The infiltration characteristics of expansive soil considering fracture under wet-dry cycle conditions.

Expansive soils exhibit a relatively low permeability coefficient when structurally intact, allowing for their treatment as a homogeneous medium in calculations. However, the susceptibility of the slope's shallow area to numerous primary and secondary cracks under the influence of wetting and drying cycles challenges this approach. Failing to account for the impact of these surface cracks on the soil's permeability can result in a significant discrepancy between calculated and actual conditions. This study initially validated a predictive model for the soil-water characteristic curve that incorporates the effects of wetting and drying cycles. Subsequently, leveraging the fracture volume ratio parameter (pv) and the bimodal distribution characteristics of the dual-pore structure, we proposed a permeability coefficient model for expansive soils that considers fracture effects. This model was integrated with the validated soil-water characteristic curve model to facilitate the analysis of expansive soil's infiltration characteristics under cyclic wetting and drying conditions. The findings indicate that the predictive model accurately captures the hysteresis effect of expansive soil's soil-water characteristics. Moreover, the permeability coefficient model, which accounts for fractures, effectively reflects the infiltration properties of cracked expansive soil and enables the prediction and calculation of its permeability under multiple cycles of wetting and drying. This study introduces a predictive model for the soil-water characteristic curve, leveraging the hysteresis properties of expansive soil. Additionally, it presents a model for calculating the permeability coefficient of expansive soil, utilizing a dual-peak characteristic function. The development of these models establishes a theoretical basis for the computation and analysis of the soil's permeability attributes.

Dynamic fracture mechanism and fragment characteristics of sandstone specimens with asymmetrical conjugate fissures under static pre-compression.

This paper systematically investigates the dynamic mechanical response and fragment characteristics of sandstone with asymmetrical conjugate fissures subjected to preexisting static stress based on the split Hopkinson pressure bar apparatus. The cross-fissured sandstone exhibits significant variations in mechanical behavior when exposed to higher dynamic strain rates under identical static pre-stress. The cross-fissured sandstone with a higher dynamic strain rate is characterized by a greater coupled strength under the same static pre-stress; for a given dynamic load, the highest coupled strength occurs under the static pre-stress of 60% UCS. The failure mode of the cross-fissured sandstone is predominantly governed by the dynamic strain rate, independent of static pre-stress variations considered in this investigation. At lower dynamic strain rates, the specimens typically exhibit a mixed tensile-shear failure mode, characterized by the dominance of larger fragments in the broken specimens. In contrast, under high dynamic impacts, the sandstone tends to fail in a shear-dominated manner, resulting in smaller fragments with a more uniform size distribution. Furthermore, the study explores how varying dynamic strain rates and static pre-stress influence the fragment characteristics of the cross-fissured sandstone. Higher dynamic strain rates and increased static pre-stress generally lead to smaller mean fragment sizes. This phenomenon is quantitatively described by fitting fragment size distributions using the Generalized Extreme Value (GEV) distribution, revealing a decrease in the location parameter (µ) and an increase in fractal dimension. These metrics indicate that higher dynamic strain rates and static pre-stress result in sandstone specimens breaking into smaller fragments with a more homogeneous size distribution. These findings contribute to a deeper understanding of rock dynamics, with potential implications for engineering applications involving similar geological configuration under dynamic loading conditions.

Evaluation of the pit and fissure system in primary and permanent molars with micro-computed tomography and 3D printing.

This study aimed to characterize the anatomical and physiological features of pits and fissures in primary and permanent molars by microtomographic (micro-CT) examination and three-dimensional (3D) printing. The occlusal surfaces of 84 primary molars and 60 permanent third molars were examined. The samples were scanned with micro-CT and the occlusal surface separated. The areas of the crown, its occlusal part, and fissures and pits were calculated. Digital impression of the occlusal surface was created and 3D printed. The frequency of different fissure types was determined by direct observation. Data were subjected to statistical analysis using Mann-Whitney U Test and chi-square test (p < 0.05). There was statistically significant difference between the ratio of occlusal surface and the crown area for the molars in primary and permanent dentitions (24.78% and 28.85% respectively, p < 0.05). In terms of the percentage ratio of the fissure area to the occlusal surface (24.24% and 22.30%) and the fissure area to the crown (6.02% and 6.52%), no significant difference was observed (p > 0.05). V-shaped fissures were predominant in both primary and permanent teeth, with a higher occurrence in primary dentition (59.48%, p < 0.05). Permanent molars exhibited a higher prevalence of I-type and U-type fissure configurations compared to primary molars (p < 0.05), with I-type fissures being the least common in primary molars. In both dentitions there was no statistically significant difference in the prevalence of IK-configuration (p > 0.05). The fissure depth was significantly greater in permanent molars than primary molars (p < 0.05). In conclusion, this study revealed remarkable diversity in fissure morphology among primary and permanent molars.

