High sensitivity methods for automated rib fracture detection in pediatric radiographs.

Rib fractures are highly predictive of non-accidental trauma in children under 3 years old. Rib fracture detection in pediatric radiographs is challenging because fractures can be obliquely oriented to the imaging detector, obfuscated by other structures, incomplete, and non-displaced. Prior studies have shown up to two-thirds of rib fractures may be missed during initial interpretation. In this paper, we implemented methods for improving the sensitivity (i.e. recall) performance for detecting and localizing rib fractures in pediatric chest radiographs to help augment performance of radiology interpretation. These methods adapted two convolutional neural network (CNN) architectures, RetinaNet and YOLOv5, and our previously proposed decision scheme, "avalanche decision", that dynamically reduces the acceptance threshold for proposed regions in each image. Additionally, we present contributions of using multiple image pre-processing and model ensembling techniques. Using a custom dataset of 1109 pediatric chest radiographs manually labeled by seven pediatric radiologists, we performed 10-fold cross-validation and reported detection performance using several metrics, including F2 score which summarizes precision and recall for high-sensitivity tasks. Our best performing model used three ensembled YOLOv5 models with varied input processing and an avalanche decision scheme, achieving an F2 score of 0.725 ± 0.012. Expert inter-reader performance yielded an F2 score of 0.732. Results demonstrate that our combination of sensitivity-driving methods provides object detector performance approaching the capabilities of expert human readers, suggesting that these methods may provide a viable approach to identify all rib fractures.

Urinary Symptoms Among People With Neurogenic Lower Urinary Tract Dysfunction (NLUTD) Vary by Bladder Management.

Objectives: To determine whether assessment and decision-making around urinary symptoms in people with neurogenic lower urinary tract dysfunction (NLUTD) should depend on bladder management. Methods: Three surveys of urinary symptoms associated with NLUTD (USQNBs) were designed specific to bladder management method for those who manage their bladders with indwelling catheter (IDC), intermittent catheter (IC), or voiding (V). Each was deployed one time to a national sample. Subject matter experts qualitatively assessed the wording of validated items to identify potential duplicates. Clustering by unsupervised structural learning was used to analyze duplicates. Each item was classified into mutually exclusive and exhaustive categories: clinically actionable ("fever"), bladder-specific ("suprapubic pain"), urine quality ("cloudy urine"), or constitutional ("leg pain"). Results: A core of 10 "NLUTD urinary symptoms" contains three clinically actionable, bladder-specific, and urine quality items plus one constitutional item. There are 9 (IDC), 11 (IC), and 8 (V) items unique to these instruments. One decision-making protocol applies to all instruments. Conclusion: Ten urinary symptoms in NLUTD are independent of bladder management, whereas a similar number depend on bladder management. We conclude that assessment of urinary symptoms for persons with NLUTD should be specific to bladder management method, like the USQNBs are.

Fetal Inferior Vena Cava Thrombosis Associated With Non-Immune Hydrops Fetalis and Maternal Mirror Syndrome.

Prenatal assessment of the inferior vena cava (IVC) should be considered in pregnancies with atypical presentations of fetal ascites and placentomegaly. We examine a case of a 25-year-old gravida 2 para 1 type 1 diabetic female at 29 and 4/7 weeks' gestation. Ultrasound (US) showed fetal ascites and placentomegaly with increased middle cerebral artery peak systolic velocity (MCA-PSV) suspicious of fetal anemia. Cordocentesis with intrauterine transfusion briefly resolved the fetal ascites, though the mother developed pulmonary edema and pleural effusion, suggestive of mirror syndrome. On US, fetal ascites returned and progressed to non-immune hydrops fetalis, prompting delivery. Neonatal US revealed a heterogenous and calcified thrombus within the IVC.

Molecular identity crisis: environmental DNA metabarcoding meets traditional taxonomy-assessing biodiversity and freshwater mussel populations (Unionidae) in Alabama.

