Polarization-Dependent Memory and Erasure in Quantum Dots/Graphene Synaptic Devices.

We demonstrate excitatory and inhibitory properties in a single heterostructure consisting of two quantum dots/graphene synaptic elements using linearly polarized monochromatic light. Perovskite quantum dots and PbS quantum dots were used to increase and decrease photocurrent weights, respectively. The polarization-dependent photocurrent was realized by adding a polarizer in the middle of the PbS quantum dots/graphene and perovskite quantum dots/graphene elements. When linearly polarized light passed through the polarizer, both the lower excitatory and upper inhibitory devices were activated, with the lower device with the stronger response dominating to increase the current weight. In contrast, the polarized light was blocked by the polarizer, and the above device was only operated, reducing the current weight. Furthermore, two orthogonal polarizations of light were used to perform the sequential processes of potentiation and habituation. By adjustment of the polarization angle of light, not only the direction of the current weight but also its level was altered.

Arthroscopic Broström-Gould repair has comparable radiological and clinical outcomes compared to traditional open Broström-Gould repair in high-demand patients.

PURPOSE: This study sought to confirm whether traditional open Broström-Gould repair and arthroscopic Broström-Gould repair for chronic ankle instability (CAI) would produce comparable radiological and clinical outcomes in high-demand patients. METHODS: This retrospective case-cohort study included high-demand patients, as determined by a pre-injury Tegner Activity Level ≥ 6, who underwent Broström-Gould repair and were followed up for ≥ 2 years. Patients were divided into the arthroscopic Broström-Gould repair group (AS Group) and the open Broström-Gould repair group (Open Group). Perioperative radiological assessments were performed. The Tegner Activity Levels, Foot and Ankle Outcome Scores (FAOSs), Karlsson and Peterson (K-P) scores, and American Orthopaedic Foot and Ankle Society ankle-hindfoot (AOFAS) scores were evaluated clinically. RESULTS: A total of 65 patients (31 from the AS Group and 34 from the Open Group) were included in the study. There were no differences in age, sex, body mass index, preoperative anterior talar translation, talar tilt, signal-to-noise ratio, FAOS, K-P score, or AOFAS score between the two groups (n.s.). The preinjury median Tegner Activity Level was 7 and unchanged at the final follow-up in both groups. Postoperative stress radiographs showed improvement; however, the groups did not differ significantly. The FAOS, K-P scores, and AOFAS scores improved in each group (P < 0.001). However, the clinical scores did not differ between the groups (all n.s.). CONCLUSIONS: Traditional open and arthroscopic Broström-Gould repair for CAI in high-demand patients had comparable radiological and clinical outcomes. Clinically, arthroscopic Broström-Gould repair may represent a viable surgical alternative to open Broström-Gould repair in high-demand patients. LEVEL OF EVIDENCE: Level III.

Polyamine Oxidase Expression Is Downregulated by 17ß-Estradiol via Estrogen Receptor 2 in Human MCF-7 Breast Cancer Cells.

Polyamine levels decrease with menopause; however, little is known about the mechanisms regulated by menopause. In this study, we found that among the genes involved in the polyamine pathway, polyamine oxidase (PAOX) mRNA levels were the most significantly reduced by treatment with 17ß-estradiol in estrogen receptor (ESR)-positive MCF-7 breast cancer cells. Treatment with 17ß-estradiol also reduced the PAOX protein levels. Treatment with selective ESR antagonists and knockdown of ESR members revealed that estrogen receptor 2 (ESR2; also known as ERß) was responsible for the repression of PAOX by 17ß-estradiol. A luciferase reporter assay showed that 17ß-estradiol downregulates PAOX promoter activity and that 17ß-estradiol-dependent PAOX repression disappeared after deletions (-3126/-2730 and -1271/-1099 regions) or mutations of activator protein 1 (AP-1) binding sites in the PAOX promoter. Chromatin immunoprecipitation analysis showed that ESR2 interacts with AP-1 bound to each of the two AP-1 binding sites. These results demonstrate that 17ß-estradiol represses PAOX transcription by the interaction of ESR2 with AP-1 bound to the PAOX promoter. This suggests that estrogen deficiency may upregulate PAOX expression and decrease polyamine levels.

