Stripping away ion hydration shells in electrical double-layer formation: Water networks matter.

The double layer at the solid/electrolyte interface is a key concept in electrochemistry. Here, we present an experimental study combined with simulations, which provides a molecular picture of the double-layer formation under applied voltage. By THz spectroscopy we are able to follow the stripping away of the cation/anion hydration shells for an NaCl electrolyte at the Au surface when decreasing/increasing the bias potential. While Na+ is attracted toward the electrode at the smallest applied negative potentials, stripping of the Cl- hydration shell is observed only at higher potential values. These phenomena are directly measured by THz spectroscopy with ultrabright synchrotron light as a source and rationalized by accompanying molecular dynamics simulations and electronic-structure calculations.

Dilute Povidone-Iodine Solution Soaking Is Ineffective in Improving Outcomes of Necrotizing Fasciitis Caused by Diabetic Foot.

ABSTRACT: Wound soaking is a physical debridement method that helps reduce bacterial colonization and consequently promotes wound healing. Although soaking in povidone-iodine solution was ineffective in reducing bacterial colonization in acute trauma wounds, there is still a lack of evidence supporting the efficacy of this method in treating severe soft tissue infection. This study aimed to explore the effects of wound soaking in 1% dilute povidone-iodine solution on necrotizing fasciitis caused by diabetic foot ulcers. We retrospectively reviewed and finally included 153 patients who were admitted because of diabetic foot ulcers after undergoing fasciotomy for necrotizing infection from January 2018 to December 2021. Results showed no statistical difference in the outcomes between patients in the soaking and nonsoaking groups. End-stage renal disease (P = 0.029) and high serum C-reactive protein level (P = 0.007) were the only independent factors for below-knee amputation in the univariate and multivariate logistic regression analyses. Therefore, soaking diabetic wounds with severe infection in 1% dilute povidone-iodine solution may not reduce the hospital length of stay, risk of below-knee amputation, and readmission rate.

Total Surface Area of a Through-and-Through Oromandibular Defect Is Associated With Thromboembolic Events for Reconstruction With a Single Fibula Free Flap.

BACKGROUND: Reconstruction of through-and-through composite oromandibular defects (COMDs) has been a challenge to plastic surgeons for decades. When using a free osteoseptocutaneous fibular flap, the skin paddle is restricted by the orientation of the peroneal vessels and the inset of bone segment(s). Although the combination of double flaps for extensive COMDs is viable and reliable, the decision of single- or double-flap reconstruction is still debated, and the risk factors leading to complications and flap failure of single-flap reconstruction are less discussed. AIM AND OBJECTIVES: The aim of this study was to determine objectively predictive factors for postoperative vascular complications in through-and-through COMDs reconstructed with a single fibula flap. METHODS: This was a retrospective cohort study in patients who underwent single free fibular flap reconstruction for through-and-through COMDs in a tertiary medical center from 2011 to 2020. The enrolled patients' characteristics, surgical methods, thromboembolic event, flap outcomes, intensive care unit care, and total hospital length of stay were analyzed. RESULTS: A total of 43 consecutive patients were included in this study. Patients were categorized into a group without thromboembolic events (n = 35) and a group with thromboembolic events (n = 8). The 8 subjects with thromboembolic events were failed to be salvaged. There was no significant difference in age, body mass index, smoking, hypertension, diabetes mellitus, and history of radiotherapy. The length of bony defect (6.70 ± 1.95 vs 9.04 ± 2.96, P = 0.004) and the total surface area (105.99 ± 60.33 vs 169.38 ± 41.21, P = 0.004) were the 2 factors that showed a significant difference between the groups. Total surface area was the only significant factor in univariate logistic regression for thromboembolic event (P = 0.020; odds ratio, 1.02; 95% confidence interval [CI], 1.003-1.033) and also in multivariate logistic regression analysis after adjusting confounding factors (P = 0.033; odds ratio, 1.026; 95% CI, 1.002-1.051).The cutoff level of total surface area in determining thromboembolic event development was 159 cm2 (P = 0.005; sensitivity of 75% and specificity of 82.9%; 95% CI, 0.684-0.952). CONCLUSIONS: Free fibula flap has its advantages and drawbacks on mandible restoration. Because there is a lack of indicators before, a large total surface area may be an objective reference for single-flap reconstruction of through-and-through COMDs due to an elevated risk of thromboembolic event.

Accuracy of the Application of 3-Dimensional Printing Models in Orbital Blowout Fractures-A Preliminary Study.

