Strong Interaction between Titanium Carbonitride Embedded in Mesoporous Carbon Nanofibers and Pt Enables Durable Oxygen Reduction.

Platinum (Pt) supported on high surface area carbon has been the most widely used electrocatalyst in proton exchange membrane fuel cell (PEMFC). However, conventional carbon supports are susceptible to corrosion at high potentials, leading to severe degradation of electrochemical performance. In this work, titanium carbonitride embedded in mesoporous carbon nanofibers (m-TiCN NFs) are reported as a promising alternative to address this issue. Benefiting from the interpenetrating conductive pathways inside the one-dimensional (1D) nanostructures and the embedded TiCN nanoparticles (NPs), m-TiCN NFs exhibit excellent stability at high potentials and interact strongly with Pt NPs. Subsequently, m-TiCN NFs-supported Pt NPs deliver remarkably enhanced oxygen reduction reaction (ORR) activity and durability, with negligible activity decay and less than 5% loss of electrochemical surface area（ECSA） after 50 000 cycles. Moreover, the fuel cell assembled by this catalyst delivers a maximum power density of 1.22 W cm-2 and merely 3% loss after 30 000 cycles of accelerated durability tests under U.S. Department of Energy (DOE) protocols. The improved ORR activity and durability are attributed to the superior corrosion resistance of the m-TiCN NF support and the strong interaction between Pt and m-TiCN NFs.

Realizing multiferroics in α-Ga2S3via hole doping: a first-principles study.

Using first-principles calculations, we report the realization of multiferroics in an intrinsic ferroelectric α-Ga2S3 monolayer. Our results show that the presence of intrinsic gallium vacancies, which is the origin of native p-type conductivity, can simultaneously introduce a ferromagnetic ground state and a spontaneous out-of-plane polarization. However, the high switching barrier and thermodynamic irreversibility of the ferroelectric reversal path disable the maintenance of ferroelectricity, suggesting that the defect-free form should be a prerequisite for Ga2S3 to be multiferroic. Through applying strain, the behavior of spontaneous polarization of the pristine α-Ga2S3 monolayer can be effectively regulated, but the non-magnetic ground state does not change. Strikingly, via an appropriate concentration of hole doping, stable ferromagnetism with a high Curie temperature and robust ferroelectricity can be concurrently introduced in the α-Ga2S3 monolayer. Our work provides a feasible method for designing 2D multiferroics with great potential in future device applications.

Precise Engineering of the Electrocatalytic Activity of FeN4-Embedded Graphene on Oxygen Electrode Reactions by Attaching Electrides.

Using first-principles calculations combined with a constant-potential implicit solvent model, we comprehensively studied the activity of oxygen electrode reactions catalyzed by electride-supported FeN4-embedded graphene (FeN4Cx). The physical quantities in FeN4Cx/electrides, i.e., work function of electrides, interlayer spacing, stability of heterostructures, charge transferred to Fe, d-band center of Fe, and adsorption free energy of O, are highly intercorrelated, resulting in activity being fully expressed by the nature of the electrides themselves, thereby achieving a precise modulation in activity by selecting different electrides. Strikingly, the FeN4PDCx/Ca2N and FeN4PDCx/Y2C systems maintain a high oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activity with the overpotential less than 0.46 and 0.62 V in a wide pH range. This work provides an effective strategy for the rational design of efficient bifunctional catalysts as well as a model system with a simple activity-descriptor, helping to realize significant advances in energy devices.

Reaction mechanism of atomic layer deposition of aluminum sulfide using trimethylaluminum and hydrogen sulfide.

Atomic layer deposition (ALD) is a nanopreparation technique for materials and is widely used in the fields of microelectronics, energy and catalysis. ALD methods for metal sulfides, such as Al2S3 and Li2S, have been developed for lithium-ion batteries and solid-state electrolytes. In this work, using density functional theory calculations, the possible reaction pathways of the ALD of Al2S3 using trimethylaluminum (TMA) and H2S were investigated at the M06-2X/6-311G(d, p) level. Al2S3 ALD can be divided into two consecutive and complementary half-reactions involving TMA and H2S, respectively. In the TMA half-reaction, the methyl group can be eliminated through the reaction with the sulfhydryl group on the surface. This process is a ligand exchange reaction between the methyl and sulfhydryl groups via a four-membered ring transition state. TMA half-reaction with the sulfhydrylated surface is more difficult than that with the hydroxylated surface. When the temperature increases, the reaction requires more energy, owing to the contribution of the entropy. In the H2S half-reaction, the methyl group on the surface can further react with the H2S precursor via a four-membered ring transition state. The orientation of H2S and more molecules have minimal effect on the H2S half-reaction. The reaction involving H2S through a six-membered ring transition state is unfavorable. In addition, the methyl and sulfhydryl groups on the surface can both react with the adjacent sulfhydryl group on the subsurface to form and release CH4 or H2S in the two half-reactions. Furthermore, sulfhydryl elimination occurs more easily than methyl elimination on the surface. These findings for the TMA and H2S half-reactions of Al2S3 ALD may be used for studying precursor chemistry and improvements in the preparation of other metal sulfides for emerging applications.

