Fracture through tracking pin sites following a robotic-assisted total knee arthroplasty.

The use of computer-navigated, robotic-assisted total knee arthroplasty (TKA) is expanding as the result of widespread efforts to improve the precision of implant placement and to restore mechanical, anatomic, and kinematic alignment. The procedure requires placement of femoral and tibial pins to mount the robotic tracking system. Fractures through tracking pin sites following robotic-assisted TKA are rare; only 30 cases have been reported to our knowledge. It is probable that this complication will become more frequent as the use of robotic-assisted TKAs continues to grow. We report the case of a 67-year-old female who suffered a fracture of the femur through two pin sites 3 months after a robotic-assisted TKA. We believe that this report is the first case in the radiologic literature. Our case demonstrates some of the difficulties of recognizing this complication and raises questions about appropriate post-operative imaging.

Utility of deep learning super-resolution in the context of osteoarthritis MRI biomarkers.

BACKGROUND: Super-resolution is an emerging method for enhancing MRI resolution; however, its impact on image quality is still unknown. PURPOSE: To evaluate MRI super-resolution using quantitative and qualitative metrics of cartilage morphometry, osteophyte detection, and global image blurring. STUDY TYPE: Retrospective. POPULATION: In all, 176 MRI studies of subjects at varying stages of osteoarthritis. FIELD STRENGTH/SEQUENCE: Original-resolution 3D double-echo steady-state (DESS) and DESS with 3× thicker slices retrospectively enhanced using super-resolution and tricubic interpolation (TCI) at 3T. ASSESSMENT: A quantitative comparison of femoral cartilage morphometry was performed for the original-resolution DESS, the super-resolution, and the TCI scans in 17 subjects. A reader study by three musculoskeletal radiologists assessed cartilage image quality, overall image sharpness, and osteophytes incidence in all three sets of scans. A referenceless blurring metric evaluated blurring in all three image dimensions for the three sets of scans. STATISTICAL TESTS: Mann-Whitney U-tests compared Dice coefficients (DC) of segmentation accuracy for the DESS, super-resolution, and TCI images, along with the image quality readings and blurring metrics. Sensitivity, specificity, and diagnostic odds ratio (DOR) with 95% confidence intervals compared osteophyte detection for the super-resolution and TCI images, with the original-resolution as a reference. RESULTS: DC for the original-resolution (90.2 ± 1.7%) and super-resolution (89.6 ± 2.0%) were significantly higher (P < 0.001) than TCI (86.3 ± 5.6%). Segmentation overlap of super-resolution with the original-resolution (DC = 97.6 ± 0.7%) was significantly higher (P < 0.0001) than TCI overlap (DC = 95.0 ± 1.1%). Cartilage image quality for sharpness and contrast levels, and the through-plane quantitative blur factor for super-resolution images, was significantly (P < 0.001) better than TCI. Super-resolution osteophyte detection sensitivity of 80% (76-82%), specificity of 93% (92-94%), and DOR of 32 (22-46) was significantly higher (P < 0.001) than TCI sensitivity of 73% (69-76%), specificity of 90% (89-91%), and DOR of 17 (13-22). DATA CONCLUSION: Super-resolution appears to consistently outperform naïve interpolation and may improve image quality without biasing quantitative biomarkers. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:768-779.

Hyperechoic Abdominal Fat: A Sentinel Sign of Inflammation.

One of the most useful sonographic signs of acute abdominal inflammation is the identification of increased echogenicity of the surrounding fat. Hyperechoic fat results from vasodilation and edema extending from an adjacent source of infection or inflammation. These changes are mediated by such factors such as bradykinin, histamine, and various cytokines. The recognition of hyperechoic fat on sonography may be an important indicator of the primary source of pathology. In addition, it often reflects a more advanced degree of transmural pathology, such as "walled-off" perforation of a hollow viscus. This pictorial essay will present a variety of examples of hyperechoic inflamed fat involving different abdominal organs and will illustrate the diagnostic value of this finding.

Detail Photophysical Studies of Sulfonated Polyaniline in Aqueous Medium.

Sulfonated polyaniline (SPANI) has emerged as a promising polymer in the past few decades due to its solubility in water and relatively moderate conductivity. However, to date, literature data on the optical characterization of SPANI are very limited and preliminary in nature. In the present work, SPANI is synthesized by direct sulfonation of emeraldine salt form of polyaniline with chlorosulfonic acid in an inert solvent. Detail photophysical properties of SPANI are investigated in aqueous medium by using steady state (concentration, temperature, pH, and excitation wavelength dependence) and time-resolved spectroscopic techniques. The steady state fluorescence emission measurements are carried out carefully to avoid inner filter effect (especially secondary inner filter effect or reabsorption effect) as well as scattering. Two ground state conformations of SPANI are suggested to exist in aqueous medium. Excitation wavelength dependence of the fluorescence emission spectra is attributed to red-edge effect. All these observations are nicely corroborated by the fluorescence lifetime data of SPANI obtained from time-resolved measurements. All these new findings are extremely important in view of the potential applications of SPANI in polymer optoelectronics.

The central nervous system manifestations of localized craniofacial scleroderma: a study of 10 cases and literature review.

