Quality performance evaluation of thin walled PLA 3D printed parts using the taguchi method and grey relational analysis

This paper investigates the quality performance of FDM 3D printed models with thin walls. The design of experiments method (DOE) was used and nine models of the same size were fabricated in a low-cost 3D printer using polylactic acid (PLA) material. Two limited studied parameters were considered (extraction temperature and wall thickness), each one having three levels. External X and Y dimensions were measured using a micrometer, as well as four surface roughness parameters (Ra, Rz, Rt, Rsm) with a surface tester. Two optimization techniques (the Taguchi approach and Grey relational analysis) were utilized along with statistical analysis to examine how the temperature and wall thickness affect the dimensional accuracy and the surface quality of the parts. The results showed that high extraction temperature and median wall thickness values optimize both dimensional accuracy and surface roughness, while temperature is the most important factor

Synergistic exploitation of geoinformation methods for post-earthquake 3D mapping of Vrisa traditional settlement, Lesvos Island, Greece

The aim of this paper is to present the methodology followed and the results obtained by the synergistic exploitation of geo-information methods towards 3D mapping of the impact of the catastrophic earthquake of June 12th 2017 on the traditional settlement of Vrisa on the island of Lesvos, Greece. A campaign took place for collecting: a) more than 150 ground control points using an RTK system, b) more than 20.000 high-resolution terrestrial and aerial images using cameras and Unmanned Aircraft Systems and c) 140 point clouds by a 3D Terrestrial Laser Scanner. The Structure from Motion method has been applied on the high-resolution terrestrial and aerial photographs, for producing accurate and very detailed 3D models of the damaged buildings of the Vrisa settlement. Additionally, two Orthophoto maps and Digital Surface Models have been created, with a spatial resolution of 5cm and 3cm, respectively. The first orthophoto map has been created just one day after the earthquake, while the second one, a month later. In parallel, 3D laser scanning data have been exploited in order to validate the accuracy of the 3D models and the RTK measurements used for the geo-registration of all the above-mentioned datasets. The significant advantages of the proposed methodology are: a) the coverage of large scale areas; b) the production of 3D models having very high spatial resolution and c) the support of post-earthquake management and reconstruction processes of the Vrisa village, since such 3D information can serve all stakeholders, be it national and/or local organizations

Nasal Symptoms in Patients with Obstructive Sleep Apnoea and Their Association with Continuous Positive Airway Pressure Usage

The role of nasal symptoms in continuous positive airway pressure (CPAP) tolerance is not completely clear. This study aimed to investigate the association between CPAP usage and nasal symptoms, either prior to, or developing during, CPAP use in patients with obstructive sleep apnoea (OSA). Two hundred thirty patients were studied and divided into high-, low-, and non-CPAP users. Nasal symptoms and related quality of life parameters were evaluated prior to CPAP initiation and after three months. We also investigated predictive factors for CPAP usage. Non-CPAP users had significantly worse baseline scores for runny nose compared with high and low users (1.34 vs. 0.68 and 0.75, respectively, p = 0.006). There were no other significant differences between the groups. Runny nose was an independent predictive factor for lower CPAP usage (p = 0.036). An evaluation after three months showed worsening in runny nose score in high-CPAP users (p = 0.025) but not in low- and non-users. There were no significant changes in other nasal symptoms. Our study demonstrates that nasal symptoms were very common in this population but rhinorrhoea was the only symptom associated with poorer CPAP adherence. Moreover, rhinorrhoea worsened after a three-month trial of high-CPAP usage

Inflammatory markers in isolated adenotonsillar tissue from children with obstructive sleep disordered breathing

