Bridging Groups Research Articles

Optimal anticoagulation strategy for left ventricular assist device patients undergoing thoracentesis: a retrospective study

Abstract Background Left ventricular assist devices (LVADs) are associated with thromboembolic risks necessitating anticoagulation, yet balancing these risks with bleeding concerns remains challenging. Current practice involves warfarin with a target INR of 2-3 alongside anti-platelet therapy. However, consensus on anticoagulation management is lacking, particularly during sub-therapeutic INR or procedural settings. Common strategies include bridging anticoagulation with heparin or enoxaparin, temporary cessation of anticoagulation during the procedure or uninterrupted anticoagulation. Purpose To evaluate and compare the incidence of bleeding and thromboembolic events in LVAD patients undergoing thoracentesis, with a focus on determining the optimal anticoagulation strategy during procedures. Methods Retrospective data was collected over one year from LVAD patients undergoing thoracentesis at a large academic center. Patients were categorized into ‘bridge’ (received intravenous heparin for bridging during thoracentesis) and ‘no-bridge’ (did not receive bridging anticoagulation) groups. Warfarin was paused before procedure and resumed after procedure in both groups. Baseline characteristics, including age, sex, race, BMI, LVAD type, and INTERMACS profile, were recorded. Primary outcomes were major bleeding and thromboembolic events within 30 days of warfarin cessation. Statistical analysis used t-test/Wilcoxon for continuous variables and Chi-square/Fisher exact test for categorical variables. A p-value <0.05 was considered significant. Results During the study, twenty LVAD patients underwent thirty-two thoracenteses (nineteen bridge, thirteen no-bridge). The demographics were similar among the two groups. Warfarin was held for an average of 5.5 ± 4.6 days before and resumed 4.1 ± 4.6 days after the procedure in the bridge group and 3.8± 3.2 days before and 1.7 ± 2.5 days after in the no-bridge group. Major bleeding occurred in 73.7% of bridge group cases versus 30.8% of no-bridge group cases (p=0.059). 63.2% of bridge group patients had a bloody pleural effusion on thoracentesis compared to 46.2% of no-bridge group patients (p value= 0.34). Average transfusion requirements were 2.8 units and 2 units in the bridge and the no-bridge groups respectively (p=0.658). Thromboembolic events included a 10.5% ischemic CVA rate in the bridge group, with none in the no-bridge group. No other arterial thromboembolic events, pump thrombosis or DVT/PE were observed in either group. Conclusion In LVAD patients undergoing thoracentesis, a non-bridging strategy does not appear to elevate the risk of thrombosis compared to a bridging approach. Moreover, the incidence of bleeding, while not statistically significant, trended higher in the bridging group.

Results of hepatocellular carcinoma downstaging through hepatic transarterial chemoembolization in liver transplantation.

Liver transplantation plays an important role in treating hepatocellular carcinoma (HCC). However, diagnosis often occurs when the tumor size exceeds Milan criteria. In this context, locoregional treatments are frequently indicated. The aim of this study is to evaluate cirrhotic patients with HCC undergoing transarterial chemoembolization (TACE) for downstaging. This retrospective study assessed medical records of patients aged 18 years or older, diagnosed with HCC, who underwent TACE with the aim of downstaging. In the survival analysis, the Kaplan-Meier method was used. P-value <0.05 was considered statistically significant. One hundred and twenty-three patients were evaluated, of which 44.7% underwent liver transplantation after downstaging. Mortality in these patients was 32.7% and the probability of survival at 1, 2, and 5 years after liver transplantation was, respectively, 80%, 70.8%, and 57%. When comparing with the unsuccessful group, there was a significant difference regarding number of nodules, size of the largest nodule, and response by Modified Response Evaluation Criteria in Solid Tumor. The characteristics of the group undergoing TACE for downstaging and the group undergoing TACE as a bridge to transplantation were also compared, and patients were selected through the propensity score. A more significant number of nodules was observed in patients who underwent downstaging (P = 0.014) and they exceeded Milan criteria in the explanted liver more frequently (P = 0.007). Survival in the downstaging group and in the bridge group was not different (P = 0.342). Liver transplantation in patients with HCC after successful downstaging proved to be effective, as patients had adequate survival.