Expression of Polyamine Oxidase in Fibroblasts Induces MMP-1 and Decreases the Integrity of Extracellular Matrix.

Polyamine oxidase (PAOX) (N1-acetylpolyamine oxidase) is a major enzyme in the polyamine catabolism pathway that generates hydrogen peroxide. Hydrogen peroxide plays a crucial role in skin aging via extracellular matrix (ECM) degradation by increasing the matrix metalloproteinase-1 (MMP-1) levels. We analyzed the integrity of the ECM in foreskin fibroblasts using PAOX expression. PAOX increased the MMP-1 secretion and type Ι collagen degradation in 2D and 3D cultures of fibroblasts, respectively. Similarly, PAOX overexpression increased the messenger ribonucleic acid (mRNA) level of MMP-1. PAOX expression induced polyamine catabolism, decreased the spermine levels, and increased the putrescine levels. However, the exogenous polyamine treatment did not change the MMP-1 and type I collagen levels as much as PAOX expression. PAOX expression increased the reactive oxygen species (ROS) production in fibroblasts, and exogenous hydrogen peroxide increased both the ROS production and MMP-1 secretion. Furthermore, N-acetylcysteine, an antioxidant, reversed the PAOX-induced ROS production and MMP-1 secretion. PAOX induced the signaling pathways that activate activator protein-1 (AP-1) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which are important transcription factors for MMP-1 transactivation. We concluded that PAOX increased the ROS levels in fibroblasts, leading to an increase in MMP-1 expression. Therefore, we propose that PAOX is a potential target molecule in protecting the ECM integrity.

Relationship between Coronary Artery Calcification and Central Chorioretinal Thickness in Patients with Subclinical Atherosclerosis.

PURPOSE: To evaluate the relationship between coronary artery calcification and subfoveal thicknesses of individual chorioretinal layers in subjects with subclinical atherosclerosis by using enhanced-depth imaging optical coherence tomography. METHODS: In this retrospective, noninterventional, cross-sectional study, we included 193 eyes from 193 subjects and divided them into three cardiovascular (CV) risk groups based on coronary artery calcification (CAC) scores calculated from cardiac-gated computed tomography: low (CAC = 0; n = 77), intermediate (CAC = 1-300; n = 83), and high (CAC >300; n = 33). Central macula individual retinal layer thicknesses and subfoveal choroidal thickness were measured and compared among groups. Multivariate linear regression was used to evaluate associations of subfoveal choroidal thickness or central retinal thickness with CAC scores. RESULTS: Average subfoveal choroidal thickness differed significantly among low, intermediate, and high CV risk groups (all p < 0.05). There were no statistically significant changes in segmented retinal layer thickness of the central macula. Multivariate regression analyses showed that higher CAC scores were significantly negatively associated with subfoveal choroidal thickness (ß = -2.169, p < 0.001). CONCLUSIONS: Higher CAC scores were significantly associated with subfoveal choroidal thinning in subjects with subclinical atherosclerosis. Prominent reductions in the subfoveal choroidal layer could provide a useful biomarker for predicting CV risk in patients of advanced age with subclinical atherosclerosis.

ASSOCIATIONS BETWEEN INDIVIDUAL RETINAL LAYER THICKNESSES AND DIABETIC PERIPHERAL NEUROPATHY USING RETINAL LAYER SEGMENTATION ANALYSIS.

