Reverse Conditions Research Articles

Trastuzumab-induced Takotsubo Cardiomyopathy leading to LV Thrombosis and Thromboembolic Stroke: A Case Report

Abstract Background Left ventricular thrombus (LVT) formation is an uncommon phenomenon, typically observed in acute cardiac settings and hypercoagulable states. Takotsubo cardiomyopathy (TC) is a reversible condition originally thought to be linked to immense emotional stress. The occurrence of chemotherapy-related cardiotoxicity presenting with TC and LVT formation is a relatively new concept that remains not fully understood. Case Summary We present the case of a 77-year-old woman with Stage IV breast cancer being treated with trastuzumab and capecitabine therapy, who presented to our hospital with symptoms of right-sided weakness, facial droop and slurred speech. She was admitted for acute left frontal lobe infarction due to an occluded distal left posterior M2 branch of the left middle cerebral artery. As part of thromboembolic stroke work-up, TTE was obtained which showed moderately to severely decreased left ventricular systolic function (LVEF 35%) with wall motion abnormalities suggestive of TC and a 0.9 x 1 cm echogenic structure in the LV consistent with LVT. She was started on therapeutic anticoagulation and was discharged on oral warfarin with INR goal of 2-3. Both capecitabine and trastuzumab were held during her hospitalization. Repeat TTE after two weeks showed an LVEF of 60% with normal LV systolic function and absence of any LVT. Symptoms-wise her right-sided weakness was improving. She was continued on capecitabine and warfarin for now, and continued to follow up outpatient with oncology, cardiology and neurology. Discussion This case highlights TC and LVT as rare but life-threatening complications of trastuzumab-induced cardiotoxicity. We emphasize the importance of early diagnosis to prevent further complications, such as acute thromboembolic stroke, and the necessity of prompt therapeutic interventions to reduce morbidity and mortality. Additionally, we address the multifactorial etiology of TC and the need for frequent TTE monitoring in patients undergoing trastuzumab therapy to diagnose these complications early.

Posterior Reversible Encephalopathy Syndrome in a Young Sudanese Female

Posterior reversible encephalopathy syndrome (PRES) is a rare, reversible radio-neurological condition. It commonly presents with seizures, visual disturbances, headaches, impaired level of consciousness, and other focal neurological findings. PRES is often associated with high blood pressure and can result from various causes, including autoimmune disorders, certain medications, and eclampsia. Pathophysiologically, it is characterized by reversible vasogenic cerebral edema predominantly in the occipital and parietal lobes. We report a case of a young Sudanese female with systemic lupus erythematosus (SLE), presenting with generalized seizures and headache. These symptoms occurred without fever and were associated with high blood pressure. Neuro- radiological imaging findings, typical clinical presentation, and the reversibility of the condition confirmed the diagnosis of PRES. This is, to the best of our knowledge, the first case report of PRES in SLE patients from El Obeid, North Kordofan, Western Sudan.

Posterior Reversible Encephalopathy Syndrome in a Young Sudanese Female

Posterior reversible encephalopathy syndrome (PRES) is a rare, reversible radio-neurological condition. It commonly presents with seizures, visual disturbances, headaches, impaired level of consciousness, and other focal neurological findings. PRES is often associated with high blood pressure and can result from various causes, including autoimmune disorders, certain medications, and eclampsia. Pathophysiologically, it is characterized by reversible vasogenic cerebral edema predominantly in the occipital and parietal lobes. We report a case of a young Sudanese female with systemic lupus erythematosus (SLE), presenting with generalized seizures and headache. These symptoms occurred without fever and were associated with high blood pressure. Neuro- radiological imaging findings, typical clinical presentation, and the reversibility of the condition confirmed the diagnosis of PRES. This is, to the best of our knowledge, the first case report of PRES in SLE patients from El Obeid, North Kordofan, Western Sudan.