Clinical Outcomes of Concomitant Coronary Artery Bypass Grafting During Ventricular Septal Myectomy.

The clinical characteristics and survival outcomes of patients who underwent concomitant coronary artery bypass grafting during septal myectomy have not been well studied. We reviewed patients who underwent both septal myectomy and coronary artery bypass grafting from 2009 to 2020. Causes of concomitant grafting and their impact on survival were analyzed. The median follow-up period was 5.1 years. A total of 320 patients underwent both grafting and myectomy. Of these, 69.7% and 28.1% underwent grafting attributed to atherosclerotic coronary artery disease and myocardial bridging, respectively. Patients who underwent grafting for coronary artery disease tended to be older, had a longer bypass time, and required more grafts compared with patients undergoing procedures because of myocardial bridging (all P<0.05). Postoperatively, the left ventricular outflow gradient significantly decreased from 85.4 mm Hg to 12.8 mm Hg (P<0.001) without perioperative death. The cumulative survival rates were 96.2% and 97.6% at 5 years in the coronary artery disease and myocardial bridging groups, respectively, and they were comparable to that of general myectomy cohort (hazard ratio [HR], 1.06 [95% CI, 0.47-2.36], P=0.895 and HR 0.75 [95% CI, 0.23-2.46], P=0.636, respectively). Sudden death accounted for 45.5% (5 of 11) of postoperative mortality. Analysis of composite end point events showed decreased morbidity with at least one arterial graft in the overall cohort (HR, 0.47 [95% CI, 0.23-0.94], P=0.034). Concomitant grafting in septal myectomy was found to be a safe procedure. Patients who underwent such surgery experienced favorable postoperative outcomes comparable to those who underwent septal myectomy alone, with a 5-year survival rate of >95% and improved functional class of >90%.

Alkylaluminum Complexes Featuring Bridged Bis-Formylfluorenimide Ligands for Hydroboration of Aldehyde, Ketone, and Imines.

Three bis-formylfluorenimide ligands with different bridging groups were designed and synthesized, leading to the successful preparation of six novel alkylaluminum complexes through their reaction with alkylaluminum reagents (AlMe3 or AlEt3). Complexes 1 and 2 were obtained by the reaction of 1,2-propylene-bridged diamine (L1) with AlMe3 or AlEt3. By reacting 1,2-cyclohexylene-bridged diamine (L2) with AlMe3 or AlEt3 to obtain complexes 3 and 4. The above ligands formed a bidentate four-coordinate structure with alkylaluminum, which involved the elimination of one alkyl group as the ligand reacted with alkylaluminum. The complexes 5 and 6 were synthesized through the reaction of 1,2-phenylene-bridged diamine (L3) with AlEt3 in toluene or tetrahydrofuran. Notably, L3 exhibited unique reactivity compared with the other ligands, which formed a tridentate four-coordinated structure when reacting with alkylaluminum. The formation of the tridentate complex resulted from the introduction of a benzimidazole derivative or tetrahydrofuran (THF) molecule along with the elimination of two alkyl groups during its coordination with alkylaluminum. All complexes were characterized via 1H NMR, 13C NMR, and elemental analysis, with structural determination confirmed through X-ray. Furthermore, the catalytic activity in the hydroboration reaction of aldehyde, ketone, and imines was investigated with these complexes as catalysts. Among them, complex 1 demonstrated excellent catalytic performance (up to 99% yield) and broad substrate compatibility (more than 30 substrates) at low catalyst loading (1 mol %) under mild reaction conditions.