Belgian consensus guideline on the management of anal fissures.

Introduction: Acute and chronic anal fissures are common proctological problems that lead to relatively high morbidity and frequent contacts with health care professionals. Multiple treatment options, both topical and surgical, are available, therefore evidence-based guidance is preferred. Methods: A Delphi consensus process was used to review the literature and create relevant statements on the treatment of anal fissures. These statements were discussed and modulated until sufficient agreement was reached. These guidelines were based on the published literature up to January 2023. Results: Anal fissures occur equally in both sexes, mostly between the second and fourth decades of life. Diagnosis can be made based on cardinal symptoms and clinical examination. In case of insufficient relief with conservative treatment options, pharmacological sphincter relaxation is preferred. After 6-8 weeks of topical treatment, surgical options can be explored. Both lateral internal sphincterotomy as well as fissurectomy are well-established surgical techniques, both with specific benefits and risks. Conclusions: The current guidelines for the management of anal fissures include recommendations for the clinical evaluation of anal fissures, and their conservative, topical and surgical management.

Experimental and Meshless Numerical Simulations on the Crack Propagation of Semi-Circular Bending Specimens Containing X-Shaped Fissures Under Three-Point Bending.

Cracks in rock and concrete have a great adverse effect on the stability of engineering structures; however, there are few studies on X-shaped fissures which widely exist in rock and concrete structures. Based on this background, three-point bending fracture tests of SCB specimens containing X-shaped fissures are carried out. The momentum equations in the SPH method are improved, and the crack propagations of SCB specimens under three-point bending are simulated. The results show that cracks grow simply along the vertical direction in the sample with no X-shaped fissures, and the existence of an X-shaped fissure changes the crack growth path and final failure modes of the SCB samples. The crack propagation simulation results are consistent with the experimental results, which verifies the rationality of the improved SPH method. The load-displacement curves mainly present three typical stages: the initial compaction stage, linear elastic deformation stage, and failure stage. The peak load decreases first then increases with an increase in eccentricity. With an increase in X-shaped fissure length and decrease in X-shaped fissure angle, the peak load decreases. The damage counts remain at 0 at the initial loading stage, corresponding to the initial compaction stage and the linear elastic deformation stage, and increase sharply at the later loading stage, corresponding to the failure stage, which is consistent with the experimental results. The influence mechanisms of X-shaped fissures on the crack propagation paths are discussed; the existence of different X-shaped fissure morphologies aggravate the tensile stress concentration at specific positions, leading to different crack propagation modes in the experiments. The research results can provide a certain reference for understanding the failure mechanisms of engineering structures containing X-shaped fissures and promote the applications of the SPH method into the simulations of cross-fissure crack propagations.

Spectrum of Diagnoses in Female Patients With Proctologic Symptoms Presenting to the Surgery Unit of a Tertiary Care Center.

