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This research aims to assign the specific and potential sources that control migration and transformation mechanisms of ammonium/nitrate contaminants of surface and groundwater systems in the southwestern Nile Delta, Egypt. To achieve that, an integration of hydrogeochemistry, multiple environmental stable isotopes (δ2H-H2O, δ18O-H2O, δ15N-NH4, and δ15N-NO3) coupled with three-dimensional nitrogen transport numerical model (MODFLOW-MT3D) was done. A set of representative water samples (20 canals and drainage water) and 14 groundwater samples were collected and analyzed for physical, chemical, and stable isotope analysis. NH4+ and NO3− concentrations in surface water samples varied from 0.29 to 124 mg/l and 0.52 to 39.67 mg/l, respectively. For groundwater samples, NH4+ and NO3− concentrations varied from 0.21 to 1.75 mg/l and 0.33 to 32.8 mg/l, respectively. Total risk quotient (THQ) level of nitrate (oral and dermal effects) from drinking water exceeds unity for all water samples indicating a potential noncancer risk for the southwestern Nile Delta residents. The potential sources of nitrogen compound pollution are water from sewage treatment plants used for irrigation, sludge and animal manure, septic tanks, soil nitrogen, and artificial fertilizers according to results of δ15N values. Results of ammonium/nitrate modeling in shallow groundwater aquifers are compared with observed concentrations and are found to be in good agreement. Some recommendations are given to decrease nitrogen loads in the study area through suggested a need for adoption of N-fertilizer management practices and treatment of sewage water before to application in agricultural activities.

Background The importance of cardiac examination is supported by the ever-increasing incidence of heart disease. Traditional examination and auscultation techniques may not provide the level of sensitivity required for identifying certain conditions. Development of cardiac ultrasound (echocardiography) techniques has added greatly to the discipline. Ultrasound images do not only provide a means of diagnosis but allow for the development of treatment modalities and easy monitoring of disease progression. Results Cardiac images may be obtained via several techniques; some are invasive while most are not. Transthoracic ultrasound may be achieved via several windows in different planes of view and is non-invasive. While it allows for better imaging of all cardiac structures, some parts such as the mitral and aortic valve function can be viewed best by transesophageal echocardiography, a more invasive technique. Each modality and window tend to be more sensitive to certain cardiac structures than others. Conclusions This review discusses the different modalities and their advantages and provides a comparison to other imaging modalities.

Transgender reassignment surgeries have become a major topic of interest within the last decade. Although there are numerous surgical techniques for male-to-female reassignment, a physician must assess each patient's anatomy and past medical history to determine the most suitable technique. Additionally, patient preference is important. The neovaginal constructive technique most commonly used in male-to-female reassignment surgery is penile skin inversion, but various other techniques and tissues can also be used including pelvic peritoneum, buccal mucosa, and bowel. Surgical text descriptions were enhanced by creating new anatomical illustrations. Donor and recipient site anatomies, and the surgical technique leading to creation of the neovagina, are demonstrated in detail with relevant illustrations. A review of the literature concerning the anatomy, procedure development, and outcomes is presented. The pelvic peritoneum was originally used in neovaginal construction for females with vaginal agenesis as a result of MRKH syndrome. The use of this technique to create a neovagina in male-to-female transgender reassignment surgery has become appealing owing to the relative ease of the procedure, low complication rates, and overall high patient satisfaction. This technique offers a potential new choice for transgender male-to-female neovaginal construction, but further studies are needed to confirm its successful use in transgender surgery. Clin. Anat. 31:175-180, 2018. © 2017 Wiley Periodicals, Inc.

This anatomical study was performed to elucidate the pertinent foraminal and lateral L5 nerve anatomy to enhance our understanding of possible neurologic causes of failed decompression surgery. Persistent extraforaminal L5 nerve compression is a possible cause of persistent symptoms following lumbosacral surgery. The amount of extraforaminal space for the L5 ventral ramus was examined in fifty adult human skeletons (100 sides). Based on morphology, the specimens were then categorized (types I-IV) on the basis of the bony space available for the nerve at this location. Next, 25 embalmed adult cadavers (50 sides) underwent bilateral dissection of the lower lateral lumbar region. The type of bony extraforaminal outlet was documented for each cadaver on the basis of our skeletal analysis. Lastly, segments (intra- and extra-foraminal) of the L5 ventral ramus were excised and examined histologically. Types I-IV outlets were found in 43, 31, 20 and 6 skeletal sides, respectively. For cadavers, 22,15, 10 and 3 sides were found to have types I-IV bony outlets, respectively. In cadavers, all type IV outlets and 70% of the type III bony configurations adjacent to the L5 ventral ramus had signs of neural irritation/injury including vascular hyalinization and increased fibrosis distal to the intervertebral foramen. No distal segments of type I and type II outlets showed histological signs of neural compromise. Patients with symptoms referable to L5 nerve compression for whom no proximal pathology is identified could warrant investigation of the more distal extraforaminal segment of this nerve.