Development and validation of a risk prediction model for acute kidney injury in coronary artery disease

BackgroundAcute Kidney Injury (AKI) is a sudden and often reversible condition characterized by rapid kidney function reduction, posing significant risks to coronary artery disease (CAD) patients. This study focuses on developing accurate predictive models to improve the early detection and prognosis of AKI in CAD patients.MethodsWe used Electronic Health Records (EHRs) from a nationwide CAD registry including 54 429 patients. Initially, univariate analysis identified potential predictors. Subsequently, a stepwise multivariate logistic model integrated clinical significance and data distribution. To refine predictor selection, we applied a random forest algorithm. The top 10 variables, including admission to the surgical department, EGFR, hemoglobin, and others, were incorporated into a logistic regression-based prediction model. Model performance was assessed using the area under the curve (AUC) and calibration analysis, and a nomogram was developed for practical application.ResultsDuring hospitalization, 2,112 (3.88%) patients in the overall population of both the development and validation groups experienced AKI within 30 days. The final prediction model exhibited strong discrimination with an AUC of 0.867 (95% CI: 0.858 to 0.876) and well calibration capability in both the development and validation groups. Key predictors included surgical department admission, eGFR, hemoglobin, chronic kidney disease history, male sex, white blood cell count, age, left ventricular ejection fraction, acute myocardial infarction at admission, and congestive heart failure history. Bootstrap resampling confirmed model stability (Harrell's optimism-correct AUC = 0.866). The nomogram provided a practical tool for AKI risk assessment.ConclusionThis study introduced a refined AKI risk prediction model for CAD patients. This model showed adaptability to subgroups and held the potential for early AKI alerts and personalized interventions, thereby enhancing patient care.

Enhanced Performance of Polymer Photodetectors Using a Metal-Doped Zinc Oxide Interfacial Layer.

Organic photodetectors (OPDs) are cheaper and more flexible than conventional photodetectors based on inorganic precursors, but their wider commercial application is limited by their low electron extraction efficiency under reverse bias conditions (when operating under photoconductive mode). Zinc oxide (ZnO) has shown promise as an electron transport layer for OPDs owing to its wide band gap, but its electron extraction efficiency has been limited by issues such as photoinstability and the formation of surface detects. This study investigated the effects of doping ZnO nanoparticles with indium gallium (i.e., Indium gallium zinc oxide (IGZO)) and ytterbium gallium (i.e., Ytterbium gallium zinc oxide (YGZO)) on the electron extraction efficiency, conductivity, and dark current suppression of the resulting OPD. Both dopants blended uniformly into the sol-gel ZnO framework, which reduced the roughness and improved the surface properties. Compared with ZnO, both IGZO and YGZO slightly shifted the absorption spectra and reduced the dark current density while improving the specific detectivity under reverse bias conditions. We introduce a metric called the Jones factor (JF) as the ratio of the specific detectivity under zero bias conditions to the specific detectivity under reverse bias conditions. Both IGZO and YGZO had much lower JF values than ZnO, which indicates that their specific detectivity drops much less than that of ZnO when the OPD shifts from photovoltaic mode (i.e., zero bias) to photoconductive mode (i.e., reverse bias). Thus, they are potentially better materials for the electron transport layer of the OPDs with a higher electron extraction efficiency.

Fusobacterium nucleatum and Treponema denticola are robust biomarkers for gingivitis and periodontitis in small dogs

