Pediatric chest wall masses: spectrum of benign findings on ultrasound.

A palpable finding along the chest wall is a frequent indication for pediatric US. Accurate identification of benign lesions can reassure families and appropriately triage children who need follow-up, cross-sectional imaging, or biopsy. In this pictorial essay, we review chest wall anatomy, illustrate US techniques and discuss key US imaging features of common benign lesions and normal variants.

Chiral Heterobimetallic Bismuth-Rhodium Paddlewheel Catalysts: A Conceptually New Approach to Asymmetric Cyclopropanation.

Cyclopropanation reactions of styrene derivatives with donor-acceptor carbenes formed in situ are significantly more enantioselective when catalyzed by the heterobimetallic bismuth-rhodium complex 5 a endowed with N-phthalimido tert-leucine paddlewheel ligands rather than by its homobimetallic dirhodium analogue 1 a. This virtue is likely the result of two synergizing factors: the conical shape of 5 a translates into a narrower calyx-like chiral binding site about the catalytically active Rh center; the Bi atom, although fully solvent exposed, does not decompose aryl diazoacetates and is hence incapable of promoting a racemic background reaction. Moreover, ligand variation proved that successful catalyst design mandates that the anisotropy of the conical heterobimetallic core be matched by proper directionality of the ligand sphere.

Enhanced Electrophilicity of Heterobimetallic Bi-Rh Paddlewheel Carbene Complexes: A Combined Experimental, Spectroscopic, and Computational Study.

Dirhodium paddlewheel complexes are indispensable tools in modern organometallic catalysis for the controlled decomposition of diazo-compounds. Tuning the reactivity of the thus-formed transient carbenes remains an active and dynamic field of research. Herein, we present our findings that the distal metal center plays an as yet underappreciated role in modulating this reactivity. Replacement of one rhodium atom in the bimetallic core for bismuth results in the formation of a significantly more electrophilic carbene complex. Bismuth-rhodium catalysts thereby facilitate previously unknown modes of reactivity for α-diazoester compounds, including the cyclopropanation of alkenes as electron deficient as trichloroethylene. While dirhodium paddlewheel complexes remain the catalysts of choice for many carbene-mediated transformations, their bismuth-rhodium analogues exhibit complementary reactivity and show great potential for small molecule and solvent activation chemistry. DFT calculations highlight the importance of metal-metal bonding interactions in controlling carbene electrophilicity. The paucity of these interactions between the 4d orbitals of rhodium and the 6p orbitals of bismuth results in weaker π-back-bonding interactions for bismuth-rhodium carbene complexes compared to dirhodium carbene complexes. This leads to weakening of the rhodium-carbene bond and to a more carbene-centered LUMO, accounting for the observed enhancement in bismuth-rhodium carbene electrophilicity. These findings are supported by a detailed spectroscopic study of the "donor-donor" carbene complexes Rh2(esp)2C( p-MeOPh)2 (19) and BiRh(esp)2C( p-MeOPh)2 (20), employing a combination of UV-vis and resonance Raman spectroscopy. The results reveal that carbene chemoselectivity in MRh(L)4 catalysis can be modulated to a previously unrecognized extent by the distal metalloligand.

A few selected contributions to electron and photon collisions with H2 and H 2 + .

We discuss a number of aspects regarding the physics of H 2 + and H2. This includes low-energy electron scattering processes and the interaction of both weak (perturbative) and strong (ultrafast/intense) electromagnetic radiation with those systems.

Unified Concept of Effective One Component Plasma for Hot Dense Plasmas.

Orbital-free molecular dynamics simulations are used to benchmark two popular models for hot dense plasmas: the one component plasma (OCP) and the Yukawa model. A unified concept emerges where an effective OCP (EOCP) is constructed from the short-range structure of the plasma. An unambiguous ionization and the screening length can be defined and used for a Yukawa system, which reproduces the long-range structure with finite compressibility. Similarly, the dispersion relation of longitudinal waves is consistent with the screened model at vanishing wave number but merges with the OCP at high wave number. Additionally, the EOCP reproduces the overall relaxation time scales of the correlation functions associated with ionic motion. In the hot dense regime, this unified concept of EOCP can be fruitfully applied to deduce properties such as the equation of state, ionic transport coefficients, and the ion feature in x-ray Thomson scattering experiments.

Experimental and Computational Studies of the Copper Borate Complexes [(NHC)Cu(HBEt3 )] and [(NHC)Cu(HB(C6 F5 )3 )].

The synthesis of the Cu-borate complexes [(6Mes)Cu(HBR3 )] featuring the unusual [HBEt3 ]- (5) and [HB(C6 F5 )3 ]- (6) ligands is described. Experimental and computational studies show both compounds feature a direct Cu-H interaction, but that while 5 is two-coordinate, 6 displays an additional, stabilizing Cu-Cipso (C6 F5 ) interaction.

