A Novel Approach for Powder Bed Fusion of Ceramics Using Two Laser Systems.

The one-step AM process is considered the goal many researchers seek in the field of Additive Manufacturing (AM) of high-technology ceramics. Among the several AM techniques, only Powder Bed Fusion (PBF) can directly print high-technology ceramics using one step. However, the PBF technique faces numerous challenges to efficiently be employed in the PBF of ceramics. These challenges include the formation of cracks, generated thermal stress, effective laser-powder interaction, and low acquired relative density. This study developed a new preheating mechanism for ceramic materials using two laser systems to surpass beyond these challenges and successfully print ceramics with a single-step AM method. One laser is used to preheat the powder particles before the second laser is utilised to complete the melting/sintering process. Both lasers travel along the same scanning path. There is a slight delay (0.0001 s) between the preheating laser and the melting/sintering laser to guarantee that the melting/sintering laser scans a properly preheated powder. To further facilitate testing of the preheating system, a numerical model has been developed to simulate the preheating and melting process and to acquire proper process parameters. The developed numerical model was shown to determine the correct process parameters without needing costly and time-consuming experiments. Alumina samples (10 × 10 × 6 mm3) were successfully printed using alumina powder as feedstock. The surface of the samples was nearly defect-free. The samples' relative densities exceeded 80%, the highest reported relative density for alumina produced by a single-step AM method. This discovery can significantly accelerate the transition to a one-step AM process of ceramics.

Congenital Epulis Diagnosed Antenatally.

Background: Congenital epulis is a benign gingival tumor whose differential diagnosis includes other oral-facial masses such as teratoma, hemangioma, lymphatic malformation and dermoid cysts. This tumor can cause obstruction of the airway or feeding problems in the newborn. Surgical excision is the treatment of choice. Case Report: We present a case of congenital epulis, diagnosed prenatally with ultrasonography. Conclusion: Although difficult, a defined prenatal image of congenital epulis is possible by means of accurate high-resolution ultrasonography. It facilitates the narrowing down of differential diagnosis. The confirmatory final diagnosis relies on histopathological examination.

Multi-Layer Simulation of the Powder Bed Selective Laser Processing of Alumina for Residual Stress and Distortion Evaluation.

A numerical model was developed to simulate the real process of alumina powder bed selective laser processing (PBSLP) to thoroughly investigate the residual stress and distortion experienced in printed parts when multi-layer scanning with a CO2 laser source is considered. The model contains a user-defined function (UDF) for the laser source, temperature-dependent material properties, scanning strategies, and build orientations, and it is solved using ANSYS 2020R2. In addition, the model's validation was confirmed with experimental results. The results revealed that a high scanning speed (up to 1200 mm/s) and low laser power are effective for the PBSLP of alumina, owing to alumina's high absorptivity for CO2 lasers, and a high manufacturing rate can be achieved. During the multi-layer printing simulation, the accumulated heat inside the part increased gradually with an increased number of printed layers. Additionally, the calculated residual stress exceeded the yield limit for all the studied build orientations due to the printed part's high-temperature difference. When preheating was applied, the residual stress decreased by 23% and the distortion decreased by 54%. For the successful PBSLP of ceramics, commercial printers cannot be used effectively. A particular printer equipped with a temperature controller and a preheating system is required for ceramics.

Compound blue nevus: A misleading pigmented melanocytic tumor.

Compound blue nevus had clinical and histological similarities with other heavily pigmented melanocytic tumor, like the pigmented epithelioid melanocytoma. Distinctive genomic aberrations have allowed differentiating it. The defining characteristic of blue nevi family is the presence of activating mutations in the G protein α-subunits, GNAQ and GNA11.

An efficient design for real-time obstructive sleep apnea OSA detection through esophageal pressure Pes signal.