IntroductionPeriodontal disease is one of the most common oral diseases in dogs and humans. It starts with gingivitis, a reversible condition, and progresses to an irreversible condition, periodontitis. Unlike humans, the etiology of periodontal disease in dogs has not been widely studied. Many studies suggest that bacteria strongly implicated in human periodontal disease might also play a role in canine periodontal disease. In contrast to studies examining only the prevalence of bacteria, a recent study analyzed 336 gingival crevicular fluid (GCF) samples in dogs to evaluate the prevalence of 11 putative periodontopathic bacteria and the correlation and association of bacterial numbers individually and in combination with periodontal disease stages. Results showed that Treponema denticola (Td) was a strong prognostic biomarker for periodontitis in dogs. However, a limitation of this study was that samples were grouped according to the periodontal status of the target tooth only, without assessment of the overall oral health. Furthermore, the findings of this study revealed a need for validation in a larger sample size.Materials and methodsThis study ensured that the overall oral health assessment of dogs under 20 kg matched with sampled groups, thus eliminating the influence of environmental factors on the results. Furthermore, 1,054 GCF samples were analyzed using quantitative real-time polymerase chain reaction (qPCR) for 12 bacteria, including the same 11 putative periodontopathic bacteria [Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Td, Fusobacterium nucleatum (Fn), Prevotella nigrescens (Pn), Prevotella intermedia (Pi), Parvimonas micra (Pm), Eubacterium nodatum (En), Campylobacter rectus (Cr), and Eikenella corrodens (Ec)] and Porphyromonas gulae (P. gulae), suspected to be a major causative agent of periodontitis in dogs in some statistical evaluatioins.ResultsInterestingly, the present study found that Fn was strongly associated with gingivitis and reconfirmed a strong association between Td and periodontitis (irreversible periodontal disease). However, Aa showed no relevance, and P. gulae was not significantly associated with periodontal disease in dogs in this study.ConclusionThese findings suggest that Fn and Td would be robust biomarkers for the severity of periodontal disease in small dogs.

The sensitivity to pragmatic-conceptual representations in garden path double relatives in L1 Mandarin

Abstract The aim of this study is to investigate how pragmatic-conceptual representations can be integrated into theories of first language acquisition. Experiment 1, using a sentence–picture judgment task, examined how children (N = 53, aged 4–6 years) used prosody boundaries as cues for a recursive interpretation when the recursive relatives (i.e., SO and OO)1 were garden path structures. The results showed that children below six-year had a stronger preference for recursive reading than adults under the conjunction-biased prosody condition and that children after six years of birth exhibited an adult-like preference for recursive readings under the recursion-biased prosody condition. Experiment 2 explored whether and how reversibility (e.g., “a dog eats a banana” vs “a dog kisses a cat”) in the action schema affected the production of OO and SO in Mandarin-speaking children (N = 137, age: 4–8 years). The results showed that adult-like production of OO in both reversible and irreversible conditions appeared at the age of six. The adult-like production ability of SO showed a one-year delay in the reversible condition (seven years under the reversible condition versus six years under the irreversible condition). The study suggests that some pragmatic-conceptual representations (such as the action schema) may be precursors of language and serve as a default analysis in language acquisition, while the mapping of the prosody domain onto syntax matures over time.

Atypical imaging manifestations in non-alcoholic Wernicke's encephalopathy: a potentially reversible neurological condition not to be missed.

Atypical imaging manifestations in non-alcoholic Wernicke's encephalopathy: a potentially reversible neurological condition not to be missed.

Predictive Factors of Amputation in Diabetic Foot.

