Upcycling of polyethylene to gasoline through a self-supplied hydrogen strategy in a layered self-pillared zeolite.

Conversion of plastic wastes to valuable carbon resources without using noble metal catalysts or external hydrogen remains a challenging task. Here we report a layered self-pillared zeolite that enables the conversion of polyethylene to gasoline with a remarkable selectivity of 99% and yields of >80% in 4 h at 240 °C. The liquid product is primarily composed of branched alkanes (selectivity of 72%), affording a high research octane number of 88.0 that is comparable to commercial gasoline (86.6). In situ inelastic neutron scattering, small-angle neutron scattering, solid-state nuclear magnetic resonance, X-ray absorption spectroscopy and isotope-labelling experiments reveal that the activation of polyethylene is promoted by the open framework tri-coordinated Al sites of the zeolite, followed by ß-scission and isomerization on Brönsted acids sites, accompanied by hydride transfer over open framework tri-coordinated Al sites through a self-supplied hydrogen pathway to yield selectivity to branched alkanes. This study shows the potential of layered zeolite materials in enabling the upcycling of plastic wastes.

Efficacy and tolerability of paroxetine in adults with social anxiety disorder: A meta-analysis of randomized controlled trials.

OBJECTIVE: The present study aimed to estimate the comprehensive efficacy and tolerability of paroxetine in adult patients with social anxiety disorder (SAD). METHODS: We conducted a comprehensive literature review of the PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials databases for eligible randomized controlled trials (RCTs). The efficacy outcome was the mean change of different kinds of scale scores as well as response and remission rates. The secondary outcome was tolerability, defined as the discontinuation rate and the incidence of adverse events (AEs). RESULTS: Our meta-analysis included 13 RCTs. Mean changes in the Liebowitz Social Anxiety Scale (LSAS) total score, fear and avoidance subscale of LSAS scores were all significantly greater in patients with SAD that received paroxetine compared to those received placebo (total: MD = 13.46, 95%CI 10.59-16.32, P < .00001; fear: MD = 6.76, 95%CI 4.89-8.62, P < .00001; avoidance: MD = 6.54, 95%CI 4.63-8.45, P < .00001). Response and remission rates were both significantly greater in patients with SAD that received paroxetine compared to those received placebo (response: OR = 3.02, 95%CI 2.30-3.97, P < .00001; remission: OR = 3.14, 95%CI 2.25-4.39, P < .00001). There was no significant difference in discontinuation rate due to any reason between two groups (OR = 1.06, 95%CI 0.81-1.39, P = .65). Discontinuation rate due to AEs was higher in paroxetine than placebo group (OR = 3.41, 95%CI 2.45-4.72, P < .00001) whereas the rate due to lack of efficacy was higher in placebo as compared with paroxetine group (OR = 0.14, 95%CI 0.09-0.22, P < .00001). The incidence of any AE was significantly increased in patients that received paroxetine (OR = 1.83, 95%CI 1.43-2.35, P < .00001). CONCLUSION: Paroxetine was an effective and well-tolerated treatment option for adult patients with SAD.

A new heterozygous G duplicate in exon1 (c.100dupG) of gelsolin gene causes Finnish gelsolin amyloidosis in a Chinese family.

OBJECTIVES: In this study, we report a case of Finnish gelsolin amyloidosis (FGA) in a Chinese family. METHODS: The proband presented with a range of clinical symptoms that included epileptic seizures and multiple lesions in the brain. Whole exome sequencing of the Gelsolin (GSN) gene was performed, and the GSN mutation was identified through comparison with the known human genome sequences using Genetic Testing Intelligent Execution System. RESULTS: The GSN gene sequencing revealed that a heterozygous G duplicate in exon1 (c.100dupG) of the GSN gene, which caused a frameshift in GSN transcript translation in the proband, his mother and daughter, but his brother did not have it. CONCLUSION: We presented a new autosomal dominant heterozygous G duplicate mutation in exon1 of GSN gene, leading to FGA in a Chinese family.