BACKGROUND: Application of 3-dimensional (3D) printing technology has grown in the medical field over the past 2 decades. In managing orbital blowout fractures, 3D printed models can be used as intraoperative navigators and could shorten the operational time by facilitating prebending or shaping of the mesh preoperatively. However, a comparison of the accuracy of computed tomography (CT) images and printed 3D models is lacking. MATERIAL AND METHODS: This is a single-center retrospective study. Patients with unilateral orbital blowout fracture and signed up for customized 3D printing model were included. Reference points for the 2D distance were defined (intersupraorbital notch distance, transverse horizontal, sagittal vertical, and anteroposterior axes for orbital cavity) and measured directly on 3D printing models and on corresponding CT images. The difference and correlation analysis were conducted. RESULTS: In total, 9 patients were reviewed from June 2017 to December 2020. The mean difference in the intersupraorbital notch measurement between the 2 modules was -0.14 mm (P = 0.67). The mean difference in the distance measured from the modules in the horizontal, vertical, and anteroposterior axes of the traumatic orbits was 0.06 mm (P = 0.85), -0.23 mm (P = 0.47), and 0.51 mm (P = 0.32), whereas that of the unaffected orbits was 0.16 mm (P = 0.44), 0.34 mm (P = 0.24), and 0.1 mm (P = 0.88), respectively. Although 2D parameter differences (<1 mm) between 3D printing models and CT images were discovered, they were not statistically significant. CONCLUSIONS: Three-dimensional printing models showed high identity and correlation to CT image. Therefore, personalized models might be a reliable tool of virtual surgery or as a guide in realistic surgical scenarios for orbital blowout fractures.

Cation enrichment in the ion atmosphere is promoted by local hydration of DNA.

Electrostatic interactions are central to the structure and function of nucleic acids, including their folding, condensation, and interaction with proteins and other charged molecules. These interactions are profoundly affected by ions surrounding nucleic acids, the constituents of the so-called ion atmosphere. Here, we report precise Fourier Transform-Terahertz/Far-Infrared (FT-THz/FIR) measurements in the frequency range 30-500 cm-1 for a 24-bp DNA solvated in a series of alkali halide (NaCl, NaF, KCl, CsCl, and CsF) electrolyte solutions which are sensitive to changes in the ion atmosphere. Cation excess in the ion atmosphere is detected experimentally by observation of cation modes of Na+, K+, and Cs+ in the frequency range between 70-90 cm-1. Based on MD simulations, we propose that the magnitude of cation excess (which is salt specific) depends on the ability of the electrolyte to perturb the water network at the DNA interface: In the NaF atmosphere, the ions reduce the strength of interactions between water and the DNA more than in case of a NaCl electrolyte. Here, we explicitly take into account the solvent contribution to the chemical potential in the ion atmosphere: A decrease in the number of bound water molecules in the hydration layer of DNA is correlated with enhanced density fluctuations, which decrease the free energy cost of ion-hydration, thus promoting further ion accumulation within the DNA atmosphere. We propose that taking into account the local solvation is crucial for understanding the ion atmosphere.

Probing Local Electrostatics of Glycine in Aqueous Solution by THz Spectroscopy.

Based upon precise terahertz (THz) measurements of the solvated amino acid glycine and accompanying ab-initio molecular-dynamics simulations, we show that the N-C-C-O open/close mode at 315 cm-1 serves as a sensitive, label-free probe for the local protonation of the amide group. Experimentally, we can show that this holds not only for glycine but also for diglycine and valine. The approach is more general, since the changes due to protonation result in intensity changes which can be probed by THz time domain (0-50 cm-1 ) as well as by precise THz-FT spectroscopy (50-400 cm-1 ). A detailed analysis allows us to directly correlate the titration spectra with pKa values. This demonstrates the potential of THz spectroscopy to probe the charge state of a natural amino acid in water in a label-free manner.

[Influence of femoral neck area on larger anteversion angle of lag screw guide pin initial placement in proximal femoral intramedullary nail fixation].

