Heterogeneous integration of graphene and Si CMOS for gas sensing applications

Detecting presence of gas molecules is of prominent importance for controlling chemical processes, safety systems, and industrial and medical applications. Despite enormous progress in this field over past few decades on developing and improving various types of gas sensors, sensors with higher sensitivity, selectivity, lower sensing limit, and lower cost that can perform at room temperature are highly sought-after. Discovery of graphene and its succeeding progress in nanotechnology has paved the way to design ultra-sensitive gas sensors that can detect individual gas molecules while operating at room temperature. Graphene is a promising candidate for gas sensing applications due to its unique transport properties, exceptionally high surface-to-volume ratio, and low electrical noise. In this dissertation, a graphene gas sensor fully integrated with silicon CMOS platform is presented, and its performance for detecting NO₂ and NH₃ gas molecules is investigated. This integration helps benefit the high gas sensitivity of graphene at room temperature as well as the compact size, robustness, low cost, and advantages of standard industrial scale production of CMOS technology. Recent progress in large scale growth of CVD graphene paves the path toward commercialization of graphene-based CMOS sensors to provide highly sensitive low-cost sensors for industrial applications. To best of our knowledge, this work is the first integration of mono-layer graphene and silicon CMOS. Also, this is the first implementation of graphene integrated gas sensor. Heterogeneous integration of monolayer graphene and silicon CMOS can introduce a platform to exploit the unique electronic properties of monolayer graphene for gas sensing applications and also take a step further toward commercialization of ultrasensitive monolithic graphene-based gas sensors. Furthermore, we were able to enhance sensitivity of CVD graphene to NH₃ by almost an order of magnitude. We experimentally showed that sensitivity of graphene to NH₃ can be enhanced by 7 folds compared to as-fabricated graphene by introducing NO₂ molecules as dopants. We observed this enhancement for graphene sensors microfabricated on SiO₂/Si substrate, as well as our integrated graphene-CMOS sensors. This finding not only increases current understanding on adsorption mechanisms of molecules to graphene, but also takes another step toward commercialization of graphene sensors.Electrical and Computer Engineerin

In Vitro Comparison of Apical Leakage in Root Canals Obturated with 0.04 and 0.02 Tapered Gutta-Percha

INTRODUCTION: Gutta-percha is the most commonly used material for root canal obturation; it has been recently manufactured with different tapers. The aim of this in vitro study was to compare microleakage of canals obturated with standard gutta-percha (0.02 taper) or the new 0.04 taper gutta-percha master cone using the cold lateral condensation technique. MATERIALS AND METHODS: Forty-four extracted single rooted teeth were selected. The crowns were removed and all the canals were prepared using RaCe rotary files. The teeth were then divided into experimental (n=2) and control (n=2) groups. In the first study group, the teeth were obturated with 0.02 taper gutta-percha master cone and lateral condensation. In the second study group, the canals were obturated by 0.04 tapered master cones and the same obturation method. The degree of leakage was measured using fluid filtration method. Data were analyzed statistically by student t-test. RESULTS: There was no significant difference between the mean microleakage of two experimental groups (P=0.558). CONCLUSION: Lateral condensation technique using 0.04 tapered master cones can provide an effective apical seal similar to 0.02 gutta-percha cones

Is there any correlation between Estradiol supplementation, as luteal phase support, and clinical pregnancy in ART cycles? A cross-sectional study

Background: Endometrial receptivity is one of the important factors in assisted reproductive technology (ART) success. In the luteal phase of an ART cycle, serum estradiol (E2) and progesterone are often placed in low levels. Supporting the luteal phase with progesterone is a usual method. Objective: To evaluate the effects of E2 supplementation plus progesterone on the luteal phase support in the antagonist protocol who have undergone intracytoplasmic sperm injection-embryo transfer cycles. Materials and Methods: In this cross-sectional study, 200 patients with antagonist stimulation protocol, who had undergone intracytoplasmic sperm injection treatment, were divided into two groups based on the use of E2 supplementation. In both groups, 400 mg progesterone suppositories (Cyclogest®), twice a day/vaginally, was administered starting from the day of oocyte collection until the fetal heart activity. However, in the E2 group, in addition to progesterone, 4 mg tablet of E2 was received daily. Beta hCG was checked 14 days after the embryo transfer, and the clinical pregnancy rate was the main endpoint. Results: The patients’ characteristics were matched, and insignificant differences were observed, except for endometrial thickness. The clinical outcomes showed the rate of pregnancy was higher in the E2 group compared to the control group; nonetheless, statistically, there was no noticeable difference. Conclusion: E2 supplementation had no beneficial effect in the luteal phase support of IVF cycles. Nevertheless, more studies are required to confirm the supportive role of E2 supplementation for embryo implantation and to improve the outcomes in ART cycles. Key words: Luteal phase, Estradiol, Progesterone, ICSI, Pregnancy rate