Large space-based communication networks have been growing in numbers of satellites, with plans to launch more than 10,000 satellites into Low Earth Orbit (LEO). While these constellations offer many advantages over ground-based communication systems, they pose a significant threat when they fail and generate space debris. Given the reliability of current satellites, engineers can use failure modeling to design satellite constellations that are more resilient to satellite failures. Several authors have analyzed the reliability of geostationary satellites, but few have expanded the work to multiple-satellite systems. To address this gap, we constructed a simulation model to show the performance of satellite constellations with different satellite reliability functions over time. The simulation model is broken down into four key parts: a satellite constellation model, a network model, a failure model, and a performance metric. We use a Walker star constellation, which is the most common constellation for LEO broadband satellite constellations. The network consists of satellite-to-satellite connections and satellite-to-groundstation connections, which routes data using a shortest-path algorithm. The failure model views satellites as either operational or failed (no partial failures) and considers the groundstation operator’s knowledge or lack thereof of the satellites’ operational status and uses satellite reliability to estimate the expected data throughput of the system. We also created a performance metric that measures how well the entire network is operating and helps us compare candidate constellations. We used the model to estimate performance for a range of satellite reliabilities, and for groundstations with different numbers of communication dishes (effectively, satellite-ground links). Satellite reliability is a significant contributing factor to the long-term constellation performance. Using the reliability of small-LEO satellites, we found that a constellation of 1,200 small-LEO satellites completely fails after less than 30 days, given that we do not consider partial failures. Satellite constellations with higher satellite reliability, such as large geostationary satellites, last less than 50 days. We expect the constellations in our model to perform worse than real satellite systems, since we are only modeling complete failures, however these findings provide a useful worst-case baseline for designing sustainable satellite constellations. We also found that the number of groundstation-to-satellite communication links at each groundstation is not a significant factor for more than five communication links, meaning that adding more communication antennas to existing satellite groundstations would not improve constellation performance significantly.

The sigmoid sinus is a continuation of the transverse sinus and becomes the sigmoid sinus where the tentorium cerebelli ends. It begins inferior to the temporal bone, posteromedial to the mastoid cells, and runs to the jugular foramen, extending through an S-shaped groove, where it meets the superior jugular bulb. This chapter details the embryology, anatomy, and clinical significance of this important intradural venous sinus located at the skull base

Childbirth can be a traumatic experience on the female body. Some techniques may be implemented to make the process smoother and decrease the potential lacerations that can occur. Episiotomies have been used by obstetricians and midwives to help make the fetal decent down the vaginal canal less turbulent. A physician must use his best judgment on when it is necessary to make this incision and what form of incision to make. Before making an incision one must understand the female external and internal anatomy and thoroughly comprehend the stages of birth to understand how and what complications can occur. Even though an episiotomy is a minor incision, it is still a surgical incision nonetheless and as with any form of surgery there are both risks and benefits that are to be considered. Nevertheless, episiotomies have proven to help ease births that are complicated by shoulder dystocia, prevent severe lacerations, and decrease the second stage of labor. The following comprehensive review provides a description of the female anatomy, as well as an extensive description of why, when, and how an episiotomy is done. Clin. Anat. 30:362-372, 2017. © 2017 Wiley Periodicals, Inc.

Objective Fracture of the odontoid process is a critical injury to diagnose and often treat. The aim of this anatomic study was to present a comprehensive understanding of this part of the C2 vertebra. Methods We used 20 C2 vertebrae. Samples underwent imaging (computed tomography [CT] with and without three-dimensional reconstruction, micro-CT, 1.5T magnetic resonance imaging) and sagittal and coronal sectioning using a bone saw. Sectioned specimens were imaged under a digital handheld microscope, and transillumination of the bone was used to highlight its internal trabecular pattern. Three samples underwent infusion of the odontoid process with a hardening substance and were then decalcified. Results Internal trabecular patterns of the odontoid process of all specimens were discernible. In sagittal and coronal sections, trabecular patterns were highlighted with transillumination, but the patterns were much clearer using the digital microscope. Magnetic resonance imaging and CT provided the least detail of the imaging methods, but the trabecular patterns could be identified. Three-dimensional reconstruction of CT data was the preferred imaging method over magnetic resonance imaging and CT without three-dimensional reconstruction. The most distinct trabecular and cortical patterns were seen using micro-CT. Osteoporosis was seen in 2 specimens (10%). Five specimens (25%) were found to have a subdental synchondrosis. For most specimens, the trabeculae were found throughout the odontoid process. Conclusions Improved knowledge of the anatomy, structural composition, and variations within the C2 vertebra may allow for better treatment options and patient care.

