Enforcing Dirichlet boundary conditions in physics-informed neural networks and variational physics-informed neural networks.

In this paper, we present and compare four methods to enforce Dirichlet boundary conditions in Physics-Informed Neural Networks (PINNs) and Variational Physics-Informed Neural Networks (VPINNs). Such conditions are usually imposed by adding penalization terms in the loss function and properly choosing the corresponding scaling coefficients; however, in practice, this requires an expensive tuning phase. We show through several numerical tests that modifying the output of the neural network to exactly match the prescribed values leads to more efficient and accurate solvers. The best results are achieved by exactly enforcing the Dirichlet boundary conditions by means of an approximate distance function. We also show that variationally imposing the Dirichlet boundary conditions via Nitsche's method leads to suboptimal solvers.

Parameters and outcomes in 525 patients operated on for oral squamous cell carcinoma.

PURPOSE: This report analyzed the outcomes of patients undergoing surgery for oral squamous cell carcinoma (OSCC) to identify the value of prognostic factors. MATERIAL AND METHODS: A total of 525 patients were studied who had undergone surgery for oral squamous cell carcinoma (OSCC) between 2000 and 2011, of whom 222 had received postoperative radiation-therapy (PORT) and or chemoradiation-therapy (PORTC). For each patient, personal data, histological findings, treatment and outcome were recorded and analyzed statistically. Survival curves were calculated using the Kaplan-Meier algorithm, and the difference in survival among subgroups was examined. RESULTS: The overall survival (OS) and disease-specific survival (DSS) 5-year survival rate in the 525 patients were respectively 71.38% and 73.18%. The differences in the overall survival and disease-specific 5-year survival were significant (p < 0.05) for age < 40 years, site of origin, N status, staging, grading, osseous medullar infiltration, and perineural invasion. In patients undergoing radiation therapy, only perineural invasion negatively influenced the survival prognosis. In 150 pT1 cases of tongue and floor-of-mouth cancer, an infiltration depth (ID) > 4 mm was statistically correlated with poorer prognosis. CONCLUSIONS: The results demonstrate an improvement in the 5-year OS and DSS rates during the past decade compared with the previous decade. Univariate analysis revealed that age, tumor staging, and lymph node involvement, extracapsular spread, grading, perineurial invasion, infiltration depth, and osseus medullary invasion were associated significantly with overall survival and disease-specific survival.

Correction of a mandibular asymmetry after fibula reconstruction using a custom-made polyetheretherketone (PEEK) onlay after implant supported occlusal rehabilitation.

This study describes an unusual case of mandibular asymmetry after fibula free flap reconstruction in a young man following major facial trauma that was corrected using a custom-made polyetheretherketone prosthesis. There is little information in the literature on the use of alloplasts to correct mandibular asymmetry as interest in 'aesthetic re-modelling' has traditionally focused on nasal, zygomatic and chin regions. This report demonstrates that this technique can be used successfully to address selected cases of mandibular asymmetry.

Correlation between Skp2 expression and nodal metastasis in stage I and II oral squamous cell carcinomas.

PURPOSE: The aim of this study was to investigate the role of S-phase kinase associated protein (Skp2) in the development of nodal metastasis and to assess its influence on prognosis in stage I and II oral squamous cell carcinomas (OSCCs). EXPERIMENTAL DESIGN: Seventy-one patients affected by OSCC (stage I-II) were observed in the period ranging from March 2003 to December 2006. The research was performed using immunohistochemical and histopathological analysis. RESULTS: The overall survival rate was 89.6% at 3 years, 87% at 5 years and 80.7% at 10 years. Patients with vascular or perineural invasion showed no statistically significant survival difference when compared with the ones with no invasion. The tumour depth of invasion did not prove to be related to the metastatic potential. Nine of the seventeen patients with Skp2 positive nuclei (≥20%) developed nodal metastasis. Conversely, only 6 of the 54 patients with a nuclear positivity lower than 20% developed a laterocervical metastasis (P=0.001). When comparing survival curves of Skp≥20% and Skp2<20% OSCCs, no significant P value emerged from the statistical analysis. CONCLUSIONS: This study is the first to report an important correlation between an Skp2 expression lower than 20% and the capability of the tumour not to develop nodal laterocervical metastases (P=0.001).

Induction chemotherapy followed by concurrent chemoradiotherapy in advanced head and neck squamous cell carcinoma.

BACKGROUND: A phase II study was carried out to investigate an induction regimen with cisplatin, paclitaxel followed by radiotherapy concurrent with weekly cisplatin for locally advanced squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: Stage III-IV disease patients were eligible. Two cisplatin (100 mg/m2) and paclitaxel (175 mg/m2) courses were administered every 21 days followed by standard fractionated external beam radiotherapy (approximately 70 Gy), concomitant to weekly cisplatin (30 mg/m2). RESULTS: Thirty-five patients were enrolled: over 70% had unresectable disease with bulky lesions. Grade 3-4 neutropenia developed in 14% and G3 mucositis in 23%. Locoregional control was achieved in 51%. Median time to progression and overall survival were 10,7 and 17 months respectively; 2- and 3-year survival rates were 30% and 25% respectively. CONCLUSION: Our induction two-drug regimen followed by chemoradiotherapy with concurrent weekly cisplatin was well tolerated with low acute toxicity and good locoregional control and survival rate.

Total temporomandibular joint prosthesis as a surgical option for severe mouth opening restriction. A case report of a bilateral intervention.