The use of environmental DNA (eDNA) to assess aquatic biodiversity is a growing field with great potential for monitoring and managing threatened species, like freshwater mussel (Unionidae) populations. Freshwater mussels are globally imperiled and serve essential roles in aquatic systems as a food source and as a natural water filter making their management essential for ecosystem health. Unfortunately, mussel populations are often understudied, and challenges exist to accurately and efficiently describe the full suite of species present. Multispecies eDNA approaches may also be more challenging where freshwater mussel populations are most diverse due to ongoing and significant taxonomic restructuring that has been further complicated by molecular phylogenies using mitochondrial genes. For this study, we developed a microfluidic metabarcoding array that targets a wide range of species, from invertebrates to fishes, with an emphasis on detecting unionid mussels known to be present in the Sipsey River, Alabama. We compared mussel species diversity across six sites with well-studied mussel assemblages using eDNA surveys and traditional quadrat surveys in 2016. We examined how factors such as mussel population density, biomass and location in the river substrate impacted our ability to detect certain species; and investigated unexpected eDNA detections through phylogenetic analysis. Our eDNA results for fish and mussel species were broadly consistent with the data from traditional electrofishing and quadrat-based field surveys, although both community eDNA and conventional sampling detected species unique to that method. Our phylogenetic analysis agreed with other studies that treat Pleurobema decisum and P. chattanoogaense as synonymous species; however, they are still listed as unique species in molecular databases which complicates their identity in a metabarcoding assay. We also found that Fusconaia flava and F. cerina are indistinguishable from one another using a portion of the NADH dehydrogenase Subunit 1 (ND1) marker, which may warrant further investigation into whether or not they are synonymous. Our results show that many factors impacted our ability to detect and correctly identify Unionidae mussel species. Here we describe the obstacles we faced, including the murky phylogeny of Unionidae mussels and turbid river conditions, and our development of a potentially impactful freshwater mussel monitoring eDNA assay.

Urinary Symptoms Are Unrelated to Leukocyte Esterase and Nitrite Among Indwelling Catheter Users.

Objectives: To explore the association between dipstick results and urinary symptoms. Method: This was a prospective 12-month observational study of real-time self-administered urine dipstick results and symptoms in a community setting that included 52 spinal cord injury/disease (SCI/D) participants with neurogenic lower urinary tract dysfunction (NLUTD) who use an indwelling catheter. Symptoms were collected using the Urinary Symptom Questionnaire for Neurogenic Bladder-Indwelling Catheter (USQNB-IDC). The USQNB-IDC includes actionable (A), bladder (B1), urine quality (B2), and other (C) symptoms; analyses focused on A, B1, and B2 symptoms. Dipstick results include nitrite (NIT +/-), and leukocyte esterase (LE; negative, trace, small, moderate, or large). Dipstick outcomes were defined as strong positive (LE = moderate/large and NIT+), inflammation positive (LE = moderate/large and NIT-), negative (LE = negative/trace and NIT-), and indeterminate (all others). Results: Nitrite positive dipsticks and moderate or large LE positive dipsticks were each observed in over 50% of the sample in every week. Strong positive dipstick results were observed in 35% to 60% of participants in every week. A, B1, or B2 symptoms co-occurred less than 50% of the time with strong positive dipsticks, but they also co-occurred with negative dipsticks. Participants were asymptomatic with a strong positive dipstick an average of 30.2% of the weeks. On average, 73% of the time a person had a negative dipstick, they also had no key symptoms (95% CI, .597-.865). Conclusion: No association was observed between A, B1, and B2 symptoms and positive dipstick. A negative dipstick with the absence of key symptoms may better support clinical decision-making.

Independence of Urinary Symptoms and Urinary Dipstick Results in Voiders With Neurogenic Bladder.

Background: Urinary symptoms and urinary tract infection (UTI) are frequent and burdensome problems associated with neurogenic lower urinary tract dysfunction. Objectives: To determine whether an association exists between urinary symptoms and urine dipstick results among individuals with spinal cord injury (SCI) or multiple sclerosis (MS). Methods: Prospective 12-month cohort study of 76 participants with SCI or MS who manage their bladders by voiding. Eligibility criteria included adults ≥18 years old, at least three UTIs since diagnosis, and residence in the United States. Participants completed the Urinary Symptoms Questionnaire for Neurogenic Bladder-Voider version (USQNB-V) biweekly (26 assessments) and tested their urine by dipstick at the same time. Symptom burden was estimated based on endorsements of USQNB-V symptoms classified as clinically actionable (9), bladder function (8), and urine quality (4). Urine dipstick results assessed were leukocyte esterase (LE) and nitrite (NIT). Results: Participants were stratified into four groups based on etiology of neurologic dysfunction and whether they ever experienced any urinary symptoms (USx): SCI+USx (n = 14), SCI+NoUSx (n = 5), MS+USx (n = 32), and MS+NoUSx (n = 25). In descending order, symptom burden was greatest for the MS+USx group, followed by both SCI groups; it was lowest for MS+NoUSx. We assessed multiple definitions of "positive" dipstick and found evidence of independence of USQNB-V symptoms and urinary dipstick results with each definition. In each group, the median (and majority) of strong positive dipsticks did not coincide with any symptoms. Conclusion: Among people with SCI or MS who void, self-administered urine dipstick results and urinary symptom reporting contribute independent information for clinical decision making.

Optimizing Care of Patients With Right Bundle Branch Block Undergoing Transcatheter Aortic Valve Replacement.

