Thermo-hydraulic performance of solar air heater having discrete D-shaped ribs as artificial roughness.

In this paper, the thermo-hydraulic performance of a solar air heater (SAH) duct roughened with discrete D-shaped ribs is numerically investigated using ANSYS Fluent 2020 R2. The numerical investigation is carried out at rib radius to transverse pitch ratio (r/Pt) from 0.1 to 0.35 and longitudinal pitch to rib radius ratio (Pl /r) from 4 to 10 under various operating conditions with Reynolds number (Re) varied from 10,200 to 20,200. The numerical results are validated with previous experimental results for the Nusselt number (Nu) values, and good agreement is found with mean absolute percentage error (MAPE) of 3.6%. Based on the results of the numerical investigation, it was found that the value of Nu and the friction factor (f) decreases with the increase of the value of Pl/r, while the ratio r/Pt is kept constant. From the overall analysis, it is concluded that the optimum results are obtained for r/Pt of 0.25 and Pl/r = 4, and the maximum thermo-hydraulic performance parameter is 1.12. Further correlations are developed for the value of Nu and f for the whole range of r/Pt as 0.10-0.35 and Pl/r as 4-10. According to the developed correlations, the values of Nu are within ± 2% of the results of CFD, while the values of f are within ± 2.7% of the results of CFD.

Ex vivo interaction study of NaYF4 :Yb,Er nanophosphors with isolated mitochondria.

Ex vivo interaction of NaYF4 :Yb,Er nanophosphors with isolated mitochondria has been investigated. The nanophosphors were synthesized using the hydrothermal method. The synthesized NaYF4 :Yb,Er nanophosphors were characterized for physicochemical properties. The NaYF4 :Yb,Er nanophosphors showed successful upconversion with excitation wavelength lying in the near-infrared region. The effect of synthesized NaYF4 :Yb,Er nanophosphors on mitochondria isolated from the chicken heart tissue was examined through ROS generation capacity, membrane fluidity, and complex II activity. The exposer of NaYF4 :Yb,Er nanophosphors to isolated mitochondria inhibits ROS generation activity as compared to control. The mitochondria membrane fluidity of the lipid bilayer and complex-II activity of mitochondria was observed to be unaltered after the interaction with NaYF4 :Yb,Er nanoparticles. The results confirm that synthesized NaYF4 :Yb,Er nanoparticles can be used as a safe contrast agent.

Experimental and RSM-Based Process-Parameters Optimisation for Turning Operation of EN36B Steel.

The main objective of this article is to perform the turning operation on an EN36B steel work-billet with a tungsten carbide tool, to study the optimal cutting parameters and carry out an analysis of flank-wear. Experimental and simulation-based research methodology was opted in this study. Experimental results were obtained from the lab setup, and optimisation of parameters was performed using RSM (response surface methodology). Using RSM, cutting-tool flank-wear was optimised, and the cutting parameters which affect the flank wear were determined. In results main effect plot, contour plot, the surface plot for flank-wear and forces (Fx, Fy and Fz) were successfully obtained. It was concluded that tool flank-wear is affected by depth of cut, and that flank-wear generally increases linearly with increasing cutting-speed, depth of cut and feed-rate. To validate the obtained results, predicated and measured values were plotted and were in very close agreement, having an accuracy level of 96.33% to 98.92%.

Total Synthesis and Conformational Analysis of Naturally Occurring Lipovelutibols along with Lead Optimization of Lipovelutibol D.