PURPOSE: To evaluate clinical correlations between the thicknesses of individual retinal layers in the foveal area of diabetic patients and the presence of diabetic peripheral neuropathy (DPN). METHODS: This retrospective, observational, cross-sectional study enrolled a total of 120 eyes from 120 patients. The eyes were divided into 3 groups: normal controls (n = 42 eyes), patients with diabetes mellitus (n = 42 eyes) but no DPN, and patients with diabetes mellitus and DPN (n = 36 eyes). The primary outcome measures were the thickness of all retinal layers in the central 1-mm zone measured using the segmentation analysis of spectral-domain optical coherence tomography. Correlations between the thicknesses of the individual retinal layers and the presence of DPN were also analyzed. Logistic regression analyses were used to determine which change in layer thickness had the most significant association with the presence of DPN. RESULTS: The mean thicknesses and the ratios of retinal nerve fiber layers to total retina thicknesses in the DPN group were 10.77 ± 1.79 µm and 4.10 ± 0.55%, which was significantly lower than those in normal controls and the diabetes mellitus with no DPN group (P = 0.014 and P = 0.001, respectively). Logistic regression analyses also showed that the decrease in thicknesses of the retinal nerve fiber layers and the inner nuclear layer are significant factors for predicting a higher risk for DPN development (odds ratio = 7.407 and 1.757; P < 0.001 and P = 0.001, respectively). CONCLUSION: A decrease in the retinal nerve fiber layer and the inner nuclear layer thickness was significantly associated with the presence of DPN.

Transferrable superhydrophobic TiO2 nanorods on reduced graphene oxide films using block copolymer templates.

Superhydrophobic surfaces are normally fixed on the chosen materials. Here, we report transferrable superhydrophobicity which was enabled by fabricating TiO2 nanorods on a reduced graphene oxide (rGO) film. Superhydrophobic TiO2 nanorods were first synthesized from a nanoporous template of block copolymers (BCPs). The controllability over the dimension and shape of nanopores of the BCP template allowed for the adjustment of TiO2 nanostructures for superhydrophobicity. Since the rGO film provided effective transferring, TiO2 nanorods were conveyed onto a flexible polymer film and a metal substrate. Thus, the surface of the designated substrate was successfully changed to a superhydrophobic surface without alteration of its inherent characteristics.

Intravitreal Bevacizumab for Traumatic Choroidal Rupture.

PURPOSE: To report a case of visual loss associated with traumatic choroidal rupture after blunt ocular trauma that was successfully treated with an early intravitreal bevacizumab injection despite the absence of choroidal neovascularization (CNV). CASE REPORT: A 14-year-old boy presented with visual disturbance in his left eye after sustaining an ocular contusion 4 weeks earlier. The best-corrected visual acuity (BCVA) in the left eye was 20/50. Funduscopic examination revealed macular choroidal rupture accompanied by subretinal hemorrhage. Optical coherence tomography (OCT) showed accumulation of subretinal fluid around a disrupted retinal pigment epithelium/Bruch membrane complex extending into the juxtafoveolar area, but there was no active leakage suggestive of CNV on fluorescein angiography. Intravitreal bevacizumab (1.25 mg) injection was performed to treat persistent serous retinal detachment at macula causing visual loss. There was a reduction of subretinal fluid and concomitant improvement of BCVA to 20/30 within 1 week after intravitreal bevacizumab injection. The BCVA recovered to 20/25 in the left eye after 4 weeks, and only a minimal amount of residual fluid remained according to OCT. Complete resolution of subretinal fluid was observed by OCT at the 6-week follow-up examination, and BCVA improved to 20/20. Good visual acuity (20/20) and stable macula were maintained in the left eye at 1 year of follow-up without recurrence of subretinal fluid accumulation or hemorrhage and CNV. There were no ocular or systemic complications associated with intravitreal bevacizumab injection. CONCLUSIONS: Early intravitreal bevacizumab injection could be an effective treatment option for patients with vision loss associated with traumatic choroidal rupture and subretinal fluid within the posterior pole before development of CNV.

Suppression of stent-induced tissue hyperplasia in rats by using small interfering RNA to target matrix metalloproteinase-9.

