Emission Spectra of Isomeric Trifluorotoluidines

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Solid crystalline polymorphism in M-21

This paper reports on the different solid crystalline (SC) forms of 4-cyano-4'-heptyloxy biphenyl (M-21) as revealed through differential scanning calorimetric, polarizing microscopic and infrared spectroscopic investigations. There are three solid crystalline modifications, namely SCI,SCII,SCIII. The appearance and preponderance of the SC forms depend critically on the manner in which the liquid crystalline melt solidifies. Each SC phase has its CN stretching band split into two components because of Davydov or correlation splitting. The position, separation and relative intensities of the two components characterize each SC phase. The systematic study of the variations in these three features with temperature leads to interesting information about the intermolecular ordering forces and the spatial arrangement of the molecules in the unit cell. It is shown that the intermolecular interactions of the dipolar nature play a dominant role in the SC phases but contribute negligibly in stabilizing the nematic phase. The angle between the correlated molecules in the unit cell changes in the order SCI> SCII > SCIII > nematic = 0, resulting in parallel arrangement of molecules in the nematic phase

Irreversible pulpitis - A source of antibiotic over-prescription?

Antibiotic resistance is a growing public health concern. Antibiotics continue to be prescribed by some clinicians to resolve dental pain even though research indicates that antibiotics are not effective for treating conditions such as irreversible pulpitis. The objective of this study was to determine the extent to which current research and evidence around irreversible pulpitis has been translated into dental practice and the gaps in dentists’ knowledge. An on-line clinical vignette format survey questionnaire about treatment of irreversible pulpitis was distributed to the members of the Academy of Operative Dentistry and Academy of General Dentistry (US based international dental bodies). Their responses were recorded and evaluated. A total of 403 dentists participated in the survey. Over a third (39.3%) indicated they would prescribe antibiotics for symptomatic irreversible pulpitis in a permanent tooth occurring without any signs of systemic infection. The rest indicated they would not prescribe antibiotics; most of them would prescribe an analgesic combined with pulpectomy. Those who had undertaken advanced education training achieved a significantly higher mean knowledge score compared to those with just a primary dental degree (p=0.011). Similarly, full or part time academicians had a higher mean knowledge score than the clinicians who work only in private practice (p=0.014). Some dentists continue to prescribe antibiotics inappropriately for alleviating pain due to irreversible pulpitis. Antibiotic prescribing practices of dentists with advanced education or academic engagement were better as compared to the other participants. There is clear evidence of antibiotic over-prescribing for irreversible pulpitis which needs to be addressed urgently

Outcomes in randomised controlled trials in prevention and management of carious lesions:a systematic review

Abstract Background Inconsistent outcome reporting is one significant hurdle to combining results from trials into systematic reviews. Core outcome sets (COS) can reduce this barrier. The aim of this review was to map outcomes reported in caries prevention and management randomised controlled trials (RCT) as a first step to COS development. We also investigated RCT characteristics and reporting of primary outcomes and sample size calculations. Methods PubMed, Embase, Web of Knowledge and Cochrane CENTRAL were systematically searched (1 January 1968 to 25 August 2015). Inclusion criteria: RCTs comparing any technique for prevention or management of caries with another or placebo and RCTs comparing interventions to support patients undergoing treatment of caries (without setting, dentition or age restrictions). Categories were developed through piloting and group consensus and outcomes grouped accordingly. Results Of 4773 search results, 764 were potentially relevant, full text was available for 731 papers and 605 publications met the inclusion criteria and were included. For all outcomes across the time periods 1968–1980 and 2001–2010, reporting of outcome ‘caries experience’ reduced from 39% to 18%; ‘clinical performance of the restoration’ reporting increased from 33% to 42% although there was a reduction to 22% in 2011–2015. Emerging outcome domains include ‘lesion activity’ and ‘pulp health-related outcomes’, accounting for 1% and 0%, respectively, during 1968–1980 and 10% and 4% for 2011–2015. Reporting ‘resource efficiency’ and ‘quality of life measures’ have remained at a low level. No publications reported tooth survival independent of an index such as DMFT or equivalent. Primary outcomes were only identified as such in 414 (68%) of the reports. Conclusions Over the past 50 years, outcome reporting for trials on prevention and management of carious lesions have tended to focus on outcomes measuring caries experience and restoration material clinical performance with lesion activity and cost-effectiveness increasingly being reported. Patient-reported and patient-focused outcomes are becoming more common (although as secondary outcomes) but remain low in use. The challenge with developing a COS will be balancing commonly previously reported outcomes against those more relevant for the future. Trial registration PROSPERO, CRD42015025310 . Registered on 14 August 2015, Trials (Schwendicke et al., Trials 16:397, 2015) and COMET initiative online (COMET, 2017)