Objectives: 1) To investigate the relationship between urine levels of CysLTs and severity of SDB in children. 2) To characterize cells expressing LT1-R and LT2-R in tonsillar tissue and assess serum CRP levels in children with and without SDB. Material: 1) Nineteen children with moderate-to-severe SDB (mean [±SD] age, 5.4±1.6 years; OAHI: 14.4±9.6 episodes/h), 29 subjects with mild SDB (5.1±1.5 years; OAHI: 2.9±0.8 episodes/h), 26 children with primary snoring (PS) [7±2.6 years; OAHI: 1.1±0.3 episodes/h] and 18 control subjects (6.4±2.5 years; OAHI: 0.7±0.3 episodes/h) were studied. 2) Fifteen children (mean age ± SD: 6.4±2.1 years; AHI: 9.6±5.6 episodes/h) who had tonsillectomy (± adenoidectomy) because of SDB and 11 control subjects (7.5±2.8 years; 0.7±0.3 episodes/h) who were operated for recurrent tonsillitis/otitis. Methods: 1) Morning urine concentrations of CysLTs were measured in children with symptoms of SDB and in control subjects with recurrent tonsillitis and without snoring who underwent polysomnography and were expressed in pg/mL per mg/dL of urine creatinine. 2) Immunohistochemistry with LT1-R and LT2-R antibodies was used to examine tonsils from children of both groups. All participants underwent preoperative polysomnography and measurement of morning serum CRP. Results: 1) Children with moderate-to-severe SDB had higher log-transformed urine CysLTs levels than those with mild SDB, PS, or control subjects (2.39±0.51 vs 2.06±0.26 vs 2.11±0.25 vs 1.86±0.28; p0.05). Conclusions: 1) Urine excretion of CysLTs is related to SDB severity in children. This finding indicates that 5-lipoxygenase pathway products participate in the pathogenesis of obstructive sleep apnea in childhood. 2) Tonsils of children with SDB but not of controls have enhanced expression of cysteinyl leukotriene receptors in T lymphocytes without an associated increase in serum CRP concentration. Upregulation of LT1-R and LT2-R could potentially promote tonsillar enlargement in children with obstructive sleep apnea.Σκοπός: 1) Να ερευνηθεί η σχέση μεταξύ επιπέδων CysLTs στα ούρα και βαρύτητας ΑΔΑΥ στα παιδιά. 2) Να χαρακτηριστούν τα κυττάρα που εκφράζουν τους LT1-R και LT2-R στον αμυγδαλικό ιστό και να μετρηθούν τα επίπεδα CRP ορού σε παιδιά με και χωρίς ΑΔΑΥ. Υλικό: 1) 19 παιδιά με μέτρια-σοβαρή ΑΔΑΥ (μέση ηλικία 5,4±1,6 έτη, ΟΑΗΙ=14,4±9,6 επεισόδια/ώρα), 29 παιδιά με ήπια ΑΔΑΥ (5,1±1,5 έτη, ΟΑΗΙ=2,9±0,8 επεισόδια/ώρα), 26 παιδιά με πρωτοπαθές ροχαλητό (7±2,6 έτη, ΟΑΗΙ=1,1±0,3 επεισόδια/ώρα) και 18 μάρτυρες (6,4±2,5 έτη, ΟΑΗΙ=0,7±0,3 επεισόδια/ώρα). 2) 15 παιδιά που υποβλήθηκαν σε αμυγδαλεκτομή λόγω ΑΔΑΥ (μέση ηλικία 6,4±2,1 έτη, ΑΗΙ=9,6±5,6 επεισόδια/ώρα) και 11 μάρτυρες που χειρουργήθηκαν λόγω υποτροπιάζουσας αμυγδαλίτιδας/ωτίτιδας (7,5±2,8 έτη, ΑΗΙ=0,7±0,3 επεισόδια/ώρα). Μέθοδος: 1) Μετρήθηκαν οι πρωινές συγκεντρώσεις CysLTs στα ούρα παιδιών με συμπτώματα ΑΔΑΥ και μαρτύρων με υποτροπιάζουσα αμυγδαλίτιδα και χωρίς ροχαλητό, που υποβλήθηκαν σε πολυκαταγραφική μελέτη ύπνου. 2) Χρησιμοποιήθηκε ανοσοϊστοχημεία με αντισώματα έναντι LT1-R και LT2-R για να εξεταστούν οι αμυγδαλές των παιδιών των δύο ομάδων. Σε όλα τα παιδιά πραγματοποιήθηκε προεγχειρητική πολυκαταγραφική μελέτη ύπνου και μέτρηση των πρωινών επιπέδων CRP ορού. Αποτελέσματα: 1) Τα παιδιά με μέτρια-σοβαρή ΑΔΑΥ είχαν υψηλότερα επίπεδα InCysLTs στα ούρα σε σύγκριση με εκείνα με ήπια ΑΔΑΥ, πρωτοπαθές ροχαλητό ή τους μάρτυρες (2,39±0,51 έναντι 2,06±0,26, 2,11±0,25 και 1,86±0,28 αντίστοιχα, p0,05). Συμπεράσματα: 1) Η απέκκριση CysLTs στα ούρα σχετίζεται με τη βαρύτητα της ΑΔΑΥ στα παιδιά. Το εύρημα αυτό υποδηλώνει ότι τα κυστεϊνυλικά λευκοτριένια συμμετέχουν στην παθογένεση της ΑΔΑΥ στην παιδική ηλικία. 2) Οι αμυγδαλές παιδιών με ΑΔΑΥ εμφανίζουν αυξημένη έκφραση υποδοχέων λευκοτριενίων στα Τ-λεμφοκύτταρα, χωρίς συνοδό αύξηση στα επίπεδα CRP. Η αυξημένη έκφραση των LT1-R και LT2-R ίσως προάγει την αμυγδαλική υπερτροφία σε παιδιά με ΑΔΑΥ

