Low Molecular Weight Research Articles

Metal-Organic Frameworks in Surface Enhanced Raman Spectroscopy-Based Analysis of Volatile Organic Compounds.

Volatile Organic Compounds (VOC) are a major class of environmental pollutants hazardous to human health, but also highly relevant in other fields including early disease diagnostics and organoleptic perception of aliments. Therefore, accurate analysis of VOC is essential, and a need for new analytical methods is witnessed for rapid on-site detection without complex sample preparation. Surface-Enhanced Raman Spectroscopy (SERS) offers a rapidly developing versatile analytical platform for the portable detection of chemical species. Nonetheless, the need for efficient docking of target analytes at the metallic surface significantly narrows the applicability of SERS. This limitation can be circumvented by interfacing the sensor surface with Metal-Organic Frameworks (MOF). These materials featuring chemical and structural versatility can efficiently pre-concentrate low molecular weight species such as VOC through their ordered porous structure. This review presents recent trends in the development of MOF-based SERS substrates with a focus on elucidating respective design rules for maximizing analytical performance. An overview of the status of the detection of harmful VOC is discussed in the context of industrial and environmental monitoring. In addition, a survey of the analysis of VOC biomarkers for medical diagnosis and emerging applications in aroma and flavor profiling is included.

Curcumin in Turmeric (Curcuma longa L.) for Treatment of Oral Lichen Planus: A Narrative Review

Background: Turmeric (Curcuma longa L.) has long been used as a traditional medicine. The primary active component of turmeric is curcumin. It has potential anti-inflammatory effects and high antioxidant activity. Curcumin contained in turmeric has been reported as an effective treatment for Oral lichen planus (OLP). OLP is a chronic autoimmune, inflammatory disease of the oral mucosa associated with systemic disease. This disease involves the skin and mucous membranes (mucocutaneous) of stratified squamous epithelium. Purpose: This narrative review conducted on Google Scholar, PubMed, Research Gate, and ScienceDirect databases aims to study the effectiveness of curcumin contained in Turmeric (C. longa L.) in OLP treatment. Review(s): OLP is a condition of the oral mucosa that is a chronic autoimmune mucocutaneous disease. As many as 0.5% to 2.2% of cases of OLP occur in the adult population. Systemic and topical corticosteroid drugs are usually used to treat OLP. However, the use of these drugs has many side effects, so it needs searching for a new active substance to treat OLP. Curcumin is a hydrophobic polyphenol extracted from the rhizome of the herb Curcuma longa (turmeric), which has a low molecular weight. The repeated use of steroids can cause side effects that cause atrophy of the mucosa and candidiasis. One natural product that is superior to corticosteroids is curcumin. This is due to curcumin's anti-inflammatory, antioxidant, and chemopreventive properties in several diseases. Conclusion: This review suggests that OLP treatment using curcumin in Turmeric (C. longa L.) is effective because curcumin exhibits antioxidant, anti-inflammatory, antimicrobial, and anticarcinogenic activities, as well as immunomodulatory properties.

Saccharina Japonica Polysaccharides Suppress High‐Fat Diet‐Induced Obesity and Modulate Gut Microbiota Composition and Function

