Multicenter study on visual color difference thresholds. A secondary analysis of light, medium, and dark tooth-colored specimens.

PURPOSE: This secondary analysis further analyzed variations in the 50:50% perceptibility and acceptability thresholds (PT and AT, respectively) pertaining to light, medium, and dark tooth-colored specimen sets. METHODS: Primary raw data from the original study was retrieved. Visual thresholds (Perceptibility - PT and Acceptability - AT) were analyzed among the three specimen sets - light, medium, and dark. The Wilcoxon signed-rank test was used for paired specimens, and the Wilcoxon rank-sum nonparametric test was used for independent specimens (α= 0.001). RESULTS: The 50:50% CIEDE2000 PT and AT values were significantly higher for the light-colored specimen set when compared with the medium and dark-colored specimens: 1.2, 0.7, 0.6, respectively (PT) and 2.2, 16, 14 (AT), respectively (P< 0.001). Independent of the observer group, the highest PT and AT values were always found for the light-colored specimen sets (P< 0.001). Dental laboratory technicians had the lowest visual thresholds, but not significantly different from the other observer groups studied (P> 0.001). Similarly, all research sites had statistically higher visual thresholds for the light-colored specimen set than for the medium- or dark-colored sets, except for two sites that showed statistically similar results for medium-colored specimens but were significantly different from the dark-colored set. Among the different research sites, sites 2 and 5 registered significantly higher PT thresholds for the light specimens (1.5 and 1.6, respectively), and site number 1 had a significantly higher AT threshold relative to the other sites. The 50:50% perceptibility and acceptability thresholds were significantly different among light-, medium-, and dark-colored specimens for different research sites and observer groups. CLINICAL SIGNIFICANCE: The visual perception of color difference related to light-, medium-, and dark-colored specimens varied based on observer group and their geographic location. Therefore, a greater understanding of factors that affect visual thresholds, with the observers being "the most forgiving" for color differences among the light shades, will allow diverse clinicians to overcome some of the challenges of clinical color matching.

Pulmonary Open, Robotic, and Thoracoscopic Lobectomy (PORTaL) Study: Survival Analysis of 6646 Cases.

OBJECTIVE: The aim of this study was to analyze overall survival (OS) of robotic-assisted lobectomy (RL), video-assisted thoracoscopic lobectomy (VATS), and open lobectomy (OL) performed by experienced thoracic surgeons across multiple institutions. SUMMARY BACKGROUND DATA: Surgeons have increasingly adopted RL for resection of early-stage lung cancer. Comparative survival data following these approaches is largely from single-institution case series or administrative data sets. METHODS: Retrospective data was collected from 21 institutions from 2013 to 2019. Consecutive cases performed for clinical stage IA-IIIA lung cancer were included. Induction therapy patients were excluded. The propensity-score method of inverse-probability of treatment weighting was used to balance baseline characteristics. OS was estimated using the Kaplan-Meier method. Multivariable Cox proportional hazard models were used to evaluate association among OS and relevant risk factors. RESULTS: A total of 2789 RL, 2661 VATS, and 1196 OL cases were included. The unadjusted 5-year OS rate was highest for OL (84%) followed by RL (81%) and VATS (74%); P =0.008. Similar trends were also observed after inverse-probability of treatment weighting adjustment (RL 81%; VATS 73%, OL 85%, P =0.001). Multivariable Cox regression analyses revealed that OL and RL were associated with significantly higher OS compared with VATS (OL vs. VATS: hazard ratio=0.64, P <0.001 and RL vs. VATS: hazard ratio=0.79; P =0.007). CONCLUSIONS: Our finding from this large multicenter study suggests that patients undergoing RL and OL have statistically similar OS, while the VATS group was associated with shorter OS. Further studies with longer follow-up are necessary to help evaluate these observations.

Influence of Physicochemical Properties of Ni/Clinoptilolite Catalysts in the Hydrogenation of Acetophenone.

