increase in carotenoid and chlorophyll contents. Likewise, DcAL4 transgenic kiwi (Actinidia deliciosa) lines show increased carotenoid and chlorophyll content and higher survival rate compared to control plants after chronic salt treatment. Therefore, DcAL4 and DcAL7 encode functional transcription factors, while ectopic expression of DcAL4 provides increased tolerance to salinity in Arabidopsis and Kiwi plants.

Carrot protoplasts as a suitable method for protein subcellular localization.

Carrot (Daucus carota) is a useful plant model for the study of carotenoid biosynthesis, specifically in roots which are enriched in carotenoids. Carrot genome and transcriptome sequences, complemented by optimized methods for carrot transformation, contribute to a comprehensive toolbox for exploring pathway regulation. To expand the repertoire of tools available for the study of D. carota, we present protocols for the isolation of protoplasts from D. carota cell suspension cultures and polyethylene glycol (PEG)-mediated transformation. To obtain carrot protoplasts, in vitro somatic embryogenesis from epicotyls is induced. The somatic embryogenic tissue that develops is transferred to liquid medium to obtain a suspension of cells which are homogenized and incubated with cell-wall degrading enzymes to release protoplasts. For transfection, protoplasts are incubated with a plasmid encoding a protein of interest prior to examination of protein localization by light microscopy. As an example, we demonstrate nuclear localization of a carrot transcription factor, DcAREB3.

A medical escape room to build intern workplace social capital in an internal medicine residency program.

PURPOSE: Trainee well-being is a growing focus in graduate medical education. One emerging area in occupational literature is the psychosocial environment of the workplace, of which a large component is workplace social capital (WSC). WSC encompasses how well a group connects to one another. Medical escape rooms (MERs) recently have been studied in various healthcare settings and are one proposed intervention to increase WSC. METHODS: This is a single-center before-and-after survey study at the Loyola University Medical Center in 2021 to measure the effect of a MER on WSC amongst interns. Our Chief Resident created a 1-hour MER. WSC scores were measured using a modified version of a validated WSC scale. Scores were analyzed with paired t-test analysis and chi-square analysis. Open-ended feedback was also collected. RESULTS: Of 52 eligible intern residents, 51 (98%) participated in the MER, and 41 (80%) completed the pre- and post-activity survey. All six survey statements had a greater percentage of positive responses following the MER. The average score across all participants and questions was 4.66 out of 5 on the pre-survey, and 4.90 on the post-survey (p < 0.001). CONCLUSIONS: The MER significantly improved intern resident WSC scores, and proved a valuable addition to our curriculum.

Acute Limb Ischemia Due to Arterial Thrombosis Associated With Coronavirus Disease 2019.

OBJECTIVES: To describe a case of acute limb ischemia caused by arterial thrombosis due to coronavirus disease 2019. DESIGN: Clinical observation of a patient. SETTING: Academic medical center. PATIENT: A 59-year-old female with history of hypertension, hyperlipidemia, and prior smoking. INTERVENTION: Clinical observation and data extraction from electronic medical records. MEASUREMENTS AND MAIN RESULTS: We report a case of peripheral arterial thrombosis associated with coronavirus disease 2019, resulting in acute limb ischemia of the right lower extremity. This event was heralded by a sudden and significant elevation in d-dimer levels. At the time of surgery, a long, gelatinous clot was retrieved from the right popliteal artery. Perioperatively, she continued to have absent pedal Doppler signals and after multiple embolectomy attempts, required distal arterial cut down with removal of additional thrombi and resultant improvement of distal arterial flow. CONCLUSIONS: This case demonstrates the importance of regularly checking d-dimer levels and vigilant monitoring for arterial thrombotic events, as they can rapidly become catastrophic.

A virtual ELISA to quantitate COVID-19 antibodies in patient serum.

Enzyme-linked immunosorbent assays (ELISAs) are used widely in biotechnology, pharmaceutical, and clinical medicine labs. At the same time, they appear to be underrepresented in chemistry and biochemistry curricula, even though their sensitivity, selectivity, and ease of use would argue for their widespread use. We describe here an online ELISA activity suitable for stand-alone use or in conjunction with an actual wet lab ELISA. Specifically, we offer real and mock data for a hypothetical ELISA to detect plasma antibodies to COVID-19 in infected patients who have had the disease. Much of the activity focuses on chemical and mathematical models to fit ELISA or any macromolecule/ligand binding data, a skill that addresses perhaps the most relevant and difficult learning goal of an ELISA experiment.

