Relationship between lymph nodes examined and survival benefits with postoperative radiotherapy in oral cavity squamous cell carcinoma patients with stage T1-2N1M0.

Background: This study aims to explore the relationship between the lymph nodes examined and survival benefits of postoperative radiotherapy in oral cavity squamous cell carcinoma patients with stage T1-2N1M0. Methods: This study retrieved patients who underwent dissection of the primary site and neck lymph nodes for pT1-2N1M0 oral cavity squamous cell carcinoma without adverse nodal features from the Surveillance, Epidemiology, and End Results database from 2004 to 2015. Propensity score matching analysis was conducted, and the best cutoff value of the lymph nodes examined was determined by X-tile. Cancer-specific survival was the primary outcome. Univariable and multivariable analyses were performed to assess the relation between postoperative radiotherapy and cancer-specific survival, adjusting for other prognostic factors. Results: A total of 469 patients were finally enrolled according to our exclusion criteria, and then 119 pairs of patients were matched by propensity score matching analysis. The best cutoff value of the lymph nodes examined was determined by X-tile, stratifying patients into lymph nodes examined ≤16 group and lymph nodes examined >16 group. For the whole matched cohort, the choice of postoperative radiotherapy had no correlation with other factors (all p's > 0.05), and postoperative radiotherapy made no contribution to a better survival outcome for patients (p = 0.289). After stratified by the lymph nodes examined, in the lymph nodes examined ≤16 group, significantly improved CSS was found for those who undertook postoperative radiotherapy compared to those who just received surgery (unadjusted hazard ratio, 0.541; 95% confidence interval, 0.333-0.878; p = 0.013). Conclusions: Our study revealed that pT1-2N1M0 oral cavity squamous cell carcinoma patients were more likely to benefit from postoperative radiotherapy when unsatisfactory neck dissection was conducted, indicating that the number of lymph nodes examined might be a factor when clinicians do therapeutic planning for early-stage oral cavity squamous cell carcinoma patients.

Organic Field-Effect Transistor Fabricated on Internal Shrinking Substrate.

In the development of flexible organic field-effect transistors (OFET), downsizing and reduction of the operating voltage are essential for achieving a high current density with a low operating power. Although the bias voltage of the OFETs can be reduced by a high-k dielectric, achieving a threshold voltage close to zero remains a challenge. Moreover, the scaling down of OFETs demands the use of photolithography, and may lead to compatibility issues in organic semiconductors. Herein, a new strategy based on the ductile properties of organic semiconductors is developed to control the threshold voltage at close to zero while concurrently downsizing the OFETs. The OFETs are fabricated on prestressed polystyrene shrink film substrates at room temperature, then thermal energy (160 °C) is used to release the strain. The OFETs conformally attached to the wrinkled structure are shown to locally amplify the electric field. After shrinking, the horizontal device area is reduced by 75%, and the threshold voltage is decreased from -1.44 to -0.18 V, with a subthreshold swing of 74 mV dec-1 and intrinsic gain of 4.151 × 104 . These results reveal that the shrink film can be generally used as a substrate for downsizing OFETs and improving their performance.

Three-Dimensional Stretchable Microelectronics by Projection Microstereolithography (PµSL).

Stretchable and flexible electronics conformal to human skin or implanted into biological tissues has attracted considerable interest for emerging applications in health monitoring and medical treatment. Although various stretchable materials and structures have been designed and manufactured, most are limited to two-dimensional (2D) layouts for interconnects and active components. Here, by using projection microstereolithography (PµSL)-based three-dimensional (3D) printing, we introduce a versatile microfabrication process to push the manufacturing limit and achieve previously inaccessible 3D geometries at a high resolution of 2 µm. After coating the printed microstructures with thin Au films, the 3D conductive structures offer exceptional stretchability (∼130%), conformability, and stable electrical conductivity (<5% resistance change at 100% tensile strain). This fabrication process can be further applied to directly create complicated 3D interconnect networks of sophisticated active components, as demonstrated with a stretchable capacitive pressure sensor array here. The proposed scheme allows a simple, facile, and scalable manufacturing route for complex, integrated 3D flexible electronic systems.

Size-dependent fracture behavior of GaN pillars under room temperature compression.

Gallium nitride (GaN) offers high electron mobility, breakdown voltage and saturation velocity, and is an ideal candidate for advanced electronic and power devices. Meanwhile, it can also be used for microelectromechanical systems (MEMS) and micro/nano-mechanical devices. These applications fundamentally rely on its mechanical properties and structural reliability, in particular at the micro/nanoscale. In this paper, single crystalline [0001]-oriented GaN pillars with diameters ranging from ∼200 nm to ∼1.5 µm were microfabricated and systematically characterized by in situ compression tests inside a SEM/TEM at room temperature. It showed that a crack would nucleate at the top of the pillars with diameters >800 nm and propagate axially during compression. However, pillars with diameters less than 700 nm would deform plastically without splitting, with maximum stress up to 10 GPa. The corresponding yield/fracture strengths show a strong size effect, which increases from ∼4 GPa to ∼11 GPa with the diameter decreasing from ∼1.5 µm to ∼400 nm. In situ TEM compression tests suggest that the formation of slip bands on the (01[combining macron]11) plane dominates the plastic deformation of the pillars with diameters of ∼200-700 nm, while both crack splitting and slip bands were observed in the pillars with diameters around 700 to 800 nm during the brittle-to-ductile transition. This work provides critical insights for developing robust GaN-based MEMS and power electronic applications.