Limbic encephalitis associated with antibodies against the α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic acid receptor: a case report.

We report a case of a 51-year-old man with limbic encephalitis (LE) associated with antibodies against the α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic acid receptor (AMPAR). The patient presented with anterograde memory loss for 2 months. Cranial magnetic resonance and electroencephalogram were normal. AMPAR antibodies were found in blood serum and cerebrospinal fluid. All other test results were unremarkable. CT scans found a tumor in the right lobus superior pulmonis. A CT-guided needle biopsy was performed and pathological results showed small cell lung cancer (SCLC). The patient was diagnosed with LE associated with AMPAR antibodies and SCLC. Three months after immunotherapy and tumor removal, patient's memory was partially restored. We recommend that AMPAR antibodies should be detected in patients with classic LE with or without tumor. Prompt treatment of the tumor and immunotherapy are important.

Three-dimensional graphene oxide foams loaded with AuPd alloy: a sensitive electrochemical sensor for dopamine.

The authors describe a chemical sensor for dopamine (DA). It is based on the use of three-dimensional graphene oxide (3D rGO) loaded with varying amounts of AuPd bimetallic nanoparticles (3D rGO/AuPd NPs). The 3D rGO acts as an effective substrate providing a large surface area and allowing fast electron transfer. The interaction between 3D rGO and surface AuPd NPs increases the activity of the sensing material. These composites were fabricated as the active layer on an indium tin oxide for DA determination. The electrode showed the best performance at a working potential of 0.25 V (vs. the saturated calomel reference electrode) and a scan rate of 100 mVs-1. The best electrode exhibits good sensitivity (4670 µA·mM-1·cm-2), a wide linear response (0.5 µM to 135 µM), and a low detection limit (0.2 µM). It is also selective, easily reproducible, and stable. It was applied to the determination of DA in spiked human serum and in clinical DA hydrochloride injections. The excellent performance of this electrode is attributed to the efficient electron transfer and large specific surface area of 3D rGO and to the high electrocatalytic activity of AuPd NPs due to the synergistic effect between the 3D rGO substrate and the AuPd alloy NPs. Graphical abstract An three-dimensional reduced graphene oxide (3D rGO) foam was loaded with AuPd bimetallic nanoparticles and applied to dopamine (DA) detection in human serum and an injection fluid.

Purulent meningitis caused by Rhodococcus equi: A case report.

RATIONALE: Purulent meningitis refers infection of the subarachnoid space by various purulent bacteria and the corresponding inflammation of the leptomeninges. However, purulent meningitis due to Rhodococcus equi is extremely rare. PATIENT CONCERNS: A 40-year-old man presented with fever and intermittent headache for 6 days. Two hours prior to admission, he developed epileptic seizures. DIAGNOSES: Brain computed tomography and magnetic resonance imaging showed intracerebral malacic lesions. Bacterial culture of cerebrospinal fluid revealed the presence of R. equi. A diagnosis of purulent meningitis caused by R. equi was made. INTERVENTIONS: The patient was treated with intravenous meropenem (1000 mg every 8 hours) for 19 days; then he was discharged and instructed to continue the intravenous meropenem for two weeks. After a follow-up period of 2 months, the patient had recovered completely. OUTCOMES: After a follow-up period of 2 months, the patient had recovered completely. LESSONS: Central nervous system infection caused by R. equi is rare. Early bacterial culture of CSF is important for timely diagnosis. With sufficient antibiotic therapy, the prognosis can be favorable.

Selective Antimicrobial Activities and Action Mechanism of Micelles Self-Assembled by Cationic Oligomeric Surfactants.