Pulmonary embolism response team implementation improves awareness and education among the house staff and faculty.

A subset of high-risk pulmonary embolism (PE) patients requires advanced therapy beyond anticoagulation. Significant variation in delivery of care has led institutions to standardize their approach by developing Pulmonary Embolism Response Team (PERT). We sought to assess the impact of PERT implementation on house staff and faculty education. After implementation of PERT, we employed a targeted educational intervention aimed to improve PERT awareness, familiarity with treatment options, role of echocardiogram and Doppler ultrasound, and knowledge of acute PE risk stratification tools. We conducted an anonymous survey among the house staff and faculty before and after intervention to assess the impact of PERT implementation on educational objectives among clinicians. Initial and follow up samples included 115 and 109 responses. The samples were well represented across the subspecialties and all levels of training, as well as junior and senior faculty. Following the educational campaign, awareness of the program increased (72.2-92.6%, p < 0.01). Proportion of clinicians with reported comfort level of managing PE increased (82.4-90.8%, p = 0.07). Proportion of clinicians with self-reported comfort with explaining all available treatment modalities to patients increased (49.1-67.9%, p = 0.005). Proportions of responders who correctly identified the role of echocardiography in risk stratification of patients with known PE increased (73.9-84.4%, p = 0.07). Accurate clinical risk stratification of acute PE increased (60.2-73.8%, p = 0.03). The implementation of a targeted educational program at a tertiary care center increased awareness of PERT among house staff and faculty and improved physician's accuracy of clinical risk stratification and comfort level with management of acute PE.

Increasing heroin, cocaine, and buprenorphine arrests reported to the Maine Diversion Alert Program.

BACKGROUND: The opioid overdose crisis is especially pronounced in Maine. The Diversion Alert Program (DAP) was developed to combat illicit drug use and prescription drug diversion by facilitating communication between law enforcement and health care providers with the goal of limiting drug-related harms and criminal behaviors. Our objectives in this report were to analyze 2014-2017 DAP for: (1) trends in drug arrests and, (2) differences in arrests by offense, demographics (sex and age) and by region. METHODS: Drug arrests (N=8193, 31.3% female, age=33.1±9.9) reported to the DAP were examined by year, demographics, and location. RESULTS: The most common substances of the 10,064 unique charges reported were heroin (N=2203, 21.9%), crack/cocaine (N=945, 16.8%), buprenorphine (N=812, 8.1%), and oxycodone (N=747, 7.4%). While the overall number of arrests reported to the DAP declined in 2017, the proportion of arrests involving opioids (heroin, buprenorphine, or fentanyl) and stimulants (cocaine/crack cocaine, or methamphetamine), increased (p<.05). Women had significantly increased involvement in arrests involving sedatives and miscellaneous pharmaceuticals (e.g. gabapentin) while men had an elevation in stimulant arrests. Heroin accounted for a lower percentage of arrests among individuals age >60 (6.6%) relative to young-adults (18-29, 22.3%, p<.0001). Older-adults had significantly more arrests than younger-adults for oxycodone, hydrocodone, and marijuana. CONCLUSION: Heroin had the most arrests from 2014 to 2017. Buprenorphine, fentanyl and crack/cocaine arrests increased appreciably suggesting that improved treatment is needed to prevent further nonmedical use and overdoses. The Diversion Alert Program provided a unique data source for research, a harm-reduction tool for health care providers, and an informational resource for law enforcement.

Descriptive, observational study of pharmaceutical and non-pharmaceutical arrests, use, and overdoses in Maine.