Background: Diabetic foot ulcers are a common complication of diabetes mellitus, often leading to progressive sensory deficits, impaired vascularization, and a predisposition to ulceration and gangrene. Untreated ulcers may cause recurrent infections that endanger a patient's life. Amputation of part of the limb up to a well-vascularized level is one of the treatments employed for untreated ulcers. Objectives: Laboratory data were analyzed with the aim of identifying risk factors related to surgical amputation treatment of diabetic foot. We believe it is useful to identify risk factors that can be altered from a reversible condition in the clinical decision-making of treatment, thus manifesting themselves in a timely manner to provide the patient with an alternative to surgical amputation of the lower limb. Methods: Our retrospective study was conducted by the Department of Orthopedics and Traumatology at the Fondazione Policlinico Universitario Agostino Gemelli IRCCS in Rome. We recruited 200 patients who underwent lower limb amputation for diabetic foot between 2017 and 2021 and had blood tests both 30 days and within 5 days before the first surgery. Results: This case-control study revealed a significant negative correlation between hemoglobin (Hb) levels and the occurrence of leg amputations. In contrast, C-reactive protein (CRP) levels, the neutrophil-to-lymphocyte ratio (NLR), and the platelet-to-lymphocyte ratio (PLR) showed significant positive correlations with leg amputations. A 3-year follow-up of the cases also revealed a significative positive correlation between age, white blood cells (WBC) count, NLR, PLR, and death at 3 years. Conclusions: Our findings suggested that lower Hb levels and elevated CRP, NLR, and PLR levels in patients with diabetic foot disease may be associated with a higher risk of lower-limb amputation. Unexpectedly, this study also demonstrated that elderly age, WBC, CRP, NLR and PLR levels may be associated with a negative prognosis for these patients. These findings highlighted the importance of monitoring these laboratory values in diabetic patients to identify individuals at higher risk of leg amputations and implement appropriate interventions to prevent or minimize the occurrence of this severe complication.

Inline Measurement of Light Beam Induced Current (LBIC) Under High-Injection and Reverse Bias Conditions

Quality control in solar cell production relies on characterization methods that are fast enough to yield information on the properties of each solar cell in less than about one second. Imaging techniques such as electroluminescence (EL) are well established methods revealing spatially resolved quality mappings. Scanning techniques such as light beam induced current (LBIC) are common laboratory methods yielding complementary information but do not meet the speed requirements. In our work, we analyse an inline implementation of the LBIC method which is extended with respect to its measurement parameters, i.e., both the laser power and a solar cell bias-voltage are varied. As these extended conditions differ from conventional LBIC-applications at zero bias and low injection, we compare our inline-LBIC images with EL images and conventional LBIC images by means of an image contrast analysis. We find that our method resembles more the EL imaging as variations in the local series resistance are prominently detected. Thus, the proposed LBIC approach with extended measurement parameter range can yield both local short circuit information and local series resistance information. With our setup, measurement speeds around 700 ms are achieved.

Mechanism of Non-blasting Supercritical CO2 Fracturing in Rocks Under Reverse Fault Conditions: Dynamic and Quantitative Monitoring Using Coda Waves

Mechanism of Non-blasting Supercritical CO2 Fracturing in Rocks Under Reverse Fault Conditions: Dynamic and Quantitative Monitoring Using Coda Waves

Geometric theory of (extended) time-reversal symmetries in stochastic processes: I. Finite dimension

Abstract In this article, we analyze three classes of time-reversal of a Markov process with Gaussian noise on a manifold. We first unveil a commutativity constraint for the most general of these time-reversals to be well defined. Then we give a triad of necessary and sufficient conditions for the stochastic process to be time-reversible. While most reversibility conditions in the literature require knowledge of the stationary probability, our conditions do not, and therefore can be analytically checked in a systematic way. We then show that the mathematical objects whose cancellation is required by our reversibility conditions play the role of independent sources of entropy production. Furthermore, we give a geometric interpretation of the so-called irreversible cycle-affinity as the vorticity of a certain vector field for a Riemannian geometry given by the diffusion tensor. We also discuss the relation between the time-reversability of the stochastic process and that of an associated deterministic dynamics: its Stratonovitch average. Finally, we show that a suitable choice of a reference measure—that can be considered as a prior or a gauge, depending on the context—allows to study a stochastic process in a way that is both coordinate-free and independent of the prescription used to define stochastic integrals. When this reference measure plays the role of a gauge choice, we interpret our previous results through the lens of gauge theory and prove them to be gauge-invariant.

