Mononitration of durene

Reaction conditions under which the nitration of durene give predominantly, and in high yield, mononitrodurene (I), rather than dinitrodurene were found. The nitrating agent was No2+RF6-. Nitration with nitrosulfuric acid also gave mononitrodurene; however, byproducts such as 2.3.5.6-Me4C6HCH2C6H2Me3-2,4,5, were also formed. The NO2 PF6- gave an intermediate additional compound with durene. The reaction carried out with 3.6-dideuterodurene in D2O shows no isotope effect

Collodial particles at a range of fluid-fluid particles

The study of solid particles residing at fluid-fluid interfaces has become an established area in surface and colloid science recently experiencing a renaissance since around 2000. Particles at interfaces arise in many industrial products and processes like anti-foam formulations, crude oil emulsions, aerated foodstuffs and flotation. Although they act in many ways like traditional surfactant molecules, they offer distinct advantages also and the area is now multi-disciplinary involving research in the fundamental science and potential applications. In this Feature Article, a flavour of some of this interest is given based on recent work from our own group and includes the behaviour of particles at oil-water, air-water, oil-oil, air-oil and water-water interfaces. The materials capable of being prepared by assembling various kinds of particles at fluid interfaces include particle-stabilised emulsions, particle-stabilised aqueous and oil foams, dry liquids, liquid marbles and powdered emulsions

Laser performance of perylenebis (dicarboximide) dyes with long secondary alkyl chains

The laser performance and related photophysical properties of two very soluble perylene dyes with long chain secondary alkyl groups were investigated in cyclohexane solution. With a dye laser as pump source a tuning range of 555–580 nm was obtained at an optimum concentration of 3×10–4 M. The quantum efficiencies (=0.29 and 0.21) were better than 1/2 that of rhodamine 6G. No photodegradation was observed over an excitation period of several hours

Immunoglobulin Allotypes and Immune Response to Meningococcal Group B Polysaccharide

Serum samples were collected from 120 healthy adult volunteers (105 Caucasians and 15 Negros) before and after immunization with meningococcal polysaccharide (MPS) group B vaccine. Antibodies to MPS group B were measured and sera were typed for several Gm and Km(l) allotypes. A significant association was found between the Km(l) allotype and immune response to MPS group B in Caucasians

Analyzing the Effectiveness of Remote Laboratories at WPI During the Coronavirus Pandemic

Our project explored how this pandemic has impacted laboratory classes at WPI. We aimed to understand and analyze student perceptions and faculty experiences of online labs. We grouped the classes into chemistry, physics, and engineering and investigated the ability to learn material, teamwork, focus, and motivation. Chemistry classes had a relatively positive response to these variables, specifically in learning material and teamwork. Physics classes also had a relatively positive response to all variables, specifically in learning material and focus. Engineering classes had a negative response to every variable. Our recommendation for WPI, if they use a phased reopening, would be to give preference to students in higher level classes to have opportunities for in-person labs

Trends in Depressed Mood and Suicidal Behaviors Among Female High School Students Who Engaged in Physical Fighting

The objective of this article is to identify prevalence changes in depressed mood/suicidal behaviors among female high school students reporting physical fighting. This research analyzed the national combined data set of the Youth Risk Behavior Surveillance (YRBS) cross-sectional surveys from 2001 to 2015. Logistic regression analyzed the time trends. Two multiple logistic regression models were built. A quadratic trend was present with an initial decrease followed by an increase 2009 to 2015 (p < .001). The odds and severity of depressed mood/suicidal behaviors were greater among female youths with four or more fights and for other violent events, which were even greater when accounting for electronic bullying. The odds of depressed mood/suicidal behaviors among female adolescents engaged in physical fighting has been increasing with electronic bullying contributing to polyvictimization

Color changes upon cooling of Lepidoptera scales containing photonic nanoarchitectures, and a method for identifying the changes

The effects produced by the condensation of water vapor from the environment in the various intricate nanoarchitectures occurring in the wing scales of several Lepidoptera species were investigated by controlled cooling (from 23° C, room temperature to -5 to -10° C) combined with in situ measurements of changes in the reflectance spectra. It was determined that all photonic nanoarchitectures giving a reflectance maximum in the visible range and having an open nanostructure exhibited alteration of the position of the reflectance maximum associated with the photonic nanoarchitectures. The photonic nanoarchitectures with a closed structure exhibited little to no alteration in color. Similarly, control specimens colored by pigments did not exhibit a color change under the same conditions. Hence, this method can be used to identify species with open photonic nanoarchitectures in their scales. For certain species, an almost complete disappearance of the reflectance maximum was found. All specimens recovered their original colors following warming and drying. Cooling experiments using thin copper wires demonstrated that color alterations could be limited to a width of a millimeter or less. Dried museum specimens did not exhibit color changes when cooled in the absence of a heat sink due to the low heat capacity of the wings

Molecular Design Parameters of Anthraquinone Dyes for Guest-Host Liquid-Crystal Applications : Experimental and Computational Studies of Spectroscopy, Structure and Stability

A set of five anthraquinone dyes with bis(4-propylphenyl) substituent groups, connected via sulfide or amine linkages at the 1,5-positions or directly at the 2,6-positions, have been studied in solution by UV-vis spectroscopy and electrochemistry, allied with density functional theory calculations of structures, electronic transitions, and redox potentials. The visible transitions and redox potentials are shown to vary with the HOMO and LUMO energies, with the variation in both color and redox stability between the dyes being attributable principally to variations in the HOMOs located mainly on the substituents and outer anthraquinone rings. The calculated molecular structures and visible transition dipole moments are shown to vary subtly with substituent, giving variations in the molecular aspect ratios, minimum moment of inertia axes, and transition dipole moment vector orientations that can rationalize the alignment trends reported in the literature for such anthraquinone dyes in liquid crystal hosts, showing why 1,5-disulfide and 2,6-diphenyl substituents give better designs than 1,5-diamine substituents. The computational approaches reported here are shown to give good matches with experimental trends, indicating that they may be used more generally to aid the rational molecular design of dyes for applications as guests in liquid crystal hosts

Renal Disease in Essential Mixed Cryoglobulinaemia: LONG-TERM FOLLOW-UP OF 44 PATIENTS

The mode of presentation of renal disease in 44 patients with essential mixed cryoglobulinaemia (EMC) was: acute renal failure (two patients), acute nephritic syndrome (six patients), nephrotic syndrome (eight patients), proteinuria and/or haematuria (28 patients). Renal biopsy, performed in 35 patients, showed proliferative lesions in 33, while only minimal glomerular changes were seen in the remaining two. Immunofluorescence studies showed: IgG (85 per cent), IgA (36 per cent), IgM (90 per cent), C3 (90 per cent), Clq (47 per cent), and C4 (33 per cent) deposits, mainly located in subendothelial position. On electron microscopy, crystalloid structure of deposits and monocyte infiltration of capillary loops were the outstanding feature. The survival rate was 75 per cent at 10 years from the onset of clinical symptoms. Thirty-nine patients were followed for three to 146 months (mean 53·8). Twelve patients died, cardiovascular disease and infection being the commonest cause of death. Thirteen patients showed acute renal failure or acute nephritic syndrome: nine recovered completely, whereas the remaining four died during the acute renal episode. Three patients developed chronic renal failure, but only one required chronic dialysis. The ominous significance of renal impairment in EMC should therefore be revaluated. The high prevalence of hypertension (28/44 patients) which was refractory to treatment in six, may be important to the clinical outcom