Speeding-up Hybrid Functional based Ab Initio Molecular Dynamics using Multiple Time-stepping and Resonance Free Thermostat

Ab initio molecular dynamics (AIMD) based on density functional theory (DFT) has become a workhorse for studying the structure, dynamics, and reactions in condensed matter systems. Currently, AIMD simulations are primarily carried out at the level of generalized gradient approximation (GGA), which is at the 2nd rung of DFT-functionals in terms of accuracy. Hybrid DFT functionals which form the 4th rung in the accuracy ladder, are not commonly used in AIMD simulations as the computational cost involved is $100$ times or higher. To facilitate AIMD simulations with hybrid functionals, we propose here an approach that could speed up the calculations by ~30 times or more for systems with a few hundred of atoms. We demonstrate that, by achieving this significant speed up and making the compute time of hybrid functional based AIMD simulations at par with that of GGA functionals, we are able to study several complex condensed matter systems and model chemical reactions in solution with hybrid functionals that were earlier unthinkable to be performed.Comment: 45 pages, 9 figures, 5 table

Studies on the antidiarrhoeal activity of Aegle marmelos unripe fruit: Validating its traditional usage

<p>Abstract</p> <p>Background</p> <p><it>Aegle marmelos </it>(L.) Correa has been widely used in indigenous systems of Indian medicine due to its various medicinal properties. However, despite its traditional usage as an anti-diarrhoeal there is limited information regarding its mode of action in infectious forms of diarrhoea. Hence, we evaluated the hot aqueous extract (decoction) of dried unripe fruit pulp of <it>A. marmelos </it>for its antimicrobial activity and effect on various aspects of pathogenicity of infectious diarrhoea.</p> <p>Methods</p> <p>The decoction was assessed for its antibacterial, antigiardial and antirotaviral activities. The effect of the decoction on adherence of enteropathogenic <it>Escherichia coli </it>and invasion of enteroinvasive <it>E. coli </it>and <it>Shigella flexneri </it>to HEp-2 cells were assessed as a measure of its effect on colonization. The effect of the decoction on production of <it>E. coli </it>heat labile toxin (LT) and cholera toxin (CT) and their binding to ganglioside monosialic acid receptor (GM1) were assessed by GM1-enzyme linked immuno sorbent assay whereas its effect on production and action of <it>E. coli </it>heat stable toxin (ST) was assessed by suckling mouse assay.</p> <p>Results</p> <p>The decoction showed cidal activity against <it>Giardia </it>and rotavirus whereas viability of none of the six bacterial strains tested was affected. It significantly reduced bacterial adherence to and invasion of HEp-2 cells. The extract also affected production of CT and binding of both LT and CT to GM1. However, it had no effect on ST.</p> <p>Conclusion</p> <p>The decoction of the unripe fruit pulp of <it>A. marmelos</it>, despite having limited antimicrobial activity, affected the bacterial colonization to gut epithelium and production and action of certain enterotoxins. These observations suggest the varied possible modes of action of <it>A. marmelos </it>in infectious forms of diarrhoea thereby validating its mention in the ancient Indian texts and continued use by local communities for the treatment of diarrhoeal diseases.</p

Overdenture locator attachments for atrophic mandible

Implant-supported overdentures provide a good opportunity for dentists to improve oral health and quality-of-life of patients. Atrophic mandible poses a significant challenge to successful oral rehabilitation with dental implants. In this article, the fabrication of lower overdenture by two narrow platform implants is described with dual retentive, resilient, self-locating locator attachment system. The locator attachment system has the lowest profile in comparison with the ball and bar attachments and is versatile up to 40΀ of divergence between two implants. By using locators as attachments, we can meet functional, economic and social expectation of patients with ease and satisfaction

Median cleft of mandible and lower lip with ankyloglossia and ectopic minor salivary gland on tongue