High-Performance Bipolar Membranes for Direct Seawater Electrolysis

Hydrogen (H2) is an important energy carrier for the development and maintenance of a low-carbon economy through sustainable energy generation. Direct seawater electrolysis (DSWE), which produces hydrogen using seawater, an infinite resource, as an electrolyte, is a very promising process. However, hydroxide ions generated from the hydrogen evolution reaction at the cathode cause precipitation of multi-valent cations contained in seawater, which blocks the active sites of the catalyst and induces high cell voltage. In this study, a high-performance bipolar membrane (BPM) was developed to effectively prevent the formation of inorganic deposits in the direct seawater electrolysis process. BPM has a structure in which a cation-exchange layer and an anion-exchange layer are superimposed and the characteristic of generating H+ and OH- ions by decomposing water molecules under reverse bias conditions. Therefore, the BPM has been actively used to produce acids and bases from salts, and its use has recently been expanding in energy conversion processes such as a fuel cell. In this study, a high-performance BPM was fabricated using woven fabric support and a specially designed transition metal-based catalyst that can significantly improve water decomposition performance. The prepared membrane had an efficient water-splitting catalyst and a 3D bipolar interface, showing excellent water-splitting capability and interfacial stability. In addition, it was confirmed that using the prepared BPM greatly contributes to stable hydrogen production when applied to the DSWE process. This work was supported in part by the NRF grants (NRF-2022M3H4A4097521) as well as by the framework of the research and development program of the KIER (No. C2-2473).

(Invited) Beta-Gallium Oxide-Based Devices Towards Grid-Scale Electronics

Gallium Oxide is an emerging ultra-wide band gap semiconductor with promising material properties relevant for high performance power electronic devices. The availability of large area bulk substrates using melt growth techniquesand the wide range of tunable n-type conductivity makes it a compelling semiconductor material platform for next-generation power devices. Lateral Devices: Homoepitaxial Si-doped channel layers are grown using metal-organic vapor phase epitaxy (MOVPE) on NCT and Synoptics (010) Ga2O3 bulk substrates after chemical cleaning to minimize impurities at the substrate-epitaxial layer interface, necessary for pinching off the lateral field effect transistors. Excellent electron mobilities, contact resistance values, breakdown voltages and power figures of merit are demonstrated in β-Ga2O3 epitaxial films and devices. MOVPE-grown β-Ga2O3 thin films with electron mobility values close to the predicted theoretical maximum (~ 200 cm2/Vs) are achieved at low (600°C) and high (800°C) growth temperatures. A low-temperature MOVPE masked ohmic contact regrowth technique is developed with a low contact resistance value. Multi-kilovolt (up to 4.5 kV) class β-Ga2O3 transistors are demonstrated with state-of-the-art power figures of merit exceeding several times the theoretical maximum of Silicon. A channel-buffer stack engineering is demonstrated that enabled record-high electron mobility values in doped β-Ga2O3 films. High-current (> 100 mA/mm) and VBR (up to ~ 3kV) β-Ga2O3 MOSFETs are realized on an engineered β-Ga2O3 /SiC composite substrate – for enhanced bottom-side device cooling. Tri-Gate β-Ga2O3 MESFETs with record high power figure of merit (~1 GW/cm2) are demonstrated. We report on the demonstration of kV-class β-Ga2O3 MOSFETs fabricated on 1-in. bulk substrates using metalorganic vapor phase epitaxy (MOVPE) with disilane (Si2H6) as the silicon precursor. In this talk, we will highlight some of these critical advances in β-Ga2O3 epitaxy/devices, pushing the boundary of β-Ga2O3device performance. Vertical Devices: Gallium Oxide devices are very attractive for next-generation grid-scale power rectifiers and transistors. We report a vertical β-Ga2O3 Schottky barrier diode (SBD) with BaTiO3 as field plate oxide on a low doped thick epitaxial layer exhibiting 2.1 kV breakdown voltage. A thick drift layer of 11 μm with a low effective doping concentration of 8 × 1015 cm–3 is used to achieve high breakdown voltage. Using the high-k dielectric with a dielectric constant of 248, the breakdown voltage increases from 816 V for the non-field-plated SBD to 2.1 kV (>2× improvement) for the field-plated SBD without compromising the on-state performance.We introduce vertical Schottky barrier diodes (SBDs) based on β-Ga2O3 with trench architecture, featuring a high-permittivity dielectric RESURF structure. These diodes are designed for application demanding high voltage and current capacities while maintaining ultra-low reverse leakage currents. The trench design plays a pivotal role in reducing the electric field at the metal–semiconductor junction, thereby yielding minimal reverse leakage attributed to field emission under high reverse bias conditions. Additionally, the incorporation of a high-k dielectric helps to suppress leakage through the trench bottom corner dielectric layer. The incorporation of a trench geometry, coupled with the high-permittivity dielectric RESURF, effectively reduces the surface electric field at the metal-semiconductor junction. This reduction facilitates the use of a lower work-function anode contact, further diminishing the turn-on voltage. The use of high-k dielectric also significantly reduces the dielectric leakage contribution to the overall reverse leakage of the diode. Large-area SBDs with areas of 1mm2 and 4mm2 exhibit pulsed forward current of 6A/20A and a catastrophic breakdown voltage of 1.74kV/1.4kV, surpassing other β-Ga2O3-based large-area power diodes, while small-area SBDs (200×200 µm2) do not exhibit catastrophic breakdown until 3kV. The large-area SBDs also demonstrate lower capacitance, stored charge, and stored energy compared to commercial SiC SBDs, indicating potential for superior switching performance. The combination of lower stored charge and a low forward voltage drop results in an excellent trade-off between conduction and switching power loss, yielding a QCVF figure of merit comparable to commercial bare die SiC SBDs.We report on the fabrication and characterization of a NiOx/β-Ga2O3 heterojunction diode (HJD) that uses a metallic Nickel (Ni) target to deposit NiOx layers via reactive RF magnetron sputtering and lift-off processing with >3 kV breakdown voltage, record-low reverse current leakage under high reverse bias, and high junction electric fields (4 MV/cm). The breakdown voltage was measured to be greater than 3 kV with a noise floor-level reverse leakage current density (~10-6 A/cm2) until 3 kV. Such rapid advances in Gallium Oxide device engineering will unleash the potential for these devices for next-generation grid-scale power electronics. We acknowledge funding from the Coherent/II–VI Foundation and AFOSR.