Heterogeneous catalytic hydrogenation is an interesting alternative to conventional methods that use inorganic hydrides. The hydrogenation of acetophenone under heterogeneous conditions with the supported catalysts based on Ni is the most useful due to its redox properties and lower cost. As is well-known, catalyst support can significantly affect catalyst performance. We have investigated the influence of various physical-chemical parameters on the selective reaction of the hydrogenation of acetophenone by using different nickel catalysts on clinoptilolite supports, in four different forms: natural, previously modified with NH3 (Ni/Z+NH4 +), with HNO3 (Ni/Z+H+), and thermally treated (Ni/Z 500 °C). In particular, our work focuses on determining the influence of the mentioned physical-chemical parameters on the percentages of conversion and the selectivity of the catalysis. This study aims to identify the combination of parameters that allows for obtaining the best catalytic results. The identification of the physical-chemical parameters that determine the percentages of conversion and selectivity allows us to design optimal catalysts.

Pulmonary Open, Robotic, and Thoracoscopic Lobectomy study: Outcomes and risk factors of conversion during minimally invasive lobectomy.

OBJECTIVE: Conversion to thoracotomy continues to be a concern during minimally invasive lobectomy. The aim of this propensity-matched cohort study is to analyze the outcomes and risk factors of intraoperative conversion during video-assisted thoracoscopic surgery (VATS) and robotic lobectomy (RL). METHODS: Data from consecutive lobectomy cases performed for clinical stage IA to IIIA lung cancer was retrospectively collected from the Pulmonary Open, Robotic, and Thoracoscopic Lobectomy study consortium of 21 institutions from 2011 to 2019. The propensity-score method of inverse-probability of treatment weighting was used to balance the baseline characteristics across surgical approaches. Univariate logistic regression models were applied to test risk factors for conversion. Multivariable logistic regression analysis was conducted using a stepwise model selection method. RESULTS: Seven thousand two hundred sixteen patients undergoing lobectomy were identified: RL (n = 2968), VATS (n = 2831), and open lobectomy (n = 1417). RL had lower conversion rate compared with VATS (3.6% vs 12.9%; P < .0001). In the multivariable regression model, tumor size and neoadjuvant therapy were the most significant risk factors for conversion, followed by prior cardiac surgery, congestive heart failure, chronic obstructive pulmonary disease, VATS approach, male gender, body mass index, and forced expiratory volume in 1 minute. Conversions for anatomical reasons were more common in VATS than RL (66.6% vs 45.6%; P = .0002); however, conversions for vascular reasons were more common in RL than VATS (24.8% vs 14%; P = .01). The rate of emergency conversions was comparable between RL and VATS (0.5% vs 0.7%; P = .25) with no intraoperative mortalities. CONCLUSIONS: Converted minimally invasive lobectomies were not associated with worse perioperative mortality compared with open lobectomy. Compared with VATS lobectomy, RL is associated with a lower probability of conversion in this propensity-score matched cohort study.

Pulmonary Open, Robotic, and Thoracoscopic Lobectomy (PORTaL) Study: An Analysis of 5721 Cases.

OBJECTIVE: The aim of this study was to analyze outcomes of open lobectomy (OL), VATS, and robotic-assisted lobectomy (RL). SUMMARY BACKGROUND DATA: Robotic-assisted lobectomy has seen increasing adoption for treatment of early-stage lung cancer. Comparative data regarding these approaches is largely from single-institution case series or administrative datasets. METHODS: Retrospective data was collected from 21 institutions from 2013 to 2019. All consecutive cases performed for clinical stage IA-IIIA lung cancer were included. Neoadjuvant cases were excluded. Propensity-score matching (1:1) was based on age, sex, race, smoking-status, FEV1%, Zubrod score, American Society of Anesthesiologists score, tumor size, and clinical T and N stage. RESULTS: A total of 2391 RL, 2174 VATS, and 1156 OL cases were included. After propensity-score matching there were 885 pairs of RL vs OL, 1,711 pairs of RL vs VATS, and 952 pairs of VATS vs OL. Operative time for RL was shorter than VATS ( P < 0.0001) and OL ( P = 0.0004). Compared to OL, RL and VATS had less overall postoperative complications, shorter hospital stay (LOS), and lower transfusion rates (all P <0.02). Compared to VATS, RL had lower conversion rate ( P <0.0001), shorter hospital stay ( P <0.0001) and a lower postoperative transfusion rate ( P =0.01). RL and VATS cohorts had comparable postoperative complication rates. In-hospital mortality was comparable between all groups. CONCLUSIONS: RL and VATS approaches were associated with favorable perioperative outcomes compared to OL. Robotic-assisted lobectomy was also associated with a reduced length of stay and decreased conversion rate when compared to VATS.