Obstructive Sleep Apnea (OSA) is a potentially common sleep disorder in which the upper airways are collapsed either partially or completely. The golden standard method for treating OSA, is the full night Continuous Positive Airway Pressure (CPAP). Yet, due to the ensuing discomfort, it incurs on patients, researchers have been motivated to investigate other alternatives, whereby, OSA can be effectively treated. Recently, an increasingly popular OSA treatment has been developed that consists in activating the protrusion muscles of the tongue by stimulating the Hypoglossal Nerve (HGN). In this context, the present work is conducted to propose the design of apnea detector module as part of an implantable HGN stimulator based on the esophageal Pressure Pes signal as a new approach for controlling OSA occurrence. Specifically, an effective real-time apnea event detecting algorithm is put forward. Following the achievement of satisfactory simulation results, attained through the Modelsim simulation tool, we proceeded with assessing the possibility of its hardware implementation on a Field-Programmable Gate Array (FPGA) device. To this end, the apnea detector module was synthesized and designed. The low power consumption and the small size, characterizing this module, which have made it possible to integrate it as part of a wirelessly-powered implantable HGN stimulator.

Quality of life and associated factors in parents of children with late diagnosed phenylketonuria. A cross sectional study in a developing country (Tunisia).

Objectives We investigated the quality of life (QOL) in parents of children with late treated phenylketonuria (PKU) and its associated factors. Methods We conducted a cross sectional study in the reference center of inherited metabolic disease in Tunisia. We used the Tunisian version of the 36-item short-form health survey questionnaire (SF-36). We compared variables in the groups with and without impaired QOL and the SF-36 scores between subgroups of parents and children and between our sample and the Tunisian general population based on published data. We looked for associations between SF-36 scores and quantitative variables. Linear regression and logistic binary regression were used for multivariate analysis. Results Sixty-five parents from 42 families participated. QOL was impaired in 61% of them. The mean SF-36 score was 55.3 ± 25.07. The physical component sub-score was higher than that reported in the Tunisian general population (63.66 ± 27.77 vs. 50.11 ± 8.53; p<0.001). The mental component sub-score was comparable to that reported in the Tunisian general population (46.99 ± 25.94 vs. 47.96 ± 9.82; p=0.830). Gender (mothers) (p=0.008), low monthly income (p = 0.027), low education (p=0.011), and autism in PKU children (p = 0.001) were associated with impaired QOL. Conclusions We identified at risk parents for altered quality of life among parents of PKU children. Our findings were used to develop a psychological and social support strategy for at-risk parents and to promote the implementation of newborn screening of this treatable disease in our low-income country.

Cysts and tumors of the jaws treated by marsupialization: A description of 4 clinical cases.

Since the 4th edition of the World Health Organization's Classification of Head and Neck Tumours was published in January of 2017, the keratocystic odontogenic tumor is back into the cyst category as odontogenic keratocyst (OKC). Depending on the size of the cyst, its location and the patients' age, several treatment options are available: curettage, enucleation, radical treatment and marsupialization. The marsupialization is a conservative technique used in early tumor stages, as curative treatment for the odontogenic cyst. Despite its disadvantages and controversies, the marsupialization remains an interesting therapeutic choice in the case of large cysts, or in very young or old patients. We describe, in this article, four clinical cases of odontogenic cysts. We report the surgical management and the subsequent evolution of the patients. The discussion focuses on the indications, advantages and limitations of the odontogenic cyst's marsupialization. We review the specific conditions of the odontogenic cysts that could make the marsupialization the optimal therapeutic option. In our cases, the marsupialization proved to be a conservative technique which allowed the respect of neighboring anatomical structures, particularly in the case of large cysts, but requires prolonged clinical and radiological monitoring. Pathological entity for our cases was different. Thus, the treatment outcome may be different too. This series is very small and the reader should be cautious about drawing broad conclusions regarding the optimal therapeutic choice. Key words:Marsupialization, odontogenic cyst.

Neuromuscular Involvement in Glycogen Storage Disease Type III in Fifty Tunisian Patients: Phenotype and Natural History in Young Patients.