Surgical Treatment Options for Epiglottic Collapse in Adult Obstructive Sleep Apnoea: A Systematic Review

The critical role of epiglottis in airway narrowing contributing to obstructive sleep apnoea (OSA) and continuous positive airway pressure (CPAP) intolerance has recently been revealed. This systematic review was conducted to evaluate available surgical treatment options for epiglottic collapse in adult patients with OSA. The Pubmed and Scopus databases were searched for relevant articles up to and including March 2022 and sixteen studies were selected. Overall, six different surgical techniques were described, including partial epiglottectomy, epiglottis stiffening operation, glossoepiglottopexy, supraglottoplasty, transoral robotic surgery, maxillomandibular advancement and hypoglossal nerve stimulation. All surgical methods were reported to be safe and effective in managing selected OSA patients with airway narrowing at the level of epiglottis. The surgical management of epiglottic collapse can improve OSA severity or even cure OSA, but can also improve CPAP compliance. The selection of the appropriate surgical technique should be part of an individualised, patient-specific therapeutic approach. However, there are not enough data to make definitive conclusions and additional high-quality studies are required

Rates of RLN and SLN injury : Data from national quality registries and the literature

The impact of thyroid surgery on voice is a key performance indicator of surgical quality. This chapter discusses factors that can impact on the incidence of both recurrent and external laryngeal nerve (external branch of superior laryngeal nerve-EBSLN) injury. The literature is reviewed and reported incidence of nerve palsy following thyroid surgery is presented. Particular reference is made to the British and Scandinavian database registries. The present evidence supports that the true injury rate is underreported. Factors that might influence nerve injury are presented in an evidence-based manner. A centrally important dynamic in this area of study is that there is clear positive correlation between the rate of postoperative vocal cord examination and palsy. Overall, 10 % of patients can sustain a temporary laryngeal palsy following thyroidectomy. Permanent voice problems are common and the true incidence of permanent palsy remains unknown. There is little doubt, however, that the literature grossly underestimates its true incidence. Thirty percent of patients with a known vocal palsy may not complain of voice symptoms which again endorses the importance of routine post- operative vocal cord examination. Voice change secondary to EBSLN injury is also common and again the true incidence remains unknown. This situation prevails due to the difficulty of precise diagnosis with extant non- invasive methods of cord examination. The importance of surgical volume to patient outcomes is emphasized. Surgery for cancer particularly when involving nodal dissection has been identified as a significant and higher risk for nerve palsy as have been revision and more extensive thyroid surgery. Similarly, higher rates of nerve injury are reported with retrosternal goitres. The literature is unclear as to whether the side of thyroidectomy is a risk factor or whether certain benign pathology such as Graves' disease confers a higher risk of injury

Association between Patient- and Partner-Reported Sleepiness Using the Epworth Sleepiness Scale in Patients with Obstructive Sleep Apnoea

Excessive daytime sleepiness in obstructive sleep apnoea (OSA) is often measured differently by patients and their partners. This study investigated the association between patient- and partner-completed Epworth Sleepiness Scale (ESS) scores and a potential correlation with OSA severity. One hundred two participants, 51 patients and 51 partners, completed the ESS before and three months after initiating CPAP treatment. There was no significant difference when comparing patients’ and partners’ ESS scores at baseline (10.75 ± 5.29 vs. 11.47 ± 4.96, respectively) and at follow-up (6.04 ± 4.49 vs. 6.41 ± 4.60, respectively). There was a strong correlation between patients’ and partners’ ESS scores on both (baseline and follow-up) assessments (p < 0.001). There was significant improvement in patients’ and partners’ ESS scores after CPAP therapy (p < 0.001). There was no significant difference in patients’ or partners’ ESS scores between patients with mild, moderate or severe OSA. There was no significant correlation between oxygen desaturation index (ODI) and ESS score reported either by patient or by partner. In conclusion, our study revealed a strong correlation between patient- and partner-reported ESS scores. However, neither patient- nor partner-completed ESS scores were associated with OSA severity

Nasal Symptoms in Patients with Obstructive Sleep Apnoea and Their Association with Continuous Positive Airway Pressure Usage