Determination of thickness-dependent damping constant and plasma frequency for ultrathin Ag and Au films: nanoscale dielectric function.

This paper is devoted to determine an analytical expression for the thickness dependent complex dielectric function for the case of Ag and Au thin films. Free and bound electron contributions are dealt with independently. Using Drude model for the former and taking experimental refractive index values for Ag and Au thin films, we apply a previously developed method to determine for the first time damping constant and plasma frequency parameters for specific film thicknesses. Fitting separately each one of these parameters allowed us to find an analytical expression for their dependence on arbitrary film thickness and consequently for the free electron contribution. Concerning bound electrons, its contribution for small wavelengths is the same for all analyzed thicknesses and may be set equal to the bulk bound contribution. Taking these facts into account, the complex dielectric function is rewritten analytically, in terms of bulk dielectric function plus corrective film thickness dependent terms. From the fitting process for the damping constant we determine that electron scattering at the film boundary is mainly inelastic for both silver and gold thin films. It is also shown that, in accordance with theoretical studies, plasma frequency shows a red shift as the film thickness decreases.

Textural Characterization by Using an Alternative Langmuir Isotherm and a New Thickness Function.

Samples with micropores can not be adequately described by using the Langmuir isotherm. The Langmuir expression is obtained by using the monolayer assumption, which is not valid in samples with micropores. Then, we propose to include in the isotherm a corrective parameter related to the sample porosity. We show that the modified isotherm enables us to describe the experimental values for different samples (aluminas, clays, silicas, zeolites, and zirconias) in low and full relative pressure ranges. Indeed, a new thickness function for the adsorbate layer in terms of the relative pressure is proposed. Then, a better description of the external surface areas, mesopores, and micropores of the samples can be obtained with the new thickness function. The VBS model with this new thickness shows a better pore distribution description.

Conversion to Thoracotomy in Non-Small Cell Lung Cancer: Risk Factors and Perioperative Outcomes.

Objective: We aimed to identify predictors of conversion to thoracotomy and test the hypothesis that conversion is associated with inferior perioperative outcomes in non-small cell lung cancer (NSCLC). Methods: We queried the National Cancer Database for patients with stage I to III NSCLC undergoing minimally invasive surgery (MIS) during 2010 to 2016. We compared clinicopathologic factors between patients undergoing MIS with and without conversion. We fitted multivariable regression models to identify independent predictors of conversion and compare perioperative outcomes between the 2 groups. Results: A rising trend in the use of MIS was accompanied by a declining trend in the rate of conversion to thoracotomy. A total of 11.3% of the 83,219 cases were converted. Conversion was associated with a higher Charlson-Deyo score, squamous histology, nodal involvement, high tumor grade, tumor size ≥5 cm, and a higher T stage (P < 0.05). Successful MIS without conversion was predicted by advanced age, sublobar resection, robotic approach, and treatment at an academic high-volume facility (P < 0.05). Conversion was linked to longer hospital stays, higher 30-day and 90-day mortality, and unplanned readmission (P < 0.05), irrespective of the type of MIS approach. Conclusions: Conversion rates for video-assisted and robot-assisted thoracoscopic surgery have seen a decline in recent years. Irrespective of the type of MIS approach, conversion was associated with inferior perioperative outcomes. The robotic approach and treatment at an academic high-volume facility were associated with a lower likelihood of conversion. Early recognition of the individual risk factors for conversion may help to counsel patients about the likelihood of, and detriments associated with, conversion and ultimately reduce conversion rates.