BACKGROUND AND STUDY AIMS: We evaluated the efficacy of small interfering RNA (siRNA) in targeting matrix metalloproteinase (MMP-9) to suppress stent-induced tissue hyperplasia in a rat esophageal model. METHODS: The silencing effect of the candidate siRNA (termed (MMP-9 siRNA) was evaluated in 9 L rat glial cells. Four groups of rats (n = 10, each group) were used: Eso-S, stent insertion only, comparison; Eso-R, stent insertion plus treatment with MMP-9 siRNA complexed with Chol-R9 for delivery, experimental; Eso-P, stent insertion plus treatment with pCMV-luc complexed with Chol-R9, for confirmation of Chol-R9 delivery effect; and Eso-N, no stent insertion and no treatment, controls. All rats were sacrificed at 3 weeks. The therapeutic efficacy of the MMP-9 siRNA/Chol-R9 complex was assessed. RESULTS: The most potent MMP-9 siRNA was selected. Compared with the Eso-S group, the Eso-R group showed significantly less tissue hyperplasia with a lower percentage of granulation tissue and smaller granulation tissue area, and also significantly lower MMP-9 level. CONCLUSIONS: MMP-9 siRNA/Chol-R9 is effective for inhibiting stent-induced tissue hyperplasia in a rat esophageal model.

Heart rate variability as a preictal marker for determining the laterality of seizure onset zone in frontal lobe epilepsy.

Determining the laterality of the seizure onset zone is challenging in frontal lobe epilepsy (FLE) due to the rapid propagation of epileptic discharges to the contralateral hemisphere. There is hemispheric lateralization of autonomic control, and heart rate is modulated by interactions between the sympathetic and parasympathetic nervous systems. Based on this notion, the laterality of seizure foci in FLE might be determined using heart rate variability (HRV) parameters. We explored preictal markers for differentiating the laterality of seizure foci in FLE using HRV parameters. Twelve patients with FLE (6 right FLE and 6 left FLE) were included in the analyzes. A total of 551 (460 left FLE and 91 right FLE) 1-min epoch electrocardiography data were used for HRV analysis. We found that most HRV parameters differed between the left and right FLE groups. Among the machine learning algorithms applied in this study, the light gradient boosting machine was the most accurate, with an AUC value of 0.983 and a classification accuracy of 0.961. Our findings suggest that HRV parameter-based laterality determination models can be convenient and effective tools in clinical settings. Considering that heart rate can be easily measured in real time with a wearable device, our proposed method can be applied to a closed-loop device as a real-time monitoring tool for determining the side of stimulation.

MPFL reconstruction with proximal rather than distal femoral tunnel position leads to less favorable short-term results.

BACKGROUND: This study aimed to compare the clinical and radiological outcomes of medial patellofemoral ligament (MPFL) reconstruction (MPFLR) between anatomic femoral tunnel positions: proximal (near adductor tubercle [AT]) and distal (near medial epicondyle [ME]). HYPOTHESIS: MPFLR with the proximal femoral tunnel position has worse clinical and radiological outcomes than those with the distal femoral tunnel position. PATIENTS AND METHODS: Fifty-five patients who underwent isolated MPFLR with proximal or distal femoral tunnels with at least 2 years of follow-up were retrospectively analyzed. Based on postoperative CT images, 28 patients were classified as group AT and the remaining 27 patients were classified as group ME. The International Knee Documentation Committee, Lysholm, Tegner, Kujala scores, and complications were evaluated. Radiologically, the Caton-Deschamps Index (CDI), patellar tilt angle, patellofemoral osteoarthritis (PFOA), patellofemoral cartilage status by the International Cartilage Repair Society (ICRS) grade, bone contusion, and MPFL graft signal intensity were evaluated. RESULTS: All clinical scores significantly improved in both groups (p<0.01). No statistically significant difference was noted between the two groups in regards to their preoperative demographic data, postoperative clinical scores, complications, or radiological findings (CDI, patellar tilt angle, PFOA, bone contusion, and graft signal intensity). The group AT had worse cartilage status on the medial facet of the patella (p=0.02). The ICRS grade for the medial facet of the patella statistically progressed in group AT compared to group ME (p=0.04) as well. DISCUSSION: Both groups showed significantly improved clinical outcomes. However, for the medial facet of the patella, MPFLR with the proximal femoral tunnel position had worse cartilage status and ICRS grade progression than those with the distal femoral tunnel position. LEVEL OF EVIDENCE: III; retrospective comparative study.