This work reports that cationic micelles formed by cationic trimeric, tetrameric, and hexameric surfactants bearing amide moieties in spacers can efficiently kill Gram-negative E. coli with a very low minimum inhibitory concentration (1.70-0.93 µM), and do not cause obvious toxicity to mammalian cells at the concentrations used. With the increase of the oligomerization degree, the antibacterial activity of the oligomeric surfactants increases, i.e., hexameric surfactant > tetrameric surfactant > trimeric surfactant. Isothermal titration microcalorimetry, scanning electron microscopy, and zeta potential results reveal that the cationic micelles interact with the cell membrane of E. coli through two processes. First, the integrity of outer membrane of E. coli is disrupted by the electrostatic interaction of the cationic ammonium groups of the surfactants with anionic groups of E. coli, resulting in loss of the barrier function of the outer membrane. The inner membrane then is disintegrated by the hydrophobic interaction of the surfactant hydrocarbon chains with the hydrophobic domains of the inner membrane, leading to the cytoplast leakage. The formation of micelles of these cationic oligomeric surfactants at very low concentration enables more efficient interaction with bacterial cell membrane, which endows the oligomeric surfactants with high antibacterial activity.

Synthesis and aggregation behavior of a hexameric quaternary ammonium surfactant.

A star-shaped hexameric quaternary ammonium surfactant (PAHB), bearing six hydrophobic chains and six charged hydrophilic headgroups connected by an amide-type spacer group, was synthesized. The self-assembly behavior of the surfactant in aqueous solution was studied by surface tension, electrical conductivity, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, and NMR techniques. The results reveal that there are two critical aggregate concentrations during the process of aggregation, namely C(1) and C(2). The aggregate transitions are proved to be caused by the changes of the surfactant configuration through hydrophobic interaction among the hydrocarbon chains. Below C(1), PAHB may present a star-shaped molecular configuration due to intramolecular electrostatic repulsion among the charged headgroups, and large aggregates with network-like structure are observed. Between C(1) and C(2), the hydrophobic interaction among the hydrophobic chains may become stronger to make the hydrophobic chains of the PAHB molecules curve back and pack more closely, and then the network-like aggregates transfer to large spherical aggregates of ∼100 nm. Beyond C(2), the hydrophobic interaction may become strong enough to cause the PAHB molecular configuration to turn into a pyramid-like shape, resulting in the transition of the spherical large aggregates to spherical micelles of ∼10 nm. Interestingly, the PAHB displays high emulsification ability to linear fatty alkyls even at very low concentration.

Disassembly of amyloid fibrils by premicellar and micellar aggregates of a tetrameric cationic surfactant in aqueous solution.

We report a finding that not only the micelles but also the premicellar aggregates of a star-like tetrameric quaternary ammonium surfactant PATC can disassemble and clear mature ß-amyloid Aß(1-40) fibrils in aqueous solution. Different from other surfactants, PATC self-assembles into network-like aggregates below its critical micelle concentration (CMC). The strong self-assembly ability of PATC even below its CMC enables PATC to disaggregate the Aß(1-40) fibrils far below the charge neutralization point of the Aß(1-40) with PATC. There may be two key features of the fibril disassembly induced by the surfactant. First, the positively charged surfactant molecules bind with the negatively charged Aß(1-40) fibrils through electrostatic interaction. Second, the self-assembly of the surfactant molecules bound onto the Aß(1-40) fibrils disaggregate the fibrils, and the surfactant molecules form mixed aggregates with the Aß(1-40) molecules. The result reveals a structural approach of constructing efficient disassembly agents to mature ß-amyloid fibrils.

Molecular conformation-controlled vesicle/micelle transition of cationic trimeric surfactants in aqueous solution.

Two star-like trimeric cationic surfactants with amide groups in spacers, tri(dodecyldimethylammonioacetoxy)diethyltriamine trichloride (DTAD) and tri(dodecyldimethylammonioacetoxy)tris(2-aminoethyl)amine trichloride (DDAD), have been synthesized, and the aggregation behavior of the surfactants in aqueous solution has been investigated by surface tension, electrical conductivity, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, and NMR techniques. Typically, both the surfactants form vesicles just above critical aggregation concentration (CAC), and then the vesicles transfer to micelles gradually with an increase of the surfactant concentration. It is approved that the conformation of the surfactant molecules changes in this transition process. Just above the CAC, the hydrophobic chains of the surfactant molecules pack more loosely because of the rigid spacer and intramolecular electrostatic repulsion in the three-charged headgroup. With the increase of the surfactant concentration, hydrophobic interaction becomes strong enough to pack the hydrophobic tails tightly and turn the molecular conformation into a pyramid-like shape, thus leading to the vesicle to micelle transition.