Robotic-assisted thoracoscopic surgery demonstrates a lower rate of conversion to thoracotomy than video-assisted thoracoscopic surgery for complex lobectomies.

OBJECTIVES: Locally advanced lung cancers present a significant challenge to minimally invasive thoracic surgeons. An increasing number of centres have adopted robotic-assisted thoracoscopic surgeries for these complex operations. In this study, we compare surgical margins achieved, conversion rates to thoracotomy, perioperative mortality and 30-day readmission rates for robotic and video-assisted thoracoscopic surgery (VATS) lobectomy for locally advanced lung cancers. METHODS: Using the National Cancer Database, we identified patients with non-small-cell lung cancer who received neoadjuvant chemotherapy/radiotherapy, had clinical N1/N2 disease or in the absence of these 2 features had a tumour >5 cm treated with either robotic or VATS lobectomy between 2010 and 2016. Perioperative outcomes and conversion rates were compared between robotic and VATS lobectomy. RESULTS: A total of 9512 patients met our inclusion criteria with 2123 (22.3%) treated with robotic lobectomy and 7389 (77.7%) treated with VATS lobectomy. Comparable R0 resections, 30- and 90-day mortality and 30-day readmission rates were observed for robotic and VATS lobectomy while a higher rate of conversion to thoracotomy was observed for VATS (aOR = 1.99, 95% confidence interval = 1.65, 2.39, P < 0.001). CONCLUSIONS: Our analysis of the National Cancer Database suggests that robotic lobectomy for complex lung resections achieves similar perioperative outcomes and R0 resections as VATS lobectomy with the exception of a lower rate of conversion to thoracotomy.

500 Consecutive Robotic Lobectomies for Non-Small Cell Lung Cancer: Perioperative and Oncologic Outcomes.

OBJECTIVE: Clinical adoption of robotic lobectomy for management of lung cancer is rapidly increasing across the world. Several studies have evaluated the technique with regards to perioperative and cost outcomes, with evidence beginning to grow regarding long-term oncologic outcomes. We report perioperative and oncologic outcomes in our single institution experience with 500 consecutive robotic lobectomies, including a significant portion for locally advanced disease. METHODS: This study is a retrospective review of the first 500 robotic lobectomies performed at our institution from 2010 to 2018. Segmentectomy, pneumonectomy, and lobectomy for other conditions were excluded. Descriptive statistics and Kaplan-Meier survival analysis are presented. RESULTS: Pathologic stage distribution was IA in 194 (39%), IB in 54 (11%), IIA in 41 (8%), IIB in 109 (22%), IIIA in 83 (17%), IIIB in 11 (2%), and IV in 8 (2%). Elective conversion occurred in 26 cases (5.2%) and emergent conversion occurred in 3 cases (0.6%). Mean length of stay was 3.7 days (1 to 40). The most common complications encountered were atrial fibrillation in 71 (14.2%) and prolonged air leak in 49 (9.8%). Thirty-day mortality occurred in 3 patients (0.6%). Nodal upstaging was 16.6%. Stage specific overall survival outcomes included an 84% survival for stage IA patients, 73% for IB, 68% for IIA, 63% for IIB, and 49% for IIIA disease. CONCLUSIONS: Robotic lobectomy for lung cancer is a feasible technique for treatment of non-small cell lung cancer with low perioperative morbidity and mortality. Furthermore, excellent oncologic outcomes can be achieved with this approach.

Clinical and economic comparative effectiveness of robotic-assisted, video-assisted thoracoscopic, and open lobectomy.