Four lipopeptaibols, namely, lipovelutibols A-D, were recently isolated from psychrotrophic fungus Trichoderma velutinum and reported to have significant cytotoxic activity against HL-60, MDA-MD-231, A549, and LS180 cancer cell lines. In the present study, these peptides were synthesized in a solution using a segment condensation approach. The conformational analysis of these peptides carried out using CD spectrophotometry revealed the formation of 310-helix, and the NMR-VT experiments showed intramolecular hydrogen bonding for NH-5, NH-6, and NH-7. Lipovelutibol D showed potent cytotoxic activity and was chosen for lead optimization. It involved N- and C-terminal truncation, N- and C-terminal modification, random deletion, l/d configuration replacement, and other synthetic analogues. These were tested against various breast cancer cell lines. The C-terminal aldehyde analogue resulting from lead optimization of lipovelutibol D was found to have almost twofold enhanced cytotoxicity against MDA-MB-231 breast cancer cell lines.

14-Residue peptaibol velutibol A from Trichoderma velutinum: its structural and cytotoxic evaluation.

Velutibol A (1), a new 14-residue peptaibol was isolated from the Himalayan cold habitat fungus Trichoderma velutinum. The structural characterization was carried out by 1D and 2D NMR studies, and tandem mass studies, and Marfey's method aided in determining the stereochemistry of the amino acids. The CD analysis revealed folding of the peptide in a 310-helical conformation. The intramolecular H-bonding was determined by an NMR-VT experiment. Cytotoxic evaluation was carried out against a panel of cancer cell lines. The cell cycle assay was carried out on human myeloid leukaemia (HL-60) cells and revealed the formation of apoptotic bodies and DNA damage in a dose-dependent manner. Three other peptaibols namely velutibol B (2), velutibol C (3), and velutibol D (4) were also isolated in trace amounts from the psychotropic fungus and characterized through tandem mass spectroscopy and Marfey's analysis.

Endodontic management of mandibular canine with two roots and two canals: a rare case report.

BACKGROUND: In general, mandibular canines have a single root and a single canal. The occurrence of two roots and two canals is a rare entity ranging from 1 to 5%. The anatomy of root canal morphology plays a decisive role in determining the conditions under which endodontic treatment can be performed effectively. Successful endodontic treatment comprises proper diagnosis, meticulous cleaning and shaping followed by three dimensional obturation. Failure to do so may lead to postoperative diseases, pain and further complications. This paper reports successful management of a mandibular canine with two roots and two canals. CASE PRESENTATION: 45-year-old Nepalese women with a non-significant medical history presented with a chief complaint of pain in a lower left front tooth. The pain disturbed her sleep and lingered for several minutes even after removal of a thermal stimulus. Clinical examination and testing revealed generalized severe attrition with tenderness to percussion in the mandibular left canine. Electric pulp test for all the mandibular anteriors revealed almost no response in the mandibular left canine. Intraoral periapical radiographs in different angulations were taken which revealed two roots and two canals. A clinical diagnosis of chronic irreversible pulpitis with symptomatic apical periodontitis was made and root canal therapy was performed following the standard protocols. CONCLUSION: Although the prevalence of two roots and two canals in mandibular canine is very low, the clinician should always be mindful of variations in the number of roots and canals for proper management of such cases.

Lipovelutibols A-D: Cytotoxic Lipopeptaibols from the Himalayan Cold Habitat Fungus Trichoderma velutinum.

Four novel lipovelutibols A (1), B (2), C (3), and D (4) containing six amino acid residues with leucinol at the C-terminus and a fatty acyl moiety (n-octanoyl) at its N-terminus were isolated from the psychrotrophic fungus Trichoderma velutinum collected from the Himalayan cold habitat. The structures (1-4) were determined by NMR and MS/MS, and the stereochemistry of amino acids by Marfey's method. Lipopeptaibols 2 and 4 were found to contain d-isovaline, a nonproteinogenic amino acid, but lacked α-aminoisobutyric acid, characteristic of peptaibols. Cytotoxic activity of 2 and 4 was observed against HL-60, LS180, MDA-MB-231, and A549 cancer cell lines.

Construction of a three-dimensional finite element model of maxillary first molar and it's supporting structures.