Median cleft of lower lip and mandible is a rare anomaly. This Cleft has also been described as Cleft No. 30 of Tessier&#x2032;s classification. In minor forms only lower lip is cleft. Frequently, the cleft extends into the mandibular symphysis and the tongue is attached to the cleft alveolar margin. At times the tongue may be bifid or absent, hyoid absent, thyroid cartilage underdeveloped, strap muscles atrophic, manubrium sterni absent, clavicles widely spaced etc. The earliest report of this anomaly was by Couronne&#x2032; in 1819. Since then very few cases have been reported in literature with variations. We describe a male child who presented at the age of 6 months with an ectopic salivary gland on the dorsum of the tongue in addition to median cleft of lower lip, ankyloglossia and notching of the mandible. Excision of mass on dorsum of tongue, release of ankyloglossia and lip from the alveolus followed by repair was done. No bony work was done since the mandible was only notched. On post-operative follow-up at 18 months, dentition was delayed in both maxillary as well as mandibular teeth and there was a gap between the lower central incisors. At the age of 2 years 4 months, the dentition is still not complete and the gap between the lower central incisors is very apparent. There is a supernumerary upper central incisor on right side. There is no mobility between the two segments of mandible. Speech is normal. A regular follow-up will be done to study the eruption of permanent central incisors at the age of 7 years and till eruption of all permanent teeth to assess the occlusion and to decide whether any bony work is needed or not

Destructive radiolucent lesion involving right maxillary alveolus: Report of a rare case

Ewing′s sarcoma/primitive neuroectodermal tumor (ES/PNET) usually arises in the long bones of extremities. It is uncommon to find ES in the head and neck region, particularly in gnathic bones. It comprises 6-8% of all primary bone malignancies. Only 1% of cases is reported with jaw involvement and has mandibular predilection. Even with early intervention, patients with metastasis have approximately 20% chance of 5-year survival. Here, we report a rare case of ES involving right maxillary alveolus

Median cleft of mandible and lower lip with ankyloglossia and ectopic minor salivary gland on tongue

Median cleft of lower lip and mandible is a rare anomaly. This Cleft has also been described as Cleft No. 30 of Tessier's classification. In minor forms only lower lip is cleft. Frequently, the cleft extends into the mandibular symphysis and the tongue is attached to the cleft alveolar margin. At times the tongue may be bifid or absent, hyoid absent, thyroid cartilage underdeveloped, strap muscles atrophic, manubrium sterni absent, clavicles widely spaced etc. The earliest report of this anomaly was by Couronne' in 1819. Since then very few cases have been reported in literature with variations. We describe a male child who presented at the age of 6 months with an ectopic salivary gland on the dorsum of the tongue in addition to median cleft of lower lip, ankyloglossia and notching of the mandible. Excision of mass on dorsum of tongue, release of ankyloglossia and lip from the alveolus followed by repair was done. No bony work was done since the mandible was only notched. On post-operative follow-up at 18 months, dentition was delayed in both maxillary as well as mandibular teeth and there was a gap between the lower central incisors. At the age of 2 years 4 months, the dentition is still not complete and the gap between the lower central incisors is very apparent. There is a supernumerary upper central incisor on right side. There is no mobility between the two segments of mandible. Speech is normal. A regular follow-up will be done to study the eruption of permanent central incisors at the age of 7 years and till eruption of all permanent teeth to assess the occlusion and to decide whether any bony work is needed or not

Median cleft of mandible and lower lip with ankyloglossia and ectopic minor salivary gland on tongue

Median cleft of lower lip and mandible is a rare anomaly. This Cleft has also been described as Cleft No. 30 of Tessier's classification. In minor forms only lower lip is cleft. Frequently, the cleft extends into the mandibular symphysis and the tongue is attached to the cleft alveolar margin. At times the tongue may be bifid or absent, hyoid absent, thyroid cartilage underdeveloped, strap muscles atrophic, manubrium sterni absent, clavicles widely spaced etc. The earliest report of this anomaly was by Couronne' in 1819. Since then very few cases have been reported in literature with variations. We describe a male child who presented at the age of 6 months with an ectopic salivary gland on the dorsum of the tongue in addition to median cleft of lower lip, ankyloglossia and notching of the mandible. Excision of mass on dorsum of tongue, release of ankyloglossia and lip from the alveolus followed by repair was done. No bony work was done since the mandible was only notched. On post-operative follow-up at 18 months, dentition was delayed in both maxillary as well as mandibular teeth and there was a gap between the lower central incisors. At the age of 2 years 4 months, the dentition is still not complete and the gap between the lower central incisors is very apparent. There is a supernumerary upper central incisor on right side. There is no mobility between the two segments of mandible. Speech is normal. A regular follow-up will be done to study the eruption of permanent central incisors at the age of 7 years and till eruption of all permanent teeth to assess the occlusion and to decide whether any bony work is needed or not