BACKGROUND: We sought to evaluate trends and clinical and economic outcomes between robotic-assisted lobectomy (RL), video-assisted thoracoscopic lobectomy (VL), and open pulmonary lobectomy (OL). METHODS: Patients who underwent a lobectomy for malignancy from January 1, 2008, to September 30, 2015, were identified in the Premier Healthcare Database. Propensity score matched (PSM) comparisons were performed between RL versus VL and RL versus OL. Patient characteristics were applied to generate propensity scores. In-hospital and perioperative 30-day outcomes and costs were compared within matched cohorts. RESULTS: From 2008 to 2015, there was a marked decline for OL (71% to 43%, P<0.0001) with a significant increase in RL (1% to 17%, P<0.0001) and VL (28% to 41%, P<0.0001). In the early period (January 2008 to December 2012), total operating room time was longer (P<0.0001) and admission to ICU was more common for RL compared to VL or OL (P<0.0001) although the total length of ICU stay was shorter for RL compared to VL or OL (P<0.0001). In the late period (January 2013 to September 2015), RL was associated with significantly lower rates of complications (P<0.05), conversions, and shorter length of stay than VL and OL. When hospital volume was not considered, costs were higher for RL than VL and OL. In hospitals where >25 lobectomies were performed annually, the total cost of RL was comparable to VL (P=0.09) and OL (P=0.11). CONCLUSIONS: During the study period, the utilization of RL increased substantially and was associated with improved perioperative outcomes compared with VL and OL. When annual hospital volume was >25 cases, these clinical advantages persisted and there was no significant cost difference between RL, VL, or OL. RL is an effective and cost-comparable approach for lobectomy in patients with lung malignancy.

Towards Improving Skin Cancer Diagnosis by Integrating Microarray and RNA-Seq Datasets.

Many clinical studies have revealed the high biological similarities existing among different skin pathological states. These similarities create difficulties in the efficient diagnosis of skin cancer, and encourage to study and design new intelligent clinical decision support systems. In this sense, gene expression analysis can help find differentially expressed genes (DEGs) simultaneously discerning multiple skin pathological states in a single test. The integration of multiple heterogeneous transcriptomic datasets requires different pipeline stages to be properly designed: from suitable batch merging and efficient biomarker selection to automated classification assessment. This article presents a novel approach addressing all these technical issues, with the intention of providing new sights about skin cancer diagnosis. Although new future efforts will have to be made in the search for better biomarkers recognizing specific skin pathological states, our study found a panel of 8 highly relevant multiclass DEGs for discerning up to 10 skin pathological states: 2 healthy skin conditions a priori, 2 cataloged precancerous skin diseases and 6 cancerous skin states. Their power of diagnosis over new samples was widely tested by previously well-trained classification models. Robust performance metrics such as overall and mean multiclass F1-score outperformed recognition rates of 94% and 80%, respectively. Clinicians should give special attention to highlighted multiclass DEGs that have high gene expression changes present among them, and understand their biological relationship to different skin pathological states.

Leukemia multiclass assessment and classification from Microarray and RNA-seq technologies integration at gene expression level.

In more recent years, a significant increase in the number of available biological experiments has taken place due to the widespread use of massive sequencing data. Furthermore, the continuous developments in the machine learning and in the high performance computing areas, are allowing a faster and more efficient analysis and processing of this type of data. However, biological information about a certain disease is normally widespread due to the use of different sequencing technologies and different manufacturers, in different experiments along the years around the world. Thus, nowadays it is of paramount importance to attain a correct integration of biologically-related data in order to achieve genuine benefits from them. For this purpose, this work presents an integration of multiple Microarray and RNA-seq platforms, which has led to the design of a multiclass study by collecting samples from the main four types of leukemia, quantified at gene expression. Subsequently, in order to find a set of differentially expressed genes with the highest discernment capability among different types of leukemia, an innovative parameter referred to as coverage is presented here. This parameter allows assessing the number of different pathologies that a certain gen is able to discern. It has been evaluated together with other widely known parameters under assessment of an ANOVA statistical test which corroborated its filtering power when the identified genes are subjected to a machine learning process at multiclass level. The optimal tuning of gene extraction evaluated parameters by means of this statistical test led to the selection of 42 highly relevant expressed genes. By the use of minimum-Redundancy Maximum-Relevance (mRMR) feature selection algorithm, these genes were reordered and assessed under the operation of four different classification techniques. Outstanding results were achieved by taking exclusively the first ten genes of the ranking into consideration. Finally, specific literature was consulted on this last subset of genes, revealing the occurrence of practically all of them with biological processes related to leukemia. At sight of these results, this study underlines the relevance of considering a new parameter which facilitates the identification of highly valid expressed genes for simultaneously discerning multiple types of leukemia.