Identification of new major histocompatibility complex-B Haplotypes in Bangladesh native chickens.

OBJECTIVE: The major histocompatibility complex in chicken demonstrates a great range of variations within varities, breeds, populations and that can eventually influence their immuneresponses. The preset study was conducted to understand the major histocompatibility complex-B (MHC-B) variability in five major populations of Bangladesh native chicken: Aseel, Hilly, Junglefowl, Non-descript Deshi, and Naked Neck. METHODS: These five major populations of Bangladesh native chicken were analyzed with a subset of 89 single nucleotide polymorphisms (SNPs) in the high-density MHC-B SNP panel and Kompetitive Allele-Specific polymerase chain reaction genotyping was applied. To explore haplotype diversity within these populations, the results were analyzed both manually and computationally using PHASE 2.1 program. The phylogenetic investigations were also performed using MrBayes program. RESULTS: A total of 136 unique haplotypes were identified within these five Bangladesh chicken populations, and only one was shared (between Hilly and Naked Neck). Phylogenetic analysis showed no distinct haplotype clustering among the five populations, although they were shared in distinct clades; notably, the first clade lacked Naked Neck haplotypes. CONCLUSION: The present study discovered a set of unique MHC-B haplotypes in Bangladesh chickens that could possibly cause varied immune reponses. However, further investigations are required to evaluate their relationships with global chicken populations.

Primary orbital pleomorphic liposarcoma: an aggressive course.

An aggressively poor course of primary orbital pleomorphic liposarcoma is presented. A 59-year-old man had suffered from multiple local recurrences and died 1 year after diagnosis of orbital pleomorphic liposarcoma. The tumor invaded into the brain only 10 months after exenteration. The patient had a history of partial tumor resection via anterior orbitotomy before total exenteration. It was assume that such an unusual poor course might be due to histologic findings, which revealed a high-grade pleomorphic liposarcoma with a high mitotic count (25/10 high-power field) or previous-done anterior orbitotomy, which was able to seed the tumor cells.

SOD3 Suppresses the Expression of MMP-1 and Increases the Integrity of Extracellular Matrix in Fibroblasts.

The superoxide dismutase (SOD) family functions as a reactive oxygen species (ROS)-scavenging system by converting superoxide anions into hydrogen peroxide in the cytosol (SOD1), mitochondria (SOD2), and extracellular matrix (SOD3). In this study, we examined the potential roles of SOD family members in skin aging. We found that SOD3 expression levels were significantly more reduced in the skin tissues of old mice and humans than in young counterparts, but SOD1 and SOD2 expression levels remained unchanged with aging. Accordingly, we analyzed the effects of SOD3 on intracellular ROS levels and the integrity of the extracellular matrix in fibroblasts. The treatment of foreskin fibroblasts with recombinant SOD3 reduced the intracellular ROS levels and secretion of MMP-1 while increasing the secretion of type I collagen. The effects of SOD3 were greater in fibroblasts treated with the TNF-α. SOD3 treatment also decreased the mRNA levels and promoter activity of MMP-1 while increasing the mRNA levels and promoter activities of COL1A1 and COL1A2. SOD3 treatment reduced the phosphorylation of NF-κB, p38 MAPK, ERK, and JNK, which are essential for MMP-1 transactivation. In a three-dimensional culture of fibroblasts, SOD3 decreased the amount of type I collagen fragments produced by MMP-1 and increased the amount of nascent type I procollagen. These results demonstrate that SOD3 reduces intracellular ROS levels, suppresses MMP-1 expression, and induces type I collagen expression in fibroblasts. Therefore, SOD3 may play a role in delaying or preventing skin aging.

