Reinjury Following Return to Play.

Radiologists are frequently called on for guidance regarding return to play (RTP) for athletes and active individuals after sustaining a musculoskeletal injury. Avoidance of reinjury is of particular importance throughout the rehabilitative process and following resumption of competitive activity. Understanding reinjury risk estimation, imaging patterns, and correlation of clinical and surgical findings will help prepare the radiologist to identify reinjuries correctly on diagnostic imaging studies and optimize management for a safe RTP.

Multifocal emphysematous osteomyelitis, a do not miss diagnosis for the emergency radiologist: a case report with literature review.

Emphysematous osteomyelitis (EO) is an uncommon fatal condition with high morbidity and mortality. Simultaneous involvement of the axial and appendicular skeleton with multifocal disease is even rarer, with only a few cases being reported in the literature. We present a case of multifocal emphysematous osteomyelitis in a 56-year-old woman with concurrent emphysematous pyelonephritis complicated by psoas and epidural abscesses. The causative organism in our patient was Escherichia coli. Emergency radiologists should be aware of this condition and differentiate it from other benign entities that can present with intraosseous gas. Prompt diagnosis is important given the high morbidity and mortality with this condition. This case report emphasizes the specific pattern of intraosseous gas seen with EO, which can help diagnose EO with confidence.

Metal-free trifunctionalization of phenylacetylenes: an efficient one-pot two-step synthesis of gem-bis(dithiocarbamates).

The synthesis of phenacyl-bis(dithiocarbamates) has been reported by metal-free trifunctionalization of phenylacetylene systems by following a one-pot two-step strategy. Phenyl acetylene undergoes molecular bromine-mediated oxidative bromination followed by nucleophilic substitution with the freshly prepared dithiocarbamate salt which is prepared by the prompt reaction of amine and CS2 in the presence of triethylamine base. A series of gem-bis(dithiocarbamates) are prepared using various secondary amines and phenylacetylene systems containing different substituents.

Role of Shear-Wave Elastography in Achilles Tendon in Psoriatic Arthritis and Its Correlation with Disease Severity Score, Psoriasis Area and Severity Index.

Purpose The aim of this study was to compare accuracy of shear-wave elastography (SWE) with gray scale (GS) ultrasound and power Doppler (pD) for diagnosing Achilles tendinopathy in psoriatic patients with and without arthritis and correlation with achillodynia and disease severity score, psoriasis area and severity index (PASI). Methods A total of 100 Achilles tendons were evaluated where 56% were cases of psoriatic arthritis with achillodynia; 44% were controls of psoriasis without arthritis in this prospective study. Evaluation was done with GS, pD, SWE at proximal, mid, and distal third of the tendon. Qualitative (color maps) and quantitative data, elastic modulus, kilopascal (kPa), were generated. Pearson's correlation was done to see association between kPa, PASI and clinical symptoms, achillodynia, scored using visual analog scale (VAS). Results Significant negative correlation was seen between duration of arthritis, VAS and PASI with SWE values with r = -0.34, -0.47, and -0.41, respectively. SWE could identify abnormal tendons in 71/100 (71%) in the overall study, 53/56 (94.6%) in cases, and 18/44 (40.9%) in control. The statistical significance was set at p ≤ 0.05. In comparison, conventional ultrasound, GS, and pD together could identify 13/56 (23.21%) in cases and no abnormal tendon was identified in the control group. Conclusion SWE is a reliable, noninvasive, and valuable tool to detect early tendinopathy and monitor progression of disease.

Catalytic Enantioselective Radical Transformations Enabled by Visible Light.

Visible light has been recognized as an economical and environmentally benign source of energy that enables chemoselective molecular activation of chemical reactions and hence reveal a new horizon for the design and discovery of novel chemical transformations. On the other hand, asymmetric catalysis represents an economic method to satisfy the increasing need for enantioenriched compounds in the chemical and pharmaceutical industries. Therefore, combining visible light photocatalysis with asymmetric catalysis creates a wider range of opportunities for the development of mechanistically unique reaction schemes. However, there arise two main problems like undesirable photochemical background reactions and difficulties in controlling the stereochemistry with highly reactive photochemical intermediates which can pose a serious challenge to the development of asymmetric visible light photocatalysis. In recent years, several methods have been developed to overcome these challenges. This review summarizes the recent advances in visible light-induced enantioselective reactions. We divide our discussion into four categories: Asymmetric photoredox organocatalysis, asymmetric transition metal photoredox catalysis, asymmetric photoredox Lewis acid catalysis and asymmetric photoinduced energy transfer catalysis. Special emphasis has been given to different catalytic activation modes that enable the construction of challenging carbon-carbon and carbon-heteroatom bond in an enantioselective fashion. A brief analysis of substrate scope and limitation as well as reaction mechanism of these reactions has been included.

Analysis of Antichiral Thermomechanical Metamaterials with Continuous Negative Thermal Expansion Properties.

Negative thermal expansion is an interesting and appealing phenomenon for various scientific and engineering applications, while rarely occurring in natural materials. Here, using a universal antichiral metamaterial model with bimetal beams or strips, a generic theory has been developed to predict magnitude of the negative thermal expansion effect from model parameters. Thermal expansivity of the metamaterial is written as an explicit function of temperature and only three design parameters: relative node size, chirality angle, and a bimetal constant. Experimental measurements follow theoretical predictions well, where thermal expansivity in the range of negative 0.0006-0.0041 °C-1 has been seen.

Synthesis of Phenolic Compounds via Palladium Catalyzed C-H Functionalization of Arenes.

Phenol and its derivatives are extremely useful compounds in organic synthesis, medicinal chemistry and material sciences. The synthesis of phenols involving selective construction of the C-O bond at a C-H bond of arenes using transition-metal catalysis represents the most appealing strategy. Indeed, active research is currently going on for the synthesis of valuable phenolic compounds using a transition-metal-catalyzed C-H functionalization strategy. This short review summarizes recent advances on palladium-catalyzed C-O bond forming reactions that enable direct access to phenolic compounds. These catalytic reactions proceed either via C-H esterification with trifluoroacetic acid/trifluoroacetic anhydride followed by in situ hydrolysis of the ester or via direct C-H hydroxylation. A brief analysis of substrate scope and limitation, reaction mechanism as well as synthetic utility of these reactions has been included.

Intrinsic noise induced coherence resonance in a glow discharge plasma.

Experimental evidence of intrinsic noise induced coherence resonance in a glow discharge plasma is being reported. Initially the system is started at a discharge voltage (DV) where it exhibited fixed point dynamics, and then with the subsequent increase in the DV spikes were excited which were few in number and with further increase of DV the number of spikes as well as their regularity increased. The regularity in the interspike interval of the spikes is estimated using normalized variance. Coherence resonance was determined using normalized variance curve and also corroborated by Hurst exponent and power spectrum plots. We show that the regularity of the excitable spikes in the floating potential fluctuation increases with the increase in the DV, up to a particular value of DV. Using a Wiener filter, we separated the noise component which was observed to increase with DV and hence conjectured that noise can play an important role in the generation of the coherence resonance. From an anharmonic oscillator equation describing ion acoustic oscillations, we have been able to obtain a FitzHugh-Nagumo like model which has been used to understand the excitable dynamics of glow discharge plasma in the presence of noise. The numerical results agree quite well with the experimental results.