BACKGROUND: Our aim was to describe the natural history of neuromuscular involvement (NMI) in glycogen storage disease type III (GSDIII). METHODS: We conducted a longitudinal study of 50 Tunisian patients, 9.87 years old in average. RESULTS: NMI was diagnosed at an average age of 2.66 years and was clinically overt in 85% of patients. Patients with clinical features were older (p = 0.001). Complaints were dominated by exercise intolerance (80%), noticed at 5.33 years in average. Physical signs, observed at 6.75 years in average, were dominated by muscle weakness (62%). Functional impairment was observed in 64% of patients, without any link with age (p = 0.255). Among 33 patients, 7 improved. Creatine kinase (CK) and aspartate aminotransferase (AST) levels were higher with age.Electrophysiological abnormalities, diagnosed in average at 6.5 years, were more frequent after the first decade (p = 0.0005). Myogenic pattern was predominant (42%). Nerve conduction velocities were slow in two patients. Lower caloric intake was associated with more frequent clinical and electrophysiological features. Higher protein intake was related to fewer complaints and physical anomalies. CONCLUSION: Neuromuscular investigation is warranted even in asymptomatic patients, as early as the diagnosis of GSDIII is suspected. Muscle involvement can be disabling even in children. Favorable evolution is possible in case of optimal diet.

High Frequency of Cardiovascular Complications in Tunisian Kawasaki Disease Patients: Need for a Further Awareness.

BACKGROUND: The outcome of Kawasaki disease (KD) depends on cardiovascular complications (CVCs). OBJECTIVES: This study aimed to explore diagnostic features and CVCs in Tunisian patients with KD. METHODS: In total, 33 Tunisian patients (age, 2.9 ± 2.2 years) fulfilling the diagnosis criteria of KD, were retrospectively reviewed. Nonparametric tests were used to compare the two groups with regards to coronary complications (CCs). RESULTS: Diagnosis of KD was established at day 11 ± 5.1 from the beginning of the fever. Apyrexia was obtained in an average of 29 h after completion of intravenous immunoglobulin. CVCs were identified in 52% of cases: CC in 15 patients (giant aneurysm >8 mm in five patients) and non-CCs in 6 patients (severe in three patients). CCs were more frequently associated with the male sex (p = 0.037), fever lasting >8 days (p = 0.028) and longer time to apyrexia (p = 0.031). CONCLUSION: In Tunisia, better knowledge and monitoring of KD are warranted.

A lower energetic, protein and uncooked cornstarch intake is associated with a more severe outcome in glycogen storage disease type III: an observational study of 50 patients.

Background Glycogen storage disease type III (GSDIII), due to a deficiency of glycogen debrancher enzyme (GDE), is particularly frequent in Tunisia. Phenotypic particularities of Tunisian patients remain unknown. Our aim was to study complications of GSDIII in a Tunisian population and to explore factors interfering with its course. Methods A retrospective longitudinal study was conducted over 30 years (1986-2016) in the referral metabolic center in Tunisia. Results Fifty GSDIII patients (26 boys), followed for an average 6.75 years, were enrolled. At the last evaluation, the median age was 9.87 years and 24% of patients reached adulthood. Short stature persisted in eight patients and obesity in 19 patients. Lower frequency of hypertriglyceridemia (HTG) was associated with older patients (p<0.0001), higher protein diet (p=0.068) and lower caloric intake (p=0.025). Hepatic complications were rare. Cardiac involvement (CI) was frequent (91%) and occurred early at a median age of 2.6 years. Severe cardiomyopathy (50%) was related to lower doses of uncooked cornstarch (p=0.02). Neuromuscular involvement (NMI) was constant, leading to a functional discomfort in 64% of cases and was disabling in 34% of cases. Severe forms were related to lower caloric (p=0.005) and protein intake (p<0.015). Conclusions A low caloric, protein and uncooked cornstarch intake is associated with a more severe outcome in GSDIII Tunisian patients. Neuromuscular and CIs were particularly precocious and severe, even in childhood. Genetic and epigenetic factors deserve to be explored.

Primary Gingival Melanoma: An Important Entity.

Primary melanoma of the mandibular gingiva is extremely rare. It is often misinterpreted as a benign pigmented process. The prognosis of this entity is very poor. We report here the first case of primary gingival melanoma described in the Tunisian literature about a 55-year-old smoker having cerebral and pulmonary metastases from gingival melanoma at diagnosis. Our patient underwent brain radiotherapy at a dose of 18 Gy in three sessions but he died with a decline of 3 months before starting systemic therapy. Therefore, each new case should be illustrated to make clinicians aware about the importance of the early diagnosis to improve the poor diagnosis of this entity.