Recent studies have highlighted the potential of Saccharina japonica Polysaccharides (SJPs) in alleviating high‐fat diet (HFD)‐induced obesity by regulating gut microbiota, which warrants further exploration to elucidate the underlying structure‐activity relationship. In this study, five polysaccharide fractions (Sj‐T, Sj‐T‐1, Sj‐T‐2, Sj‐T‐3, and Sj‐T‐4) with different structure characteristics were prepared from S. japonica, and their effects on HFD‐induced obesity and gut microbiota composition were investigated using C57BL/6J mice. The results revealed that oral administration of Sj‐T considerably suppressed HFD‐induced obesity, glucose metabolic dysfunction, and other disordered symptoms. While, Sj‐T‐2, which has the lowest molecular weight, was the most effective in alleviating HFD‐induced obesity and had the second‐best effect on improving HFD‐induced impaired glucose tolerance among the five SJPs. Supplementation with SJPs significantly modulated HFD‐induced gut microbiota dysbiosis both at the phylum and species levels, such as enriching Desulfobacterota and Actinobacteriota, while suppressing the abundance of Bacteroidota. Sj‐T also dramatically restored the gut microbiota composition by modulating the abundance of many crucial gut bacterial taxa, including s_Bacteroides_acidifaciens, s_Lachnospiraceae _bacterium, and g_Lachnospiraceae_NK4A136_group. Besides, SJPs also dramatically altered the function of gut microbiota, including many carbohydrate‐metabolism enzymes. This study highlights the potential of SJPs in preventing obesity and restoring intestinal homeostasis in obese individuals.

Impact of pre- and post-fermentation fining with polyvinylpolypyrrolidone on the chemical stability and aromatic profile of Viognier wine.

Polyvinylpolypyrrolidone (PVPP) is a synthetic, insoluble polymer that can be added to white wines to improve the chemical stability of the final product by precipitating unstable low molecular weight phenolic compounds responsible for visual defects and undesirable flavor characteristics (e.g., excessive bitterness and/or astringency). The objective of this study was to characterize the effects of PVPP on the quality characteristics of Viognier wine when added pre- or post-fermentation as compared to an untreated control wine. Both PVPP-treated wines contained significantly lower concentrations of monomeric phenolics and browning pigments than the control wine (p≤0.05). The addition of PVPP prior to fermentation conferred protection against oxidation of the wine as measured by acetaldehyde concentration (p≤0.05). Analysis of the volatile aroma profile of each wine by headspace solid phase microextraction gas chromatographymass spectrometry (HS-SPME-GC-MS)revealed that the overarching aroma profiles of the PVPP-treated wines were significantly different from the control wine, but there was no difference between wines treated with PVPP pre-fermentation versus those treated post-fermentation. Specifically, statistically significant differences were observed in 9 of the 22 quantified aroma compounds, including those notably associated with the "stone fruit" aroma of Viognier. A negative correlation was identified between aroma compound concentration removal and the hydrophobicity of each compound, suggesting that the observed differences in aroma may be due to adsorption of aroma compounds by PVPP. The findings from this study present risks and benefits to wine quality upon treatment with PVPP at commercially recommended levels, and provide potentially valuable information for industrial wine producers.

Synthesis and Characterization of Low Molecular Weight Irradiated Chitosan in Various Water Levels and Gamma-Ray Doses

Chitosan is a biopolymer derived from marine animal shell waste that exhibits numerous pharmacological activities. However, its high molecular weight limits the application in various fields due to its low solubility. Therefore, this study aims to synthesize low molecular weight chitosan using varying water content and doses of gamma irradiation. To initiate chitosan degradation, H2O (5 and 10 mL) was added, followed by gamma ray irradiation at doses of 5 and 10 kGy. The Molecular Weight (MW) of degraded chitosan was determined using Gel Permeation Chromatography (GPC), while Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize the functional groups and degree of deacetylation of chitosan. The study found that the molecular weight of irradiated chitosan decreased as the irradiation dose and H2O addition increased. The addition of 10 mL of water and gamma irradiation at a dose of 10 kGy has been found to reduce the molecular weight of chitosan to 118 kDa, with a high deacetylation degree of 86.78%. The FTIR analysis showed no significant changes in the functional groups, indicating that gamma irradiation did not affect the structure of chitosan.

Design and Characterization of Chitosan-Based Smart Injectable Hydrogel for Improved Sustained Release of Antinarcotics.