(Invited) Durability Analysis of Meas with Reversal Tolerant Anodes Under Repeated Cell Reversal Conditions

As regulations on greenhouse gas emissions are being strengthened, polymer electrolyte fuel cells (PEFCs) are being applied as a power source in a variety of applications. Mobility such as cars, ships, trains, airplanes, etc. have dynamic operating conditions. Because these operating conditions affect the durability of fuel cells, many studies have been reported analyzing durability of the membrane electrode assemblies (MEAs) by applying repeated operating conditions. 'Cell Reversal’, where the fuel cell voltage drops below 0V, is one of these operating conditions. This phenomenon is observed when electric energy is continuously consumed under hydrogen starvation conditions at the anode or when the required electric energy suddenly increases.In this talk, first, we attempted to find the optimal additive ratio by controlling the additive content of the electrode. Second, the durability of MEAs with three different types of electrocatalysts and additives was analyzed. Lastly, we will discuss strategies to further improve the durability of MEAs with additives in the anode. Acknowledgements This research was supported by a grant from Endowment project of “Development of Basic Technologies in Eco-friendly Ship Fuel Reliability and Safety Evaluation” funded by Korea Research Institute of Ships and Ocean Engineering (PES5100), and this research was also supported by a grant from “Development on operation and reliability verification technology of 1MW class eco-friendly ship fuel and power system under ocean environment (RS-2021-KS211507/PMS5950) funded by the Ministry of Oceans and Fisheries of Korea

Osteoporosis in older patients with idiopathic normal pressure hydrocephalus.

