Diagnostics of Data-Driven Models: Uncertainty Quantification of PM7 Semi-Empirical Quantum Chemical Method.

We report an evaluation of a semi-empirical quantum chemical method PM7 from the perspective of uncertainty quantification. Specifically, we apply Bound-to-Bound Data Collaboration, an uncertainty quantification framework, to characterize (a) variability of PM7 model parameter values consistent with the uncertainty in the training data and (b) uncertainty propagation from the training data to the model predictions. Experimental heats of formation of a homologous series of linear alkanes are used as the property of interest. The training data are chemically accurate, i.e., they have very low uncertainty by the standards of computational chemistry. The analysis does not find evidence of PM7 consistency with the entire data set considered as no single set of parameter values is found that captures the experimental uncertainties of all training data. A set of parameter values for PM7 was able to capture the training data within ±1 kcal/mol, but not to the smaller level of uncertainty in the reported data. Nevertheless, PM7 was found to be consistent for subsets of the training data. In such cases, uncertainty propagation from the chemically accurate training data to the predicted values preserves error within bounds of chemical accuracy if predictions are made for the molecules of comparable size. Otherwise, the error grows linearly with the relative size of the molecules

Total Antioxidant Concentrations of Breastmilk—An Eye-opener to the Negligent

The balance between free radical production and antioxidant defenses in the body has important systemic and oral health implications. There is convincing evidence that breastmilk containing antioxidants is important in the prevention of diseases in infancy. This study compared the total antioxidant concentration of human breastmilk expressed at different stages of lactation, stored at various temperatures and durations. Expressed breastmilk (EBM) samples of the third, seventh and 30th day were collected from women who had term and preterm deliveries (n=20). Another cohort of women (n=20) was also assessed; these women were more than five months postpartum and lactating. The total antioxidant capacity (TAC) of EBM was assessed at zero hours at room temperature, at 48 hours, one week post-refrigeration (4 °C), and freezing (-8 °C) respectively using the phosphomolybdenum method. The highest antioxidant levels were found in colostrum. The TAC of EBM reduced with time and at post-refrigeration and after freezing (p<0.0005). No significant difference in the mean TAC was observed between the EBM samples obtained from women with either term or preterm deliveries. The progressive loss of antioxidant content of EBM emphasizes the need of awareness and curtailment of the practice of storing and later use of EBM

Repeated exposure of acidic beverages on esthetic restorative materials: an in-vitro surface microhardness study

Background: A manifold increase in the consumption of aerated beverages has witnessed a twin increase in tooth wear and raised demand for esthetic restorative materials. This study aimed to evaluate the surface microhardness changes of esthetic restorative materials following treatment with aerated beverages in an in-vitro situation. Material and Methods: The initial surface microhardness of the restorative materials GC Fuji II LC, GC Fuji IX, Nano Glass ionomer, Resin and Nano composite was recorded. These materials were studied under 3 groups that included those exposed to the acidic beverages daily, weekly once in a month and those that had no exposures at all. The final surface microhardness of the materials was recorded following experimentation and was subjected to statistical comparisons. Results: The restorative materials were compared for their surface microhardness changes following respective treatments using the T-test and One-way ANOVA analysis. Inter-comparisons between the groups showed statistical significance (p<.05), when treated with both the beverages. The five restorative materials revealed surface microhardness loss; the maximum reduction noticed with the Nano glass ionomer cement tested (p<.0005). Conclusions: The surface microhardness of restorative materials markedly reduced upon repeated exposures with acidic beverages; the product with phosphoric acid producing the maximum surface microhardness loss

Bayesian calibration of interatomic potentials for binary alloys

Developing reliable interatomic potential models with quantified predictive accuracy is crucial for atomistic simulations. Commonly used potentials, such as those constructed through the embedded atom method (EAM), are derived from semi-empirical considerations and contain unknown parameters that must be fitted based on training data. In the present work, we investigate Bayesian calibration as a means of fitting EAM potentials for binary alloys. The Bayesian setting naturally assimilates probabilistic assertions about uncertain quantities. In this way, uncertainties about model parameters and model errors can be updated by conditioning on the training data and then carried through to prediction. We apply these techniques to investigate an EAM potential for a family of gold-copper systems in which the training data correspond to density-functional theory values for lattice parameters, mixing enthalpies, and various elastic constants. Through the use of predictive distributions, we demonstrate the limitations of the potential and highlight the importance of statistical formulations for model error.Comment: Preprint, 28 pages, 18 figures, accepted for publication in Computational Materials Science on 7/11/202

Interdisciplinary Approach for Salvaging a Carious Multirooted teeth: A Case Report

Hemisection denotes sectioning of root with its accompanying crown portion of molars.The outcomes is predictable and success rates are high. In this case report a 29 year old male patient with severe class-III furcation involvement of mandibular molar, which was treated with hemisection and restoration followed by fixed prosthodontic prosthesis

HIV and cancer registry linkage identifies a substantial burden of cancers in persons with HIV in India.