The treatment adherence of narcotics-addicted individuals with reduced incidences of relapse can be enhanced by a sustained drug release formulation of antinarcotics. So far, different drug formulations have been reported with sustained drug release periods of 28 and 35 days. To further enhance this duration, different formulations of injectable hydrogels (IHs) have been developed by combining low molecular weight (LMW) and high molecular weight (HMW) chitosan (CS) with guar gum (GG) and crosslinking them by sodium bi phosphate dibasic. The structural, morphological, and physicochemical properties of LMW-CS IH, and HMW-CS IH were evaluated using Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and rheological, swelling, and biodegradation analysis. The HMW-CS IH showed high crosslinking, increased thermal stability, high mechanical strength, elevated swelling, and low biodegradation. The antinarcotic drugs naltrexone (NTX) and disulfiram (DSF) were loaded separately into the HMW-CS IH and LMW-CS IH. The release of NTX and DSF was investigated in phosphate buffer saline (PBS) and ethanol (0.3%, 0.4%, and 0.5%) over a 56-day period using an UV spectrophotometer. The drug release data were tested in zero-order, first-order, and Korsemeyer-Peppas mathematical models. In PBS, all prepared formulations followed non-Fickian drug release, while in ethanol, only NTX HMW-CS IH followed non-Fickian release in all three different concentrations of ethanol.

Blood-supplementing effect of low molecular weight peptides of E-Jiao on chemotherapy-induced myelosuppression: evaluation of pharmacological activity and identification of bioactive peptides released in vivo.

Background: Equus asinus L. [Equidae; Asini Corri Colla] (donkey-hide gelatin, E-Jiao) is a traditional Chinese medicine renowned for its exceptional blood-supplementing effect. However, the specific components that contribute to its efficacy remain elusive. This study aimed to demonstrate that peptides are responsible for E-Jiao's blood-supplementing effect and to explore the specific peptides contributing to its efficacy. Methods: The low molecular weight peptides of E-Jiao (LMEJ) were obtained using an in vitro digestion method. LMEJ and peptides in the rat bloodstream were characterized by peptidomics analysis. The blood-supplementing effect of LMEJ was assessed using blood-deficient zebrafish and mouse models. The effect of the peptides detected in rat blood was evaluated using the same zebrafish model, and network pharmacology analysis was performed to investigate the underlying mechanisms. Results: A total of 660 unique peptides were identified within LMEJ. Both E-Jiao and LMEJ significantly alleviated myelosuppression in mice but only LMEJ attenuated myelosuppression in zebrafish. After the administration of E-Jiao to rats, 67E-Jiao-derived peptides were detected in the bloodstream, 41 of which were identical to those identified in LMEJ. Out of these 41 peptides, five were synthesized. Subsequent verification of their effects revealed that two of them were able to alleviate myelosuppression in zebrafish. Network pharmacology study suggested that E-Jiao may exert a blood-supplementing effect by regulating signaling pathways such as JAK-STAT, IL-17 and others. These results indicated that peptides are at least partially responsible for E-Jiao's efficacy. Conclusion: This study provides a crucial foundation for further exploration of the bioactive components of E-Jiao.

A production platform for disulfide-bonded peptides in the periplasm of Escherichia coli

