Maria Kalogirou

Sulfation and lean/rich desulfation of a NOx storage reduction catalyst: Experimental and simulation study

A detailed study of the sulfation and desulfation phenomena of a NOx storage reduction catalyst using synthetic gas bench is presented. The experimental observations and results were put together, in order to develop a model, which can simulate the NOx storage reduction catalyst behavior during the sulfation and desulfation conditions. The target is to use the model for simulation of the lean/rich desulfation strategies, in order to comprehend the complicated phenomena and ultimately predict the sulfur speciation at the outlet of the NOx storage reduction catalyst. Sulfation tests in the presence and in the absence of O2 at different temperatures were conducted, in order to identify the different sulfation sites. Desulfation tests with constantly rich conditions and lean/rich oscillation, using H2 as the reducing gas, were performed in order to investigate the reaction pathways of the decomposition of the sulfates. Additionally, some preliminary investigation was performed using CO and decane in the reducing gas mixture, in order to evaluate the NOx storage reduction behavior under more realistic gas composition for diesel exhaust gas. The important role of the accurate prediction of sulfur axial distribution at the desulfation onset was identified. It was found that cerium oxides play a critical role in the sulfation process by increasing the sulfur capacity of the NOx storage reduction catalyst. Finally, it was clarified that the oxygen stored on cerium oxides strongly affects the selectivity of the desulfation products by oxidizing H2S and controlling H2 availability.

Evaluation of metal based fuel-borne catalysts for diesel particulate filter regeneration

An investigation of the effects of metal-based fuel-borne catalysts on the loading and regeneration performance of Diesel Particulate Filters (DPFs) installed on a test vehicle is presented. A test protocol that comprises regeneration attempts at steady state speeds following a loading phase for about 100 km was applied for the performance screening. None of the additives tested led to a complete regeneration of the filter under normal driving conditions. This was possible only if engine operation was modified in order to increase exhaust temperature. Methylcyclopentadienyl Manganese Tricarbonyl (MMT) in the higher concentration mixture in the fuel was found to be the most effective of the additives tested in terms of regeneration onset temperature.

A Bilateral, Non-syndromic, Type III Second Branchial Arch Sinus in a Neonate: a Case Report

The incidence of a second branchial arch sinus accounts for 26-60% of all existing congenital malformations deriving from the branchial apparatus. They are most usually detected between 14 months and 7 years of age, while their incidence during neonatal period and infancy accounts for 0.06% of all cases. The aim of this case study is to emphasize three rare characteristic features: the manifestation during neonatal period, the bilateral localization and the ultrasonographic diagnostic documentation. A 25 days old girl was admitted by her parents due to the presence of mucoid excretion from two small openings found on the neck. These openings were found bilaterally, between the mid and lower third of the anterior border of sternocleidomastoid muscle. Diagnosis was confirmed via ultrasonography. The patient underwent elective surgery during early infancy and both branchial fistulas were excised. Patients postoperative course was uneventful. IN CONCLUSION - in cases of a bilateral second branchial arch sinus, the branchio-oto-renal (BOR) or branchio-otic (BO) syndromes must be excluded; - ultrasound scan can be used for the thorough evaluation of the sinus anatomic course and the relationship with the adjacent anatomic structures; - rompt diagnosis and early therapeutic intervention, even during neonatal period, ensures an uneventful post-operation course.

Fountain’s Sign as a Diagnostic Key in Acute Idiopathic Scrotal Edema: Case Report and Review of the Literature

The acute idiopathic scrotal edema (AISE) is a self-limited disease of unknown etiology, characterized by edema and erythema of the scrotum and the dartos, without expansion to the underlying layers of scrotums wall or to the endoscrotal structures. Boys younger than 10 years old are usually involved in 60-90% of all cases. Diagnosis is made after exclusion of other causes of acute scrotum. We present a case of a 7-year old boy, who was admitted to the Emergency Department due to development of scrotal edema and erythema over the last 48 hours, which extended to the base of the penis. The patient mentioned that he first noticed the erythema on the anterior surface of the right hemiscrotum, which gradually extended. Physical examination did not reveal presence of pathology involving the endoscrotal structures, indicative of need for urgent surgical intervention. Transillumination was negative for blue dot sign. Ultrasonographic examination of the scrotum documented the homogeneity of the testicular parenchyma, while color Doppler revealed the presence of fountains sign (equal arterial blood supply to both testicles). Conservative strategy was followed and the patient gradually improved within the next three days. In conclusion, meticulous physical examination along with ultrasonographic examination of the suffering scrotum, especially with the highlighting of fountains sign with color Doppler, document the diagnosis of AISE. Thus, need for urgent surgical investigation of the suffering scrotum due to diagnostic doubt is limited.