A Comparison of the Stability and Reactivity of Diamido- and Diaminocarbene Copper Alkoxide and Hydride Complexes.

The mononuclear N-heterocyclic carbene (NHC) copper alkoxide complexes [(6-NHC)CuOtBu] (6-NHC = 6-MesDAC (1), 6-Mes (2)) have been prepared by addition of the free carbenes to the tetrameric tert-butoxide precursor [Cu(OtBu)]4, or by protonolysis of [(6-NHC)CuMes] (6-NHC = 6-MesDAC (3), 6-Mes (4)) with tBuOH. In contrast to the relatively stable diaminocarbene complex 2, the diamidocarbene derivative 1 proved susceptible to both thermal and hydrolytic ring-opening reactions, the latter affording [(6-MesDAC)Cu(OC(O)CMe2C(O)N(H)Mes)(CNMes)] (6). The intermediacy of [(6-MesDAC)Cu(OH)] in this reaction was supported by the generation of Cu2O as an additional product. Attempts to generate an isolable copper hydride complex of the type [(6-MesDAC)CuH] by reaction of 1 with Et3SiH resulted instead in migratory insertion to generate [(6-MesDAC-H)Cu(P(p-tolyl)3)] (9) upon trapping by P(p-tolyl)3. Migratory insertion was also observed during attempts to prepare [(6-Mes)CuH], with [(6-Mes-H)Cu(6-Mes)] (10) isolated, following a reaction that was significantly slower than in the 6-MesDAC case. The longer lifetime of [(6-Mes)CuH] allowed it to be trapped stoichiometrically by alkyne, and also employed in the catalytic semi-reduction of alkynes and hydrosilylation of ketones.

Unexpected migratory insertion reactions of M(alkyl)2 (M=Zn, Cd) and diamidocarbenes.

The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH3 and P4 . Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6-MesDAC-R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6-MesDAC)MR2 ], exhibiting barriers to migratory insertion which increase in the order MR2 = ZnEt2 < ZnMe2 < CdMe2 . Compound [(6-MesDAC-Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent ß-H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M-R, M-H).

Bonding and structure in dense multi-component molecular mixtures.

We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH4:NH3:H2O) for various compositions and temperatures (2000 K ≤ T ≤ 10,000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the nature of these systems engendered by variations in the concentration ratios. A basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers.

MRI findings in pediatric patients with scurvy.

In modern times scurvy is a rarely encountered disease caused by ascorbic acid (vitamin C) deficiency. However, sporadic cases of scurvy persist, particularly within the pediatric population. Recent individual case reports highlight an increased incidence of scurvy among patients with autism or developmental delay, with isolated case reports detailing the magnetic resonance imaging (MRI) findings of scurvy in these pediatric populations. We present the MRI findings of scurvy in four patients with autism or developmental delay, and review the literature on MRI findings in pediatric patients with scurvy. Despite its rarity, the radiologist must consider scurvy in a pediatric patient with a restricted diet presenting with arthralgia or myalgia.

Copper diamidocarbene complexes: characterization of monomeric to tetrameric species.

Treatment of CuCl with 1 equiv of the in situ prepared N-mesityl-substituted diamidocarbene 6-MesDAC produced a mixture of the dimeric and trimeric copper complexes [(6-MesDAC)CuCl]2 (1) and [(6-MesDAC)2(CuCl)3] (2). Combining CuCl with isolated, free 6-MesDAC in 1:1 and 3:2 ratios gave just 1 and 2, respectively, while increasing the ratio to >5:1 allowed the isolation of small amounts of the tetrameric copper complex [(6-MesDAC)2(CuCl)4] (3). Efforts to bring about metathesis reactions of 1 with MO(t)Bu (M = Li, Na, K) proved successful only for M = Li to afford the spectroscopically characterized ate product [(6-MesDAC)CuCl·LiO(t)Bu·2THF] (5). Attempts to crystallize this species instead gave a 1:1 mixture of 1 and the monomer [(6-MesDAC)CuCl] (6). The X-ray structures of 1-3 and 1 + 6, along with the cation [Cu(6-MesDAC)2](+) (4), have been determined.

Maladministrations in nuclear medicine: revelations from the Australian Radiation Incident Register.