BackgroundRecombinant peptide production in Escherichia coli provides a sustainable alternative to environmentally harmful and size-limited chemical synthesis. However, in-vivo production of disulfide-bonded peptides at high yields remains challenging, due to degradation by host proteases/peptidases and the necessity of translocation into the periplasmic space for disulfide bond formation.ResultsIn this study, we established an expression system for efficient and soluble production of disulfide-bonded peptides in the periplasm of E. coli. We chose model peptides with varying complexity (size, structure, number of disulfide bonds), namely parathyroid hormone 1–84, somatostatin 1–28, plectasin, and bovine pancreatic trypsin inhibitor (aprotinin). All peptides were expressed without and with the N-terminal, low molecular weight CASPON™ tag (4.1 kDa), with the expression cassette being integrated into the host genome. During BioLector™ cultivations at microliter scale, we found that most of our model peptides can only be sufficiently expressed in combination with the CASPON™ tag, otherwise expression was only weak or undetectable on SDS-PAGE. Undesired degradation by host proteases/peptidases was evident even with the CASPON™ tag. Therefore, we investigated whether degradation happened before or after translocation by expressing the peptides in combination with either a co- or post-translational signal sequence. Our results suggest that degradation predominantly happened after the translocation, as degradation fragments appeared to be identical independent of the signal sequence, and expression was not enhanced with the co-translational signal sequence. Lastly, we expressed all CASPON™-tagged peptides in two industry-relevant host strains during C-limited fed-batch cultivations in bioreactors. We found that the process performance was highly dependent on the peptide-host-combination. The titers that were reached varied between 0.6–2.6 g L−1, and exceeded previously published data in E. coli. Moreover, all peptides were shown by mass spectrometry to be expressed to completion, including full formation of disulfide bonds.ConclusionIn this work, we demonstrated the potential of the CASPON™ technology as a highly efficient platform for the production of soluble peptides in the periplasm of E. coli. The titers we show here are unprecedented whenever parathyroid hormone, somatostatin, plectasin or bovine pancreatic trypsin inhibitor were produced in E. coli, thus making our proposed upstream platform favorable over previously published approaches and chemical synthesis.

Enhancement in Anticancer Activity of Chitosan Tailored Imidazole-2-Thiosemicarbazones against MCF-7 Cancer Cell Line by Coordination with Copper(II) Ions

The coordination behavior of new batch synthesized chitosan imidazole-2-thiosemicarbazones tailored from both the low molecular weight commercial chitosan and high molecular weight crab shell chitosan was confirmed by Fourier Transform Infrared (FT-IR) and magnetic susceptibility measurements. Chlorine content in the complexes was estimated by potentiometric titration technique. The study showed the tridentate NNS tridentate coordination with copper (II) ion in a square planar orientation with the remaining valence satisfied by coordination with chloride ion. The MTT assay studies showed an enhancement in the anticancer activity of these chitosan thiosemicarbazone ligands upon their coordination with copper (II) ions against the human breast cancer (MCF-7) cell line in vitro. The minimal cytotoxicity of both the ligands and complexes against the normal mouse embryonic fibroblast (NIH3T3) cells revealed the selective attraction of these biomaterial chitosan derivatives towards the cancer cells with non-toxicity to healthy cells. There was only a marginal effect of molecular weight (Mw) and degree of deacetylation (DDA) of chitosan upon the anticancer activity of these chitosan derivatives.

Apixaban versus low molecular weight heparin in patients with cancer associated venous thromboembolism: A systematic review and meta analysis

Background: Optimal treatment regimen for patients with cancer-associated venous thromboembolism (CA-VTE) remain unclear. Therefore, we sought to compare the outcomes of (VKAs) versus direct apixaban and low molecular weight heparin (LMWH) in patients with CA-VTE. Methods: MEDLINE, Embase, and Cochrane Central databases were searched for randomized controlled trials (RCTs) and observational studies comparing efficacy and safety of apixaban and LMWH in patients with CA-VTE. Major bleeding, clinically relevant non major bleeding (CRNMB), recurrence of pulmonary embolism (PE), deep venous thrombosis (DVT) and bleeding related mortality were among outcomes of interest. Mantel-Haenszel weighted random-effects model was used to calculate relative risks (RRs) with 95 percent confidence intervals (CIs). Results: The analysis included 12011 patients from 3 RCTs and 2 observational studies. Compared to LMWH, apixaban significantly decreased the risk of major bleeding (RR 0.67 [95% CI 0.54, 0.83]; P=0.0003, I2=0%) without significantly changing the risk of clinically relevant non major bleeding (RR 0.96 [95% CI 0.64, 0.1.45]; P=0.85, I2=57%). Patients on apixaban had a noticeably reduced the risk of recurrence of PE than those taking LMWH, according to a meta-analysis (RR 0.56 [95% CI 0.32, 0.99]; P=0.05, I2=0%). There was no discernible difference between apixaban and LMWH in bleeding related mortality events (RR 0.20 [95% CI 0.01, 4.18]; P=0.30, I2=NA%), and recurrence of DVT (RR 0.60 [95% CI 0.22, 1.59]; P=0.23, I2=32%), Conclusion: Due to its lower risk of severe bleeding and reduced PE recurrence, apixaban may be a preferable treatment option for CA-VTE, but additional research is required to validate these conclusions and evaluate its long-term efficacy and safety.