Several conservative treatment approaches to the disorders of the temporomandibular joint (TMJ) have been described in the literature. Nonetheless, in a minority of cases not respondent to reversible conservative therapies a surgical approach to the TMJ is needed. In recent years, a total temporomandibular joint replacement with alloplastic prosthesis have been introduced as a treatment option in the presence of a severely damaged or mutilated joint, mainly resulting from severe joint diseases, as in the case of complex inflammatory-degenerative diseases, or failure of previous surgeries. The present paper described a case report of a bilateral temporomandibular joint replacement intervention in a female patient with severe mouth opening restriction and pain in the TMJ area. Also, a discussion of the potential indications for TMJ replacement has been provided, along with the description of the surgical procedure.

Transverse maxillary distraction with a bone-anchored appliance: dento-periodontal effects and clinical and radiological results.

In 29 adult patients presenting with maxillary deficiency, a bone-anchored palatal distractor (Surgi-Tec NV, Brugge, Belgium) was applied after osteotomy of the anterolateral walls of the maxillary sinuses, midpalatal suture, and, eventually, separation of the pterygomaxillary sutures. Expansion proceeded at a rate of 0.33-0.66 mm per day and the device was retained for 4-6 months for consolidation. Active orthodontic therapy was started after 8-10 weeks. The increment of arch width and the perimeter were evaluated using dental casts. Tooth thermal sensitivity and the periodontal side effects of treatment were monitored clinically after distraction, at device removal, and after 1 year. Bone healing was also investigated during the procedure using conventional radiological techniques. This experience confirms that transverse maxillary distraction is an effective technique in adult patients, leading to the formation of new bone. There were no noticeable intraoperative complications, but postsurgical periodontal side effects were documented. The procedure offers advantages over traditional teeth-borne appliances in terms of rapidity of treatment and the absence of mechanical forces acting on the teeth. Further evaluation is required to assess the long-term stability and periodontal consequences of this technique.

[Facial anthropometry and aesthetic perception in young italian subjects: their use for orthognatic surgery]. / Antropometria e percezione estetica del volto in un campione di popolazione italiana. Considerazioni ai fini della chirurgia ortognatica.

BACKGROUND: Aesthetic requests of patients undergoing orthognatic surgery have increased over time and represent nowadays the leading subjective motivation for the patient and a major aim of the treatment for the surgeon. In this regard, anthropometric evaluation has considerably improved the diagnostic capacity of the orthodontist and of the surgeon. Aim of the study is to provide the orthognatic surgeon with anthropometric normal values based on a sample of aesthetically pleasant Italian subjects and to discuss the use of a simplified aesthetical analysis in the set-up of the surgical plan and in the evaluation of treatment outcome. METHODS: The present study analyses 94 Italian subjects, by means of anthropometric measurements on photographic images, considering 28 facial proportions and 33 angular values. These figures were compared with the aesthetic judgement provided by 3 common observers and 3 orthodontists. The aesthetic score was attributed on a subjective discrete scale (common observer: above average/average/below average; orthodontist: eumorphic/ dismorphic). Data were also compared with similar evaluations on North-American and African subjects reported in the international literature. RESULTS: This study confirms the sexual dismorphism and the ethnic variability already reported by other Authors and documents specific morphological characters in the Italian population. CONCLUSIONS: The described method appears acceptably simple and consistent for clinical application. Its use in orthognatic surgery may provide objective and reproducible data for evaluating the aesthetic outcome of treatment.

MET receptor is overexpressed but not mutated in oral squamous cell carcinomas.

Oral squamous cell carcinoma (SCC) is a neoplasm characterized by a high degree of local invasion and an elevated rate of metastasis to cervical lymph nodes. It has been shown that the Hepatocyte Growth Factor/Scatter Factor Receptor Met is constitutively activated in many human tumors of epithelial origin and that it plays a critical role to confer invasive properties to neoplastic cells. Most frequently, Met activation is due to receptor overexpression, but also point mutations in the tyrosine kinase domain can lead to deregulated activation. Here we show that in all the primary tumors examined this receptor is overexpressed. Direct sequencing of Met mRNAs failed to find any activating mutation in its intracellular domain. Moreover, in cell lines derived from squamous cell carcinomas, HGF-induced activation of Met resulted in the acquisition of invasive properties. All together these data suggest that the MET oncogene is involved in progression of squamous cell carcinoma toward an invasive-metastatic behavior.

[Incidence of psychopathologic symptoms in patients treated for mouth cancer]. / Valutazione dell'incidenza dei sintomi psicopatologici in pazienti trattati per carcinoma del cavo orale.

BACKGROUND: The first aim of the study is to evaluate the possible onset of anxiety, major or minor forms of depression and delirium in patients treated for head and neck malignancies. The second aim is to study the possible association between the psychological conditions and the different parameters connected with the treatment (site of tumor, time of hospitalisation and surgery, kind of reconstruction). METHODS: The study included 35 patients (21 males; 14 females) with diagnosis of head and neck squamous cell carcinoma (HNSCC). All the patients were examined before surgery, during the preoperative phase, and after surgery. Three evaluation questionnaires were used during the interview: Spielberg's StaiY1 and Y2 test, to evaluate anxiety, and Zung Self-Rating Depression scale, to evaluate depression. RESULTS: Patients revealed anxiety before surgery, while after intervention the level was normal. There was a prevalence of anxiety over depression. There was no correlation between diagnosis, site of tumor, time of hospitalisation and psychological symptoms. An association between time of surgery, kind of reconstruction, anxiety and depression was found. The patients with a higher degree of anxiety were more tending to delirium. CONCLUSIONS: Malignancy of the head and neck causes considerable physical and psychological problems which may adversely affect the quality of life during and after treatment. The better reconstruction is correlated with the lower psychopathological problems. The study underlines the need to offer psychological support during diagnostic and therapeutic procedures.