Integrative Neuro-social cognitive Strategy Programme for Instilling REcovery (INSPIRE): a community-based cognitive remediation trial-study procotol

BackgroundAdults with schizophrenia experience a range of neurocognitive problems that affect their daily functioning. Evidence for the efficacy of cognitive remediation in schizophrenia has been established, but its implementation in under-resourced community-based settings is less well-studied. In recent years, interventions have also focused on the strategy-learning approach in favor of drill-and-practice. Moreover, there is an increasing recognition to address social cognition and negative symptoms alongside neurocognition.This study attempts to carry out cognitive remediation in a community mental health setting. The Neuropsychological and Educational Approach to Remediation (NEAR) is used as the cognitive remediation intervention. Neurocognitive and social cognitive games will be introduced during the computer-assisted cognitive exercises sessions. In addition, the instructional technique will foster the use of metacognition and cognitive strategies. Moreover, metamotivation training will be the focus of some bridging sessions to enhance motivation to engage in goal-directed learning behaviors.The aims of the study are to 1) investigate the effects of cognitive remediation on neurocognition, social cognition and functional outcomes of participants with schizophrenia/schizoaffective disorders in community mental health settings; and 2) explore the mediators for change (eg: metamotivation, metacognition and negative symptoms) in cognitive performance and functional outcomes.MethodsThis randomized controlled trial will be conducted in three Singapore Anglican Community Services (SACS) centers, where standard psychiatric rehabilitation is delivered. Participants who are randomized to the experimental arm will receive cognitive remediation and psychiatric rehabilitation, while those randomized to the control arm will receive standard psychiatric rehabilitation only. Cognitive remediation is carried out three times a week for 12 weeks. It consists of computer-assisted cognitive exercises, as well as bridging groups to aid transfer of learning to daily living. Baseline, post-intervention and eight-week follow-up measurements will be collected. Group by time differences in cognitive performance, negative symptoms, metamotivation, metacognition, functioning and recovery will be analyzed across the three time points. Mediators for improvement in cognitive performance and functioning will also be explored.DiscussionFindings of this research will add to the body of knowledge about the key therapeutic ingredients within a strategy-based cognitive remediation program and improve its implementation within under-resourced community settings.Trial registrationThis study has been registered with ClinicalTrials.gov (ID: NCT06286202). Date of registration: 29 February 2024. Date of last update: 21 May 2024.

Prior coronary stent does not exclude major pulmonary resection regardless of antiplatelet therapy.

We assessed the safety of general thoracic surgery in patients with prior coronary stents undergoing lung resection, based on differences in perioperative antiplatelet therapy management. We retrospectively examined 150 patients with coronary artery stents who underwent pulmonary resection between July 2009 and July 2018. The impact of the antiplatelet agent on thoracic surgery safety was assessed by comparing perioperative outcomes, including major adverse cardiac and cerebrovascular events, among the discontinued antiplatelet therapy (group D), heparin bridging (group H), and continuous antiplatelet therapy (group C) groups. Groups D, H, and C included twenty-four, eighty-four, and forty-two patients, respectively. Second-generation drug-eluting stents were used in > 50% of the patients. No significant differences were found in the estimated blood loss, transfusion rate, or operative duration. Major adverse cardiac and cerebrovascular events occurred in four (2.7%) patients, which was comparable among the groups. In group H, postoperative heart failure and transient ischemic attack with stroke occurred in one patient each. Major bleeding occurred in two (4.7%) patients in group C. Pulmonary resection surgical outcomes in patients with coronary artery stents were feasible regardless of antiplatelet therapy continuation. However, discontinuing dual-antiplatelet or single-antiplatelet therapy in such patients may be reasonable because this generation of drug-eluting stents has a higher safety profile than bare-metal and first-generation drug-eluting stents.

DYNAMIC BEHAVIOUR AND DAMPING OF STEEL RAILWAY BRIDGES AT A SPEED OF 200 KM/H

AbstractThe subject of the paper is the comprehensive information on experiments carried out on a group of railway bridges near Břeclav, Vranovice and Soběslav, covering filler beams, steel girder bridges and composite bridges. The subject was to determine the behavior of bridges at higher speeds and to determine the value of damping as a basis for the preparation of HSR lines in the Czech Republic.This paper describes the structures investigated and recapitulates selected findings, particularly related to the damping. Also, the general findings from a number of tests focusing on damping are also given.