Effectiveness of topical hyaluronic acid of different molecular weights in xerosis cutis treatment in elderly: a double-blind, randomized controlled trial.

Dry skin is a common dermatological condition that frequently affects the elderly. A contributing cause to dry skin is a reduced concentration of hyaluronic acid (HA) in both the epidermis and dermis. The effectiveness of moisturizer containing HA as a therapy for dry skin is impacted by its specific molecular weight. Low molecular weight HA (LMWHA) is believed to be more effective in replenishing skin hydration in aging skin compared to High Molecular Weight HA (HMWHA) due to its ability to penetrate the stratum corneum. However, there is a lack of clinical research supporting this claim. A double-blind, randomized controlled trial was conducted on 36 residents of a nursing home in Jakarta. The participants, aged between 60 and 80 years, had been diagnosed with dry skin. Each test subject was administered three distinct, randomized moisturizing lotions (LMWHA, HMWHA, or vehicle), to be topically applied to three separate sites on the leg. Skin capacitance (SCap), transepidermal water loss (TEWL), and specified symptom sum score (SRRC) were measured at weeks 0, 2, and 4. After four weeks of therapy, area that was treated with LMWHA showed greater SCap values compared to the area treated with HMWHA (56.37 AU vs. 52.37 AU, p = 0.004) and vehicle (56.37 AU vs. 49.01 AU, p < 0.001). All groups did not show any significant differences in TEWL and SRRC scores. No side effects were found in all groups. The application of a moisturizer containing LMWHA to the dry skin of elderly resulted in significant improvements in skin hydration compared to moisturizers containing HMWHA and vehicle. Furthermore, these moisturizers demonstrated similar safety in treating dry skin in the elderly. ClinicalTrials.gov Identifier NCT06178367, https://clinicaltrials.gov/study/NCT06178367 .

Proton-driven sodium secretion in a saline water animal

Aquatic animals residing in saline habitats either allow extracellular sodium concentration to conform to environmental values or regulate sodium to lower levels. The latter strategy requires an energy-driven process to move sodium against a large concentration gradient to eliminate excess sodium that diffuses into the animal. Previous studies of invertebrate and vertebrate species indicate a sodium pump, Na+/K+ ATPase, powers sodium secretion. We provide the first functional evidence of a saline-water animal, Aedes taeniorhynchus mosquito larva, utilizing a proton pump to power this process. Vacuolar-type H+ ATPase (VHA) protein is highly expressed on the apical membrane of the posterior rectal cells, and in situ sodium flux across this epithelium increases significantly in larvae held in higher salinity and is sensitive to Bafilomycin A1, an inhibitor of VHA. We also report the first evidence of splice variants of the sodium/proton exchanger, NHE3, with both high and low molecular weight variants highly expressed on the apical membrane of the posterior rectal cells. Evidence of NHE3 function was indicated with in situ sodium transport significantly inhibited by a NHE3 antagonist, S3226. We propose that the outward proton pumping by VHA establishes a favourable electromotive gradient to drive sodium secretion via NHE3 thus producing a hyperosmotic, sodium-rich urine. This H+- driven Na+ secretion process is the primary mechanism of ion regulation in salt-tolerant culicine mosquito species and was first investigated over 80 years ago.

Engineering a Hydrazone and Triazole Crosslinked Hydrogel for Extrusion-Based Printing and Cell Delivery.