OBJECTIVES: The Maine Diversion Alert Program grants healthcare providers access to law enforcement data on drug charges. The objectives of this report were to analyse variations in drug charges by demographics and examine recent trends in arrests, prescriptions of controlled substances and overdoses. DESIGN: Observational. SETTING: Arrests, controlled prescription medication distribution and overdoses in Maine. PARTICIPANTS: Drug arrestees (n=1272) and decedents (n=2432). PRIMARY OUTCOME MEASURES: Arrestees were analysed by sex and age. Substances involved in arrests were reported by schedule (I-V or non-controlled prescription) and into opioids, stimulants or other classes. Controlled substances reported to the Drug Enforcement Administration (2007-2017) were evaluated. Drug-induced deaths (2007-2017) reported to the medical examiner were examined by the substance(s) identified. RESULTS: Males were more commonly arrested for stimulants and schedule II substances. More than two-thirds of arrests involved individuals under the age of 40. Individuals age >60 were elevated for oxycodone arrests. Over three-fifths (63.38%) of arrests involved schedule II-IV substances. Opioids accounted for almost half (44.6%) of arrests followed by stimulants (32.5%) and sedatives (9.1%). Arrests involving buprenorphine exceeded those for oxycodone, hydrocodone, methadone, tramadol and morphine, combined. Prescriptions for hydrocodone (-56.0%) and oxycodone (-46.9%) declined while buprenorphine increased (+58.1%) between 2012 and 2017. Deaths from 2007 to 2017 tripled. Acetylfentanyl and furanylfentanyl were the most common fentanyl analogues identified. CONCLUSIONS: Although the overall profile of those arrested for drug crimes in 2017 involve males, age <40 and heroin, exceptions (oxycodone for older adults) were observed. Most prescription opioids are decreasing while deaths involving opioids continue to increase in Maine.

Solid-Liquid Interdiffusion (SLID) Bonding of p-Type Skutterudite Thermoelectric Material Using Al-Ni Interlayers.

Over the past few years, significant progress towards implementation of environmentally sustainable and cost-effective thermoelectric power generation has been made. However, the reliability and high-temperature stability challenges of incorporating thermoelectric materials into modules still represent a key bottleneck. Here, we demonstrate an implementation of the Solid-Liquid Interdiffusion technique used for bonding Mmy(Fe,Co)4Sb12 p-type thermoelectric material to metallic interconnect using a novel aluminium⁻nickel multi-layered system. It was found that the diffusion reaction-controlled process leads to the formation of two distinct intermetallic compounds (IMCs), Al3Ni and Al3Ni2, with a theoretical melting point higher than the initial bonding temperature. Different manufacturing parameters have also been investigated and their influence on electrical, mechanical and microstructural features of bonded components are reported here. The resulting electrical contact resistances and apparent shear strengths for components with residual aluminium were measured to be (2.8 ± 0.4) × 10-5 Ω∙cm² and 5.1 ± 0.5 MPa and with aluminium completely transformed into Al3Ni and Al3Ni2 IMCs were (4.8 ± 0.3) × 10-5 Ω∙cm² and 4.5 ± 0.5 MPa respectively. The behaviour and microstructural changes in the joining material have been evaluated through isothermal annealing at hot-leg working temperature to investigate the stability and evolution of the contact.

Unraveling the induction of phytoene synthase 2 expression by salt stress and abscisic acid in Daucus carota.

Phytoene synthase (PSY) is the first committed enzyme of the carotenoid biosynthesis pathway and the most important point of regulation. Carotenoids are precursors of abscisic acid (ABA), which mediates abiotic stress tolerance responses in plants. ABA activates the synthesis of its own precursors through induction of PSY expression. Carrot, a species that accumulates very high amounts of carotenoids in its reserve root, has two PSY paralog genes that are expressed differentially in the root. Here, we determined that DcPSY2 expression is induced by salt stress and ABA. A DcPSY2 promoter fragment was obtained and characterized. Bioinformatic analysis showed the presence of three ABA responsive elements (ABREs). Through overexpressing pPSY2:GFP in Nicotiana tabacum we determined that all three ABREs are necessary for the ABA response. In the carrot transcriptome, we identified three ABRE binding protein (DcAREB) transcription factor candidates that localized in the nucleus, but only one, DcAREB3, was induced under ABA treatment in carrot roots. We found that AREB transcription factors bind to the carrot DcPSY2 promoter and transactivate the expression of reporter genes. We conclude that DcPSY2 is involved in ABA-mediated salt stress tolerance in carrot through the binding of AREB transcription factors to its promoter.

ZT Optimization: An Application Focus.