Dual stimulation in unexpected poor responder POSEIDON classification group 1, sub–group 2a: A cross-sectional study

Background: Poor ovarian response management is a complex and controversial issue in the field of reproductive medicine. Objective: The aim of this study was to apply double stimulation in the same cycle in unexpected poor responders in POSEIDON classification group 1, sub group 2a and compare assisted reproductive technology outcomes between luteal phase and follicular phase ovarian stimulation. Materials and Methods: In this cross-sectional study, 10 women with age < 35 yr, antral follicle count > 5, and anti-müllerian hormone > 1.2 ng/mL were enrolled. All participants received conventional antagonist protocol in the follicular phase and only the cycles with retrieved oocytes < 4 in this phase included. The luteal phase ovarian stimulation was initiated from the day of first oocytes retrieval by 300 IU of human menopausal gonadotropin / day. When dominant follicles amounted to 14 mm in mean diameter, 0.25 mg/day of gonadotropin-releasing hormone antagonist was initiated and 10,000 IU human chorionic gonadotropin was injected when at least two follicles with a mean diameter of 17 mm were observed. Oocyte retrieval was carried out 34-36 hr following human chorionic gonadotropin injection. Finally, a comparison was made between the two phase in terms of the number of retrieved oocytes as well as the number of obtained embryos and fertilization rates. Results: Numbers of retrieved oocytes (p = 0.004), mature oocytes (p = 0.016), and embryos (p = 0.013) was significantly higher in luteal phase in compared with follicular phase. Quality of embryos was similar in two phases. Conclusion: Double stimulation protocol can increase number of retrieved oocytes in unexpected PORs. Key words: Dual stimulation, Poor responder, POSEIDON classification, Luteal-phase, Follicular phase, Ovarian stimulation

The largest bilateral gemination of permanent maxillary central incisors: report of a case

Gemination is defined as an attempt to make two teeth from one enamel organ. Bilateral presentation of this phenomenon is very rare, with prevalence of 0.01% to 0.04% in the primary, and 0.05% in the permanent dentition. This paper describes a rare case of huge bilateral gemination of permanent maxillary central incisors in a nine-yearold Iranian boy with poor aesthetic. The patient did not have history of anomaly in his primary dentition and in his family either. This type of dental anomaly can cause clinical problems in the form of malocclusion, poor aesthetic, and impaction of adjacent teeth, caries, and periodontal destruction

Tongue squamous cell carcinoma in a patient with systemic sclerosis: A case report

Objective: Systemic sclerosis (SS) is a chronic autoimmune disease of connective tissue, which involves skin and internal organs, and results in collagen deposition and fibroblasts activation. Studies have reported a higher risk of malignancy in patients with progressive systemic sclerosis (PSS).The aim of this study is to report a case of tongue squamous cell carcinoma (SCC) in a patient with PSS.Case: A 46-year-old woman with SS presented to the Department of Oral Medicine of Shahid Beheshti University of Medical Sciences Dental School with chief complaint of an ulcer on her tongue. During intraoral examination, an asymptomatic ulcer measuring 2.0×1.5 cm was discovered on the right lateral border of the tongue. Incisional biopsy under local anesthesia was performed and histopathological report confirmed presence of squamous cell carcinoma. After further evaluation, surgery was performed, followed by three sessions of brachytherapy and six sessions of chemotherapy. After 26 months of follow-up, there was no evidence of recurrence.Conclusion: Periodic screening examinations are necessary to discover possible malignancies in primary stages in patients with SS

Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: a comparison study

Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically analyzed with the Mann-Whitney test. The reliability and degrees of agreement between two observers were also determined by the mean of Cohen's Kappa analysis. Results: CBCT had a statistically significant superiority than other studied techniques in detection of both erosive and osteophytic lesions with different sizes. There were significant differences between tomography and panoramic in correct detection of both erosive and osteophytic lesions with 1mm and 1.5 mm in size. However, there were no significant differences between Tomography and Panoramic in correct detection of both erosive and osteophytic lesions with 0.5 mm in size. Conclusions: CBCT images provide a greater diagnostic accuracy than spiral tomography and panoramic radiography in the detection of condylar bone erosions and osteophytes

Salivary and serum anti-desmoglein 1 and 3 ELISA and indirect immunofluorescence in pemphigus vulgaris: Correlations with serum ELISA, indirect immunofluorescence and disease severity

Anti-desmoglein (anti-Dsg) ELISA and indirect immunofluorescence (IIF) are used for the diagnosis of pemphigus vulgaris (PV). The value of salivary ELISA, serum ELISA, and IIF in the diagnosis of PV, and the correlation of salivary anti-Dsg1 and anti-Dsg3 ELISA with serum ELISA, serum and salivary IIF titers, and disease severity in patients with PV were evaluated. Fifty newly diagnosed patients with PV were enrolled in the study. Demographic data and disease-severity scores were recorded for each patient. Anti-Dsg1 and anti-Dsg3 ELISA and IIF were performed on both serum and salivary samples. Given the cut-off value of 20 RU/mL for Dsg1 and Dsg3, serum Dsg1 and Dsg3 ELISA were positive in 41 (82%) and 40 (80%) patients, and saliva Dsg1 and the Dsg3 ELISA were positive in 2 (4%) and 3 (6%) patients, respectively. Using the cut-off value of 13.4 RU/mL and 7.7 RU/mL for Dsg3 and Dsg1 salivary ELISA, 25 (50%) and 23 (46%) patients tested positive for Dsg3 and Dsg1, respectively. Serum IIF results were positive in 35 (70%) patients, and salivary IIF results were positive in 16 (32%) patients. Salivary anti-Dsg1 and anti-Dsg3 showed moderate correlations with the total pemphigus disease area index (PDAI) score (r=0.466, P&lt;0.001), (r=0.459, P&lt;0.001), respectively. A moderate correlation between serum IIF and salivary IIF was also detected (r=0.413, P&lt;0.001). Salivary anti-Dsg1 and anti-Dsg3 ELISA could be used as a safe and noninvasive method for the diagnosis of PV under certain circumstances, especially in children or elderly patients. Salivary ELISA is superior to salivary IIF. </p

Synthesis and Preformulation Studies of KTTKS and PAL-KTTKS as Anti-Wrinkle Peptides

Introduction: Skin aging is a complicated process which is one of the major issues in the field of dermatology and cosmetic products. Peptides are one of the novel ingredients included in the anti-aging formulations. KTTKS (Lys-Thr-Thr-Lys-Ser) and its derivative, PAL-KTTKS (Palmitic acid-KTTKS), have attracted a lot of attention in arresting or delaying skin aging, but unfortunately, there are almost no preformulation studies available about them. Methods and Results:Both peptides were synthesized by solid phase peptide synthesis and identified by Mass spectroscopy technique. UV absorption ability, percentage of crystallinity, melting point, decomposition temperature and thermal behavior of both peptides were analyzed by UV spectroscopy, XRD, TGA and DSC techniques respectively. Partition coefficient was also determined by ACD/chemsketch software. In addition stability studies for the aqueous solution of KTTKS were performed at 32 and 37 ℃. &nbsp;The results of UV spectroscopy showsthe wavelength of maximum absorbance of both peptides is in the vacuum UV range. Based on the results of melting point and TGA apparatuses, KTTKS and PAL- KTTKS decompose at about 154 ℃ and 112 ℃ respectively and there is no melting point for them before decomposition. The results of DSC thermogramsindicate an endothermic peak at the temperature below 60 ℃ for both peptides which is probably due to intrinsic structural rearrangement or evaporation of volatile solvents. Crystallinity percentage for KTTKS and PAL-KTTKS are 62% and 32% respectively. cLogp of KTTKS is -3.27 and cLogp of PAL-KTTKS is 3.32. Conclusions: The results of this investigation can be employed for the formulation of these peptides for TTD