Holey penta-hexagonal graphene: a promising anode material for Li-ion batteries.

Carbon allotropes are widely used as anode materials in Li batteries, with graphite being commercially successful. However, the limited capacity and cycling stability of graphite impede further advancement and hinder the development of electric vehicles. Herein, through density functional theory (DFT) computations and ab initio molecular dynamics (AIMD) simulations, we proposed holey penta-hexagonal graphene (HPhG) as a potential anode material, achieved through active site designing. Due to the internal electron accumulation from the π-bond, HPhG follows a single-layer adsorption mechanism on each side of the nanosheet, enabling a high theoretical capacity of 1094 mA h g-1 without the risk of vertical dendrite growth. HPhG also exhibits a low open circuit voltage of 0.29 V and a low ion migration barrier of 0.32 eV. Notably, during the charge/discharge process, the lattice only expands slightly by 1.1%, indicating excellent structural stability. This work provides valuable insights into anode material design and presents HPhG as a promising two-dimensional material for energy storage applications.

One-step preparation of magnetic N-doped sodium alginate-based porous carbon and efficient adsorption of bisphenol A.

To resourcefully utilize algal biomass and effectively remove bisphenol A (BPA) from water, sodium alginate (SA) was prepared as the nitrogen-doped magnetic porous carbon material (SAC/N/Fe) with well-developed pore structure according to a one-step method using K2CO3, melamine, Fe(NO3)3·9H2O as the activator, nitrogen dopant, and magnetic precursor, respectively, in this study. The best product, SAC/N/Fe-0.2, was obtained by adjusting the mass ratio of raw materials, and its specific surface area and pore volume were 2240.65 m2 g-1 and 1.44 cm3 g-1, respectively, with a maximum adsorption capacity of 1248.23 mg g-1 for BPA at 308 K. SEM, XRD, XPS, VSM, and FT-IR characterization confirmed that the iron was successfully doped, giving the porous carbon a magnetic separation function. The adsorption process of BPA was more consistent with the Langmuir model and the proposed secondary kinetics, and the adsorption effect was stable and efficient in a wide pH range and under the interference of different metal ions. At the same time, the porous carbon was easy to separate and recover with good regeneration performance.

A polymeric hydrogel electrocatalyst for direct water oxidation.

Metal-free electrocatalysts represent a main branch of active materials for oxygen evolution reaction (OER), but they excessively rely on functionalized conjugated carbon materials, which substantially restricts the screening of potential efficient carbonaceous electrocatalysts. Herein, we demonstrate that a mesostructured polyacrylate hydrogel can afford an unexpected and exceptional OER activity - on par with that of benchmark IrO2 catalyst in alkaline electrolyte, together with a high durability and good adaptability in various pH environments. Combined theoretical and electrokinetic studies reveal that the positively charged carbon atoms within the carboxylate units are intrinsically active toward OER, and spectroscopic operando characterizations also identify the fingerprint superoxide intermediate generated on the polymeric hydrogel backbone. This work expands the scope of metal-free materials for OER by providing a new class of polymeric hydrogel electrocatalysts with huge extension potentials.

Narrowing the band gap and suppressing electron-hole recombination in ß-Fe2O3 by chlorine doping.

The effects of halogen (F, Cl, Br, I, and At) doping in the direct-band-gap ß-Fe2O3 semiconductor on its band structures and electron-hole recombination have been investigated by density functional theory. Doping Br, I, and At in ß-Fe2O3 leads to transformation from a direct-band-gap semiconductor to an indirect-band-gap semiconductor because their atomic radii are too large; however, F- and Cl-doped ß-Fe2O3 remain as direct-band-gap semiconductors. Due to the deep impurity states of the F dopant, this study focuses on the effects of the Cl dopant on the band structures of ß-Fe2O3. Two impurity levels are introduced when Cl is doped into ß-Fe2O3, which narrows the band gap by approximately 0.3 eV. After doping Cl, the light-absorption edge of ß-Fe2O3 redshifts from 650 to 776 nm, indicating that its theoretical solar to hydrogen efficiency for solar water splitting increases from 20.6% to 31.4%. In addition, the effective mass of the holes in halogen-doped ß-Fe2O3 becomes significantly larger than that in undoped ß-Fe2O3, which may suppress electron-hole recombination.

Theoretical insight into surface structures of pentlandite toward hydrogen evolution.

Pentlandite (Fe,Ni)9S8 is a promising transition-metal catalyst for the hydrogen evolution reaction. However, little is explained about the long activation process that has been observed in experiments, and its facet-dependent hydrogen evolution activity is still theoretically unrevealed. To explain some experimental phenomena and to guide subsequent studies, density functional theory calculations are used to study the main synthetic surfaces: (111) and (311) in this work. The results show that the small metal cube plays an important role in the surface stability, and it is suggested that such cubes remain intact during catalysis. The linking sites serve as a bridge across the metal cubes and are the main catalytic active sites for hydrogen evolution. This is because the metal cubes can tune the electronic structures of the linking sites, and then the free energy of the linking sites is optimized. The (311) surface is a composite surface that consists of (100) and (111) facets and has the profile of a step. A surface conversion between the (311) and (111) facets may occur when the cube layer length increases. Therefore, the active sites can be feasibly engineered by the surface structures, and this could be helpful in further applications of (Fe,Ni)9S8.