Idiopathic normal pressure hydrocephalus (iNPH), a potentially reversible condition with timely intervention, may cause cognitive impairment, balance and gait disturbance, and urinary incontinence in advanced age. Osteoporosis is a progressive metabolic bone disease that increases bone fragility in older adults. Both conditions may lead to falls and fractures. Therefore, this study aims to investigate osteoporosis in older adults with iNPH. A total of 64 patients diagnosed with iNPH and 458 participants in the control group were included in the study. Demographic and clinical characteristics, including age, sex, comorbidities, laboratory findings, and comprehensive geriatric assessment parameters, were recorded. Osteoporosis was defined according to the WHO classification. The relationship between osteoporosis and iNPH was assessed with regression analysis. The mean age was higher in the iNPH group than in the control group (79.91 ± 6.36 vs 75.86 ± 6.51years, p < 0.001). The frequency of female patients was higher in the control group than in the iNPH group (81% vs 70.3%, p = 0.046). The osteoporosis frequency was higher in the iNPH group than in the controls (51.6% vs 32.1%, p = 0.002). Adjusted for age and gender, iNPH was associated with osteoporosis (odds ratio (OR), 1.750; confidence interval (CI) 95%, 1.002-3.054; p = 0.049). This study showed that osteoporosis is more common in older patients with iNPH. Therefore, screening and treatment of osteoporosis in these individuals is crucial to avoid adverse health outcomes such as fractures.

Effect of hydrogen addition on the methane-air combustion under normal and reversed gravity

The existing scientific and technical results in the field of methane-air flames stabilization by adding hydrogen under various gravitational conditions were analyzed in relation to ensuring the safe operation of rocket and space power plants. Experimental setup was created for the purpose of studying the combustion stability of such fuel compositions under the various gravity conditions. The extended ranges of stable combustion rates were obtained experimentally at different percentages of hydrogen added to methane-air mixture under the both normal and reverse gravity conditions. The existence of a lean methane-hydrogen-air flame under reverse gravity in contrast to normal gravity conditions was observed. The influence of hydrogen addition on the dynamics and flame shape at such conditions was studied. The greater influence of hydrogen in ensuring stable combustion of a lean flame under reverse gravity than under normal gravity was demonstrated. Furthermore, the findings substantiated the rationale for utilizing hydrogen to expand the operational stability of burner devices.

SEPARATION OF POLYMETOXYLATED FLAVONE FROM CITRUS FRUIT FLAVEDO EXTRACTS UNDER “MONOMERIC” REVERSE PHASE HPLC CONDITIONS

For the first time, the regularities of retention of six polymethoxylated flavones from orange peel were determined under reversed-phase chromatography on “monomeric” C18 stationary phases. These flavonoids have received recent attention as compounds with unique biological activities, including (supposedly) effects on the development of intractable Alzheimer's and Parkinson's diseases. Sinensetin (3′,4′,5,6,7-pentamethoxyflavone), 3′,4′,3,5,6,7-hexamethoxyflavone, nobiletin (3′,4′,5,6,7,8-hexamethoxyflavone), 4′,5,6,7-tetramethoxyflavone, 3′,4′,3,5,6,7,8-heptamethoxyflavone and tangeretin (4′,5,6,7,8-pentamethoxyflavone) were found in orange flavedo extract. In the HPLC-friendly retention range (approximately retention factors from 2 to 20), the elution order of the six flavones mentioned above was found to remain unchanged for a number of different trademarks of stationary phases. The largest, but not critical, changes in retention order were found when using a column with increased activity of residual silanol groups. This allows for peak assignments taking into account literature data. Attention was drawn to the fact that the addition of a methoxy group to the structure of the flavone molecule at positions 3 and 8 leads to an increase in retention, while an unusual increase in retention is observed when a methoxy group is removed from position 3′ in the presence of another methoxy group at position 4′. In this case, the addition of methoxy groups both to positions 3 and 8, and to 3′ is accompanied by a bathochromic shift in the absorption maximum of band I, despite the fact that the electron transition in this case is localized on rings B and C. It has been shown that the use of lipophilicity parameters, logP, which can be calculated using several programs, provides results that can be used with caution when predicting the retention of polymethoxyflavones under reversed-phase HPLC conditions, since not all experimental relationships correlate with the calculated logP. For citation: Oleinits E.Yu., Deineka V.I., Pronin I.S., Deineka L.A. Separation of polymetoxylated flavone from citrus fruit flavedo extracts under “monomeric” reverse phase HPLC conditions. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 12. P. 25-32. DOI: 10.6060/ivkkt.20246712.7057.