Morphometric analysis of the anterior region of the maxillary bone for immediate implant placement using micro-CT.

The purpose of this study was to elucidate the relationship between the maxillary incisor roots and surrounding alveolar structures using microscopic computerized tomography (micro-CT) for the immediate implant placement. Nineteen maxillae from 14 Korean cadavers were used in this study. All specimens were scanned and reconstructed into a three-dimensional (3D) structure using a micro-CT system. The roots of the maxillary central and lateral incisors became dramatically narrower from 6 mm above the cementoenamel junctions to the apex. The roots of the maxillary incisors and canine were located at the labial one fifths region of the alveolar bone. The angle formed by the longitudinal root axis and the alveolar bone was greatest at the maxillary canine. On the basis of the results of this study, guidelines for immediate implant placement can be suggested on the implant diameter and drilling angle to minimize damage of the alveolar plate.

Initial Transarterial Chemoembolization (TACE) Using HepaSpheres 20-40 µm and Subsequent Lipiodol TACE in Patients with Hepatocellular Carcinoma > 5 cm.

PURPOSE: To investigate clinical outcomes of drug-eluting bead transarterial chemoembolization (DEB-TACE) using HepaSpheres 20-40 µm in diameter and subsequent cisplatin-based lipiodol TACE (Cis-TACE) in patients with hepatocellular carcinoma (HCC) > 5 cm. MATERIALS AND METHODS: This study included 39 consecutive patients (34 men, 5 women; mean age, 63.5 years; range, 39-80 years) who underwent DEB-TACE using HepaSpheres 20-40 µm as first-line treatment for HCC > 5 cm (mean diameter, 8.2 cm; range, 5.1-13 cm) between September 2018 and August 2019. Patients with new tumors, residual tumors, or tumor growth after initial DEB-TACE underwent subsequent Cis-TACE. RESULTS: All 39 patients underwent initial DEB-TACE successfully, with 35 (89.7%) and three (7.7%) patients experiencing minor and major complications, respectively. After initial DEB-TACE, one patient (2.6%) achieved complete response (CR), 35 (89.7%) achieved partial response (PR), and three (7.7%) experienced progressive disease (PD). During a median follow-up period of 14.4 months (range, 0.6-23 months), 23 patients underwent Cis-TACE, with 11, three, and nine achieving CR, PR, and PD, respectively. The median overall survival time was 20.9 months (95% confidence interval (CI), 18.6-23.2 months), the median time to progression was 8.8 months (95% CI, 6.5-11.1 months), and the median time to local tumor recurrence was 16 months (95% CI, 7.4-24.6 months). CONCLUSIONS: DEB-TACE using HepaSpheres 20-40 µm in diameter can be a safe and effective initial treatment method in patients with HCC > 5 cm. Subsequent Cis-TACE constitutes a good adjuvant method to enhance tumor response after initial DEB-TACE.

Role of electrostatic interactions in the adsorption of dye molecules by Ti3C2-MXenes.

MXenes, a new class of 2D materials, have recently attracted increasing attention as promising adsorbents for environmental remediation. It has been previously demonstrated that MXenes can successfully capture selected organic dyes from aqueous media; however, to date, the adsorption performance of MXenes for a wide variety of dyes in simulated real-life aquatic environments other than clean laboratory deionized (DI) water has not been systematically investigated. In this study, we systematically investigated the adsorption performance of delaminated Ti3C2-MXenes for six different organic dyes in aquatic media at different pH levels and ionic strengths. Our results strongly suggest the importance of the electrostatic interactions between the ionizable functional groups of MXenes and dyes for removal efficiency. The electrostatic repulsions between negatively charged MXenes and certain anionic dyes reduced the removal efficiencies of MXenes for these dyes in DI water; however, the presence of divalent cations significantly improved the removal efficiencies, possibly owing to the charge screening effects and like-charge attractions mediated by cation binding to the functionalities of dyes and MXenes. These results provide a rational strategy for optimizing the conditions for efficient removal of different types of organic dyes using MXenes.

