Spectroscopic, thermal, second order and third order NLO studies of N, N’ -dimethyl urea crystal

Nonlinear optical (NLO) crystals are classified into organic, inorganic and semi organic crystals and these crystals are used in the fields of optical communication, optical computing, frequency doubling, optical data processing and opto electronics. In this work an organic NLO crystal namely DMU crystal was prepared. Slow evaporation technique was adopted to grow the single crystals of DMU after the growth period of 35 days. The harvested crystals have been subjected to various characterization techniques like XRD, FTIR, FT-Raman, TG/DTA, SHG, EDAX, impedance, optical and Z-scan studies. From the studies, is observed that DMU crystal has orthorhombic structure and it has the melting point at 105 oC and has the decomposition point at 275 oC. The relative SHG efficiency of DMU crystal was found to be more than one and third order NLO parameters were evaluated. The optical band gap of DMU crystal was found to be 5.008 eV.The results from various studies were analyzed.

Synchronous primary malignancy of head and neck- a case report

The incidence of multiple primary malignant neoplasms increases with age, reflecting an increase in overall cancer risk in older patients. Cases of two or more concurrent primary cancers are still rare, although its incidence is increasing. Here, we report the case of a 41-years female who was referred to our institution with synchronous papillary carcinoma of thyroid and Adenoid cystic carcinoma of submandibular gland. The case is being presented to emphasize that the clinicians should keep in mind that the appearance of another tumour in a patient suffering from cancer could be either a synchronous or a metachronous or a metastatic lesion

Structural analyses of \u3ci\u3ePhycodnaviridae\u3c/i\u3e and \u3ci\u3eIridoviridae\u3c/i\u3e

The Phycodnaviridae, Iridoviridae and related viruses, with diameters of 1500±2000 A Ê , are formed from large trigonal arrays of hexagonally close-packed capsomers forming the faces of icosahedra [Yan et al. (2000), Nature Struct. Biol. 7, 101-103; Nandhagopal et al. (2002), Proc. Natl Acad. Sci. USA, 99, 14758-14763]. Caspar and Klug predicted that such structures could be assembled from hexameric capsomers [Caspar & Klug (1962), Cold Spring Harbor. Symp. Quant. Biol. 27, 1-24], as was subsequently found in numerous icosahedral viruses. During the course of evolution, some viruses, including the virus families mentioned above, replaced hexameric capsomers with pseudo-hexameric trimers by gene duplication. In large dsDNA icosahedral viruses, the capsomers are organized into `pentasymmetrons\u27 and `trisymmetrons\u27. The interactions between the trimeric capsomers can be divided into three groups, one between similarly oriented trimers and two between oppositely oriented trimers (trimers related by an approximately sixfold rotation). The interactions within a trisymmetron belong to the ®rst class, whereas those between trisymmetrons and within the pentasymmetron are of the other two types. Knowledge of these distances permits a more accurate ®tting of the atomic structure of the capsomer into the cryo-electron microscopy (cryoEM) reconstruction of the whole virus. The adoption of pseudo-hexagonal capsomers places these viruses into a subset of the Caspar and Klug surface lattices

A model for interacting instabilities and texture dynamics of patterns

A simple model to study interacting instabilities and textures of resulting patterns for thermal convection is presented. The model consisting of twelve-mode dynamical system derived for periodic square lattice describes convective patterns in the form of stripes and patchwork quilt. The interaction between stationary zig-zag stripes and standing patchwork quilt pattern leads to spatiotemporal patterns of twisted patchwork quilt. Textures of these patterns, which depend strongly on Prandtl number, are investigated numerically using the model. The model also shows an interesting possibility of a multicritical point, where stability boundaries of four different structures meet.Comment: 4 pages including 4 figures, page width revise

Radiobiological Evaluation of Intensity Modulated Radiation Therapy Treatments of Patients with Head and Neck Cancer: A Dual-Institutional Study

In clinical practice, evaluation of clinical efficacy of treatment planning stems from the radiation oncologist\u27s experience in accurately targeting tumors, while keeping minimal toxicity to various organs at risk (OAR) involved. A more objective, quantitative method may be raised by using radiobiological models. The purpose of this work is to evaluate the potential correlation of OAR-related toxicities to its radiobiologically estimated parameters in simultaneously integrated boost (SIB) intensity modulated radiation therapy (IMRT) plans of patients with head and neck tumors at two institutions. Lyman model for normal tissue complication probability (NTCP) and the Poisson model for tumor control probability (TCP) models were used in the Histogram Analysis in Radiation Therapy (HART) analysis. In this study, 33 patients with oropharyngeal primaries in the head and neck region were used to establish the correlation between NTCP values of (a) bilateral parotids with clinically observed rates of xerostomia, (b) esophagus with dysphagia, and (c) larynx with dysphagia. The results of the study indicated a strong correlation between the severity of xerostomia and dysphagia with Lyman NTCP of bilateral parotids and esophagus, respectively, but not with the larynx. In patients without complications, NTCP values of these organs were negligible. Using appropriate radiobiological models, the presence of a moderate to strong correlation between the severities of complications with NTCP of selected OARs suggested that the clinical outcome could be estimated prior to treatment

Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients

Purpose: To evaluate the low contrast detectability sensitivity among 4-slice, 8-slice and 16-slice CT units using various mAs settings. Findings of the study may elucidate the most optimal imaging parameter for stereotactic radiosurgery (SRS) patients who are not MRI compatible.Methods and Materials: Low contrast targets in the CATPHAN phantom (model: CTP 504, The Phantom Laboratory) were imaged on a 4-slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) and a 16- slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) in 8-slice and 16-slice mode. The CATPHAN CTP515 low contrast targets of size 15, 9, 8, 7, 6, 5, 4, 3 and 2 mm for each contrast difference of 1%, 0.5% and 0.3% from the water-equivalent background was imaged using a SRS protocol. Two image sets per setting were acquired for mAs parameters of 300, 350 and 440. Images were evaluated in a blind study by three independent reviewers.Results: Using 300,350 and 440mAs settings on the 4-slice scanner, the average smallest diameters recorded at 1% contrast were 5 ± 1 mm, 5 ± 1 mm and 5 ± 0 mm and at 0.5% were 7 ± 2 mm, 7 ± 1 mm and 6 ± 1 mm. For the 8 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 0 mm, 6 ± 0 mm and 5 ± 0 mm, and at 0.5% were 12 ± 3 mm, 9 ± 1 mm and 6 ± 1 mm. For the 16 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 1 mm, 7 ± 1 mm and 6 ± 1 mm, and at 0.5% were 11 ± 3 mm, 8 ± 1 mm and 8 ± 1 mm. A difference was observed between the 4 and 8 - slice scanners at 300mAs (p &lt; 0.01) for each contrast level as well as the 4 and 16 slice at 440 (p &lt; 0.01) and 350 (p &lt; 0.01) mAs. Additionally, a difference was observed between each mAs for the 8 slice at 1% (p &lt; 0.01) and 0.5% (p &lt; 0.01) contrast.Conclusion: Results demonstrate consistently improved low contrast detectability as mAs was increased. CT simulation imaging parameters can be optimized to improve low contrast sensitivity for non MRI compatible SRS patients.----------------Cite this article as: Stanley D, Narayanasamy G, Breton C, Papanikolaou N, Gutierrez AN. Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients. Int J Cancer Ther Oncol 2014; 2(2):020237. DOI: 10.14319/ijcto.0202.37</p

Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients

Purpose: To evaluate the low contrast detectability sensitivity among 4-slice, 8-slice and 16-slice CT units using various mAs settings. Findings of the study may elucidate the most optimal imaging parameter for stereotactic radiosurgery (SRS) patients who are not MRI compatible.Methods and Materials: Low contrast targets in the CATPHAN phantom (model: CTP 504, The Phantom Laboratory) were imaged on a 4-slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) and a 16- slice LightSpeed Advantage™ GE CT scanner (GE Healthcare, WI) in 8-slice and 16-slice mode. The CATPHAN CTP515 low contrast targets of size 15, 9, 8, 7, 6, 5, 4, 3 and 2 mm for each contrast difference of 1%, 0.5% and 0.3% from the water-equivalent background was imaged using a SRS protocol. Two image sets per setting were acquired for mAs parameters of 300, 350 and 440. Images were evaluated in a blind study by three independent reviewers.Results: Using 300,350 and 440mAs settings on the 4-slice scanner, the average smallest diameters recorded at 1% contrast were 5 ± 1 mm, 5 ± 1 mm and 5 ± 0 mm and at 0.5% were 7 ± 2 mm, 7 ± 1 mm and 6 ± 1 mm. For the 8 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 0 mm, 6 ± 0 mm and 5 ± 0 mm, and at 0.5% were 12 ± 3 mm, 9 ± 1 mm and 6 ± 1 mm. For the 16 - slice scanner, the average smallest diameters recorded at 1% contrast were 7 ± 1 mm, 7 ± 1 mm and 6 ± 1 mm, and at 0.5% were 11 ± 3 mm, 8 ± 1 mm and 8 ± 1 mm. A difference was observed between the 4 and 8 - slice scanners at 300mAs (p &lt; 0.01) for each contrast level as well as the 4 and 16 slice at 440 (p &lt; 0.01) and 350 (p &lt; 0.01) mAs. Additionally, a difference was observed between each mAs for the 8 slice at 1% (p &lt; 0.01) and 0.5% (p &lt; 0.01) contrast.Conclusion: Results demonstrate consistently improved low contrast detectability as mAs was increased. CT simulation imaging parameters can be optimized to improve low contrast sensitivity for non MRI compatible SRS patients.----------------Cite this article as: Stanley D, Narayanasamy G, Breton C, Papanikolaou N, Gutierrez AN. Comparison of low contrast sensitivity among multi-slice CT units using various mAs setting for the potential benefit of non-MRI compatible, stereotactic radiosurgery (SRS) patients. Int J Cancer Ther Oncol 2014; 2(2):020237. DOI: 10.14319/ijcto.0202.3