Sizing and Eddy currents in magnetic core nanoparticles: an optical extinction approach.

Optical extinction is a handy and ubiquitous technique that allows us to study colloidal nanoparticles in their native state. The typical analysis of the extinction spectrum can be extended in order to obtain structural information of the sample such as the size distribution of the cores and the thickness of the coating layers. In this work the extinction spectra of Fe3O4, Fe3O4@Au, and Fe3O4@SiO2@Au single and multilayer nanoparticles are obtained by solving full Mie theory with a frequency dependent susceptibility derived from the Gilbert equation and considering the effect of Eddy currents. The results are compared with non-magnetic Mie theory, magnetic dipolar approximation and magnetic Mie theory without Eddy currents. The particle size-wavelength ranges of validity of these different approaches are explored and novel results are obtained for Eddy current effects in optical extinction. These results are used to obtain particle size and shell thickness information from the experimental extinction spectra of Fe3O4 and Fe3O4@Au nanoparticles in good agreement with TEM results, and to predict the plasmon peak parameters for Fe3O4@SiO2@Au three layer nanoparticles.

Color Range and Color Distribution of Healthy Human Gingiva: a Prospective Clinical Study.

The aim of this study is to compile a comprehensive database on color range and color distribution of healthy human gingiva by age, gender and ethnicity. Spectral reflection of keratinized gingiva at upper central incisors was measured by spectroradiometer and converted into CIELAB values. Lightness range (ΔL*) for all groups together was 26.8. Corresponding a* (green-red) and b* (blue-yellow) ranges (Δa* and Δb*) were 18.3 and 13.0. Significant differences (p < 0.05) were recorded by age for L* and a* coordinates, by gender for b* coordinate, and by ethnicity for L*, a* and b* coordinates. R(2)-values between color coordinates were 0.01 (L*/a*), 0.03 (L*/b*), and 0.12 (a*/b*). The smallest color differences were recorded between age groups 46-60 and 60 + (ΔE* = 0.9), and between Caucasians and Hispanics (ΔE* = 1.1). Color difference by gender was 1.3. When total L*a*b* ranges were divided into four equal segments, 51.7% of subjects had L* value within the third segment (from lightest to darkest), 47.1% had a* value within the third segment (from less red to redder), and 59.3% had b* value within the second segment (from less yellow to yellower). It was found that ethnicity and age had statistically significant influence on the color of human gingiva.

Color difference thresholds in dentistry.

PURPOSE: The aim of this prospective multicenter study was to determine 50:50% perceptibility threshold (PT) and 50:50% acceptability threshold (AT) of dental ceramic under simulated clinical settings. MATERIALS AND METHODS: The spectral radiance of 63 monochromatic ceramic specimens was determined using a non-contact spectroradiometer. A total of 60 specimen pairs, divided into 3 sets of 20 specimen pairs (medium to light shades, medium to dark shades, and dark shades), were selected for psychophysical experiment. The coordinating center and seven research sites obtained the Institutional Review Board (IRB) approvals prior the beginning of the experiment. Each research site had 25 observers, divided into five groups of five observers: dentists-D, dental students-S, dental auxiliaries-A, dental technicians-T, and lay persons-L. There were 35 observers per group (five observers per group at each site ×7 sites), for a total of 175 observers. Visual color comparisons were performed using a viewing booth. Takagi-Sugeno-Kang (TSK) fuzzy approximation was used for fitting the data points. The 50:50% PT and 50:50% AT were determined in CIELAB and CIEDE2000. The t-test was used to evaluate the statistical significance in thresholds differences. RESULTS: The CIELAB 50:50% PT was ΔEab = 1.2, whereas 50:50% AT was ΔEab = 2.7. Corresponding CIEDE2000 (ΔE00 ) values were 0.8 and 1.8, respectively. 50:50% PT by the observer group revealed differences among groups D, A, T, and L as compared with 50:50% PT for all observers. The 50:50% AT for all observers was statistically different than 50:50% AT in groups T and L. CONCLUSION: A 50:50% perceptibility and ATs were significantly different. The same is true for differences between two color difference formulas ΔE00 /ΔEab . Observer groups and sites showed high level of statistical difference in all thresholds. CLINICAL SIGNIFICANCE: Visual color difference thresholds can serve as a quality control tool to guide the selection of esthetic dental materials, evaluate clinical performance, and interpret visual and instrumental findings in clinical dentistry, dental research, and subsequent standardization. The importance of quality control in dentistry is reinforced by increased esthetic demands of patients and dental professionals.