OBJECTIVE: To describe the incidence, type, causes and consequences of nuclear medicine maladministrations. SETTING AND PARTICIPANTS: Review of prospectively acquired maladministration reports within the Australian Radiation Incident Register (ARIR), a mandatory incident register managed by the Australian Radiation Protection and Nuclear Safety Agency. MAIN OUTCOME MEASURES: Individual reports from 2007 to 2011 were evaluated for dose of radiation exposure and type, cause and consequence of maladministrations. Incidence was estimated using data from Medicare Australia. RESULTS: There were 149 maladministrations and the estimated incidence was 5.8 per 100,000 nuclear medicine procedures (95% CI, 5.0-6.9). About half of all maladministrations (48%) arose from an incorrect radiopharmaceutical being prepared and/or dispensed. Other causes included mistakenly injecting the wrong radiopharmaceutical because of inattention (n = 27; 18.1%); extravasations, failures in equipment or procedure leading to a non-diagnostic study (n = 25; 16.8%); misinterpreting a request form and performing an incorrect procedure (n = 13; 8.7%); or injecting an incorrect patient (n = 13; 8.7%). ARIR reports focused on active rather than latent causes. Most (n = 147) maladministrations occurred following diagnostic procedures, and the mean effective radiation dose was 7.9 mSv (range, 0.015-45 mSv). Two therapeutic maladministrations likely caused unintended organ injury. CONCLUSIONS: The ARIR provides unique insight into the type, causes and complications of maladministrations in Australia. Nearly all maladministrations occur in a diagnostic context, and the risk of patient harm appears low. Among active causes, radiopharmaceutical preparation and dispensation, and medical supervision before injection merit attention. The ARIR could be refined by attending to latent errors, addressing possible underreporting and securing more complete Medicare data.

Imaging features, classification and clinical features of intrahepatic congenital portosystemic shunts.

Congenital portosystemic shunts (CPSS) are a rare developmental anomaly diverting blood flow from the portal venous system and the liver to the systemic venous system. This case series examines the sonographic imaging findings, shunt classification, ultrasound shunt ratios, and outcomes in nine children (5 females, 4 males) admitted to our institution between 2015 and 2022 were included in this study. The shunts were initially categorized by the Parks classification and were followed by serial ultrasounds. Clinical presentation, clinical course, laboratory data, shunt ratios, and time to shunt closure were all followed on subsequent ultrasounds. The most common type of CPPS was the Type 3 shunt. In cases where shunt ratios were measured, the shunt ratio gradually decreased in tandem with decreasing ammonia levels until spontaneous closure was achieved. Predictors of lack of shunt closure included high shunt ratios and Type 4 shunts. Patients with CPPS can be followed with the shunt ratio calculation obtained from sonographic imaging, which may correlate to ammonia levels and indicate risk of hepatic encephalopathy as well as predict speed and timing of closure.

Stochastic and mixed density functional theory within the projector augmented wave formalism for simulation of warm dense matter.

Stochastic density functional theory (DFT) and mixed stochastic-deterministic DFT are burgeoning approaches for the calculation of the equation of state and transport properties in materials under extreme conditions. In the intermediate warm dense matter regime, a state between correlated condensed matter and kinetic plasma, electrons can range from being highly localized around nuclei to delocalized over the whole simulation cell. The plane-wave basis pseudopotential approach is thus the typical tool of choice for modeling such systems at the DFT level. Unfortunately, stochastic DFT methods scale as the square of the maximum plane-wave energy in this basis. To reduce the effect of this scaling and improve the overall description of the electrons within the pseudopotential approximation, we present stochastic and mixed DFT approaches developed and implemented within the projector augmented wave formalism. We compare results between the different DFT approaches for both single-point and molecular dynamics trajectories and present calculations of self-diffusion coefficients of solid density carbon from 1 to 50 eV.

Fighting 'personhood' initiatives in the United States.

'Personhood' initiatives filed in many states within the United States threaten to impose potentially significant restrictions on infertility treatment, embryo disposition, pre-natal care, abortion, contraception, and stem-cell research, all through attempts to redefine a 'person' or 'human being' as existing from the moment of fertilization or conception, and endowed with the full legal and Constitutional rights of personhood. Virginia's recent, unsuccessful attempt to pass such legislation provides both a dramatic example of these efforts and valuable lessons in the fight against them by infertility advocates and others. Arguments over loss of infertility treatment seemed more persuasive to legislatures than did restrictions on abortion or stem cell research. Indeed, persuading legislators or voters that they could be 'pro-life' and still anti-personhood initiatives was a key strategy, and consumer efforts and media attention were instrumental. The most central lessons, however, may be the degree of intensity and coordinated strategy to shift public perception that lie behind these numerous state efforts, regardless of whether the actual initiatives are won or lost.

Mixed stochastic-deterministic time-dependent density functional theory: application to stopping power of warm dense carbon.