Aggregation behavior of a tetrameric cationic surfactant in aqueous solution.

A star-shaped tetrameric quaternary ammonium surfactant PATC, which has four hydrophobic chains and charged hydrophilic headgroups connected by amide-type spacer group, has been synthesized in this work. Surface tension, electrical conductivity, ITC, DLS, and NMR have been used to investigate the relationship between its chemical structure and its aggregation properties. Interestingly, a large size distribution around 75 nm is observed below the critical micelle concentration (cmc) of PATC, and the large size distribution starts to decrease beyond the cmc and finally transfers to a small size distribution. It is proved that the large size premicellar aggregates may display network-like structure, and the size decrease beyond the cmc is the transition of the network-like aggregates to micelles. The possible reason is that intramolecular electrostatic repulsion among the charged headgroups below the cmc leads to a star-shaped molecular configuration, which may form the network-like aggregates through intermolecular hydrophobic interaction between hydrocarbon chains, while the hydrophobic effect becomes strong enough to turn the molecular configuration into pyramid-like shape beyond the cmc, which make the transition of network-like aggregates to micelles available.

Self-assembly of peptide-amphiphile C12-Abeta(11-17) into nanofibrils.

A peptide-amphiphile (C12-Abeta(11-17)) was constructed with a key fragment of amyloid beta-peptide (Abeta(11-17)) attached to dodecanoic acid through an amide bond. The self-assembly behavior of C12-Abeta(11-17) in aqueous solution is studied at 25 degrees C and at pH 3.0 and 10.0. Abeta(11-17) cannot form ordered self-assemblies. But C12-Abeta(11-17) exhibits a very strong ability to form ordered nanofibrils, and the specific fine structure of the nanofibrils can be modulated simply by adjusting the concentration or pH. The critical micelle concentration of C12-Abeta(11-17) was determined as 0.063 and 0.11 mM at pH 3.0 and 10.0, respectively, indicating a stronger assembling ability of C12-Abeta(11-17) at acidic pH. In 0.47 mM C12-Abeta(11-17) solution at pH 3.0, rodlike fibrils with a diameter of approximately 5 nm and varying length of hundreds of nanometers are observed. When the C12-Abeta(11-17) concentration increases to 1.87 mM at pH 3.0, the above rodlike fibrils pack in parallel and form tapelike fibrils through lateral association. In 1.87 mM C12-Abeta(11-17) solution at pH 10.0, twisted fibrils with regular periodicity of approximately 200 nm are formed by the twisting of approximately 20 nm wide and approximately 11 nm thick nanoribbons. The hydrophobic moiety is necessary in fibril formation, whereas the beta-sheet secondary structure of the peptide moiety plays an essential role in the twisting morphology. This work helps to understand the possible mechanism in amyloid fibrillogenesis and provides an approach to inscribe biological signals in self-assemblies with potential application in biomaterial fabrication.

Highly-ordered selective self-assembly of a trimeric cationic surfactant on a mica surface.

Novel trimeric cationic surfactant tri(dodecyldimethylammonioacetoxy)diethyltriamine trichloride (DTAD) has been synthesized, and its self-assembly morphology on a mineral surface has been studied. From its micelle solution, highly ordered bilayer patterns are obtained on a mica surface, whereas randomly distributed bilayer patches are formed on a silica substrate. The highly ordered bilayer patterns on mica are first caused by the matching of the special structure of DTAD headgroups with the negative charge sites on mica, which leads to the specific nucleation of DTAD on the mica surface via electrostatic interaction. Furthermore, hydrophobic interaction among the DTAD hydrocarbon chains results in the formation of the bilayer structure, and intermolecular hydrogen-bonding among the DTAD headgroups promotes the directional growth of such bilayer structures.