[Identification of cervical lymph node micrometastasis of tongue cancer by color Doppler and MRI].

OBJECTIVE: To assess the values of color Doppler and magnetic resonance imaging (MRI) in the identification of cervical lymph node micrometastasis of tongue cancer. METHODS: Totally 96 cases of tongue cancer with impalpable neck lymph node was examined with color Doppler and MRI within one week before surgery. Chi-square test was used to assess if the presence of regional lymph node micrometastasis, histopathological analysis as a golden standard lymph node micrometastasis. RESULTS: For the diagnosis of cervical lymph node micrometastasis, color Doppler was significantly better than MRI in sensitivity (72.5% vs 50.0%, P = 0.039) and the accuracy (78.1% vs 64.6%, P = 0.038), but no significant difference in the specificity (82.1% vs 75.0%, P = 0.357), the positive predictive value (74.4% vs 58.8%, P = 0.159) and the negative predictive value (80.7% vs 67.7%, P = 0.108). CONCLUSION: Color Doppler is better than MRI in the sensitivity and accuracy for the diagnosis of cervical lymph node micrometastasis of tongue cancer.

Sentinel lymph node biopsy versus elective neck dissection in patients with cT1-2N0 oral tongue squamous cell carcinoma.

OBJECTIVE: This study aimed to compare the value of sentinel lymph node biopsy (SLNB) with that of elective neck dissection (END) for the prediction of cervical lymph node metastasis in patients with clinically diagnosed T1-2N0 (cT1-2N0) oral tongue squamous cell carcinoma (OTSCC), and it aimed to examine the prognostic value of individualized treatment in sentinel lymph node (SLN)-negative patients. STUDY DESIGN: The study entailed a retrospective review of 82 patients with cT1-2N0 OTSCC. Thirty patients underwent SLNB, and 52 patients underwent END. RESULTS: There was a significant difference between the SLNB and END groups in the incidence of occult cervical lymph node metastasis in initial specimens (30% vs 11.5%; P = .037). However, there were no significant differences between the groups for 10-year overall and cervical recurrence-free survival rates and 10-year overall survival rate. CONCLUSIONS: SLNB is superior to END for the prediction of cervical lymph node metastasis in patients with cT1-2N0 OTSCC. Neck dissection may be reduced for SLN-negative patients, owing to the comparable prognosis of SLNB.

Arsenite induces oxidative injury in rat brain: synergistic effect of iron.

Sodium arsenite (arsenite)-induced neurotoxicity and its interaction with ferrous citrate (iron) was investigated in rat brain. In vitro data showed that arsenite (1-10 micromol/L) concentration dependently increased lipid peroxidation and the potency of arsenite was less than that of iron. The oxidative activity of arsenite, sodium arsenate (arsenate), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were evaluated by inducing lipid peroxidation in cortical homogenates, and the potency for this effect was as follows: arsenite > arsenate > MMA and DMA. Several well-known antioxidants, including glutathione, melatonin, and beta-estradiol inhibited arsenite-induced lipid peroxidation in a concentration-dependent manner. Our in vivo study employed intranigral infusion of arsenite (5 nmol) in the substantia nigra (SN) of anesthetized rats. Four hours to 7 days after infusion, lipid peroxidation was elevated while glutathione was depleted in the infused SN. The dopamine content in the striatum ipsilateral to arsenite-infused SN was first elevated 24 h and then decreased 7 days after intranigral infusion of arsenite. Using pretreatment of l-buthionine-[S,R]-sulfoximine (l-BSO, i.c.v.) to reduce glutathione content in rat brain, arsenite-induced oxidative injury was augmented. Low doses of arsenite (1.5 nmol) and iron (3 nmol) alone induced minimal oxidative injury; however, co-infusion of arsenite and iron augmented neurotoxicity, including elevated lipid peroxidation and reduced striatal dopamine content. Moreover, expression of heme oxygenase-1, alpha-synuclein aggregation, and DNA fragmentation were significantly enhanced in SN co-infused with low doses of arsenite and iron. Taken together, our study demonstrates that arsenite was less potent than iron in inducing oxidative stress. Furthermore, concomitant arsenite and iron potentiated oxidative injury in the nigrostriatal dopaminergic system, indicating that interaction of metals plays a more clinically-relevant role in pathophysiology of central nervous system neurodegeneration.