Synthesis of Hybrid Molecules with Imidazole-1,3,4-thiadiazole Core and Evaluation of Biological Activity on Trypanosoma cruzi and Leishmania donovani.

The aim of this work was to obtain and evaluate, as antiprotozoals, new derivatives of benzoate imidazo-1,3,4-thiadiazole 18-23 based on the concepts of molecular repositioning and hybridization. In the design of these compounds, two important pharmacophoric subunits of the fexnidazole prototype were used: metronidazole was used as a repositioning molecule, p-aminobenzoic acid was incorporated as a bridge group, and 1,3,4-thiadiazole group was incorporated as a second pharmacophore, which at position 5 has an aromatic group with different substituents incorporated. The final six compounds were obtained through a five-step linear route with moderate to good yields. The biological results demonstrated the potential of this new class of compounds, since three of them 19-21 showed inhibitory activity on proliferation, in the order of 50%, in the in vitro assay against epimastigotes of T. cruzi (Strain Y sensitive to nifurtimox and benznidazole) and promastigotes of L. donovani, at a single concentration of 50 μM.

A Novel Shunt Zigzag Double-Tap Low-Harmonic Multi-Pulse Rectifier Based on a Three-Stage Power Electronic Phase-Shifting Transformer.

To solve the problem of the large size of traditional industrial frequency phase-shift transformers and the harmonic distortion of multi-pulse wave rectifier systems, this paper proposes a three-stage shunt zigzag power electronic phase-shift transformer based on a double-tap multi-pulse wave rectifier, which combines the power factor correction (PFC) converter with the voltage-type SPWM inverter circuit to form a power electronic converter to realize the frequency boost and power factor correction. Through AC-DC-AC conversion, the frequency of the three-phase AC input voltage is increased, the number of core and coil turns in the transformer is reduced to reduce the size of the phase-shifter transformer, a zigzag structure of the phase-shifter transformer is used to solve the unbalanced distribution of current between the diode bridges, and a passive harmonic suppression method on the DC side is used to generate a loop current by using a group of single-phase rectifier bridges to regulate the input line current of the phase-shifter transformer. The phase-shifted voltage is input into two three-phase diode rectifier bridges to rectify and supply power to the load. Simulation and semi-physical test results show that the proposed method reduces the total harmonic distortion (THD) value of the input current of the phase-shifted transformer to 7.17%, and the THD value of the grid-side input current is further reduced to 2.49%, which meets the harmonic standard and realizes the purpose of power factor correction as well as being more suitable for high-power applications.

Facet Joint Bridging in Adolescent-Onset Adult Idiopathic Scoliosis with Thoracolumbar/Lumbar Curves

ObjectiveThis study aims to comprehend the natural history of Adolescent idiopathic scoliosis (AIS) patients and determine risk factors for facet joint bridging in adolescent-onset adult idiopathic scoliosis with thoracolumbar/lumbar (TL/L) curves. MethodsWe included 50 patients with residual AIS with TL/L curves (3 males, 47 females; age 41.5±17.3 years, TL/L Cobb angle 59.4±11.8°). They were >20 years old and diagnosed with AIS during their adolescence. Radiographic parameters were measured, and facet joint bridging was defined from axial computed tomography (CT) images. ResultsThe sagittal vertical axis (SVA) significantly increased with age (r=0.71, p<0.01). Coronal Cobb angle of the TL/L curve, L4 tilt, C7 translation, lumbar lordosis (LL), Pelvic incidence (PI) -LL, pelvic tilt (PT), and thoracolumbar kyphosis (TLK) were also correlated to age (p<0.05). There were significant differences in age, SVA, PI-LL, vertebral bridging, facet tropism, and apical vertebral rotation (AVR) between the facet joint bridging group (n=10) and the non-facet joint bridging group (n=40). In the multivariate logistic regression analysis, SVA, vertebral bridging, and AVR emerged as notable risk determinants for facet joint bridging. The threshold for facet joint bridging based on SVA was 2.1 cm (area under the curve [AUC]: 0.801; sensitivity = 90%, specificity = 65%). ConclusionThis research revealed that large SVA, the presence of vertebral bridging, and large AVR are associated with facet joint bridging in adolescent-onset adult idiopathic scoliosis patients with TL/L curves. The cut-off value for facet joint bridging based on SVA was 2.1cm.