Covalent adaptable crosslinks, such as the alkyl-hydrazone, endow hydrogels with unique viscoelastic properties applicable to cell delivery and bioink systems. However, the alkyl-hydrazone crosslink lacks stability in biologically relevant environments. Furthermore, when formed with biopolymers such as hyaluronic acid (HA), low molecular weight polymers (<60kDa), or low polymer content (<2 wt%) hydrogels are typically employed as entanglements reduce injectability. Here, a high molecular weight (>60kDa) HA alkyl-hydrazone crosslinked hydrogel is modified with benzaldehyde-poly(ethylene glycol)3-azide to incorporate azide functional groups. By reacting azide-modified HA with a multi-arm poly(ethylene glycol) (PEG) functionalized with bicyclononyne, stabilizing triazole bonds are formed through strain-promoted azide-alkyne cycloaddition (SPAAC). Increasing the fraction of triazole bonds within the hydrogel network from 0% to 12% SPAAC substantially increases stability. The slow gelation kinetics of the SPAAC reaction in the 12% SPAAC hydrogel enables transient self-healing properties and a similar extrusion force as the 0% SPAAC hydrogel. Methyl-PEG4-hydrazide is then introduced to further slowdown network evolution, which temporarily lowers the extrusion force, improves printability, and increases post-extrusion mesenchymal stem cell viability and function in the 12% SPAAC hydrogel. This work demonstrates improved stability and temporal injectability of high molecular weight HA-PEG hydrogels for extrusion-based printing and cell delivery.

Examining functional group-dependent effects on the ionization of lignin monomers using supercritical fluid chromatography/electrospray ionization mass spectrometry.

The chemical and biological conversion of biomass-derived lignin is a promising pathway for producing valuable low molecular weight aromatic chemicals, such as vanillin or guaiacol, known as lignin monomers (LMs). Various methods employing chromatography and electrospray ionization-mass spectrometry (ESI-MS) have been developed for LM analysis, but the impact of LM chemical properties on analytical performance remains unclear. This study systematically optimized ESI efficiency for 24 selected LMs, categorized by functionality. Fractional factorial designs were employed for each LM to assess ESI parameter effects on ionization efficiency using ultra-high-performance supercritical fluid chromatography/ESI-MS (UHPSFC/ESI-MS). Molecular descriptors were also investigated to explain variations in ESI parameter responses and chromatographic retention among the LMs. Structural differences among LMs led to complex optimal ESI settings. Notably, LMs with two methoxy groups benefited from higher gas and sheath gas temperatures, likely due to their lower log P and higher desolvation energy requirements. Similarly, vinyl acids and ketones showed advantages at elevated gas temperatures. The retention in UHPSFC using a diol stationary phase was correlated with the number of hydrogen bond donors. In summary, this study elucidates structural features influencing chromatographic retention and ESI efficiency in LMs. The findings can aid in developing analytical methods for specific technical lignins. However, the absence of an adequate number of LM standards limits the prediction of LM structures solely based on ESI performance data.

Underlying Roles of Polyol Additives in Promoting CO2 Capture in PEI/Silica Adsorbents.

Solid-supported amines having low molecular weight branched poly(ethylenimine) (PEI) physically impregnated into porous solid supports are promising adsorbents for CO2 capture. Co-impregnating short-chain poly(ethylene glycol) (PEG) together with PEI alters the performance of the adsorbent, delivering improved amine efficiency (AE, mol CO2 sorbed / mol N) and faster CO2 uptake rates. To uncover the physical basis for this improved gas capture performance, we probed the distribution and mobility of the polymers in the pores via small angle neutron scattering (SANS), solid-state NMR, and molecular dynamic (MD) simulation studies. SANS and MD simulations reveal that PEG displaces wall-bound PEI, making amines more accessible for CO2 sorption. Solid-state NMR and MD simulation suggest intercalation of PEG into PEI domains, separating PEI domains and reducing amine-amine interactions, providing potential PEG-rich and amine-poor interfacial domains that bind CO2 weakly via physisorption while providing facile pathways for CO2 diffusion. Contrary to a prior literature hypothesis, no evidence is obtained for PEG facilitating PEI mobility in solid supports. Instead, the data suggest that PEG chains coordinate to PEI, form larger bodies with reduced mobility compared to PEI alone. We also demonstrate promising CO2 uptake and desorption kinetics at varied temperatures, given by favorable amine distribution.