The finite element method (FEM) is a powerful computational tool for solving stress-strain problems; its ability to handle material inhomogeneity and complex shapes makes the FEM, the most suitable method for the analysis of internal stress levels in the tooth, periodontium, and alveolar bone. This article intends to explain the steps involved in the generation of a three-dimensional finite element model of tooth, periodontal ligament (PDL) and alveolar bone, as the procedure of modeling is most important because the result is based on the nature of the modeling systems. Finite element analysis offers a means of determining strain-stress levels in the tooth, ligament, and bone structures for a broad range of orthodontic loading scenarios without producing tissue damage.

Psychological impact of visible differences in patients with congenital craniofacial anomalies.

BACKGROUND: Patients with craniofacial anomalies often have appearance concerns and related social anxiety which can affect their quality of life. This study assessed the psychological impact of facial and dental appearance in patients with craniofacial anomalies in comparison to a general population control group. METHODS: The study involved 102 adult patients (51% male) with congenital craniofacial anomalies and 102 controls (49% male). Both groups completed the Nepali version of Derriford Appearance Scale (DAS) and the Psychological Impact of Dental Aesthetic Questionnaire (PIDAQ) in a clinical setting to assess appearance-related distress, avoidance, and anxiety. RESULTS: There was a significant difference between patients and controls on both PIDAQ (mean score for patients 33.25 ± 9.45 while for controls 27.52 ± 5.67, p < 0.001) and DAS59 scores (mean score for patients 159.16 ± 31.54 while for controls 77.64 ± 6.57, p < 0.001), indicating that patients experienced greater negative psychological impact of living with their appearance (PIDAQ) and more appearance-related distress (DAS) than controls. DAS scores were not associated with gender. There was no association of the place of residence (rural vs. urban) with PIDAQ or DAS59 scores. CONCLUSIONS: There is a significant psychological impact of altered facial and dental appearance in patients with craniofacial anomalies compared to controls. There was no effect of locality (rural/urban) on the psychological impact of facial and dental appearance in patients.

Supernumerary teeth in Nepalese children.

OBJECTIVE: The objectives of the present study were to investigate the prevalence and characteristics of supernumerary teeth in a patient sample of Nepalese children. STUDY DESIGN: A survey was performed on 2684 patients (1829 females and 1035 males) ranging in age from 6 to 14 for the presence of supernumerary teeth. For each patient with supernumerary teeth the demographic variables (age and sex), number, location, eruption status, and morphology were recorded. Descriptive statistics were performed. RESULTS: Supernumerary teeth were detected in 46 subjects (1.6%), of which 26 were males and 20 were females with a male : female ratio of 1.3 : 1. The most commonly found supernumerary tooth was mesiodens followed by maxillary premolars, maxillary lateral incisor, and mandibular lateral incisor. Of the 55 supernumerary teeth examined, 58.18% (n = 32) had conical morphology, followed by tuberculate (30.90%, n = 17) and supplemental (10.90%, n = 6) forms. The majority of the supernumerary teeth were erupted (56.36%, n = 31). CONCLUSION: The prevalence of supernumerary teeth in Nepalese children was found to be 1.6%, the most frequent type being mesiodens. Conical morphology was found to be the most common form of supernumerary tooth.

Translation and validation of a Nepalese version of the Psychosocial Impact of Dental Aesthetic Questionnaire (PIDAQ).