Significant research has been performed on the challenge of improving thermoelectric materials, with maximum peak figure of merit, ZT, the most common target. We use an approximate thermoelectric material model, matched to real materials, to demonstrate that when an application is known, average ZT is a significantly better optimization target. We quantify this difference with some examples, with one scenario showing that changing the doping to increase peak ZT by 19% can lead to a performance drop of 16%. The importance of average ZT means that the temperature at which the ZT peak occurs should be given similar weight to the value of the peak. An ideal material for an application operates across the maximum peak ZT, otherwise maximum performance occurs when the peak value is reduced in order to improve the peak position.

Straightforward Synthesis of 2- and 2,8-Substituted Tetracenes.

A simple regiospecific route to otherwise problematic substituted tetracenes is described. The diverse cores (E)-1,2-Ar1 CH2 (HOCH2 )C=C(CH2 OH)I (Ar1 =Ph, 4-MePh, 4-MeOPh, 4-FPh) and (E)-1,2-I(HOCH2 )C=C(CH2 OH)I, accessed from ultra-low cost HOCH2 C≡CCH2 OH at multi-gram scales, allow the synthesis of diol libraries (E)-1,2-Ar1 CH2 (HOCH2 )C=C(CH2 OH)CH2 Ar2 (Ar2 =Ph, 4-MePh, 4-iPrPh, 4-MeOPh, 4-FPh, 4-BrPh, 4-biphenyl, 4-styryl; 14 examples) by efficient Negishi coupling. Copper-catalysed aerobic oxidation cleanly provides dialdehydes (E)-1,2-Ar1 CH2 (CHO)C=C(CHO)CH2 Ar2 , which in many cases undergo titanium(IV) chloride-induced double Bradsher closure, providing a convenient method for the synthesis of regiochemically and analytically pure tetracenes (12 examples). The sequence is typically chromatography-free, scalable, efficient and technically simple to carry out.

Assessment and Training of Visuomotor Reaction Time for Football Injury Prevention.

CONTEXT: Neurocognitive reaction time has been associated with musculoskeletal injury risk, but visuomotor reaction time (VMRT) derived from tests that present greater challenges to visual stimulus detection and motor response execution may have a stronger association. OBJECTIVE: To assess VMRT as a predictor of injury and the extent to which improvement may result from VMRT training. DESIGN: Cohort study. SETTING: University athletic performance center. PARTICIPANTS: 76 National Collegiate Athletic Association Division-I FCS football players (19.5 ± 1.4 y, 1.85 ± 0.06 m, 102.98 ± 19.06 kg). INTERVENTIONS: Preparticipation and postseason assessments. A subset of players who exhibited slowest VMRT in relation to the cohort's postseason median value participated in a 6-wk training program. MAIN OUTCOME MEASURES: Injury occurrence was related to preparticipation VMRT, which was represented by both number of target hits in 60 s and average elapsed time between hits (ms). Receiver operating characteristic analysis identified the optimum cut point for a binary injury risk classification. A nonparametric repeated-measures analysis of ranks procedure was used to compare posttraining VMRT values for slow players who completed at least half of the training sessions (n = 15) with those for untrained fast players (n = 27). RESULTS: A preparticipation cut point of ≤85 hits (≥705 ms) discriminated injured from noninjured players with odds ratio = 2.30 (90% confidence interval, 1.05-5.06). Slow players who completed the training exhibited significant improvement in visuomotor performance compared with baseline (standardized response mean = 2.53), whereas untrained players exhibited a small performance decrement (group × trial interaction effect, L2 = 28.74; P < .001). CONCLUSIONS: Slow VMRT appears to be an important and modifiable injury risk factor for college football players. More research is needed to refine visuomotor reaction-time screening and training methods and to determine the extent to which improved performance values can reduce injury incidence.

Differential Contribution of the First Two Enzymes of the MEP Pathway to the Supply of Metabolic Precursors for Carotenoid and Chlorophyll Biosynthesis in Carrot (Daucus carota).