OBJECTIVE: To invstigate the influence of femoral neck area on larger anteversion angle of lag screw guide pin initial placement in proximal femoral intertrochanteric fracture treated with intramedullary nail. METHODS: From June 2014 to June 2016, 60 patients with femoral intertrochanteric fractures were treated with intramedullary nail, including 27 males and 33 females with an average age of 75 years old ranging from 49 to 88 years old. The lateral images of femoral neck were divided into areas during operation. The anteversion angle of lag screw guide pin of proximal femoral nail was observed at the time of initial insertion. The incidence of normal and larger was counted and the angle index of influencing factors was recorded. RESULTS: Among 60 patients, the screw guide pins of 23 cases were in the central region of the femoral neck and the anteversion angle was normal;screw guide pins of 37 cases were in the front area of the femoral neck, leading to larger anteversion angle. The single factor analysis showed that the independent variables influence factors of larger anteversion were internal collection of the affected limb, internal rotation of the affected limb, hip elevation and screw guide pin level(P<0.05). The multi-factor regression analysis showed that the anteversion angle larger was significantly related to the internal rotation of the affected limb and screw guide pin level, and the screw guide pin level was the most relevant(P=0.030). CONCLUSIONS: The internal rotation of the affected limb and screw guide pin level may affect the anteversion angle of femoral neck when lag screw guide pin initial insertion, cause it to be too large and the screw guide pin level is the main influencing factor.

FeatSNP: An Interactive Database for Brain-Specific Epigenetic Annotation of Human SNPs.

FeatSNP is an online tool and a curated database for exploring 81 million common SNPs' potential functional impact on the human brain. FeatSNP uses the brain transcriptomes of the human population to improve functional annotation of human SNPs by integrating transcription factor binding prediction, public eQTL information, and brain specific epigenetic landscape, as well as information of Topologically Associating Domains (TADs). FeatSNP supports both single and batched SNP searching, and its interactive user interface enables users to explore the functional annotations and generate publication-quality visualization results. FeatSNP is freely available on the internet at FeatSNP.org with all major web browsers supported.

[Photolumimescence character of novel phthalocyanine].

In the present paper, the authors study the photolumimescence spectra of the novel 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine casting film and vacuum-deposited film. Photolumimescence spectras of casting film on the quartz substrate were measured at 10, 77, 177 and 300 K, and the photolumimescence spectra of vacuum-deposited film with a thickness of about 200 nm on the silicon substrate was studied at room temperature (300 K). For 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine, the casting films all show fluorescence peaks at 942, 937, 942 and 942 nm and phosphorescence peaks at 1114, 1057, 1114 and 1114 nm in the photolumimescence spectra at 10, 77, 177 and 300 K, respectively. In the cases of 2,3-tetra-(2-isopropyl-5-methyl -benzoyl) hydrogen phthalocyanine, the peaks of excimers, which are related with the resistance ability of molecular aggregation, were found around 1673 nm as observed from photolumimescence spectra of the novel phthalocyanine casting films at 177 and 300 K. And the peak of excimers at 300 K is stronger than at 177 K also as can be seen from photolumimescence spectra of its casting films. With the increase in the temperature, the fluorescence peak was weakened and the peaks of excimers became stronger from the photoluminescence spectra of 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine casting films at 10, 77, 177 and 300 K. At the same time, the authors discussed the reason for coming into being 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine excimers as can be concluded from the structure of 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine molecules through the parameters of Chem 3D Ultra 9.0 MM2 calculation and simulated diagram of C4h isomer of 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine. The peaks of casting film and vacuum-deposited film of 2,3-tetra-(2-isopropyl-5-methyl -benzoyl) hydrogen phthalocyanine presented different maximum emission wavelength and full width at half maximum. The peak of 2,3-tetra-(2-isopropyl-5-methyl-benzoyl) hydrogen phthalocyanine vacuum-deposited films displays the maximum emission wavelengths around 1140 nm, while the maximum emission wavelengths of casting films show obvious differences compared with the vacuum-deposited films. The usual full width at half maximum is approximately 300 nm for casting film, which is in contrasts with that the full width at half maximum is about 100 nm for the vacuum-deposited film as can be seen from photolumimescence spectra of 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine casting film and photolumimescence spectra of 2,3-tetra-(2-isopropyl-5-methylbenzoyl) hydrogen phthalocyanine vacuum-deposited film.

The control of phthalocyanine properties through nitro-group electronic effect.

The UV-vis spectra of peripherally substituted tetranitrometallophthalocyanines (TNMPcs) 1a-1d and non-peripherally substituted TNMPcs 2a-2d were investigated. In comparison of 1a with 2a, there is the only difference in the substitution position of nitro-groups. The structural diversity of 1a and 2a resulted in different electronic effects of nitro-group on Pc rings, which caused them have two kinds of Q bands. The Q band in the UV-vis spectra of 1a-1d was split into two peaks, which were obviously influenced by temperature, while no split was observed in the Q band of 2a-2d. We can draw a conclusion that tuning nitro-group electronic effect is an important approach for controlling the properties of Pcs.