OBJECTIVE: The aim of this study was to develop a reliable and valid Nepali version of the Psychosocial Impact of Dental Aesthetic Questionnaire (PIDAQ). DESIGN: Cross-sectional descriptive validation study. SETTINGS: B.P. Koirala Institute of Health Sciences, Dharan, Nepal. METHODS: A rigorous translation process including conceptual and semantic evaluation, translation, back translation and pre-testing was carried out. Two hundred and fifty-two undergraduates, including equal numbers of males and females with an age ranging from 18 to 29 years (mean age: 22·33±2·114 years), participated in this study. Reliability was assessed by Cronbach's alpha coefficient and the coefficient of correlation was used to assess correlation between items and test-retest reliability. The construct validity was tested by factorial analysis. Convergent construct validity was tested by comparison of PIDAQ scores with the aesthetic component of the index of orthodontic treatment needs (IOTN-AC) and perception of occlusion scale (POS), respectively. Discriminant construct validity was assessed by differences in score for those who demand treatment and those who did not. RESULTS: The response rate was 100%. One hundred and twenty-three individuals had a demand for orthodontic treatment. The Nepali PIDAQ had excellent reliability with Cronbach's alpha of 0·945, corrected item correlation between 0·525 and 0·790 and overall test-retest reliability of 0·978. The construct validity was good with formation of a new sub-domain 'Dental self-consciousness'. The scale had good correlation with IOTN-AC and POS fulfilling convergent construct validity. The discriminant construct validity was proved by significant differences in scores for subjects with demand and without demand for treatment. CONCLUSION: To conclude, Nepali version of PIDAQ has good psychometric properties and can be used effectively in this population group for further research.

Identification of an Alternate Maxillary Apical Base Landmark from Pre-existing Substitutions.

BACKGROUND: Cephalometrically the position of maxilla is usually assessed by point A, which is one of the most common cephalometric landmarks used for spatial analysis of maxilla, however in certain scenarios we require a alternative landmark. AIMS: In this study a nearest alternative maxillary apical base landmark was identified for Point A substitutions given by different authors. METHODS AND MATERIAL: A cross sectional study was conducted on thirty (30) good quality lateral cephalograms. Only those lateral cephalograms were selected where Point A was easily identified. Landmarks: Sella (S), Nasion (N), Point A and three substitution points Y, L, X were traced. Angles formed by SN with Point A (Angle SNA) and three substitution points (Angle SNY, SNX, SNL) were measured. Correlation of angle SNA with angles SNY, SNX and SNL were derived. Statistical analysis used. RESULTS: Mean and standard deviation for Angles SNA, SNY, SNL and SNX were calculated individually for males and females. 'T' Test was applied to determine statistical significance for all the parameters i.e Age, Angles SNA, SNY, SNL and SNX respectively. Karl Pearson correlation coefficient was carried out to determine the statistical significant correlation for Angle SNA with SNY, SNL and SNX. RESULTS: A mean value of 82.8° ±1.9°, 83.1° ±1.8°, 78.3° ±2.9° and 78.7° ±2.7° for Angle's SNA, SNY, SNL and SNX respectively was observed. A statistically significant correlation was observed between angles SNA & SNY, SNL, SNX & strong positive correlation was observed with angle SNY. CONCLUSIONS: We conclude that Point Y is the most nearing maxillary apical base landmark to Point A. Hence maxillary apical base landmark can be substituted by Point Y where identification of point A is not obvious.

Assessment of the Self-Perception of Dental Appearance, Its Comparison with Orthodontist's Assessment and Demand for Treatment in Eastern Nepalese Patients.

Aims. The aim of this study was to assess the self-perception of dental appearance among Eastern Nepalese patients using aesthetic component (AC) of the index of orthodontic treatment need (IOTN) and to compare it with that of an orthodontist's assessment using the same scale and determine whether gender, area of residence, and level of education influence subject's self-perception and orthodontist's ratings. Methods. A total of 252 subjects (equal number of male and female) were conveniently selected. The average ages of subjects were 22.33 ± 2.114 years. The level of subject's perception and orthodontist's assessment was analyzed by nonparametric Chi square test. Kappa coefficient was done to verify its agreement. The Spearman's correlation test was used to check the association of educational level and age. Mann-Whitney test was used to check the associations of sex and areas of residence. Results. The demand for treatment was significantly associated with the perception of the subject and orthodontist's assessment. However, age, gender, and educational level were statistically insignificant in influencing subject perception and orthodontist's assessment. Conclusion. Patient's self-perception should be given equal importance while planning orthodontic treatment.