Temporary placement of a covered, retrievable, barbed stent for the treatment of hormone-induced benign prostatic hyperplasia: technical feasibility and histologic changes in canine prostates.

PURPOSE: To evaluate the technical feasibility of a covered, retrievable, barbed prostatic stent and to determine stent-induced histologic changes of the prostate in canine benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: BPH was induced in 8 male beagles by administration of dihydrotestosterone and beta-estradiol. Under fluoroscopy guidance, covered, retrievable, barbed stents were placed in the prostatic urethras. Urethrograms were obtained every three to 4 weeks until sacrifice. The stents were removed 8 weeks after placement. The dogs were sacrificed immediately (group A, n = 4) and 8 weeks after stent removal (group B, n = 4). Histologic changes of prostates were microscopically evaluated. RESULTS: Stent placement was technically successful in all dogs. The diameters of the prostatic urethra were 14.1 mm + or - 0.5 and 13.7 mm + or - 0.5 on urethrograms obtained immediately after and 8 weeks after stent removal (P = .268). Stent removal was successful in all dogs except one, in which the stent was obstructed by stone formation. Small sandy stones were identified attached to the removed stents of two dogs. Histologic examination revealed extensive prostatic glandular atrophy involving 95.1% + or - 2.2 (group A) and 94.5% + or - 2.4 (group B) of entire prostate (P = .773). CONCLUSIONS: A covered, retrievable, barbed prostatic stent seems to be feasible for use in hormone-induced canine BPH. The stent induced prostatic urethral dilatation, and extensive prostatic glandular atrophy persisted up to 8 weeks after stent removal.

Cu(I)-containing room temperature ionic liquids as selective and reversible absorbents for propyne.

A Cu(i)-containing room temperature ionic liquid (Cu-RTIL), prepared from CuCl and 1,3-dimethylimidazolium methylphosphite ([DMIM][MeHPO(3)]), was found to reversibly and selectively interact with propyne over propylene. Cu-RTIL exhibited 12 times higher propyne absorption capacity and 14 times higher ideal propyne/propylene selectivity than [DMIM][MeHPO(3)]. Fast atom bombardment (FAB)-mass spectral and computational results with Cu-RTIL (CuCl/[DMIM][MeHPO(3)] = 1/2) strongly imply that the Cu-RTIL contains stable methylphosphite-coordinated anionic Cu(i) species such as CuCl(MeHPO(3))(-) and Cu(MeHPO(3))(2)(-). Computational studies on the optimized structures demonstrate that the preferential absorption of propyne over propylene in a Cu-RTIL originates from the difference in the interaction mode between the coordinated phosphite ligand and propyne or propylene. Strong π-complexation of propylene and propyne with Cu in Cu-RTIL is not observed.

Selective removal of acetylenes from olefin mixtures through specific physicochemical interactions of ionic liquids with acetylenes.

Imidazolium-based ionic liquids (ILs) bearing an alkylphosphite anion, were highly efficient for the selective removal of acetylenes in olefins. Comparison of solubility data at 313 K and at atmospheric pressure shows that the solubilities of acetylene and propyne in 1,3-dimethylimidazolium methylphosphite ([DMIM][MeHPO(3)]) are about 45 and 20 times higher than those of ethylene and propylene, respectively. Computational and (1)H NMR results clearly demonstrate that there are substantial interactions between the acidic hydrogen atom or atoms of acetylenes and the phosphite anion.