A computational study of TyrGly hydration

Twenty-two conformers of the neutral tyrosine-glycine (TyrGly) dipeptide have been studied at the mPW2PLYP-D2/def2-TZVP level in the gas phase, in implicit solvent and with one explicit water molecule. Implicit solvation brings the conformers closer in energy, whereas explicit monosolvation significantly extends the range of stability of the complexes. Thus, interaction with a single water molecule preferentially stabilises some conformers over others. The most stable conformer in the gas phase remains the most stable in implicit solvation and explicit monosolvation, though the third most stable conformer in the gas phase is nearly iso-energetic in implicit solvation. The two most stable monohydrated complexes are based on the folded most stable conformer in the gas phase and only differ slightly in the orientation of the water molecule. The water molecule increases the foldedness of these structures by bridging the carboxylic acid group and phenyl OH.PostprintPostprintPeer reviewe

Awareness of dentists regarding immediate management of dental avulsion : Knowledge, attitude, and practice study.

OBJECTIVE: To assess the knowledge of practising dentists regarding immediate management of dental avulsion. METHODS:The cross-sectional analytical study was conducted in various dental colleges and teaching hospitals of Karachi, Pakistan, in October-November 2016, and comprised dentists working in academic institutions / departments or as general dental practitioners for at least 1 year. The subjects were asked to fill out a self-administered questionnaire. Questions related to knowledge and practice regarding immediate management of dental avulsion was asked and then responses were categorised as good knowledge, moderate and poor knowledge. SPSS 22 was used for data analysis.. RESULTS: Of the 282 subjects, 179 (63.5%) were females and 103(36.5%) were males. The overall mean age was 28. 33±4.7 years, and 194 (68.8%) had clinical experience of less than 5 years. Of the total, 30(11%) dentists had good knowledge while 130(46%) had moderate and 122(43%) had poor knowledge. Statistically significant association of knowledge regarding tooth avulsion was observed with the specialty (p= 0.006) and qualification (p=0.001). CONCLUSIONS: The knowledge of dentists regarding immediate management of avulsion injuries was inadequate. Knowledge was significantly associated with specialty and qualification of the dentist

The Trend, Style and Types of Qur’ānic Exegesis in Modern Times

After the revelation of the Qur’ān, there are different languages depending on the time and place. The series of explanations and interpretations have been going on which has helped the Muslim Ummah in understanding and act upon the Qur’ānic teachings. The first stage is the era of the Prophet, the second stage is the era of the Companions, the third stage is the era of the followers and the fourth stage is the era of the followers. The trend is a clear path which commentator sets for himself in the interpretation of the Holy Qur'ān is his method. The ideas and thoughts of the commentator play a fundamental role in a commentary. It is as the clear path that the commentator sets for himself in the interpretation of the Holy Qur’an is his Manhāj. The ideas and thoughts of the commentator play an essential role in this context. In this article the commentaries of modern times have been discussed under Style, Types, Manhaj and trends. There are many commentaries have been represents the modern style. Among them  Tafsı̇̄r Tadabur Qur’ān Amin Ahsan Isl┐h┘, Tafsı̇̄r Zia-ul-Qur’ān by P┘r Karam Shah Al-Azhar┘, Matalib-al-Furq┐n by Ghulam Ahmad Pervez, Tafsı̇̄r-al-Bayan by Javed Ahmad Ghamd┘ have been prominent in this respect. Keywords: Tends, Types, Style of Qur’ānic Exegesi

Age estimation of a sample of pakistani population using coronal pulp cavity Index in molars and premolars on orthopantomogram

The aim of the present study was to assess the validity of tooth-coronal index (TCI) in the age estimation. This retrospective charts review was conducted at the Aga Khan University Hospital, Karachi from January 2016 to March 2016, and comprised 315 teeth of 80 individuals. The teeth were analysed on Orthopantomogram. TCI was calculated for unrestored mandibular premolars and molars. Pearson\u27s correlation was applied to assess correlation between chronological age and TCI. Besides, 30(37.5%) subjects were male and 50(62.5%) female, and 140(44.4%) teeth were of male subjects and 175(55.6%) were of females. The mean correlation coefficient between chronological age and TCI was -0.27. The highest negative correlation was observed for tooth No.47 in males (r=-0.72) whereas among females the highest negative correlation was noted for tooth No.36 (r=- 0.61).There was very weak correlation between age and TCI of a tooth. Therefore, TCI index could not be predictably used for age estimation in the studied population