As anatomists we rely on the nomenclature of structures in order to describe them appropriately, particularly their orientation in respect to their surrounding. The terminology used by the anatomist to describe an organ, muscle, or nerve within the body is taught to medical students as law. Students learn to describe structures in the "anatomical position", which has been accepted in the literature since the original Latin Nomina Anatomica. They therefore familiarize themselves with the use of terms such as superior, inferior, posterior and anterior to describe all anatomical structures, except in respect of the heart. The heart is still described in the original Valentine position. As anatomists we owe it to the medical and research community to correct the nomenclature to minimize confusion, and to describe the heart properly in respect to its surrounding structures.

To date, no single comprehensive review has been published regarding lumbar ribs. Therefore, the present review was conducted to better elucidate these variant anatomical structures, which can be confused with transverse process fractures or result in miscounting of spine segments for surgical procedures.Using standard search engines, a review of lumbar ribs was performed.Lumbar ribs are uncommon but can be misinterpreted on imaging or cause confusion during surgery. Mutations of the FGD1 or Hox10 gene may be involved in the development of lumbar ribs. Knowledge of these structures can decrease misdiagnosis when they are present.

Transgender reassignment surgeries have become a major topic of interest within the last decade. Although there are numerous surgical techniques for male-to-female reassignment, a physician must assess each patient's anatomy and past medical history to determine the most suitable technique. Additionally, patient preference is important. The neovaginal constructive technique most commonly used in male-to-female reassignment surgery is penile skin inversion, but various other techniques and tissues can also be used including pelvic peritoneum, buccal mucosa, and bowel. Surgical text descriptions were enhanced by creating new anatomical illustrations. Donor and recipient site anatomies, and the surgical technique leading to creation of the neovagina, are demonstrated in detail with relevant illustrations. A review of the literature concerning the anatomy, procedure development, and outcomes is presented. The pelvic peritoneum was originally used in neovaginal construction for females with vaginal agenesis as a result of MRKH syndrome. The use of this technique to create a neovagina in male-to-female transgender reassignment surgery has become appealing owing to the relative ease of the procedure, low complication rates, and overall high patient satisfaction. This technique offers a potential new choice for transgender male-to-female neovaginal construction, but further studies are needed to confirm its successful use in transgender surgery. Clin. Anat. 31:175-180, 2018. © 2017 Wiley Periodicals, Inc.

Childbirth can be a traumatic experience on the female body. Some techniques may be implemented to make the process smoother and decrease the potential lacerations that can occur. Episiotomies have been used by obstetricians and midwives to help make the fetal decent down the vaginal canal less turbulent. A physician must use his best judgment on when it is necessary to make this incision and what form of incision to make. Before making an incision one must understand the female external and internal anatomy and thoroughly comprehend the stages of birth to understand how and what complications can occur. Even though an episiotomy is a minor incision, it is still a surgical incision nonetheless and as with any form of surgery there are both risks and benefits that are to be considered. Nevertheless, episiotomies have proven to help ease births that are complicated by shoulder dystocia, prevent severe lacerations, and decrease the second stage of labor. The following comprehensive review provides a description of the female anatomy, as well as an extensive description of why, when, and how an episiotomy is done. Clin. Anat. 30:362-372, 2017. © 2017 Wiley Periodicals, Inc.

As anatomists we rely on the nomenclature of structures in order to describe them appropriately, particularly their orientation in respect to their surrounding. The terminology used by the anatomist to describe an organ, muscle, or nerve within the body is taught to medical students as law. Students learn to describe structures in the "anatomical position", which has been accepted in the literature since the original Latin Nomina Anatomica. They therefore familiarize themselves with the use of terms such as superior, inferior, posterior and anterior to describe all anatomical structures, except in respect of the heart. The heart is still described in the original Valentine position. As anatomists we owe it to the medical and research community to correct the nomenclature to minimize confusion, and to describe the heart properly in respect to its surrounding structures.