[Renal involvement in glycogen storage disease type 1: Practical issues]. / Complications rénales dans la glycogénose de type 1 : quelles implications pratiques ?

AIM: To investigate risk factors of renal complications in glycogen storage disease type I, in order to identify practical implications for renal preservation. METHODS: A retrospective study of 38 patients with glycogen storage disease type I. RESULTS: The patients studied were 8.6 years old in average (1.5 to 22 years) and were followed during 7.4 ± 4.5 years. Hypercalciuria was detected in 23 patients and was related to acidosis (P=0.028), higher lactate levels (5.9 ± 3.5 versus 3.7 ± 1.7 mmol/L; P=0.013) and smaller height (-2.1 ± 1.5 SD versus -0.8 ± 1.5 SD; P=0.026). Urolithiasis was diagnosed in 7 cases. Glomerular disease (19/38) was more frequent in cases with severe hypertriglyceridemia (P=0.042) and occurred at an older age (P=0.007). Microalbuminuria occurred in 15/31 cases; ACE inhibitors were prescribed in only 8 cases. The frequency of renal complications did not differ according to the diet group (continuous enteral feeding or uncooked starch). Logistic regression concluded as risk factors: lactic acidosis for tubular disease and age>10 years for glomerular disease. CONCLUSIONS: Renal involvement is common in glycogen storage disease type I patients. Tubular abnormalities are precocious, related to lactic acidosis and may be detected by monitoring of urinary calcium. Glomerular hyperfiltration is the first stage of a progressive glomerular disease and is related to age. Practical implications for renal preservation are discussed based on our results and literature.

New C1q mutation in a Tunisian family.

Hereditary C1q deficiency (C1qD) is the most penetrant genetic factor predisposing to the development of lupus pathology with more than 93% of C1q deficient patients developing this autoimmune pathology throughout their life. It is a rare autosomal recessive deficiency, with only 67 cases reported so far including one Tunisian girl who died at the age of three from complications resulting from severe systemic lupus erythematosus. Although C1qD was confirmed in the serum of this patient using C1q ELISA and classical pathway specific functional assays, no DNA sample had been obtained from this patient. Here we report the analysis of sera and DNA of members of this patient's closer family. Our analysis identified a homozygous mutation within the gene encoding the C-chain of C1q leading to a deficiency of C1q in an older sister of our original patient. This mutation, termed g.5580G4C, represents a single basepair substitution in exon 1 of the C1q C chain gene which changes the codon of Gly61 to Arg 61. Amongst the other 14 mutations leading to C1qD, g.5580G4C represents the first reported transversion leading to human C1qD.

[Abrikosoff's tumor: a clinicopathologic study of nine cases]. / Tumeur d'Abrikosoff : etude anatomoclinique de neuf cas.

BACKGROUND: Abrikossoff's tumour or granular cell tumor or is a benign neurogenic tumour. It is ubiquitous with the most frequently affected site is the head and neck region. AIMS: To report a series of granular cell tumors and to discuss its clinicopathologic features and histogenesis. METHODS: We report a series of nine cases diagnosed between January 2004 and December 2006 in the Pathology Department of the University Hospital of Sfax. We have collected the clinical aspects and we have proceeded on a pathological, cytochemical (PAS and PAS diastasis) and immunohistochemical study. RESULTS: Nine cases of TCG are presented: 5 females and 4 males. The median age was 33.9 years (extremes: 7 and 53 years). All tumours were unique. The most common localization was in the head and neck region (5 cases). The diagnosis was suspected using standard histologic criteria and confirmed by immunohistochemistry: tumour cells expressed vimentine (90%), S100 protein (100%) and neuron specifique enolase (80%). In all cases patients were treated by excisional resection and had a benign course with no evidence of recurrence (median follow up: 2 years). CONCLUSION: Granular cell tumours are rare neoplasm which must be recognised because they demonstrate a benign behaviour after their surgical excision. Histological features of granular cell tumours are commonly characteristic but some times they can be misdiagnosed as malignant tumours especially when the biopsy is superficial. The staining for neurogen markers and PAS are useful tools.