Prokaryotic Expression, Purification, and Biological Properties of a Novel Bioactive Protein (PFAP-1) from Pinctada fucata.

Pinctada fucata meat is the main by-product of the pearl harvesting industry. It is rich in nutrition, containing a lot of protein and peptides, and holds significant value for both medicine and food. In this study, a new active protein was discovered and expressed heterogeneously through bioinformatics analysis. It was then identified using Western blot, molecular weight, and mass spectrometry. The antibacterial activity, hemolysis activity, antioxidant activity, and Angiotensin-Converting Enzyme II (ACE2) inhibitory activity were investigated. An unknown functional protein was screened through the Uniprot protein database, and its primary structure did not resemble existing proteins. It was an α-helical cationic polypeptide we named PFAP-1. The codon-optimized full-length PFAP-1 gene was synthesized and inserted into the prokaryotic expression vector pET-30a. The induced expression conditions were determined with a final isopropyl-β-d-thiogalactoside (IPTG) concentration of 0.2 mM, an induction temperature of 15 °C, and an induction time of 16 h. The recombinant PFAP-1 protein, with low endotoxin and sterility, was successfully prepared. The recombinant PFAP-1 protein exhibited strong antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) in vitro, and the diameter of the inhibition zone was 15.99 ± 0.02 mm. Its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 37.5 μg/mL and 150 μg/mL, respectively, and its hemolytic activity was low (11.21%) at the bactericidal concentration. The recombinant PFAP-1 protein significantly inhibited the formation of MRSA biofilm and eradicated MRSA biofilm. It also demonstrated potent 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) scavenging activity with a half-maximal inhibitory concentration (IC50) of 40.83 μg/mL. The IC50 of ACE2 inhibition was 5.66 μg/mL. Molecular docking results revealed that the optimal docking fraction of PFAP-1 protein and ACE2 protein was -267.78 kcal/mol, with a confidence level of 0.913. The stable binding complex was primarily formed through nine groups of hydrogen bonds, three groups of salt bridges, and numerous hydrophobic interactions. In conclusion, recombinant PFAP-1 can serve as a promising active protein in food, cosmetics, or medicine.

Prevalence and associated risk factors for men being paid for sex in Ethiopia: a multilevel analysis of 2016 Ethiopian demographic health survey data

Paying for sex is considered a high-risk sexual behavior, especially among men. Men who pay for sex are perceived to be a bridge group for sexually transmitted illnesses. In sub-Saharan Africa, the prevalence of paid sex among men is approximately 4.3%. Men paid for sex are not studied in Ethiopia. Therefore, the objective of this study was to identify factors associated with men paying for sex in Ethiopia. We analyzed data from the 2016 Ethiopian Demographic Health Survey. In the analysis, 9070 men were included. To identify factors associated with paid-for sex among men, we used a multilevel logistic regression model. A p value less than 0.05 was considered to indicate statistical significance at the 95% confidence interval (CI). In this study, 509 (5.6%) men were ever paid for sex. Men who paid for sex were significantly more likely to be rich [Adjusted Odds Ratio (AOR) = 1.70; 95% CI 1.287, 2.246], widowed or separated (AOR = 1.97; 95% CI 1.142, 3.396), had more sexual partners [AOR = 1.03; 95% CI 1.005, 1.063], had ever been tested for human immunodeficiency virus (HIV) (AOR = 1.50; 95% CI 1.173, 1.916), drank alcohol (AOR = 4.15; 95% CI 3.086, 5.576), and chewing khat (AOR = 2.28; 95% CI 1.822, 2.85); men who had ever paid for sex were significantly less likely to have higher education (AOR = .63; 95% CI .438, .898) and the lowest age at first sex (AOR = .90; 95% CI .870, .924). In conclusion, educational level, wealth status, province, marital status, age at first sexual intercourse, number of sexual partners, HIV status, alcohol consumption status, and chewing khat were significantly associated with men’s paid-for sex. From a public and sexual health perspective, more education is needed for illiterate, widowed, separated, and rich men. Additionally, preventive measures should be taken against men’s behavior through the use of alcohol or khat, having many sexual partners, and having young men.