Introduction Anorectal diseases are prevalent in the general population and may vary from benign disorders to malignant lesions that can metastasize. There is a variety of proctologic symptoms associated with each disease. The incidence of proctologic disease varies in different cultures due to dietary habits and variations in lifestyle. The present study was conducted to determine the spectrum of different proctologic diseases in female patients presenting with proctologic symptoms. Methods This cross-sectional study was conducted in the Surgery Department of Mardan Medical Complex, Mardan, and Khyber Teaching Hospital, Peshawar, from January 2022 to January 2023. Female patients with proctologic symptoms were included, while non-consenting patients were excluded. After obtaining a detailed history and examination by the experienced surgeon, digital rectal examination and proctoscopy/sigmoidoscopy were performed where necessary. Diagnoses were made, and the data regarding proctologic symptoms and their corresponding diagnoses was analyzed using Statistical Package for the Social Sciences (SPSS) version 20.0 (IBM SPSS Statistics, Armonk, NY) using mean and standard deviation for quantitative variables and frequency and percentage for qualitative variables. Results The mean age of 500 female study participants was 38.35±16.305 (range: 7-108) years. Bleeding per rectum, constipation, and pain per rectum were the commonest proctologic symptoms seen in 341 (68.2%), 287 (57.4%), and 272 (54.4%) cases, respectively. Anal fissures and hemorrhoids were the commonest proctologic diseases seen in 264 (52.8%) and 60 (12%) cases, respectively. Conclusion Bleeding per rectum is the commonest proctologic symptom in patients. Anal fissures and hemorrhoids are the commonest proctologic diseases in our setup. Bleeding per rectum and hemorrhoids in the female population cause loss of blood, which in turn will aggravate the clinical picture of underlying anemia, if any.

Robotic Right Lower Lobectomy in a Patient With V2 and V4+5 Pulmonary Vein Variation Merging Into the Lower Pulmonary Vein: A Case Report.

Several variations of pulmonary vein (PV) branching patterns exist. Since robot-assisted thoracoscopic surgery (RATS) is performed with magnified vision, it is crucial to carefully identify the running pattern of blood vessels before and during surgery. We present a case of a 77-year-old male patient with right lower lobe lung cancer. Right lower lobectomy via RATS was scheduled. Chest CT before surgery confirmed that the middle lobe PV (V4+5) merged with the inferior PV. Three-dimensional multidetector CT (3D-MDCT) subsequently confirmed that not only V4+5 but also the posterior segmental vein of the upper lobe (V2) merged with the inferior PV. We should have taped the lower lobe PV only, but we also taped the V2 and the middle lobe vein. However, since the oblique fissure was separated before cutting the taped blood vessel, the cutting of the blood vessel to be preserved was avoided. Surgeons should have a detailed understanding of the running patterns of pulmonary blood vessels before surgery to perform the procedure safely. Preoperative 3D-MDCT is useful for identifying the running pattern of blood vessels. An abnormality involving V2 and V4+5 merging into the inferior PV can also occur; hence, during right lower lobe resection, by dividing the lower lobe PV after the oblique fissure division, the surgeon can avoid unexpected transection of anomalous PVs that should be preserved.

Evolution of understanding.

From the time of Hippocrates to the early 19th century, knowledge advanced but that was an uneven process. Anatomy was basically defined by Galen and remained cast in stone until the early 16th century. Neuroanatomy was described by Galen but had little practical value, as brain surgery was not possible. The anatomy of the cranium was known and was largely correct. Care was taken to avoid the frontal air sinuses and the venous sinuses and the temporal region. The role of the brain in consciousness was not understood. It was considered the seat of the soul but there was a lack of understanding that damage to it could induce clinical symptoms such as stupor or paralysis. These were variously attributed to injuries to the meninges or the bone. This error was finally corrected in the 18th century when the brain was identified as responsible for much of the clinical disturbance following cranial trauma. All awareness that post traumatic neurological deficit was contralateral was ignored until the late 18th century, although several authors noted it. Likewise, the presence of CSF had to wait until the 18th century until it was recognized. Fissures were treated with trepanation, because of a perceived risk of infection developing between the bone and the dura. Depressed fracture fragments were elevated, replaced, or removed according to the details of the injury. Finally, for centuries surgeons blocked patients ears to reduce the sound of drilling, despite the fact that such a blocking would amplify the noise.

Significance and Clinical Implications of Morphometric and Morphological Variability in Cadaveric Liver.

Background This study aimed to identify morphological variations, conduct morphometry of the liver, and present its clinical implications. Methodology The study was conducted on 35 preserved cadaveric livers without macroscopic abnormalities. Morphological features such as shape and size were studied and variations such as the absence of lobe, accessory fissures, or accessory lobes were noted in all specimens. Results The caudate lobe was absent in one liver, and the quadrate lobe was absent in six livers. Moreover, seven livers had accessory fissures, and accessory lobes were seen in six livers. The left lobe with a lingular process was seen in three livers, and diaphragmatic grooves were present in seven livers. Conclusions The present research is helpful to radiologists, surgeons, and anatomists as it demonstrates the different morphological variations in the liver.