Prevalence of musculoskeletal disorders among dentists in teaching hospitals in Karachi

Work-related musculoskeletal pain is common among healthcare professionals, including dentists. This crosssectional study was conducted to determine the prevalence of work-related musculoskeletal disorders (MSDs) among dentists. This study was carried out from January to April 2016 at various teaching hospitals of Karachi, and comprised 230 dentists. A self-administered questionnaire, adapted from a validated Nordic questionnaire, was distributed among the participants. Descriptive statistics were computed and associations of interest were analysed using chi-square test. Of the 230 forms, 182(79.11%) were included after leaving out the incomplete ones. The overall prevalence of MSDs was 138(75.8%). The most frequent reasonsfor MSDs were lack of rest 21(15.2%) and having static postures for more than half-an-hour per procedure 38(27.5%)

13C-1H coupling constants as a conformational tool for structural assignment of quinic and octulosonic Acid

RH acknowledges funding from the Higher Education Commission of Pakistan for her visit to University of St-Andrews, as a visiting scholar. AK is thankful to the Higher Education Commission of Pakistan (Grant No. 1691) as well as to the COMSATS University Islamabad, Abbottabad Campus for financial support.A complete set of NMR coupling constants (1JC-H, 2JC-H, 3JC-H, and 3JH-H) were calculated for the eight stereoisomers of quinic acid, at the B3LYP/6-311G(d,p)/PCM(methanol) level of theory. The Fermi contact term of the coupling constants was computed with a modified, uncontracted, version of the 6-311G(d,p) basis set, with additional tight polarization functions. 1H and 13C NMR chemical shifts were determined at the same level using the gauge-invariant atomic orbital (GIAO) method. The magnitude of the spin-spin coupling constants was found to be affected by the orientation (axial or equatorial) of the coupling proton and the orientation of the hydroxy group on the coupling carbon, whereas the chemical shifts depend on the presence or absence of electron-withdrawing hydroxy groups attached to the carbon atoms involved.Publisher PDFPeer reviewe

Intramolecular BSSE and dispersion affect the structure of a dipeptide conformer

RH acknowledges funding from Higher Education Commission of Pakistan for her visit to the University of St Andrews as a visiting scholar.B3LYP and MP2 calculations with the commonly-used 6-31+G(d) basis set predict qualitatively different structures for the Tyr-Gly conformer book1, which is the most stable conformer identified in a previous study (Mol. Phys. 104, 559-570, 2006). The structures differ mainly in the ψTyr Ramachandran angle (138° in the B3LYP structure and 120° in the MP2 structure). The causes for the discrepant structures are attributed to missing dispersion in the B3LYP calculations and large intramolecular BSSE in the MP2 calculations. The correct ψTyr value is estimated to be 130°. The MP2/6-31+G(d) profile identified an additional conformer, not present on the B3LYP surface, with a ψTyr value of 96° and a more folded structure. This minimum is however likely an artefact of large intramolecular BSSE values. We recommend the use of basis sets of at least quadruple-zeta quality in DFT, DFT-D and MP2 calculations in cases where intramolecular BSSE is expected to be large.PostprintPeer reviewe

Most effective method for the management of physiologic gingival hyperpigmentation: A systematic review and meta-analysis

MATERIALS AND METHODS: A systematic review and meta-analysis were done (1919 to October 2018) using PubMed, CINHAL, Dental and Oral Science, and manual searches. Twenty-five articles were finally reviewed. Only human clinical trials were considered with physiological gingival pigmentation treated with different depigmentation methods and compared with surgical stripping. The outcome was the achievement of gingival depigmentation and its recurrence. RevMan software was used for data analysis. RESULTS: Of 26,132 articles, 25 met the inclusion criteria. Seventeen were randomized control trials and 8 were nonrandomized control trials. Most of the studies were on laser. The control group was scalpel surgery. Majority of studies showed no difference in compared treatment modality. A meta-analysis compared laser ablation with surgical stripping revealed a nonsignificance difference regarding recurrence (P = 0.75) and depigmentation (P = 0.23) and a statistically significant difference regarding postoperative pain favoring laser ablation (P ≤ 0.05). CONCLUSIONS: Surgical stripping has been the conventional treatment of choice, but our review showed that new techniques are equally effective or even better. Laser especially diode laser was the most frequently used technique and showed better esthetic outcomes, less pain, faster healing, and patients\u27 preference and satisfaction after treatment. However, laser showed more regimentation at 6-month evaluation. More good quality randomized controlled trials with different depigmentation methods are needed to draw strong conclusions