Cystic Lymphangioma of the Chest Wall in a 5-Year-Old Male Patient: A Rare and Atypical Localization—A Case Report and Comprehensive Review of the Literature

Lymphangioma is a benign congenital malformation. The extremely rare and atypical localization of a lymphangioma in the chest wall was the real motive for the present case study. A 5-year-old boy was admitted to the Emergency Department of the 1st Department of Pediatric Surgery, Aristotle University of Thessaloniki, due to the presence of a mildly painful swelling in the left lateral chest wall, which was first noticed three months ago, after a blunt injury during sport. Physical examination revealed the presence of a palpable, spherical, painful, nut-sized subcutaneous lesion in the left lateral chest wall, respectively, with the anterior axillary line, at the height of the 6th to 7th intercostal space. Presence of ecchymosis on the overlying skin was also noticed. During palpation, we did not notice fluctuation, while transillumination was not feasible. Performance of ultrasonography, including Doppler color flow imaging, followed, depicting a subcutaneous cystic lesion, 2.1⁎3.2 cm in dimensions, without extension to the thoracic cavity. Scheduled surgical excision of the lesion was decided. Histopathological examination documented the diagnosis of cystic lymphangioma. Patient is still followed up on a 6-month basis. He remains asymptomatic, after 2 years, without indication of relapse.

Paraesophageal Hernia as a Cause of Chronic Asymptomatic Anemia in a 6 Years Old Boy; Case Report and Review of the Literature

Esophageal hiatal hernia is defined as the prolapse of one or more intra-abdominal organs through the esophageal hiatus. Four types are identified: type Ι or sliding hiatal hernia, type II or paraesophageal hernia (PEH), type III or mixed hernia and type IV. Congenital type II esophageal hiatal hernia is caused by a remaining gap after the formation of pleuroperitoneal membrane. We present a case of a six years old boy admitted to our department, appearing with asymptomatic anemia, who was incidentally diagnosed with Type II esophageal hiatal hernia. After diagnostic investigation, the prolapsing stomach pouch was reduced, the hernia sac was excised, the crura of diaphragm were converged and a total fundoplication was performed, via open method. The patient had an uncomplicated postoperative period. We conclude that: 1) esophageal hiatal hernia should be included within diagnostic approach of a child with chronic non-hereditary anemia, 2) after a Type II esophageal hiatal hernia is diagnosed, a hernia repair surgery is indicated in short time, due to the severity of possible complications and 3) through the performance of total fundoplication, it is secured that the subdiaphragmatic abdominal part of esophagus will be retained, preventing the development of post-operative gastroesophageal reflux disease.

Amyand’s Hernia: an Up-to-Date Review of the Literature

Amyands hernia is defined as an inguinal hernia, containing the appendix within the hernia sac. Incidence of this rare condition rises up to 1% (0.19-1.7%) of all inguinal hernia cases. Inflammation of the appendix within the inguinal sac is even rarer, as it corresponds to 0.1% (0.07-0.13%) of all Amyands hernia cases. After a comprehensive review of the limited relevant literature, we aim through this review study to describe the pathophysiology of inflammation of the appendix - contained in the hernia sac - and present the latest data about the diagnostic approach and surgical treatment of Amyands hernia.

Multiple Gastric Erosion Early after a 3 V Lithium Battery (CR2025) Ingestion in an 18-Month-Old Male Patient: Consideration about the Proper Time of Intervention

Introduction. Button battery ingestion is considered an emergency situation in pediatric patients that needs to be managed promptly; otherwise, it may lead to serious and potentially lethal complications, especially when it is impacted in the esophagus. Less attention has been given in cases where the battery passes into the stomach, with guidelines for emergency intervention being based on the presence of symptoms. Case Report. We present a case of an 18-month-old male patient who presented to our emergency department after button battery ingestion. He did not have any symptoms and no pathological findings were encountered during clinical examination. X-ray investigation revealed the presence of the battery in the stomach. The patient was admitted for observation and two hours later he had two episodes of vomiting. He underwent urgent endoscopic removal of the battery where multiple acute gastric mucosal erosion in place of direct contact of the batterys negative pole with the mucosa of the gastric antrum was found. Conclusion. In specific cases the urgent endoscopic intervention for removal of an ingested button battery that is located in the stomach even in asymptomatic patients should be suggested.

Epididymal Adenomatoid Tumor: A Very Rare Paratesticular Tumor of Childhood

Adenomatoid tumor is an uncommon benign mesothelial neoplasm, usually localized in the epididymis. It is the most common paratesticular tumor of middle-aged patients (average age of clinical presentation: 36 years). However, these tumors in pediatric and pubertal patients are extremely rare. Due to their rarity, we present a case of adenomatoid tumor of the tail of the epididymis in a 16-year-old patient. After systematic research of the current literature, we did not find another case report of epididymal adenomatoid tumor in a male patient aged 16 years old or less. This notice and our concern, as well, about the patients surveillance protocol during the postoperative period were the motive for this case study.

Intraparenchymal Epididymal Cyst (IEC) 4 cm in Diameter in a 15-Year Old Male Patient; a Case Report and Review of the Literature

Intraparenchymal epididymal cysts (IECs) are benign cystic formations of the epididymis of unknown pathogenesis, which typically appear in adolescence or adulthood. In patients older than 14 years old their prevalence is doubled. After systematic and thorough research of the current literature, we did not find another case report of intraparenchymal epididymal cyst with similar dimensions. The male patient, 15 years old, visited our outpatient department complaining of pain in the right hemiscrotum. Diagnosis of IEC was confirmed after the conduction of ultrasound examination. Patient underwent surgical exploration of the right hemiscrotum. Resection of the IEC followed. Postoperative course was uneventful, with recession of the symptoms. In our opinion, IECs should be surgically removed, either when they are symptomatic or when they are asymptomatic, but of a diameter greater than 1 cm and without regression tendency.