The role of nasal symptoms in continuous positive airway pressure (CPAP) tolerance is not completely clear. This study aimed to investigate the association between CPAP usage and nasal symptoms, either prior to, or developing during, CPAP use in patients with obstructive sleep apnoea (OSA). Two hundred thirty patients were studied and divided into high-, low-, and non-CPAP users. Nasal symptoms and related quality of life parameters were evaluated prior to CPAP initiation and after three months. We also investigated predictive factors for CPAP usage. Non-CPAP users had significantly worse baseline scores for runny nose compared with high and low users (1.34 vs. 0.68 and 0.75, respectively, p = 0.006). There were no other significant differences between the groups. Runny nose was an independent predictive factor for lower CPAP usage (p = 0.036). An evaluation after three months showed worsening in runny nose score in high-CPAP users (p = 0.025) but not in low- and non-users. There were no significant changes in other nasal symptoms. Our study demonstrates that nasal symptoms were very common in this population but rhinorrhoea was the only symptom associated with poorer CPAP adherence. Moreover, rhinorrhoea worsened after a three-month trial of high-CPAP usage

Low Morning Serum Cortisol Levels in Children with Tonsillar Hypertrophy and Moderate-to-Severe OSA

Background: Hypertrophic tonsillar tissue in children with obstructive sleep apnea (OSA) has enhanced expression of glucocorticoid receptors, which may reflect low endogenous cortisol levels. We have evaluated the effect of the interaction between tonsillar hypertrophy and OSA severity on morning serum cortisol levels. Methods: Children with and without snoring underwent polysomnography, tonsillar size grading, and measurement of morning serum cortisol. Results: Seventy children (2-13 years old) were recruited: 30 with moderate-to-severe OSA (apnea-hypopnea index [AHI] > 5 episodes/h), 26 with mild OSA (AHI > 1 and <= 5), and 14 controls (no snoring; AHI <= 1). Tonsillar hypertrophy was present in 56.7%, 53.8%, and 42.9% of participants in each group, respectively. Application of a general linear model demonstrated a significant effect of the interaction between severity of OSA and tonsillar hypertrophy on cortisol levels (P = 0.04), after adjustment for obesity, gender, and age. Among children with tonsillar hypertrophy, subjects with moderate-to-severe OSA (n = 17; AHI 14.7 +/- 10.6), mild OSA (n = 14; AHI 2.3 +/- 1.2), and control participants (n = 6; AHI 0.7 +/- 0.2) were significantly different regarding cortisol levels (P = 0.02). Subjects with moderate-to-severe OSA had lower cortisol (16.9 +/- 8.7 mcg/dL) than those with mild OSA (23.3 +/- 4.2; P = 0.01) and those without OSA (controls) (23.6 +/- 5.3 mcg/dL; P = 0.04). In contrast, children with normal-size tonsils and moderate-to-severe OSA, mild OSA, and controls did not differ in cortisol levels. Conclusions: Children with moderate-to-severe obstructive sleep apnea and the phenotype of hypertrophic tonsils have reduced morning serum cortisol levels and potentially decreased glucocorticoid inhibitory effects on tonsillar growth

Poincare Plot Width, Morning Urine Norepinephrine Levels, and Autonomic Imbalance in Children With Obstructive Sleep Apnea

BACKGROUND: Obstructive sleep apnea (OSA) in childhood is accompanied by sympathetic overflow unopposed by the parasympathetic tone. Complex methods like power spectral analysis of heart rate variability have been applied to study this imbalance. In this report, width of Poincare scattergram of the R-R interval (parasympathetic tone) and morning urine norepinephrine concentration (sympathetic activity) were used to assess autonomic imbalance. METHODS: Poincare plot was obtained from the, electrocardiographic channel of nocturnal polysomnography and its width was measured, and norepinephrine-to-creatinine concentration ratio was calculated in morning urine specimen. RESULTS: Twenty children with obstructive sleep apnea and moderate-to-severe nocturnal hypoxemia (oxygen saturation of hemoglobin [SpO(2)] nadir <90%), 24 subjects with mild hypoxemia (SpO(2) nadir >= 90%), and 11 control subjects were recruited. Children with obstructive sleep apnea and moderate-to-severe hypoxemia had significantly narrower Poincare plot width (318.7 +/- 139.3 ms) and higher ln-transformed urine norepinephrine-to-creatinine ratio (4.5 +/- 0.6) than control subjects (484.2 +/- 104.4 ms and 3.8 +/- 0.4, respectively; P < 0.05). Ln-transformed urine norepinephrine levels were inversely related to Poincare plot width (P = 0.02). CONCLUSIONS: Subjects with obstructive sleep apnea and moderate-to-severe nocturnal hypoxemia have enhanced sympathetic activity and reduced parasympathetic drive. Poincare plot width and urine norepinephrine levels are simple measures of autonomic imbalance in pediatric obstructive sleep apnea