[Rosai -Dorfman disease: a two cases report]. / La maladie de Rosai ­ Dorfman : a propos de deux observations.

BACKGROUND: Rosai-Dorfman disease (RDD) is a benign lymphoproliferatif disorder characterized by cervical lymphadenopathies with a consistent risk of airways' compression and esthetical prejudice. Extra nodal localizations are also described. AIM: To report two pediatric cases of RDD. CASES: the first case concerned a patient with a prolonged nodal involvement of RDD. Remission seems to be natural although it coincided with a sulfaméthoxazole- triméthoprime therapy. The second case illustrated an extranodal form of RDD localized in soft tissue and paranasal sinus with extension to nasal cavity which were corticodependant. CONCLUSION: RDD is usually a benign disorder. Particular localizations, lack of effective therapy and the high risk of recurrence are important issues in this rare affection.

Congenital hyperinsulinism: review of 12 Tunisian cases.

BACKGROUND: Congenital hyperinsulinism in infancy (CHI) is a heterogeneous disorder with respect to genetics and response to therapy. Data on CHI are sporadic in North African population. AIM: To characterize the clinical features and outcome of 12 Tunisian patients with CHI. METHODS: data of patients diagnosed with CHI during the period 1989-2007 were retrospectively analyzed. Diagnosis was considered whenever hyperinsulinemia ≥ 10µ UI/ml was concomitant to hypoglycemia < 3mmol/l and/or high insulin to glucose ratio > 0.3 and/or positif glucagon test. Transient causes of hypoglycemia, adrenal and growth hormone deficiency were excluded. RESULTS: There were nine infants diagnosed at a median age of 17 months and three newborns. Permanent hyperammoniemia, found in one patient, guided to leucine-sensitive hyperinsulinism. Seven patients presented with seizures, two with psychomotor delay and one with recurrent malaises. Among 42 assays of plasmatic insulin, when in hypoglycemia, 40% only were ≥ 10µU/ml. Three patients resisted to diazoxide and underwent subtotal pancreatectomy complicated by diabetes mellitus in two cases and persistent hypoglycemia in one patient. Histological examination concluded to diffuse hyperplasia of pancreatic cells. Diazoxide was discontinued in four out the eight responders' patients. Four patients died, seven patients developed variable degrees of mental retardation and five suffered from epilepsy. CONCLUSION: Early onset forms were, as reported in the literature, mostly resistant to medical therapy. The high proportion of neurological sequelae is related to diagnosis delay or to a late surgery. We focus on the importance of a precocious diagnosis and aggressive treatment of hypoglycemia.

[A novel mutation in PEX 26 gene in Zellweger syndrome: a case report]. / Syndrome de Zellweger par une nouvelle mutation du gène PEX 26.

BACKGROUND: Zellweger syndrome is the most severe phenotype of the peroxisome biogenesis disorders caused by mutations in PEX genes. PEX 1, 6 and 26 genes are most frequently implicated. Clinical phenotype can't predict the mutated gene. AIM: To report a novel mutation in the PEX 26 gene in infant with typical Zellweger syndrome. CASE REPORT: the infant was the second child to consanguineous parents; the 1st child was dead with neonatal hypotonia. At two month of age, we noted a severe hypotonia and growth failure, characteristic facial dysmorphic features and cryptorchidism. Sensorial investigations showed optic atrophy. Cerebral tomography revealed white matter hypodensity. Radiological examination revealed calcific stippling of the patellas. The clinical diagnosis was supported by measurement of plasma very-long-chain fatty acids, with elevated C24:0/C22:0, C26:0/C22:0 ratios and decreased docosanoic acid peak. The diagnosis was confirmed by dosage of DHAP-AT activity in fibroblasts which was very low. Ultrastructural examinations showed the presence of peroxisomal ghosts. Genetic analysis demonstrated a new mutation in PEX 26 gene.The death occurred at the age of 8 months of refractor epilepsy and apneas. CONCLUSION: The poor prognosis of ZS incites paediatricians to consider this disorder in etiological investigations of precocious hypotonia. Biochemical diagnosis, available in Tunisia, offers opportunity of prenatal diagnosis in affected families.