Abstract 4138546: From Nature’s Remedy to Cardiac Emergency: A Case of Takotsubo Cardiomyopathy Induced by High-Dose Berberine Supplementation

Introduction: Takotsubo cardiomyopathy (TCM) is a reversible cardiac condition often precipitated by emotional or physical stress. Certain medications have also been implicated. While prognosis is generally favorable, associated QTc prolongation and ventricular arrhythmias can be life threatening, necessitating identification of potential triggers. This report highlights TCM in a patient using high-dose berberine, a plant alkaloid known for its hypoglycemic properties. Case description: A 69-year-old female with a history of type 2 diabetes mellitus, and hyperlipidemia presented after a syncopal event. It was preceded by sudden onset of dizziness, nausea, and vomiting. She had been using berberine for a year to lower her blood sugar and had recently switched to a higher dose of a more potent formulation. Vitals were unremarkable. Initial evaluation revealed a prolonged QTc interval of 659 ms (Figure 1A) and elevated troponin-I levels. She was treated with intravenous magnesium, which improved her QTc to 540 ms and revealed new T-wave inversions in the precordial leads. Echocardiogram showed an ejection fraction (EF) of 35%, with LV apical akinesia and hypercontractile basal segments. Cardiac catheterization ruled out significant coronary artery disease, leading to a diagnosis of TCM. Berberine was discontinued, and guideline-directed medical therapy was initiated. Given the presentation with syncope and high suspicion of aborted sudden cardiac death (SCD), she was discharged with a wearable cardioverter-defibrillator (WCD) as a precaution due to the risk of ventricular arrhythmias during recovery. At her 8-week follow-up, QTc and EF had normalized (Figure 1B), prompting WCD removal. Conclusion: The pathophysiology of berberine-induced cardiomyopathy remains uncertain and requires further research. This case underscores the importance of recognizing the potential cardiotoxic effects of berberine, particularly when used in high doses. A thorough medication and supplement history is crucial in patients presenting with unexplained cardiac symptoms. The reversible nature of TCM, when promptly recognized and treated, highlights the need for comprehensive follow-up to ensure recovery of cardiac function.

Bipolar Membranes With Controlled, Microscale 3D Junctions Enhance the Rates of Water Dissociation and Formation

AbstractA soft lithographic method is developed for making bipolar membranes (BPMs) with catalytic junctions formed from arrays of vertically oriented microscale cylinders. The membranes are cast from reusable polydimethylsiloxane (PDMS) molds made from silicon masters, which are fabricated on 2″ to 4″ wafer scales by nanosphere lithography. High‐aspect‐ratio junctions are made on a length scale similar to the thickness of optimized catalyst layers for water dissociation, creating a platform for probing the dual effects of catalysis and local electric field at the microscale BPM junction. Optimized polymer materials and nanoscale metal oxide catalysts are used in this study. 3D BPMs are tested under reverse and forward bias conditions, exhibiting superior performance relative to their 2D counterparts. Under forward bias in H2‐O2 fuel cells, 3D BPMs achieve a current density of 1500 mA cm−2, ≈7 times higher than 2D membranes made from the same materials.