Epidemiology of Malocclusion and Assessment of Orthodontic Treatment Need for Nepalese Children.

Objective. To evaluate the prevalence of malocclusion and orthodontic treatment needs among 12- to 15-year-old schoolchildren in eastern Nepal and compare the findings with those of other populations. Methods. Two thousand seventy-four children (1149 males and 925 females) aged between 12 and 15 years were evaluated. Their orthodontic treatment need was assessed using the Index of Orthodontic Treatment Needs (IOTN) (dental health component (DHC)). Angle's classes of malocclusion were also evaluated. Results. The prevalence of classes I, II, and III was 48.50%, 32.68%, and 4.32%, respectively. The IOTN showed that 21.59% had an extreme treatment need, 24.67% had severe treatment need, 24.07% had moderate treatment need, 14.7% had mild treatment need, and 15.02% had no treatment need. Conclusion. Class I malocclusion is the most common, while class III is the least prevalent in eastern Nepal. The majority of the children need orthodontic treatment.

Role of probiotics in health and disease: a review.

For some decades now, bacteria known as probiotics have been added to various foods because of their beneficial effects for human health. The mechanism of action of probiotics is related to their ability to compete with pathogenic microorganisms for adhesion sites, to antagonize these pathogens or to modulate the host's immune response. The potential application of probiotics includes prevention and treatment of various health conditions and diseases such as gastrointestinal infections, inflammatory bowel disease, lactose intolerance, allergies, urogenital infections, cystic fibrosis, various cancers, reduction of antibiotic side effects, in oral health such as prevention of dental caries, periodontal diseases and oral malodour and many other effects which are under investigation. The results of many of these clinical investigations suggests that probiotics may be useful in preventing and treating various health conditions and diseases. However, many of these clinical studies require validation so as to apply these results to clinical realm. The role of clinical trials is instrumental in such investigations and in near future the results of such trials will decide the usefulness of probiotics in health and disease. This article strives to summarize the currently available data on the potential benefits of probiotics in health and disease.

Iron-catalyzed cross-coupling of electron-deficient heterocycles and quinone with organoboron species via innate C-H functionalization: application in total synthesis of pyrazine alkaloid botryllazine A.

Here, we report an iron-catalyzed cross-coupling reaction of electron-deficient heterocycles and quinone with organoboron species via innate C-H functionalization. Iron(II) acetylacetonate along with oxidant (K2S2O8) and phase-transfer catalyst (TBAB) under open flask conditions efficiently catalyzed the cross-coupling of pyrazine with arylboronic acids and gave monoarylated products in good to excellent yields. Optimized conditions also worked for other heterocylces such as quinoxalines, pyridines, quinoline, and isoquinoline as well as quinones. In addition, we demonstrated as a first example its application for the synthesis of anticancer marine pyrazine alkaloid botryllazine A.

Supernumerary teeth in Indian children: a survey of 300 cases.

The aim of this investigation was to study children with supernumerary teeth who visited the Department of Pedodontics and Preventive Dentistry, Government Dental College and Hospital, Rohtak, Haryana, India. Only children with supernumerary teeth were included in the study while patients having supernumerary teeth with associated syndromes were excluded. Supernumeraries were detected by clinical and radiographic examination. The results indicated that males were affected more than females with a sex ratio of 2.9 : 1. Single supernumerary tooth was seen in 79% of the patients, 20% had double, and 1% had three or more supernumeraries. Premaxillary supernumeraries accounted for 93.8% of the cases. Conical shaped supernumerary teeth were the most common type (59.7%). Majority of supernumeraries remained unerupted (65%). Fusion of supernumerary tooth with a regular tooth was observed in 4% of the patients. Talon cusp, an associated dental anomaly, was seen in 5% of the cases. Simultaneous hypodontia occurred in 2.3% of patients with supernumeraries.