Synergistic effect of S-bridged Fe-Ni group on hydrogen evolution for pentlandite.

Pentlandite is reported to exhibit good catalytic activity in hydrogen evolution reaction (HER). Many studies have paid attention to metal catalysis of pentlandite. However, the nonmetal catalysis is not considered for HER. Here, we unravel one probable catalytic mechanism of pentlandite toward HER using density functional theory. In our study models, (001) and (100) surfaces are created because there are three types of S-bridged M-M groups on them. Our study reveals that (Fe-Ni)-S center has a moderate value of Gibbs free energy while the corresponding value for (Fe-Fe)-S or (Ni-Ni)-S center is largely positive or negative. In (Fe-Ni)-S group, Fe and Ni can regulate the antibonding state of S, and then balance adsorption and desorption of proton. In addition, an intrinsic electronic potential difference exists between Fe and Ni in (Fe-Ni)-S group, which may boost the charge transfer. Particularly, (Fe-Ni)-S groups are perpendicular to the surface, and four of them make up one closed loop in the surface. It is suggested that the behaviors of such configuration composed of reaction centers resemble edge sites along the layers of MoS2 toward HER. This study provides a deep insight into the synergistic effect of S-bridged Fe-Ni groups and enables the modulation of electrocatalytic reaction of pentlandite toward HER.

Perforator navigation using color Doppler ultrasound and three-dimensional reconstruction for preoperative planning of optimal lateral circumflex femoral artery system perforator flaps in head and neck reconstruction.

BACKGROUND: The authors introduce an algorithm for preoperative planning of optimal lateral circumflex femoral artery system perforator flap (LCFAPF) supplied by the best quality and the easiest dissection of the perforators and the source vessels for simplified and customized strategies in head and neck reconstruction with perforator navigation using color Doppler ultrasound and three-dimensional reconstruction (3D-CDUS PN). METHODS: Between June 2011 and September 2015, a prospective cohort study was performed with an algorithm based on defect site, perforator type, and pedicle length using 3D-CDUS PN to select optimal perforators arising from the different branches of LCFA in 108 patients. The optimal perforator and flap were determined by perforator caliber and quality, difficulty in flap dissection, and length of the source vessels. Cause and classification of the defect, flap choice, recipient vessels, postoperative course, and complications were analyzed. RESULTS: The source vessels of the perforators were lateral descending branch in 73 cases and oblique branch in 17 cases with ALTPFs, medial descending branch in 12 cases with AMTPFs, and ascending branch in 6 cases with TFLPFs. Straightforward dissection of flaps with septocutaneous (n = 40) and semi-septocutaneous (n = 17) perforators was performed in 52.8% cases. Successful exploration rate and overall flap survival rate were both 100%. Satisfactory functional and esthetic results in both recipient and donor sites with no serious complications were observed in all patients. CONCLUSIONS: Our algorithm using 3D-CDUS PN facilitates selection of optimal flap with better caliber and quality of the perforators and sufficient pedicle length for easy dissection.

Contrast-enhanced ultrasound combined with three-dimensional reconstruction in preoperative perforator flap planning.

BACKGROUND: Along with technical advancements in perforator flap surgery, great interest has been recently focused on the accuracy of preoperative perforator location through the assessment of the donor-site vascular network. The goal of the present study was to investigate the usefulness of contrast-enhanced ultrasound combined with three-dimensional reconstruction in the planning of perforator flaps. METHODS: The authors retrospectively analyzed the preoperative imaging vascular anatomy provided by contrast-enhanced ultrasound combined with three-dimensional reconstruction in 32 patients undergoing perforator flap reconstruction between 2009 and 2011. The static and dynamic features of any suitable perforator including number of branches, source vessel, running course, blood flow pattern and velocity (peak systolic velocity and resistance index), and its anatomical relationship were assessed preoperatively by the novel navigation imaging. Based on this information, the preferred perforator and the ideal donor site were selected for the flap harvesting. The accuracy of preoperative imaging data was checked during surgery. RESULT: Contrast-enhanced ultrasound provided a continuous blood flow signal and a clear and reliable image of perforators, and three-dimensional reconstruction displayed their spatial anatomical relationship and their roots. Consistent with the surgical findings, perforators were identified accurately in all 32 cases with high specificity (100 percent) and sensitivity. CONCLUSIONS: Contrast-enhanced ultrasound with three-dimensional image reconstruction provides valuable preoperative perforator navigation. It detects precisely the perforator's location, its course, and the quality of its blood flow and allows the choice of the preferred perforator and the ideal donor site. Preoperative location of perforators using contrast-enhanced ultrasound with three-dimensional image reconstruction improves flap planning and eases flap harvesting. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, IV.