The risk factors associated with delirium after lumbar spine surgery in elderly patients.

BACKGROUND: To prospectively explore the incidence and risk factors for postoperative delirium in elderly patients following lumbar spine surgery. METHODS: This prospective study enrolled 148 consecutive patients over the age of 65 who were scheduled to undergo spine surgery. Patients were screened for delirium using the short Confusion Assessment Method (CAM) postoperatively. Patient demographics and relevant medical information were collected. Logistic regression analysis was used to identify the risk factors associated with postoperative delirium. RESULTS: Eighty-three patients (56.1%) who underwent lumbar spine surgery (not coexisting with cervical or thoracic spine surgery) were enrolled in our study. Post-operative delirium was noted in 14.5% of patients over 65 years old. The presence of preoperative Parkinsonism was significantly higher in the delirium group (41.7% vs. 8.5%, P=0.002), as was a higher preoperative C-reactive protein (CRP) (7.0±15.2 vs. 1.3±2.3 mg/L, P=0.017) when compared with the non-delirium group. Of the risk factors, male sex [odds ratio (OR) =0.10, 95% confidence interval (CI): 0.01-0.66, P=0.017], Parkinsonism (OR =5.83, 95% CI: 1.03-32.89, P=0.046), and lower baseline MMSE score (OR =0.71, 95% CI: 0.52-0.97, P=0.032) were independently associated with postoperative delirium in elderly patients undergoing lumbar spine surgery. CONCLUSIONS: Post-operative delirium occurred in 14.5% of elderly patients who underwent lumbar spine surgery. Male sex, Parkinsonism, and lower baseline MMSE score were identified as independent risk factors for postoperative delirium in elderly patients following lumbar surgery.

The modified transforaminal endoscopic technique in treating intracanalicular combining foraminal and/or extraforaminal lumbar disc herniations.

BACKGROUND: To develop a modified transforaminal endoscopic spine system (TESSYS®) technique for treating intracanalicular combining foraminal and/or extraforaminal lumbar disc herniation (ICFE-LDH), and evaluate the technical efficacy and safety. METHODS: Twenty-three patients with ICFE-LDH underwent the modified TESSYS technique were enrolled. Magnetic resonance imaging (MRI) was used to verify the reduction of herniated disc. Pre- and post-operative neurological functions were compared by visual analogue scale (VAS) score, Oswestry disability index (ODI) and the modified MacNab criteria. The technical safety was evaluated by surgical complications. RESULTS: MRI demonstrated reductions of disc herniations in 22 patients (95.7%) after surgeries. The VAS scores were significantly improved at 1 year follow-up (low back: P=0.001, lower limbs: P<0.001), as well as ODI scores (P<0.001). 22 patients had achieved excellent and good recovery postoperatively according to the modified MacNab criteria. One patient (4.3%) underwent a reoperation due to postoperative recurrence of disc herniation. Another patient complained postoperative causalgia in 8 weeks, the symptom alleviated after conservative treatment at 1 year follow-up (VAS: back, 3, lower limbs, 0; ODI: 20%). The incidence rate of surgical complication was 8.7%. CONCLUSIONS: The modified TESSYS technique is a minimally-invasive, effective and safe surgery for treating ICFE-LDHs in selected patients.

Analysis of expressed sequence tags from the venom ducts of Conus striatus: focusing on the expression profile of conotoxins.

Cone snails (genus Conus) are predatory marine gastropods that use venom peptides for interacting with prey, predators and competitors. A majority of these peptides, generally known as conotoxins demonstrate striking selectivity in targeting specific subtypes of ion channels and neurotransmitter receptors. So they are not only useful tools in neuroscience to characterize receptors and receptor subtypes, but offer great potential in new drug research and development as well. Here, a cDNA library from the venom ducts of a fish-hunting cone snail species, Conus striatus is described for the generation of expressed sequence tags (ESTs). A total of 429 ESTs were grouped into 137 clusters or singletons. Among these sequences, 221 were toxin sequences, accounting for 52.1% (corresponding to 19 clusters) of all transcripts. A-superfamily (132 ESTs) and O-superfamily conotoxins (80 ESTs) constitute the predominant toxin components. Some non-disulfide-rich Conus peptides were also found. The expression profile of conotoxins also explained to some extent the pharmacological and physiological reactions elicited by this typical piscivorous species. For the first time, a nonstop transcript of conotoxin was identified, which is suggestive that alternative polyadenylation may be a means of post-transcriptional regulation of conotoxin production. A comparison analysis of these conotoxins reveals the different variation and divergence patterns in these two superfamilies. Our investigations indicate that focal hyper-mutation, block substitution and exon shuffling are three main mechanisms leading to the conotoxin diversity in a species. The comprehensive set of Conus gene sequences allowed the identification of the representative classes of conotoxins and related components, which may lay the foundation for further research and development of conotoxins.