Predictive coupled-cluster isomer orderings for some Sin{}_nCm{}_m (m,n≤12m, n\le 12) clusters; A pragmatic comparison between DFT and complete basis limit coupled-cluster benchmarks

The accurate determination of the preferred ${\rm Si}_{12}{\rm C}_{12}$ isomer is important to guide experimental efforts directed towards synthesizing SiC nano-wires and related polymer structures which are anticipated to be highly efficient exciton materials for opto-electronic devices. In order to definitively identify preferred isomeric structures for silicon carbon nano-clusters, highly accurate geometries, energies and harmonic zero point energies have been computed using coupled-cluster theory with systematic extrapolation to the complete basis limit for set of silicon carbon clusters ranging in size from SiC$_3$ to ${\rm Si}_{12}{\rm C}_{12}$. It is found that post-MBPT(2) correlation energy plays a significant role in obtaining converged relative isomer energies, suggesting that predictions using low rung density functional methods will not have adequate accuracy. Utilizing the best composite coupled-cluster energy that is still computationally feasible, entailing a 3-4 SCF and CCSD extrapolation with triple-$\zeta$ (T) correlation, the {\it closo} ${\rm Si}_{12}{\rm C}_{12}$ isomer is identified to be the preferred isomer in support of previous calculations [J. Chem. Phys. 2015, 142, 034303]. Additionally we have investigated more pragmatic approaches to obtaining accurate silicon carbide isomer energies, including the use of frozen natural orbital coupled-cluster theory and several rungs of standard and double-hybrid density functional theory. Frozen natural orbitals as a way to compute post MBPT(2) correlation energy is found to be an excellent balance between efficiency and accuracy

Valence and Charge-transfer Optical Properties for Some Si\u3csub\u3en\u3c/sub\u3eC\u3csub\u3em\u3c/sub\u3e (m, n ≤ 12) Clusters: Comparing TD-DFT, Complete-basis-limit EOMCC, and Benchmarks from Spectroscopy

Accurate optical characterization of the closo-Si12C12 molecule is important to guide experimental efforts toward the synthesis of nano-wires, cyclic nano-arrays, and related array structures, which are anticipated to be robust and efficient exciton materials for opto-electronic devices. Working toward calibrated methods for the description of closo-Si12C12 oligomers, various electronic structure approaches are evaluated for their ability to reproduce measured optical transitions of the SiC2, Si2Cn (n = 1–3), and Si3Cn (n = 1, 2) clusters reported earlier by Steglich and Maier [Astrophys. J. 801, 119 (2015)]. Complete-basis-limit equation-of-motion coupled-cluster (EOMCC) results are presented and a comparison is made between perturbative and renormalized non-iterative triples corrections. The effect of adding a renormalized correction for quadruples is also tested. Benchmark test sets derived from both measurement and high-level EOMCC calculations are then used to evaluate the performance of a variety of density functionals within the time-dependent density functional theory (TD-DFT) framework. The best-performing functionals are subsequently applied to predict valence TD-DFT excitation energies for the lowest-energy isomers of SinC and Sin−1C7−n (n = 4–6). TD-DFT approaches are then applied to the SinCn (n = 4–12) clusters and unique spectroscopic signatures of closo-Si12C12 are discussed. Finally, various long-range corrected density functionals, including those from the CAM-QTP family, are applied to a charge-transfer excitation in a cyclic (Si4C4)4 oligomer. Approaches for gauging the extent of charge-transfer character are also tested and EOMCC results are used to benchmark functionals and make recommendations

Use of single- and multi-drug regimens in the management of classic (idiopathic) trigeminal neuralgia: an 11-year experience at a single Sri Lankan institution

Aim: The aim of this retrospective study was to evaluate the outcome of medical treatment of classic trigeminal neuralgia and to assess the factors affecting the choice of drug regimen (single or multiple), and the duration of treatment for pain control.\ud \ud Methods: A total of 260 consecutive patients were included in the study. Sixty-one patients with less than 6 months' follow up were excluded. All patients were treated with carbamazepine alone or in combination with other drugs. The dosage was adjusted according to the level of pain control and side-effects.\ud \ud Results: Treatment was terminated in 99 patients (49.7%) after a mean follow-up period of 36.46 months (standard deviation: ±26.5). Of these, 39.4% were on a single drug. Carbamazepine was the drug used in 36 patients. The rest (61%) needed various combinations of drugs. One-hundred patients (50.3%) continued with medical treatment during the follow-up period. Of these, 67.4% were on multi-drug therapy.\ud \ud Conclusion: The present study showed that the administration of multidrug regimens is a useful alternative in controlling trigeminal neuralgia in patients who are unable to tolerate higher doses of carbamazepine. Age, sex, ethnicity, and the side of affliction did not have a significant influence on the choice of drug regimen and the duration of treatment for pain control