Sulfobetaine Zwitterions with Embedded Fluorocarbons: Synthesis and Interfacial Properties.

We describe the preparation of a new set of fluorinated sulfobetaine (FSB) zwitterionic polymers in which fluorocarbon moieties are attached directly to the zwitterionic components. An efficient two-step modification to the conventional sulfobetaine methacrylate monomer synthesis gave access to a series of polymer zwitterions containing varying extents of fluorocarbon character. FSB methacrylates proved amenable to homo- and copolymerizations using reversible addition-fragmentation chain transfer (RAFT) conditions, affording polymers with molecular weights ranging from 5 to 20 kDa and with low molecular weight distributions. Thin films of FSB homopolymers on glass proved stable to aqueous environments and exhibited increasing hydrophobicity with fluorocarbon content, as well as remarkably large water contact angle hysteresis values that enable pinning of water droplets on hydrophobic surfaces, reminiscent of the "petal effect" found in nature. FSB-containing copolymers in aqueous media demonstrated markedly reduced oil-water interfacial tension values, even with moderate (20-50 mol %) FSB incorporation.

Air-sea exchange of PAHs in the Taiwan Strait: Seasonal dynamics and regulation mechanisms revealed by machine learning approach

In this study, to understand the seasonal dynamics of air-sea exchange and its regulation mechanisms, we investigated polycyclic aromatic hydrocarbons (PAHs) at the air-sea interface in the western Taiwan Strait in combination with measurements and machine learning (ML) predictions. For 3-ring PAHs and most of 4- to 6-ring, volatilization and deposition fluxes were observed, respectively. Seasonal variations in air-sea exchange flux suggest the influence of monsoon transitions. Results of interpretable ML approach (XGBoost) indicated that volatilization of 3-ring PAHs was significantly controlled by dissolved PAH concentrations (contributed 24.0 %), and the gaseous deposition of 4- to 6-ring PAHs was related to more contaminated air masses originating from North China during the northeast monsoon. Henry’s law constant emerged as a secondary factor, influencing the intensity of air-sea exchange, particularly for low molecular weight PAHs. Among environmental parameters, notably high wind speed emerges as the primary factor and biological pump’s depletion of PAHs in surface seawater amplifies the gaseous deposition process. The distinct dynamics of exchanges at the air-water interface for PAHs in the western TWS can be attributed to variations in primary emission intensities, biological activity, and the inconsistent pathways of long-range atmospheric transport, particularly within the context of the monsoon transition.

Dinitrogen-bridged ruthenium(II) complexes featuring dithiocarbamate ligands

In quest of low molecular weight metal-thiolate complexes as model complexes for nitrogenase, four binuclear ruthenium(II) dinitrogen-bridged complexes featuring dithiocarbamate ligands, [{(Me3tacn)Ru(κ2-S2CNR2)}2(µ-N2)][PF6]2 (Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane; 1, R = Me; 2, R = Et; 3, R = nPr; 4, R = iPr), were synthesized by reduction of [(Me3tacn)RuIII(κ2-S2CNR2)Cl]PF6 with zinc powder in a nitrogen atmosphere. A 16-electron mononuclear ruthenium(II) species [(Me3tacn)Ru(κ2-S2CNnPr2)]PF6 (3′) was isolated during preparation of 3, which may help elucidate the formation of complexes 1-4. Molecular structures of complexes 1, 2, 4 and 3′ were established by single crystal X-ray diffraction analysis. Moreover, complexes 1-4 were characterized by infrared, 1H NMR, UV–vis, fluorescence, Raman (solid state and solution state) spectroscopies and mass spectrometry, and their electrochemical properties were also investigated. Density functional theory (DFT) calculation was performed on complex 2 to study its Lewis structure and explain the UV–vis absorption spectra. Structural and DFT analyses demonstrate that N2 activation is accompanied by electron redistribution of the dithiocarbamate ligands.

