Intrinsic Stress Field for Liquid Surfaces.

The microscopic stress field inhomogeneity in the interfacial region adjacent to the liquid surface is the fundamental origin of the liquid surface tension, but because of broadening due to capillary fluctuations, a detailed molecular level understanding of the stress field remains elusive. In this work, we deconvolute the capillary fluctuations to reveal the intrinsic stress field and show that the atomic-level contributions to the surface tension are similar in functional form across a variety of monatomic systems. These contributions are confined to an interfacial region approximately 1.5±0.1 times the particle diameter for all systems studied. In addition, the intrinsic density and stress profiles show a strong spatial correlation that should be useful in the development of a statistical mechanical theory for the prediction of surface stress and surface tension.

A quantitative theory and atomistic simulation study on the soft-sphere crystal-melt interfacial properties. I. Kinetic coefficients.

By employing non-equilibrium molecular dynamics (NEMD) simulations and time-dependent Ginzburg-Landau (TDGL) theory for solidification kinetics [Cryst. Growth Des. 20, 7862 (2020)], we predict the kinetic coefficients of FCC(100) crystal-melt interface (CMI) of soft-spheres modeled with an inverse-sixth-power repulsive potential. The collective dynamics of the local interfacial liquid phase at the equilibrium FCC(100) CMIs are calculated based on a recently proposed algorithm [J. Chem. Phys. 157, 084 709 (2022)] and are employed as the resulting parameter that eliminates the discrepancy between the predictions of the kinetic coefficient using the NEMD simulations and the TDGL solidification theory. A speedup of the two modes of the interfacial liquid collective dynamics (at wavenumbers equal to the principal and the secondary reciprocal lattice vector of the grown crystal) is observed. With the insights provided by the quantitative predictive theory, the variation of the solidification kinetic coefficient along the crystal-melt coexistence boundary is discussed. The combined methodology (simulation and theory) presented in this study could be further applied to investigate the role of the inter-atomic potential (e.g., softness parameter s = 1/n of the inverse-power repulsive potential) in the kinetic coefficient.

Rare rectal gastrointestinal stromal tumor case: A case report and review of the literature.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are rare tumors of the gastrointestinal tract accounting for less than 1% of all gut tumors. GISTs occurring in the rectum are extremely rare, and these usually present at an advanced stage compared with other sites. CASE SUMMARY: A 60-year-old male who presented with features of sensations of rectal tenesmus was referred to our department with a mass in the lower rectum that was detected during a routine checkup. Colonoscopy, transrectal ultrasound, perianal magnetic resonance imaging and ultrasonic contrast were used to diagnose the rectum GIST, and then the patient underwent complete transanal resection using the ultrasonic scalpel. The patient was discharged ten days after the operation and was defined as low risk. Therefore, he had no need to receive subsequent adjuvant therapies, and he had not suffered any anal dysfunction or had any evidence of recurrence at follow up. CONCLUSION: Surgical resection with histologically negative margins is the standard curative treatment for rectal GISTs. Appropriate surgical techniques based on the location, size, and resectability of the tumor should attract great attention from clinicians.

Can transcutaneous perianal ultrasonography be the first-line diagnostic instrument for evaluating pediatric perianal fistulas?

Background: Pediatric perianal fistula is a common disorder. It is more difficult to detect the fistula tract and internal opening (IO) in children than in adults. This study aimed to evaluate the clinical diagnostic value of transcutaneous perianal ultrasound for children with perianal fistula. Methods: A retrospective review was conducted by analysing the preoperative transcutaneous perianal ultrasound and intraoperative exploration results of 203 consecutive patients who were <3 years old and diagnosed with perianal fistula. Analyses were conducted to evaluate the accuracy and consistency of utilizing the transcutaneous perianal ultrasound in the diagnosis of the complexity and location of the IO of perianal fistulas. Results: Compared with intraoperative exploration, the preoperative transcutaneous perianal ultrasonography has almost perfect agreement (Kappa = 0.881, P < 0.001) in the diagnosis of fistula tract complexity and IO with a sensitivity of 92% and a specificity of 97%. In addition, both intraoperative exploration and transcutaneous perianal ultrasound diagnosis showed high consistency in the identification of the IO of perianal fistulas (Quadrant I Kappa = 0.831, Quadrant II Kappa = 0.773, Quadrant III Kappa = 0.735, Quadrant IV Kappa = 0.802, all P < 0.01). The IOs were mainly distributed in Quadrants IV and II in both simple and complex fistulas. Conclusions: Transcutaneous perianal ultrasound, as a non-invasive and simple imaging technique, showed high accuracy in the diagnosis and identification of the fistula classification and IO location. It could be considered a first-line diagnostic instrument for evaluating perianal fistulas among children.

Is the transperineal ultrasonography approach effective for the diagnosis of rectocele?

BACKGROUND: Transperineal ultrasonography has been used as a diagnostic imaging modality for rectocele for many years. However, the consistency of ultrasonography and defecography in evaluating the severity of rectocele was not satisfactory. This study aimed to evaluate the agreement in the measurement of rectocele parameters between the two methods in different positions and provide clinical implications for the diagnosis of rectocele. METHODS: In this pilot study, participants were recruited in an outpatient clinic of a tertiary hospital between December 2017 and December 2019. All participants separately underwent defecation proctography at sitting and squatting positions, and undertook transperineal ultrasonography at left lateral, sitting, and squatting positions. The consistency of ultrasonography and defecography was evaluated. RESULTS: Thirty female volunteers with rectocele were included in this study. The degree of anorectal angle was significantly larger at rest and during contraction, maximal Valsalva, and evacuation; the depth of the rectocele was significantly deeper during maximal Valsalva and evacuation; and the length of the perineum descending was significantly longer during contraction and maximal Valsalva in using squatting position compared to the sitting position when performing the defecation proctography. The degree of anorectal angle, the depth of rectocele, the area of levator hiatus, and the volume of the rectocele were significantly different in using squatting, sitting, and left lateral positions when performing the transperineal ultrasonography. Bland-Altman semi-quantitative plots showed good consistency in the measurement of the anorectal angle and the depth of the rectocele between proctography and ultrasonography in both sitting and squatting positions. CONCLUSIONS: The findings of our study may be considered as the preliminary evidence to support the use of transperineal ultrasonography with sitting and squatting positions as the imaging test of choice for evaluating patients with rectocele.

Biofeedback therapy combined with traditional chinese medicine prescription improves the symptoms, surface myoelectricity, and anal canal pressure of the patients with spleen deficiency constipation.

In order to observe the clinical therapeutic effects of Yiqi Kaimi Prescription and biofeedback therapy on treating constipation with deficiency of spleen qi, the 30 cases in the control group were given oral administration of Yiqi Kaimi Prescription, in combination with anus-lifting exercise; the 30 cases in the treatment group were given biofeedback therapy on the basis of the afore mentioned methods for the control group. The TCM symptom scores and anorectal pressures before and after treatment were observed and evaluated. There were significant differences in TCM symptom scores, anorectal pressure, and clinical recovery rate before and after treatment. In the treatment group, the total recovery rate was 86.66%, while in the control group it was 50%; there were significant differences between the two groups (P < 0.01). Yiqi Kaimi Prescription coupled with biofeedback therapy is clinically effective for treating constipation with deficiency of spleen qi, and thus this method is applicable for functional constipation with deficiency of spleen qi.