Study of Image Qualities From 6D Robot–Based CBCT Imaging System of Small Animal Irradiator

Purpose: To assess the quality of cone beam computed tomography images obtained by a robotic arm-based and image-guided small animal conformal radiation therapy device. Method and Materials: The small animal conformal radiation therapy device is equipped with a 40 to 225 kV X-ray tube mounted on a custom made gantry, a 1024 � 1024 pixels flat panel detector (200 mm resolution), a programmable 6 degrees of freedom robot for cone beam computed tomography imaging and conformal delivery of radiation doses. A series of 2-dimensional radiographic projection images were recorded in cone beam mode by placing and rotating microcomputed tomography phantoms on the “palm’ of the robotic arm. Reconstructed images were studied for image quality (spatial resolution, image uniformity, computed tomography number linearity, voxel noise, and artifacts). Results: Geometric accuracy was measured to be 2% corresponding to 0.7 mm accuracy on a Shelley microcomputed tomo- graphy QA phantom. Qualitative resolution of reconstructed axial computed tomography slices using the resolution coils was within 200 mm. Quantitative spatial resolution was found to be 3.16 lp/mm. Uniformity of the system was measured within 34 Hounsfield unit on a QRM microcomputed tomography water phantom. Computed tomography numbers measured using the linearity plate were linear with material density (R2 > 0.995). Cone beam computed tomography images of the QRM multidisk phantom had minimal artifacts. Conclusion: Results showed that the small animal conformal radiation therapy device is capable of producing high-quality cone beam computed tomography images for precise and conformal small animal dose delivery. With its high-caliber imaging capabilities, the small animal conformal radiation therapy device is a powerful tool for small animal research

Improvement over time in outcomes for patients undergoing endoscopic therapy for Barrett's oesophagus-related neoplasia: 6-year experience from the first 500 patients treated in the UK patient registry.

BACKGROUND: Barrett's oesophagus (BE) is a pre-malignant condition leading to oesophageal adenocarcinoma (OAC). Treatment of neoplasia at an early stage is desirable. Combined endoscopic mucosal resection (EMR) followed by radiofrequency ablation (RFA) is an alternative to surgery for patients with BE-related neoplasia. METHODS: We examined prospective data from the UK registry of patients undergoing RFA/EMR for BE-related neoplasia from 2008 to 2013. Before RFA, visible lesions were removed by EMR. Thereafter, patients had RFA 3-monthly until all BE was ablated or cancer developed (endpoints). End of treatment biopsies were recommended at around 12 months from first RFA treatment or when endpoints were reached. Outcomes for clearance of dysplasia (CR-D) and BE (CR-IM) at end of treatment were assessed over two time periods (2008-2010 and 2011-2013). Durability of successful treatment and progression to OAC were also evaluated. RESULTS: 508 patients have completed treatment. CR-D and CR-IM improved significantly between the former and later time periods, from 77% and 56% to 92% and 83%, respectively (p<0.0001). EMR for visible lesions prior to RFA increased from 48% to 60% (p=0.013). Rescue EMR after RFA decreased from 13% to 2% (p<0.0001). Progression to OAC at 12 months is not significantly different (3.6% vs 2.1%, p=0.51). CONCLUSIONS: Clinical outcomes for BE neoplasia have improved significantly over the past 6 years with improved lesion recognition and aggressive resection of visible lesions before RFA. Despite advances in technique, the rate of cancer progression remains 2-4% at 1 year in these high-risk patients. TRIAL REGISTRATION NUMBER: ISRCTN93069556