Structural anomalies of fluids: Origins in second and higher coordination shells

Compressing or cooling a fluid typically enhances its static interparticle correlations. However, there are notable exceptions. Isothermal compression can reduce the translational order of fluids that exhibit anomalous waterlike trends in their thermodynamic and transport properties, while isochoric cooling (or strengthening of attractive interactions) can have a similar effect on fluids of particles with short-range attractions. Recent simulation studies by Yan [Phys. Rev. E 76, 051201 (2007)] on the former type of system and Krekelberg [J. Chem. Phys. 127, 044502 (2007)] on the latter provide examples where such structural anomalies can be related to specific changes in second and more distant coordination shells of the radial distribution function. Here, we confirm the generality of this microscopic picture through analysis, via molecular simulation and integral equation theory, of coordination shell contributions to the two-body excess entropy for several related model fluids which incorporate different levels of molecular resolution. The results suggest that integral equation theory can be an effective and computationally inexpensive tool for assessing, based on the pair potential alone, whether new model systems are good candidates for exhibiting structural (and hence thermodynamic and transport) anomalies.Chemical Engineerin

Excited states and electron transfer reactions of fullerenes

Since the discovery of carbon clusters in the laser ablated graphite vapours, fullerenes C60 and C70 have provided a constant source of excitement for the experimental and theoretical scientists alike. Their brilliant colours in solutions and three dimensional aromaticity has fascinated the photochemists. Our group has recently characterised singlet and triplet states of fullerenes using complementary twin techniques of laser f~ash ph~tolysis and electron pulse radiolysis. Singlet - singlet (S l→Sn) absorption spectra were studied in picosecond time domain and the rates of intersystem crossing were established. Triplet states were produced directly by photoexcitation in laser flash photolysis experimen~s and by energy transfer in pulse radiolysis. Triplet-triplet (Tl→Tn) spectra were characterised and rate constants for various triplet decay channels were measured. Fullerenes have low reduction potentials and form charge transfer (CT) complexes with good donors like aliphatic and aromatic amines. Exciting photochemical behaviour was observed on photoexcitation of the CT complexes which undergo ultrafast charge separation (CS) and charge recombination {CR) reactions. The dynamics of CS and CR reactions was studied in picosecond time scales in e60-diphenylamine and C60-triphenylamine systems. Using external heavy atom effect and solvent polarity variations, various steps in the CS and CR processes generating fullerene triplet on CR were elucidated. Recent results of complexing fullerenes with suitable hydrophilic cage like γ-cyclodextrin (CD) making C60 water soluble will also be presented. Excited state behaviour of fullerene complex in CD cage would be discussed

A New Hammerstein Model for Non-Linear System Identification

In the present work a newer type of black box nonlinear model in Hammerstein structure is proposed. The model has Wavelet Network coupled with Orthonormal Basis Functions which is capable of modeling a class of non-linear systems with acceptable accuracy. Wavelet basis functions have the property of localization in both the time and frequency domains which enables wavelet networks to approximate severe non-linearities using few number of parameters. Orthonormal Basis functions possess the ability to approximate any linear time invariant system using appropriate basis functions. The efficacy of the model in modeling is demonstrated using numerical examples

Massive Pulmonary Embolism in a Recent Intracranial Hemorrhage: Case Report of Inhaled Nitric Oxide to Improve Outcomes

Acute massive pulmonary embolism (PE) has a high mortality if left untreated. The mainstay of treatment is systemic thrombolysis which has some absolute contraindications like intracranial hemorrhage (ICH). Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator that decreases pulmonary artery pressure (PAP) and allows the right ventricle of the heart to pump against less resistance. We present a case of iNO use to improve hemodynamics in a patient with a recent ICH. We believe this to be the first such case reported. A 70-year-old female with a history of PE on Eliquis initially presented for weakness and was found to have right-sided ICH. She was discharged with instructions to hold Eliquis given ICH but was readmitted eight days later in florid cardiogenic shock requiring vasopressors and hypoxic respiratory failure refractory to intubation. CT showed bilateral PE with evidence of right heart strain and IV heparin was started. Due to her history of a recent ICH, she had an absolute contraindication prohibiting the use of systemic tissue plasminogen activator (tPA). Interventional radiology (IR) consult determined that the patient was not a candidate for catheter-directed tPA due to the recent ICH, mechanical ventilation, and hemodynamic instability based on pressor requirement. Vascular surgery and extracorporeal membrane oxygenation (ECMO) consults deemed the patient not operable. The patient was then started on iNO with immediate improvement in her blood pressure. Once vitally stable, IR consult performed pulmonary angiogram and completed a thrombectomy. The patient was eventually extubated and she restarted her Eliquis. She continues to do well 16 months after discharge. In patients with massive PE with contraindications to systemic thrombolytics, providers are left with very few therapeutic interventions. A handful of case reports show that iNO improves systemic hemodynamics in postoperative patients with massive PE. This case highlights the potential for iNO to be a potential adjuvant in patients with absolute contraindications to systemic thrombolysis

Urologic manifestations of inflammatory pseudotumor: Report of 2 cases and review of the literature.

We report two adult patients with varied urologic symptoms who were found to have inflammatory pseudotumor on histopathology. The first patient had a large, solid, enhancing retroperitoneal mass lesion and presented with increased frequency of urination and recurrent urinary tract infections. The second patient had an obstructing left distal ureteric stricture and presented with painless hematuria. Though preoperative radiological diagnosis of this entity is not feasible, the present article illustrates the imaging findings in this unusual disease entity with review of the relevant literature

Role of shear layer instability in the transition of boundary layer on a bluff body

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