Acute Kidney Injury After Large Ventral Hernia Repair Requiring Transversus Abdominis Release

Background Acute kidney injury (AKI) is a known postoperative complication of open ventral hernia repair contributing to increased costs, hospital length of stay, and mortality. The aim of this study was to identify whether the muscle injury that occurs in a posterior separation of components via transversus abdominis release (TAR) contributes to a higher incidence of postoperative AKI. Methods A retrospective cohort study of patients who underwent open retrorectus ventral hernia repair with and without TAR at a single institution between 2012 and 2019 was performed. Patients who underwent a separation of components via either unilateral or bilateral transversus abdominis release were compared to those who did not undergo TAR as part of their hernia repair (non-TAR). The outcome of interest was the development of postoperative AKI. Acute kidney injury was defined as an increase in creatinine of greater than 50% of the preoperative baseline. Univariate and multivariate analyses were performed to determine the influence of TAR on the development of AKI. Results There were 523 patients who met inclusion criteria, of which 159 (30.4%) had a TAR as part of their retrorectus hernia repair. No differences were found in preoperative characteristics between the TAR and non-TAR group including age, gender, history of kidney disease, or history of diabetes. By contrast, the TAR group had significantly greater median estimated blood loss (100 mL vs 75 mL, P < .01), mean positive intraoperative fluid balance (2255 mL vs 1887 mL, P < .01), and operative duration (321 min vs 269 min, P < .001). The rate of AKI in the TAR group was 11% (n = 18) vs 6% (n = 23, P = .0503) in the non-TAR group. On multivariate analysis controlling for patient characteristics and intraoperative factors, TAR was the only factor with a significantly increased odds of AKI (OR 1.97, 95% CI 0.994-3.905, P = .0521). Conclusions In patients with large ventral hernias requiring retrorectus repair, performing a TAR is associated with a nearly 2-fold increase in the development of postoperative AKI. These findings suggest that these patients should be optimized perioperatively with emphasis on fluid resuscitation, limiting nephrotoxic medications and monitoring urine output.

Development and validation of HPLC method for the quantification of clotrimazole in a gelatin film formulation

Background Clotrimazole is used to treat topical vaginal yeast infections. Vaginal gelatin film formulations of clotrimazole were prepared, and the present study aims to develop an HPLC method for quantifying clotrimazole in the film formulation. Results The chromatographic separation of components was achieved on a Phenomenex Luna C18(2) (150 × 4.6 mm, 5 μm) stationary phase with Phenomenex Security Guard Cartridge C18 (4 × 3 mm) using acetonitrile and water (70:30% v/v) as mobile phase. The flow rate was 1.0 ml/min and the absorbance was monitored at 210 nm. Clotrimazole was eluted at 5.6 min. The procedures and capabilities of the method were evaluated against the criteria for system suitability, specificity, linearity, precision, accuracy, and robustness as defined by the ICH guidelines. The method showed good linearity (R2 = 0.999) in the range of 10–50 μg/ml and an average recovery of 101.05%. Conclusion The method could be applied for the quantification of clotrimazole in the gelatin film formulation.

A Topology-Preserving Simplification Method for 3D Building Models

Simplification of 3D building models is an important way to improve rendering efficiency. When existing algorithms are directly applied to simplify multi-component models, generally composed of independent components with strong topological dependence, each component is simplified independently. The consequent destruction of topological dependence can cause unreasonable separation of components and even result in inconsistent conclusions of spatial analysis among different levels of details (LODs). To solve these problems, a novel simplification method, which considers the topological dependence among components as constraints, is proposed. The vertices of building models are divided into boundary vertices, hole vertices, and other ordinary vertices. For the boundary vertex, the angle between the edge and component (E–C angle), denoting the degree of component separation, is introduced to derive an error metric to limit the collapse of the edge located at adjacent areas of neighboring components. An improvement to the quadratic error metric (QEM) algorithm was developed for the hole vertex to address the unexpected error caused by the QEM’s defect. A series of experiments confirmed that the proposed method could effectively maintain the overall appearance features of building models. Compared with the traditional method, the consistency of visibility analysis among different LODs is much better.

Investigation of thermodiffusion phenomenon under influence of vibration using image processing approach

Thermodiffusion is the appearance of concentration gradient in a mixture when subjected to a temperature gradient. Thermodiffusion or Soret effect plays an important role in the underground reservoir distribution. Consequently, a majority of petroleum research is focused on understanding this phenomenon. There are may experimental measurements of thermodiffusion. However, measurements conducted in a microgravity environment minimize the effect of gravity and leads to accurate results. This study demonstrates the influence of vibration on thermodiffusion measurement in a microgravity environment. The aim is to show how the variation of certain parameters such as the frequency and amplitude of translational vibration as well as the temperature would impact the composition of components in the mixture of Water-Isopropanol. The Fast Fourier Transform image processing technique is used to analyse the data obtained from optical digital interferometry. Moreover, two sets of experimental runs with negative and positive Soret coefficients are tested. The analysis shows the maximum separation of components for the case without any forced vibration. Furthermore, it is shown the increase in Rayleigh number corresponds to decrease in separation of components.

Investigation of thermodiffusion phenomenon under influence of vibration using image processing approach

Thermodiffusion is the appearance of concentration gradient in a mixture when subjected to a temperature gradient. Thermodiffusion or Soret effect plays an important role in the underground reservoir distribution. Consequently, a majority of petroleum research is focused on understanding this phenomenon. There are may experimental measurements of thermodiffusion. However, measurements conducted in a microgravity environment minimize the effect of gravity and leads to accurate results. This study demonstrates the influence of vibration on thermodiffusion measurement in a microgravity environment. The aim is to show how the variation of certain parameters such as the frequency and amplitude of translational vibration as well as the temperature would impact the composition of components in the mixture of Water-Isopropanol. The Fast Fourier Transform image processing technique is used to analyse the data obtained from optical digital interferometry. Moreover, two sets of experimental runs with negative and positive Soret coefficients are tested. The analysis shows the maximum separation of components for the case without any forced vibration. Furthermore, it is shown the increase in Rayleigh number corresponds to decrease in separation of components.