Firmness prediction in Prunus persica 'Calrico' peaches by visible/short-wave near infrared spectroscopy and acoustic measurements using optimised linear and non-linear chemometric models.

BACKGROUND: In this work, near infrared spectroscopy (NIR) and an acoustic measure (AWETA) (two non-destructive methods) were applied in Prunus persica fruit 'Calrico' (n = 260) to predict Magness-Taylor (MT) firmness. METHODS: Separate and combined use of these measures was evaluated and compared using partial least squares (PLS) and least squares support vector machine (LS-SVM) regression methods. Also, a mutual-information-based variable selection method, seeking to find the most significant variables to produce optimal accuracy of the regression models, was applied to a joint set of variables (NIR wavelengths and AWETA measure). RESULTS: The newly proposed combined NIR-AWETA model gave good values of the determination coefficient (R(2)) for PLS and LS-SVM methods (0.77 and 0.78, respectively), improving the reliability of MT firmness prediction in comparison with separate NIR and AWETA predictions. The three variables selected by the variable selection method (AWETA measure plus NIR wavelengths 675 and 697 nm) achieved R(2) values 0.76 and 0.77, PLS and LS-SVM. CONCLUSION: These results indicated that the proposed mutual-information-based variable selection algorithm was a powerful tool for the selection of the most relevant variables.

Chemopreventive effects of tolfenamic acid against esophageal tumorigenesis in rats.

The primary objective of this study is to identify small molecules that target critical transcription factors for potential application in the chemoprevention of esophageal cancer. Specificity proteins (Sp) play a critical role in the growth and metastasis of several malignancies including esophageal cancer. Researchers at the M. D. Anderson Cancer Center Orlando Cancer Research Institute have reported previously that tolfenamic acid (TA) inhibits cancer cell proliferation and tumor growth through the degradation of Sp1, Sp3, and Sp4. We evaluated the chemopreventive properties of TA against esophageal tumorigenesis in N-nitrosomethylbenzylamine (NMBA)-induced murine tumor model. Fischer-344 rats were treated with NMBA (0.5 mg/kg s.c. 3 times a week) for 5 weeks to initiate the tumor formation, and then treated with 50 mg/kg TA from week 6 through week 25. Tumor incidence, tumor multiplicity (number of papilloma per rat), and tumor volume were evaluated after 25 weeks. All rats in the control group that received only NMBA developed lesions (100% incidence), while the TA-treated group showed significantly lower (33%) tumor incidence and tumor multiplicity. Furthermore, the tumor volume was significantly diminished in the TA-treated group when compared with the control group. Using small molecules such as TA to target key transcription factors associated with tumorigenesis for the prevention of esophageal malignancies is a new and promising strategy. Results of the current study provide evidence that TA, when given orally after tumor initiation, can significantly suppress tumorigenesis induced by carcinogenic nitrosamines in rats. These appealing results demonstrate that TA may potentially serve as an effective chemopreventive agent in patient populations vulnerable to esophageal cancer.