Carotenoids and chlorophylls are photosynthetic pigments synthesized in plastids from metabolic precursors provided by the methylerythritol 4-phosphate (MEP) pathway. The first two steps in the MEP pathway are catalyzed by the deoxyxylulose 5-phosphate synthase (DXS) and reductoisomerase (DXR) enzymes. While DXS has been recently shown to be the main flux-controlling step of the MEP pathway, both DXS and DXR enzymes have been proven to be able to promote an increase in MEP-derived products when overproduced in diverse plant systems. Carrot (Daucus carota) produces photosynthetic pigments (carotenoids and chlorophylls) in leaves and in light-exposed roots, whereas only carotenoids (mainly α- and ß-carotene) accumulate in the storage root in darkness. To evaluate whether DXS and DXR activities influence the production of carotenoids and chlorophylls in carrot leaves and roots, the corresponding Arabidopsis thaliana genes were constitutively expressed in transgenic carrot plants. Our results suggest that DXS is limiting for the production of both carotenoids and chlorophylls in roots and leaves, whereas the regulatory role of DXR appeared to be minor. Interestingly, increased levels of DXS (but not of DXR) resulted in higher transcript abundance of endogenous carrot genes encoding phytoene synthase, the main rate-determining enzyme of the carotenoid pathway. These results support a central role for DXS on modulating the production of MEP-derived precursors to synthesize carotenoids and chlorophylls in carrot, confirming the pivotal relevance of this enzyme to engineer healthier, carotenoid-enriched products.

Carotenoid Biosynthesis in Daucus carota.

Carrot (Daucus carota) is one of the most important vegetable cultivated worldwide and the main source of dietary provitamin A. Contrary to other plants, almost all carrot varieties accumulate massive amounts of carotenoids in the root, resulting in a wide variety of colors, including those with purple, yellow, white, red and orange roots. During the first weeks of development the root, grown in darkness, is thin and pale and devoid of carotenoids. At the second month, the thickening of the root and the accumulation of carotenoids begins, and it reaches its highest level at 3 months of development. This normal root thickening and carotenoid accumulation can be completely altered when roots are grown in light, in which chromoplasts differentiation is redirected to chloroplasts development in accordance with an altered carotenoid profile. Here we discuss the current evidence on the biosynthesis of carotenoid in carrot roots in response to environmental cues that has contributed to our understanding of the mechanism that regulates the accumulation of carotenoids, as well as the carotenogenic gene expression and root development in D. carota.

Thermoelectric Power Generation from Lanthanum Strontium Titanium Oxide at Room Temperature through the Addition of Graphene.

The applications of strontium titanium oxide based thermoelectric materials are currently limited by their high operating temperatures of >700 °C. Herein, we show that the thermal operating window of lanthanum strontium titanium oxide (LSTO) can be reduced to room temperature by the addition of a small amount of graphene. This increase in operating performance will enable future applications such as generators in vehicles and other sectors. The LSTO composites incorporated one percent or less of graphene and were sintered under an argon/hydrogen atmosphere. The resultant materials were reduced and possessed a multiphase structure with nanosized grains. The thermal conductivity of the nanocomposites decreased upon the addition of graphene, whereas the electrical conductivity and power factor both increased significantly. These factors, together with a moderate Seebeck coefficient, meant that a high power factor of ∼2500 µWm(-1)K(-2) was reached at room temperature at a loading of 0.6 wt % graphene. The highest thermoelectric figure of merit (ZT) was achieved when 0.6 wt % graphene was added (ZT = 0.42 at room temperature and 0.36 at 750 °C), with >280% enhancement compared to that of pure LSTO. A preliminary 7-couple device was produced using bismuth strontium cobalt oxide/graphene-LSTO pucks. This device had a Seebeck coefficient of ∼1500 µV/K and an open voltage of 600 mV at a mean temperature of 219 °C.

Reclaiming identity through service to dogs in need.

Dog Tags is an animal-assisted therapy offered by the Washington Humane Society (WHS) in partnership with the Walter Reed National Military Medical Center (WRNMMC). The program is open to all ranks of enlisted service members using WRNMMC services. Dog Tags is a 3-tiered certificate program allowing Soldiers, recovering at WRNMMC, to learn and apply progressively complex and challenging elements of canine positive reinforcement training to dogs awaiting adoption at the WHS. Although each tier is a self-contained and complete curriculum, subsequent tiers build on the skills and knowledge acquired in the previous one(s). Dog Tags Warrior/trainers work with fully-screened (health and temperament) shelter dogs to provide these dogs with mental stimulation, environmental enrichment, and socialization that are vital to their successful adoption and integration into new homes. The Soldiers also benefit because they develop new skills, build positive bonds with the dogs, and continue to serve their community.