[Phenotype and mutational spectrum in Tunisian pediatric gaucher disease]. / Phénotype clinique et spectre mutationnel de la maladie de Gaucher pédiatrique en Tunisie.

BACKGROUND: Gaucher disease (GD) is a sphingolipidosis with heterogeneous phenotypic expression. The vital and / or functional prognosis may be threatened by an early visceral severe involvement in type 1 or a neurological degeneration in the more rarest neuroneupathic forms. The phenotypic and genotypic data regarding Gaucher disease are poorly known in Maghrebian countries; they are even less for pediatric forms. THE AIM of the study is to highlight the specific phenotypic and genotypic changing among the widest Gaucher pediatric cohort in the Tunisian population. METHODS: a restrospective study of a sample oh children in voluved by gaucher disease. RESULTS: Twenty one cases of GD were identified, divided into 13 cases with type 1, 5 with type 3 and 3 children with acute neurological form. The first symptoms occurred before 1 year age in one third of patients with type IGD. The clinical phenotype was severe according to the high severity score index and proportion of growth retardation. Portal hypertension was found in 8 patients. Three type 3 GD patients died before occurrence of the neurological signs. The phenotype was intermediate between the classic type 2 GD and its perinatal lethal variant. Three patients were treated with enzyme replacement therapy and 4 others had allogenic bone marrow transplantation with a favorable outcome. Three mutations dominate the genotypic spectrum of GD in this cohort. Additionally to the N370 mutation, L444P and RecNciI mutations seem to occur more frequently compared to the GD forms presenting in adulthood. CONCLUSION: This data confirm the particular severity of Gaucher disease manifesting in childhood. This was enhanced through the high frequency of severe mutations. Further studies on largest cohort are needed to more clarify the phenotypic and genotypic features of Gaucher disease in Tunisia.

[A rare congenital gingival tumor]. / Une tumeur gingivale congénitale rare.

INTRODUCTION: Congenital epulis (CE) of the newborn also known as congenital granular cell tumor or Neumann tumor is an uncommun benign tumour occuring in the anterior alveolar ridge of the jaws. It may interfer with breathing and feeding. In our study, we discuss the clinicopathologic and evolutive caracteristics and the diagnosis problems of this entity. OBSERVATION: A newborn girl, two months old, presented at birth a nodular mass in the upper alveolar crete of the maxilla. The mass measured 1.5 cm and exhibited a smooth surface. Histologically, it was composed of diffuse sheets and clusters of granular cells with abundant coarsely granular cytoplasm. The evolution was good without recurrence after five months. DISCUSSION: CE is a rare tumor; its etiopathogenesis is still unclear. The diagnosis suspected clinically is confirmed by the histopathological study. The prognosis is exellent without recurrence.

[Enzyme replacement therapy for Gaucher paediatric disease: the only Tunisian experience]. / Traitement enzymatique substitutif de la maladie de Gaucher chez l'enfant: premiere experience Tunisienne.

AIM: We report through the first Tunisian experience with enzyme replacement therapy, the goals and consensus recommendations for treatment and monitoring of paediatric non neuronopathic Gaucher disease. METHODS: Three children with Gaucher disease undergone enzyme replacement therapy with Cerezyme for severe visceral and/or bone involvement. Visceral, hematologic, bone, and growth parameters were assessed initially and under treatment. RESULTS: Two children presented with severe visceral or hematologic picture. One patient had myocardiopathy and primitive portal hypertension and another was diagnosed with cirrhosis related to Gaucher disease. Recurrent avascular necrosis and osteoporosis have justified treatment in another child. All patients received an initial dose of 60U/Kg/2 weeks. We have seen a gradual disappearance of hepatosplenomegaly and a rapid normalisation of hematological parameters in two patients. A resistance to treatment indicated splenectomy in one patient. The improvement in bone mineral density was slower. A significant growth gain was observed in patients with growth retardation. No patient had developed Cerezyme antibodies. CONCLUSION: Despite its effectiveness and safety demonstrated in these children, enzyme replacement therapy remains inaccessible because of its cost for emerging countries. The allogeneic bone marrow is an alternative therapy to encourage and to propose precociously for severe paediatric forms of Gaucher disease.