Anastomotic tension "Bridging": a risk factor for anastomotic leakage following low anterior resection.

Excessive tension at the anastomosis contributes to anastomotic leakage (AL) in low anterior resection (LAR). However, the specific tension has not been measured. We assessed whether "Bridging," characterized by the proximal colon resembling a suspension bridge above the pelvic floor, is a significant risk factor for AL following LAR for rectal cancer. This retrospective study reviewed the medical records and laparoscopic videos of 102 patients who underwent laparoscopic LAR using the double stapling technique at Yachiyo Hospital between January 2014 and December 2023. Patients were classified based on whether they had Bridging (tight or sagging) or were in a Resting state of the proximal colon, and the association between Bridging and AL was examined. AL occurred in 31.3% of the Tight Bridging group, 20% of the Sagging Bridging group, and 2.2% of the Resting group (P = 0.002). The incidence of AL was significantly higher in patients with Bridging than in those without (23.2% vs. 2.2%, P = 0.003). Multivariate analysis revealed that Bridging is an independent risk factor for AL (odds ratio = 6.97; 95% confidence interval: 1.45-33.6; P = 0.016). The presence of Bridging is a significant risk factor for AL following LAR for rectal cancer, suggesting the need for implementing preventive measures in patients with this condition.

Step-by-step design of new phenyl-1,2,3-triazole derivatives with improved anti-corrosive properties: A combined DFT and MD simulation study

In this study, 35 new inhibitors were designed theoretically through the step-by-step strategy based on a new organic non-planar inhibitor 1-benzyl-4-phenyl-1H-1,2,3-triazole (BPT). The first step is to replace one parent phenyl group by six other groups (–Cl, –Br, –OH, –NH2, –OCH3, –thiazole) with heteroatoms, trying to add the adsorption sites and reduce the energy gap. The second step is to use two bridge groups (–S–, –NH–) to displace the original bridge group (–CH2), or to delete the bridge group directly, tending to further add the adsorption sites, reduce the energy gap and change BPT to planar molecules. The final step is to use the combination of oxa and carbonylation substitution strategy on the six compounds with lowest energy gap obtained from the previous two step modifications, in order to further add the adsorption sites, reduce the energy gap and change BPT to planar molecules. Based on the quantum chemical calculations, it is found that main key parameters to anti-corrosive properties like the softness, electron affinity and energy gap were improved greatly compared to BPT. Three new planar molecules (E5, E6 and E6) which have high chemical reactivity, high binding energy with metals, and low energy gap were found successfully, which may be attractive potential inhibitors used as the corrosion inhibition to Fe-related alloy. The corrosion inhibition mechanism of E5 to E7 is different to that of BPT, in which the whole structure will make contributions to the interaction with metals to increase the binding energy and the corrosion inhibition efficiency. This work may provide a unique view for the design and development of new advanced inhibitor.