Reconstruction of the cheek after large port-wine stain lesion resection.

BACKGROUND: A laser is commonly used in treatment of port-wine stain (PWS). Although observable lightening of the stains can be achieved, complete removal is rare. A significant proportion of lesions are resistant to laser treatment, including hypertrophic lesions and scars developed after improper (unsuccessful) treatments. Alternatively, resection is used to eliminate such lesions, but the reconstruction of the aesthetic appearance of the cheek after large lesion resection remains a huge challenge. METHODS: Ten patients with a PWS larger than two-thirds of the cheek were selected for this study. In those patients, prefabricated induced expanded flaps carried by the superficial temporal vessels were prepared to cover the defect areas after resection of the PWS lesion. RESULTS: In eight patients, all the donor sites and defect areas were covered primarily with the expanded flaps, which then survived completely. All patients were satisfied with the cheek appearance after reconstruction with prefabricated induced expanded flaps, which provided a good match for color and texture, restored facial contour, placed scars in a concealed location, and achieved minimal donor-site morbidity. Two of the ten patients did not finish the original surgical plan due to infection or damage to the vascular pedicle. CONCLUSION: We show that the technique of using prefabricated expanded flaps based on the superficial temporal vessels can be an effective option for repairing large cheek defects after PWS resection.

Ultrasonographic evaluation of mandibular ameloblastoma: a preliminary observation.

OBJECTIVE: The purpose of this study was to demonstrate ultrasonographic characteristics of mandibular ameloblastoma and assess the value of ultrasonography in diagnosis of the tumor. STUDY DESIGN: Nineteen subjects with ameloblastomas in the mandibles were examined with ultrasonography. Locations, sizes, internal echoes, boundaries, and blood flow of the tumors were observed and documented. Ultrasonographic appearances of the tumors were compared with histopathological findings. Sensitivity and specificity of Doppler flow signals for prediction of active tumor proliferations were calculated. RESULTS: The main sonographic features of the tumor appeared as a complex cystic mass with solid contents. Most tumors (15/19, 79%) showed no or minimal flow signals on color Doppler flow imaging (CDFI), whereas the remaining 4 lesions demonstrated abundant flow signals. The sensitivity and specificity of the Doppler flow signals for prediction of active tumor proliferations were 100% and 94%, respectively. The ultrasonographic appearances could be classified into 4 types: multilocular (10/19, 53%), honeycomb (4/19, 21%), unilocular (3/19, 16%), and local severe destructive (2/19, 10%). CONCLUSION: Ultrasonography can be used as an effective supplementary diagnostic method for mandibular ameloblastomas. CDFI of tumor vascularity could be used to predict active tumor proliferations.

[Duplex ultrasonography and internal pudendal arteriogram in the diagnosis of trauma-associated arteriogenic erectile dysfunction (a report of 7 cases)].

OBJECTIVE: To make a comparative study of duplex ultrasonography (DU) and internal pudendal arteriogram (IPA) in the diagnosis of trauma-associated arteriogenic erectile dysfunction (ED). METHODS: Seven patients suffering from arteriogenic erectile dysfunction caused by pelvic fracture trauma underwent comprehensive history inquiries and physical examinations by duplex ultrasonography and internal pudendal arteriogram, which ruled out neurogenic erectile dysfunction. RESULTS: DU suggested penile artery blood flow injury, and IPA indicated artery injury in all the cases, including left internal pudendal artery injury, right or left common penile artery injury and bilateral common penile artery injury. CONCLUSION: Trauma-associated arteriogenic erectile dysfunction may result from common penile artery injury and internal pudendal artery injury. DU is proved valuable for evaluating hemodynamic abnormalities of cavernous artery flow, and IPA useful in locating common penile artery and internal pudendal artery injury. DU can be used as the first line diagnostic means to define trauma-associated arteriogenic ED.

[Correlation of age and sex hormones to the transition zone volume of the prostate].

OBJECTIVE: To investigate the correlation of age and sex hormones to the total volume (TV) and transition zone volume METHODS: Eighty-two men were divided into two groups with the age of 60 as the dividing line. Prostatic TV (TZV and TZV were measured with transrectal ultrasound (TRUS) and the concentrations of total testosterone (T), free testosterone (fT) and estradiol (E2) were measured with radioimmunoassay. Exponential curve regression and one-factor analysis of variance (ANOVA) were used for statistical analysis. RESULTS: Age was significantly correlated with TV, TZV and the TZV/TV ratio, P < 0.01. There was a significant positive correlation between the concentrations of fT and TZV, a negative correlation between those of E2 and TZV (P < 0.01), but no correlation between those of T and TZV (P > 0.05). CONCLUSION: The significant acceleration of the TZV of the prostate after the age of 60 is related to sex hormones.