Warm dense matter (WDM) describes an intermediate phase, between condensed matter and classical plasmas, found in natural and man-made systems. In a laboratory setting, WDM is often created dynamically. It is typically laser or pulse-power generated and can be difficult to characterize experimentally. Measuring the energy loss of high energy ions, caused by a WDM target, is both a promising diagnostic and of fundamental importance to inertial confinement fusion research. However, electron coupling, degeneracy, and quantum effects limit the accuracy of easily calculable kinetic models for stopping power, while high temperatures make the traditional tools of condensed matter, e.g. time-dependent density functional theory (TD-DFT), often intractable. We have developed a mixed stochastic-deterministic approach to TD-DFT which provides more efficient computation while maintaining the required precision for model discrimination. Recently, this approach showed significant improvement compared to models when compared to experimental energy loss measurements in WDM carbon. Here, we describe this approach and demonstrate its application to warm dense carbon stopping across a range of projectile velocities. We compare direct stopping-power calculation to approaches based on combining homogeneous electron gas response with bound electrons, with parameters extracted from our TD-DFT calculations.

Improving Performance Covertly and Remotely with Tactile Stimulation.

Tactile stimulation can be used to privately prompt or provide feedback for a variety of behaviors. However, technological limitations have primarily resulted in narrow investigations of tactile stimulation delivered on a time-based schedule by a device like a MotivAider or WatchMinder. Recent advances in smartphone and watch technologies have created new ways for practitioners to deliver tactile stimulation privately and remotely to improve behavior. The purpose of this Brief Report is to provide a case study and a description of the advantages and applications of utilizing this technology, including preserving the privacy and dignity of clients by covertly improving performance; prompting behavior based on environmental events independent of scheduled times; delivering feedback quickly, quietly, and remotely without interrupting interactions; and fading dependencies on tactile prompting and feedback.

Parsonage-turner syndrome associated with SARS-CoV2 (COVID-19) infection.

Parsonage-Turner Syndrome (PTS), also known as idiopathic brachial plexopathy or neuralgic amyotrophy, is an uncommon condition characterized by acute onset of shoulder pain, most commonly unilateral, which may progress to neurologic deficits such as weakness and paresthesias (Feinberg and Radecki, 2010 [1]). Although the etiology and pathophysiology of PTS remains unclear, the syndrome has been reported in the postoperative, postinfectious, and post-vaccination settings, with recent viral illness reported as the most common associated risk factor (Beghi et al., 1985 [2]). Various viral, bacterial, and fungal infections have been reported to precede PTS, however, currently there are no reported cases of PTS in the setting of recent infection with SARS-CoV2 (COVID-19). We present a case of a 17 year old female patient with no significant past medical or surgical history who presented with several weeks of severe joint pain in the setting of a recent viral illness (SARS-CoV2, COVID-19). MRI of the left shoulder showed uniform increased T2 signal of the supraspinatus, infraspinatus, teres minor, teres major, and trapezius muscles, consistent with PTS. Bone marrow biopsy results excluded malignancy and hypereosinophilic syndrome as other possible etiologies. Additional rheumatologic work-up was also negative, suggesting the etiology of PTS in this patient to be related to recent infection with SARS-CoV2 (COVID-19). Radiologists should be aware of this possible etiology of shoulder pain as the number of cases of SARS-CoV2 (COVID-19) continues to rise worldwide.

Rudhe syndrome: reversible right middle lobe emphysema in infants with left-to-right shunts--an historical review.

In 1971, the Swedish radiologist Ulf Rudhe wrote a provocative paper on right middle lobe emphysema in infants with left-to-right shunts in which he suggested cardiac surgery rather than lung resection. At the time, this was counter to accepted medical practice. Earlier diagnosis and better medical management of ventricular septal defect in infants has proved Rudhe correct. However, two current cases of large left-to-right shunts in infants with emphysema of the right middle lobe prompt this historical review of what seemed a closed-episode in pediatric cardiac surgery.

The Effect of Tungsten Road Nails on Upper Body Movement Asymmetry in Horses Trotting on Tarmac.

Tungsten road nails are commonly used by farriers to increase grip between the hoof and the ground surface. There is limited evidence relating the use of road nails to the fundamental mechanics of movement. Grip is important for efficient deceleration on landing and subsequent propulsion, but this must be balanced against an amount of slip to divide the landing force into horizontal as well as vertical subcomponents. Here, we conducted an intervention study to quantify the effect of lateral heel road nail placement on weight bearing and propulsion in 10 horses trotting on tarmac. Wireless inertial measurement units measured vertical movement asymmetry. Differences in head and pelvic movement asymmetry before/after subsequent application of laterally placed road nails to forelimb and hindlimb hooves in a randomized order were compared to zero value (no change) with a one-sample t-test, P < .05. Left-to-right tuber coxae movement amplitude difference was significantly more negative (-3.25 mm, P = .03), suggesting more right than left tuber coxae movement amplitude, after application of a road nail to the left hindlimb. No movement asymmetries at the poll, withers, or sacrum were detected after nail placement (all P > .055). Pelvic movement indicates a very small increase in weight bearing and propulsion provided by the hindlimb with a laterally placed road nail compared to the contralateral hindlimb. Further work is needed to investigate slip- and grip-related parameters at the level of the hoof and to investigate the long-term consequences of very small changes in movement asymmetry.