We utilized computerized record-linkage methods to link HIV and cancer databases with limited unique identifiers in Pune, India, to determine feasibility of linkage and obtain preliminary estimates of cancer risk in persons living with HIV (PLHIV) as compared with the general population.Records of 32,575 PLHIV were linked to 31,754 Pune Cancer Registry records (1996-2008) using a probabilistic-matching algorithm. Cancer risk was estimated by calculating standardized incidence ratios (SIRs) in the early (4-27 months after HIV registration), late (28-60 months), and overall (4-60 months) incidence periods. Cancers diagnosed prior to or within 3 months of HIV registration were considered prevalent.Of 613 linked cancers to PLHIV, 188 were prevalent, 106 early incident, and 319 late incident. Incident cancers comprised 11.5% AIDS-defining cancers (ADCs), including cervical cancer and non-Hodgkin lymphoma (NHL), but not Kaposi sarcoma (KS), and 88.5% non-AIDS-defining cancers (NADCs). Risk for any incident cancer diagnosis in early, late, and combined periods was significantly elevated among PLHIV (SIRs: 5.6 [95% CI 4.6-6.8], 17.7 [95% CI 15.8-19.8], and 11.5 [95% CI 10-12.6], respectively). Cervical cancer risk was elevated in both incidence periods (SIRs: 9.6 [95% CI 4.8-17.2] and 22.6 [95% CI 14.3-33.9], respectively), while NHL risk was elevated only in the late incidence period (SIR: 18.0 [95% CI 9.8-30.20]). Risks for NADCs were dramatically elevated (SIR &gt; 100) for eye-orbit, substantially (SIR &gt; 20) for all-mouth, esophagus, breast, unspecified-leukemia, colon-rectum-anus, and other/unspecified cancers; moderately elevated (SIR &gt; 10) for salivary gland, penis, nasopharynx, and brain-nervous system, and mildly elevated (SIR &gt; 5) for stomach. Risks for 6 NADCs (small intestine, testis, lymphocytic leukemia, prostate, ovary, and melanoma) were not elevated and 5 cancers, including multiple myeloma not seen.Our study demonstrates the feasibility of using probabilistic record-linkage to study cancer/other comorbidities among PLHIV in India and provides preliminary population-based estimates of cancer risks in PLHIV in India. Our results, suggesting a potentially substantial burden and slightly different spectrum of cancers among PLHIV in India, support efforts to conduct multicenter linkage studies to obtain precise estimates and to monitor cancer risk in PLHIV in India

Ethyl 2-[(2,6-dimethyl­phen­yl)hydrazono]-3-oxobutanoate

The title compound, C14H18N2O3, crystallizes with two independent mol­ecules in the asymmetric unit, having closely comparable geometries. Both mol­ecules are essentially planar [maximum deviations from the mean plane of 0.069 (1) and 0.068 (1) Å for the two mol­ecules] and contain an intra­molecular N—H⋯O hydrogen bond which generates a ring with graph-set motif S(6). In the crystal, the mol­ecules are linked into chains along the c axis by inter­molecular C—H⋯O hydrogen bonds, and inter­molecular C—H⋯π inter­actions are also present

Ethyl 1-(2,4-dichloro­benz­yl)-4-oxo-7-trifluoro­meth­yl-1,4-dihydro­quinoline-3-carboxyl­ate

In the title compound, C20H14Cl2F3NO3, the trifluromethyl group is disordered over two sets of sites in a 0.784 (10):0.216 (10) ratio. The quinoline ring system is essentially planar with a maximum deviation of 0.058 (2) Å for the N atom and forms dihedral angles of 89.23 (11) and 8.13 (17)°, respectively with the mean planes of the benzene ring and the carboxyl­ate group. In the crystal, pairs of weak C—H⋯O and C—H⋯F hydrogen bonds link mol­ecules into centrosymmetric dimers. The crystal structure is further stabilized by weak π–π [centroid–centroid distance = 3.624 (2) Å] inter­actions

Acylpeptide Hydrolase Inhibition as Targeted Strategy to Induce Proteasomal Down-Regulation

Acylpeptide hydrolase (APEH), one of the four members of the prolyl oligopeptidase class, catalyses the removal of N-acylated amino acids from acetylated peptides and it has been postulated to play a key role in protein degradation machinery. Disruption of protein turnover has been established as an effective strategy to down-regulate the ubiquitin-proteasome system (UPS) and as a promising approach in anticancer therapy