Rational design of an AIEgen for imaging lipid droplets polarity change during ferroptosis

Ferroptosis can regulate cell death by accumulating lipid peroxides, affecting the structure and polarity of lipid droplets (LDs), but clear evidence is still lacking. Fluorescence imaging is the most powerful technique for studying LDs’ function. However, developing AIE fluorescent probes with high selectivity and sensitivity for targeting LDs remains challenging. In this study, we rationally designed an AIEgen, as a novel fluorescent probe TPE-BD, by constructing a push-pull electron structure. The probe has benzo[b]thiophene-3(2H)-one 1,1-dioxide as the electron acceptor, tetraphenylethylene (AIE skeleton) as the electron donor, and thiophene as the bridging group. The optical performance of probe TPE-BD indicated that the UV–visible absorption spectrum of the probe was minimally affected by solvent polarity (except for glycerol and PBS solvents), but the fluorescence of probe is very sensitive to changes in polarity, achieving the goal of polarity detection in LDs. CCK-8 assay and cell imaging experiments demonstrated that probe TPE-BD exhibited good cell compatibility and effectively targeted LDs, enabling the monitoring of LDs’ polarity and quantity during ferroptosis.

Two new 3-D vanadoborates incorporating rare polymeric K-O-K chain or network with photocatalytic properties

The discovery of novel high-dimensional vanadorates with important photocatalytic properties is of great importance in structural chemistry and materials science. Herein, new types of three-dimensional (3-D) vanadoborates (H3O)2{[K6(H2O)10][Ni(H2O)4][V12B18O54(OH)6]}·13H2O (1) and (H3O)2{[K12(H2O)10][Zn4(B2O4H2)(B4O14H10)(V10B28O74H8)]}·2H2O (2) were synthesized by a facile and feasible hydrothermal technique and structurally characterized. 1 comprises cage-like vanadoborate cluster [V12B18O54(OH)6]10- based on the combination of one puckered [B18O36(OH)6] ring and two hexa-meric oxo-vanadate [V6O9] units, while 2 contains a rare vanadoborate cluster {[Zn4(B2O4H2)(B4O14H10)(V10B28O74H8)]}14- built up from two [B14O28(OH)4] rings, one [Zn4(B2O4H2)(B4O14H10)] unit and one ellipse-like [V10O30] ring. The 3-D framework of 1 is constructed by the linkage of rare [K6(H2O)10]n chains and {[Ni(H2O)4][V12B18O54(OH)6]}n chains, while 3-D architecture of 2 is built from the interconnection of infrequent [K12(H2O)10]n layers and vanadoborate {[Zn4(B2O4H2)(B4O14H10)- (V10B28O74H8)]}14- clusters. The documented polymeric vanadoborates are usually based on low nuclearity metal complexes as bridging groups, however, 1 and 2 present new types of the 3-D vanadoborates based on K-O-K polymeric chain or layer as bridging group. The photocatalytic results revealed 1 and 2 displayed the efficient photo-catalytic properties for degradation of methylene blue under visible light. This study offers a facile synthetic method for the preparation of new high-dimensional vanadorates as the potential photo-catalysts to eliminate the harmful methylene blue dyes in industrial wastewaters.

A polymeric copper complex based on a pyrazole derivative: Synthesis, spectroscopic, X‐ray, and biological activity studies

A novel 1D coordination polymeric copper complex based on 4‐(4′‐nitrophenylhydrazono)‐5‐trifluoromethyl‐2,4‐dihydropyrazol‐3‐one was prepared and characterized spectroscopically and thermally and via X‐ray crystallographic investigation. The prepared copper‐based structure was proved to have a 1D coordination polymer. X‐ray studies showed that the polymeric copper complex was of octahedral geometry, the ligand acted as a bidentate ligand, and the nitro group attached to the ligand acted as a bridging group. The cytotoxic activities of the copper polymer were evaluated including against MCF‐7 cells (breast cancer cell line), HepG‐2 cells (hepatocellular carcinoma), and HCT‐116 cells (colon cancer cell line). The morphological alterations of the complex treated cells were investigated using an inverted microscope. The cell cycle and apoptosis were evaluated and reported. The copper polymer exhibited the best antitumor activity against HepG‐2 cells (35.22 ± 4.80 μM) while also causing a decline in the G2/M phase and a remarkable enhancement in the early apoptosis.