Sol-gel technology in electrochromic devices

313-317<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Last two decades have witnessed renewed interest in the area of electrochromic devices (ECDs) for large area applications and also considerable advances in processing materials. Technology like sol-gel has gained a clear-cut edge over the others. The present ECD technology too seems to have taken over by the sol-gel processing. Sol-gel technology offers preparation of all components of an ECD, opening a possibility of realizing "An All Gel ECD". In sol-gel processing, precursor materials prepared by different routes have been used to deposit films either by dip or spin coating method. The present paper reviews various precursor materials and the involved sol-gel processes for preparing films of materials those can be useful for ECD fabrication.</span

Electrochromic devices: Present and forthcoming technology

320-334<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">During last two decades electrochromism in various materials has been investigated very widely. Devices based on electrochromic phenomenon have been found to be useful for a wide range of applications. Electrochromic device (ECD) technology has expanded from its only application of display devices in its early stage to various other applications including in automobile and building industries. An ECD has undergone drastic changes in its different parts and in methods of fabricating them, although the basic structure has remained the same. In particular, significant advancements in the ion conductors -the electrolytes used in ECDs have led to realization of a laminated ECD-an emerging technology of today. This review article discusses general concepts of the phenomenon of electrochromism, the most common electrochromic materials and basic configurational and operational aspects of an ECD with special emphasis to the developmental steps of the electrolytes used in them. The efforts towards commercial development of ECDs for various applications along with a brief analysis of some of the opportunities and challenges faced for successful exploitation of the ECD technology are also presented.</span

Effect of nano gamma-Al2O3 addition on ion dynamics in polymer electrolytes

Polymer electrolytes, which hold the key of successful operation of all solid state ionic devices, have been investigated. An amorphous polymer was used to facsimile fast ion transport in the gel polymer electrolytes (GPE) and room temperature conductivity >10−3 S/cm can be attained. Further, these electrolytes were transformed into composites by dispersing inorganic particles of γ-Al2O3 (11 nm in size) in varying wt.%. An enhancement in the conductivity for an optimum concentration using LiClO4 as a salt can be obtained and is described in terms of free charge carrier concentration, while the other family of Lithium salts viz. LiTf, LiIm, LiBETI decreases the conductivity marginally. FTIR spectroscopy supports the observed decrease in terms of more association between fillers and salts. It has been realized that the mechanical integrity of these composites increases manifold, without affecting the conductivity, significantly

Reassignment of Some Phenyl Vibrations in Benzotrifluoride

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A novel approach for synthesizing composite polymer electrolytes with a stereocomplex poly (methylmethacrylate) for electrochromic devices

A novel approach has been adopted for synthesizing composite polymer electrolytes with a blend of atactic poly ( methyl methacrylate) (a-PMMA) and isotactic PMMA (i-PMMA) owing to their ability to form stereocomplex structures, especially double helix like structures. Nanocomposite polymeric electrolytes based on gel polymeric electrolyte (GPE) consisting of stereocomplex PMMA, propylene carbonate ( PC) and LiClO4 has been synthesized. For the stabilization of polymer electrolytes and for good processability, fumed silica nanoparticles have been added in different proportions up to 6 wt% to GPE resulting in composite polymeric electrolytes (CPEs). Thermally stable, low volatile CPEs without the cost on electrochemical stability can thus be obtained, being promising candidates as polymeric electrolytes in many electrochemical devices in general, and in particular electrochromic windows

Effect of citric acid on properties of CeO2 films for electrochromic windows

An alcohol based sol-gel process involving cerium chloride heptahydrate and citric acid in different mole ratios has been employed for the deposition of CeO2 films. The structural, electrochemical, and optical properties of the films have been investigated using a wide range of techniques. Differential thermal analysis has shown the onset of crystallization of CeO2 at 389 degrees C. The addition of an additive (citric acid) to the precursor Sol has led to homogeneity and also a reduced ion storage capacity in the films. This observation emphasizes on the use of optimum content of the citric acid such that the films are suitable in terms of transparency as well as uniformity characteristics and also exhibit good electrochemical response. As is evidenced by the SEM study, the degree of polycrystalline grain formation in the citric acid derived films is observed to be less. The XPS results have confirmed the presence of Ce4+ State in the films. The optically passive behavior of the films is affirmed by their negligible transmission modulation upon Li ion insertion and extraction. A higher proportion of citric acid has also resulted in a reduced porosity and diminished crystallite size of the cerianite phase. The effect of the CeO2 films on the switching kinetics of the tungsten oxide (WO3) films has revealed an increase in the coloration time of the latter with the diminished crystallite size of CeO2 nanograins in the former