A review of the intelligent product across the product lifecycle

The notion of the intelligent product and its implications over the product lifecycle has gathered much interest over the years with increasing numbers of research projects. In this paper we revisit the intelligent product and review research that followed the intelligent product blueprint. We found that most research focused on specific parts of the lifecycle and most developments provided autonomy to the product in terms of environment sensing and guidance in decision making, halting autonomy at the actuation of decisions and operations. The decision making requirement proved to be the most challenging with two distinct paradigms being followed: centralised decision support systems and distributed multi-agent systems. Future directions we contemplate include the development of intelligent products that can embrace the whole lifecycle and autonomous decision making through the product's agent based software representation

Juvenile recurrent parotitis: clinical, sialographic and ultrasonographic features

Objective. Juvenile recurrent parotitis (JRP) is a rare salivary gland disease of obscure aetiology that affects children. The aim of this study was to investigate the patterns of clinical presentation, and the sialographic and ultrasonographic features of JRP in Sri Lankan children.\ud \ud Methods. The authors analysed the hospital records of 26 subjects who had been diagnosed with JRP between January 2003 and April 2006.\ud \ud Results. The subjects consisted of 15 males and 11 females (male:female ratio = 1.4:1). The age range of the sample was 2.5–16 years (mean = 8.4 years). The age of onset was biphasic, with two major peaks at 6 years (n = 6) and 10 years (n = 5) (mean = 6.73 years). Unilateral involvement was seen in 69.2% of patients. The commonest clinical features were swelling (100%), pain (80.8%) and fever (50.0%). The average frequency of recurrences of JRP in 18 patients was 7.1 times per year. The average duration of an individual episode, also in 18 patients, was 5.44 days. Sialography in 17 patients had revealed punctate sialectasis, whereas ultrasonography in 16 patients had demonstrated multiple hypoechoic areas and heterogeneous echoes\ud \ud Conclusions. This study documents the clinical features of JRP in Sri Lankan children. It has established the usefulness of sialography and ultrasonography in the diagnosis of JRP

Oral mucosal changes in iron deficiency anemia in a Sri Lankan female population

The oral mucosal changes in iron deficiency anemia were studied in a selected hospital population. A high incidence of oral lesions was present in the anemic group as compared to age- and sex-matched controls. Atrophic changes of the tongue were quite characteristic clinically, and a significant reduction in the mean epithelial thickness of the buccal mucosa was determined histologically

Conservative management of oral submucous fibrosis

Objective: To assess the effectiveness of intralesional injection of methylprednisolone and habit control in the management of oral submucous fibrosis.\ud \ud Patients and Methods: The study included 43 patients who attended the Department of Oral Medicine and Periodontology, University of Peradeniya, Peradeniya, Sri Lanka, from January 2001 to December 2003. The patients were divided into 3 groups according to maximum mouth opening of ≥20 mm (group A), maximum mouth opening from 11 to 19 mm (group B), and maximum mouth opening of ≤10 mm (group C). Bilateral submucosal injection of methylprednisolone 20 mg/0.5 mL was given to predetermined areas of the buccal mucosa once a month for 5 consecutive months. Maximum unaided mouth opening was measured using the same measuring device after each injection. All patients were informed about the causal relationship of their betel chewing habit to oral submucous fibrosis and the risks if they continued to chew betel. They were instructed to stop betel chewing, smoking, and drinking alcohol.\ud \ud Results: After 6 months of follow-up, 37 patients (86.0%) showed significant improvement (z = −5.283; p < 0.05) in mouth opening. Thirty three of 38 patients (86.8%) in group A showed improvement at 6 months' follow-up (z = −5.003; p < 0.05). Although 3 of 4 patients in group B experienced an improvement after 6 months, the difference was not statistically significant.\ud \ud Conclusion: The results strongly suggest that intralesional injection of methylprednisolone to the buccal mucosa for treatment of oral submucous fibrosis significantly improves mouth opening