BACKGROUND: Localized craniofacial scleroderma is a rare pediatric disease that involves a spectrum of discoloration, fibrosis and hemiatrophy of the face and scalp. Children with localized craniofacial scleroderma may have neurological symptoms, and in this context often undergo diagnostic imaging of the brain. OBJECTIVE: To catalogue neuroimaging abnormalities in patients with localized craniofacial scleroderma treated at our institution, review their clinical courses and compare this data with prior studies. MATERIALS AND METHODS: Following Institutional Review Board approval, an imaging database search identified 10 patients with localized craniofacial scleroderma and neuroimaging abnormalities treated at our institution. Neuroimaging exams and the electronic medical record were reviewed for each case. RESULTS: The most common indications for neuroimaging were headache or seizure (80% of cases). The most common neuroimaging abnormalities were T2-hyperintense, subcortical white matter lesions ipsilateral to the cutaneous lesion (90% of cases) on magnetic resonance imaging (MRI). Calcifications or blood products (50%), cysts (40%) and abnormal enhancement (20%) were also observed. A positron emission tomography (PET) scan obtained for a single case demonstrated diminished 18F-fluorodeoxyglucose (FDG) avidity corresponding to the dominant focus of signal abnormality on MRI. Progressive neuroimaging abnormalities were present in 30% of cases. There was no consistent relationship between changes in neurological symptoms following treatment and neuroimaging findings. CONCLUSION: Our results are similar to previously published data. In the absence of new or worsening neurological symptoms, the role of neuroimaging for follow-up of localized craniofacial scleroderma is unclear. Knowledge of intracranial neuroimaging abnormalities that are commonly associated with localized craniofacial scleroderma helps to distinguish these lesions from others that have similar appearance.

The electronic fine structure of 4-nitrophenyl functionalized single-walled carbon nanotubes.

Controlling the electronic structure of carbon nanotubes (CNTs) is of great importance to various CNT based applications. Herein the electronic fine structure of single-walled carbon nanotube films modified with 4-nitrophenyl groups, produced following reaction with 4-nitrobenzenediazonium tetrafluoroborate, was investigated for the first time. Various techniques such as x-ray and ultra-violet photoelectron spectroscopy, and near edge x-ray absorption fine structure studies were used to explore the electronic structure, and the results were compared with the measured electrical resistances. A reduction in number of the pi electronic states in the valence band consistent with the increased resistance of the functionalized nanotube films was observed.

Poly(ethylene) glycol/single-walled carbon nanotube composites.

Single-walled carbon nanotubes have been shown to exhibit extraordinary electronic and mechanical properties. However, their relative inertness limits their use in many applications. Chemical functionalization can significantly modify their properties which, in addition to improving their processibility, when mixed in polymers can enhance the overall mechanical and electrical properties of the composites. In this work, we present the results of our investigation on the chemical modification of single-walled carbon nanotubes with aryl groups containing nitro substituents, and the incorporation of the modified nanotube material into a host matrix of poly(ethylene) glycol. The carbon nanotubes and composites were characterized by a combination of cyclic voltammetry, thermogravimetric analysis (TGA), Raman spectroscopy, Dynamic Mechanical Analysis (DMA) and electrical resistance (I-V) measurements.

A new route to the production and nanoscale patterning of highly smooth, ultrathin zirconium oxide films.

Metal-stabilized bilayers, prepared by the self-assembly of octadecyltrichorosilane on an oxidized silicon surface followed by the Langmuir-Blodgett deposition of a monolayer of octadecylphosphonic acid, have been used to generate 1.6 nanometer thick, highly uniform, zirconium oxide films following annealing. Patterning of the thin films on the nanometre scale was achieved using nanodisplacement methodology, by careful control of an atomic force microscope (AFM) probe, which allowed the selective removal of the upper leaflet of the bilayer.

Purification and characterization of a potent hemolytic toxin with phospholipase A2 activity from the venom of Indian Russell's viper.

A potent toxin with phospholipase A2 (PLA2) and hemolytic activity in vitro was purified from the Russell's viper venom of eastern India (RVV-EI). The purified protein (RVV-PFIIc') of 15.3 kDa molecular weight, and a lethal toxicity dose (LD50i.p.) of 0.1 mg/kg body weight, was the most toxic PLA2 so far reported from the Indian subcontinent. The material also possessed anticoagulant activity as it enhanced the prothrombin induced plasma clotting time in vitro. The PLA2 toxin (RVV-PFIIc') was shown to be different from other PLA2s of RVV in respect to one or more of these parameters e.g. molecular weight, isoelectric pH, in vivo toxicity, specific activity of the enzyme and certain other biological activities. The first 19 amino terminal sequence (NLFQFAEMIVKMTGKEAVH) of RVV-PFIIc' showed variable degree of homology (42.1-94.7%) with those of other RVV-PLA2s described in the literature. Antisera raised against RVV-EI or RVV-PFIIc', though completely neutralized the in vivo lethal toxicity of RVV-EI or RVV-PFIIc', failed to inhibit their PLA2 activity in vitro thereby suggesting that in vivo toxicity and in vitro activity of the enzyme may not be directly related. Apart from RVV-PFIIc', at least two other PLA2 isozymes were found to be present in RVV-EI that were distinct from RVV-PFIIc' in respect to their molecular, biological as well as serological properties. The significance of these and related data in antivenom therapy is discussed.