Association of Different Anticoagulation Strategies With Outcomes in Patients Hospitalized With Acute Pulmonary Embolism.

Background Therapeutic anticoagulation is the cornerstone of treatment for pulmonary embolism (PE), but the impact of different anticoagulation strategies on patient outcomes remains unclear. In this study, we assessed the association of different anticoagulation strategies with the outcomes of patients with acute PE. Methods A retrospective chart review of 207 patients with acute PE who were admitted to one of three urban teaching hospitals in the Mount Sinai Health System (in New York City) from January 2020 to September 2022 was performed. Demographic, clinical, and radiographic data were recorded for all patients. Multivariate regression analyses were performed to assess the association of different outcomes with the approach of therapeutic anticoagulation used. Results The median age of the included patients was 65 years, and 50.2% were women. The most common approach (n = 153, 73.9%) to therapeutic anticoagulation was initial treatment with unfractionated or low molecular weight heparin followed by a direct-acting oral anticoagulant (DOAC), while heparin alone (either unfractionated or low molecular weight heparin) was used in 37 (17.9%) patients, and another 17 (8.2%) patients were treated with heparin followed by bridging to warfarin. Hospital length of stay was longer for patients in the "heparin to warfarin" group (risk-adjusted incidence rate ratio of 2.52). The rates of in-hospital bleeding, all-cause 30-day mortality, and all-cause 30-day re-admissions did not have any significant association with the therapeutic anticoagulation approach used. Conclusion Patients with acute PE who were initially treated with heparin and subsequently bridged to warfarin had a longer hospital stay. Rates of in-hospital bleeding, 30-day mortality, and 30-day re-admission were not associated with the strategy of therapeutic anticoagulation employed.

Phthalate and phthalate replacement concentrations in relationship to adiposity in a multi-racial cohort of children.

Phthalates and phthalate replacements are used in multiple everyday products, making many of them bioavailable to children. Experimental studies suggest that phthalates and their replacements may be obesogenic, however, epidemiologic studies remain inconsistent. Therefore, our objective was to examine the association between phthalates, phthalate replacements and childhood adiposity/obesity markers in children. A cross-sectional study was conducted in 630 racial/ethnically diverse children ages 4-8 years. Urinary oxidative metabolites of DINCH and DEHTP, three low molecular weight (LMW) phthalates, and eleven high molecular weight (HMW) phthalates were measured. Weight, height, waist circumference and % body fat were measured. Composite molar sum groups (nmol/ml) were natural log-transformed. Linear regression models adjusted for urine specific gravity, sex, age, race-ethnicity, birthweight, breastfeeding, reported activity level, mother's education and pre-pregnancy BMI. All children had LMW and HMW phthalate metabolites and 88% had DINCH levels above the limit of detection. One unit higher in the log of DINCH was associated with 0.106 units lower BMI z-score [β = -0.106 (95% CI: -0.181, -0.031)], 0.119 units lower waist circumference z-score [β = -0.119 (95% CI: -0.189, -0.050)], and 0.012 units lower percent body fat [β = -0.012 (95% CI: -0.019, -0.005)]. LMW and HMW group values were not associated with adiposity/obesity. We report an inverse association between child urinary DINCH levels, a non-phthalate plasticizer that has replaced DEHP in several applications, and BMI z-score, waist circumference z-score and % body fat in children. Few prior studies of phthalates and their replacements in children have been conducted in diverse populations. Moreover, DINCH has not received a great deal of attention or regulation, but it is a common exposure. In summary, understanding the ubiquitous nature of these chemical exposures and ultimately their sources will contribute to our understanding of their relationship with obesity.