Effect of Metal Coordination Environment on the Stability of Zinc Complexes and Their Reactivity with NaSH

AbstractMetal complexes with multidentate ligands are frequently used as model compounds to shed light on the (bio)‐inorganic chemistry of H2S. Zinc complexes bearing salen‐type ONNO ligands with different bridging groups are particularly relevant in this respect. Here, we describe the use of zinc complexes with the sulfur‐analogues of the ONNO ligands with the S‐donors replacing either the neutral nitrogen donors or the anionic oxygen atoms of the classical salen ligands. In addition, we studied a hexadentate cyclic ligand, with four neutral sulfur atoms and two anionic oxygens. Having two coordinative pockets this ligand is able to form a bimetallic zinc complex. We report how the different coordinative environments of the explored ligands influence the stability of the zinc complexes and their abilities to form the related hydrosulfide species.

Molecular design of free volume structure in thermally rearranged polybenzoxazole membranes for gas separation studied by positron annihilation

AbstractIn this work, 2,2‐bis(3‐amino‐4‐hydroxyphenyl) hexafluoropropane (APAF) was used as the fixed diamine monomer, and 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 4,4′‐oxydiphthalic anhydride (ODPA), 3,3′,4,4′‐biphenyltetracarboxylic diandhydride (BPDA) and pyromellitic dianhydride (PMDA) were selected as four different dianhydride monomers, respectively, to prepare the thermally rearranged polybenzoxazole (TR‐PBO) gas separation membranes with different structures via a thermal rearrangement reaction at 450°C. The microstructure of TR‐PBO membranes was investigated using X‐ray diffraction and positron annihilation spectroscopy. All the TR‐PBO membranes exhibit bimodal free volume structure, containing ultramicropores (&lt;0.7 nm) and micropores (&lt;2 nm) with size of 3.6–4.6 and 7.6–8.4 Å, respectively. As the steric hindrance of the bridging groups in the dianhydride monomers increases, the radius and number of pores in the membranes increases, leading to an increase in fractional free volume (FFV). The pure gas permeation test shows a positive correlation between gas permeability and FFV in the TR‐PBO membranes, indicating that an increase in FFV is favorable for the diffusion of gas molecules. Particularly, the ultramicropores play a decisive role on the gas selectivity. All the TR‐PBO membranes exhibit excellent gas permeaselectivity. Among them, the H2/CH4 separation performance of APAF‐6FDA and APAF‐ODPA membranes approaches the 2008 Robeson upper bound, which is due to the high number of both micropores and ultramicropores. Our results demonstrate that the free volume structure of polymer membranes can be designed by selecting monomers with different structures and utilizing thermal rearrangement reactions, allowing for the preparation of gas separation membranes with high permeability and selectivity.

Spectroscopic analysis of the sum-frequency response of the carbon-hydrogen stretching modes in collagen type I.

We studied the origin of the vibrational signatures in the sum-frequency generation (SFG) spectrum of fibrillar collagen type I in the carbon-hydrogen stretching regime. For this purpose, we developed an all-reflective, laser-scanning SFG microscope with minimum chromatic aberrations and excellent retention of the polarization state of the incident beams. We performed detailed SFG measurements of aligned collagen fibers obtained from rat tail tendon, enabling the characterization of the magnitude and polarization-orientation dependence of individual tensor elements Xijk2 of collagen's nonlinear susceptibility. Using the three-dimensional atomic positions derived from published crystallographic data of collagen type I, we simulated its Xijk2 elements for the methylene stretching vibration and compared the predicted response with the experimental results. Our analysis revealed that the carbon-hydrogen stretching range of the SFG spectrum is dominated by symmetric stretching modes of methylene bridge groups on the pyrrolidine rings of the proline and hydroxyproline residues, giving rise to a dominant peak near 2942cm-1 and a shoulder at 2917cm-1. Weak asymmetric stretches of the methylene bridge group of glycine are observed in the region near 2870cm-1, whereas asymmetric CH2-stretching modes on the pyrrolidine rings are found in the 2980 to 3030cm-1 range. These findings help predict the protein's nonlinear optical properties from its crystal structure, thus establishing a connection between the protein structure and SFG spectroscopic measurements.