OBJECTIVES: To evaluate the use of temporary-permanent pacemaker (TPP) in patients with right bundle branch block (RBBB) undergoing transcatheter aortic valve replacement (TAVR). We also sought to identify key predictors of permanent pacemaker (PPM) within 30 days of TAVR in this population. BACKGROUND: RBBB is a well-recognized risk factor for PPM post TAVR. TPP provides stable transient pacing and reduces the need for critical care beds. METHODS: This is a retrospective chart review of 371 patients who underwent TAVR at our institution. All patients with pre-existing RBBB had TPP placed prior to TAVR (n = 37). The primary outcome was the need for critical care beds. Multivariate logistic regression analysis was performed to identify predictors of PPM within 30 days of TAVR. RESULTS: 67 patients required PPM within 30 days of TAVR, and 56 implanted before discharge. 51% (19 out of 37) of TPP group required PPM before discharge compared to 11% (37 out of 334) of No TPP (p < 0.001), yet TPP group spent significantly fewer hours in a critical care bed (19 vs 28 h, p = 0.01). Length of membranous septum (LMS) <8.49 mm was the strongest independent predictor of PPM within 30 days of TAVR (RAUC of 0.80, Sensitivity 0.7 and Specificity 0.8) and 98% of patients with LMS < 7 mm required PPM within 30 days. CONCLUSION: TPP-TAVR is a well-defined multidisciplinary protocol that reduces the need for critical care beds in patients with pre-existing RBBB referred for TAVR. Additionally, LMS is the strongest predictor of PPM implantation in this population. CONDENSED ABSTRACT (100 WORDS): This study evaluated the use of temporary-permanent pacemakers (TPP) in patients with right bundle branch block (RBBB) undergoing transcatheter aortic valve replacement (TAVR). TPP-TAVR provided stable pacing allowing for early mobilization and reduced the need for critical care beds. Multivariate logistic regression analysis identified length of membranous septum (LMS) <8.49 mm in patients with RBBB as the strongest independent predictor of PPM need within 30 days of TAVR. 98% of patients with RBBB and LMS < 7 mm required PPM at 30 days regardless of other characteristics including valve type and size.

Reliability of the Urinary Symptom Questionnaires for people with neurogenic bladder (USQNB) who void or use indwelling catheters.

STUDY DESIGN: This is a descriptive psychometrics study. OBJECTIVES: Neurogenic lower urinary tract dysfunction (NLUTD), also called Neurogenic Bladder (NB), is a common and disruptive condition in a variety of neurologic diagnoses. Our team developed patient-centered instruments, Urinary Symptom Questionnaires for people with neurogenic bladder (USQNB), specific to people with NLUTD who manage their bladders with intermittent catheterization (IC), indwelling catheters (IDC), or who void (V). This article reports evidence of reliability of the IDC and V instruments. SETTING: Online surveys completed by individuals in the United States with NLUTD due to spinal cord injury (SCI), or multiple sclerosis (MS) who manage their bladder with IDC (SCI, n = 306), or by voiding (SCI, n = 103; MS, n = 383). METHODS: Reliability estimates were based on endorsement of the items on the USQNB-IDC and USQNB-V. Reliability evidence was representativeness of these symptoms for a national sample (by determining if endorsement > 10%); internal consistency estimates (by Cronbach's alpha and item correlation coefficient, ICC); and interrelatedness of the items (by inferred Bayesian network, BN). We also tested whether a one-factor conceptualization of "urinary symptoms in NLUTD" was supportable for either instrument. RESULTS: All items were endorsed by >20% of our samples. Urine quality symptoms tended to be the most commonly endorsed on both instruments. Cronbach's alpha and ICC estimates were high (>0.74), but not suggestive of redundancy. BNs showed interpretable associations among the items, and did not discover uninterpretable or unexpected associations. Neither instrument fit a one-factor model, as expected. CONCLUSIONS: The USQNB-IDC and USQNB-V instruments show sufficient, multidimensional reliability for implementation and further study.

Validity of the Urinary Symptom Questionnaires for people with neurogenic bladder (USQNB) who void or use indwelling catheters.

STUDY DESIGN: Descriptive Psychometrics Study OBJECTIVES: Neurogenic lower urinary tract dysfunction (NLUTD), or "neurogenic bladder" is a common and disruptive condition for individuals with spinal cord injury (SCI) and disease (including multiple sclerosis, MS). Our team has developed patient-centered instruments of urinary symptoms specific to patients with NLUTD, across bladder management methods. Validity evidence is needed to support the use of two new instruments, Urinary Symptom Questionnaires for people with Neurogenic Bladder (USQNB) for those who manage their bladder with indwelling catheters (IDC), or who void (V). SETTING: Online surveys completed by individuals in the United States with NLUTD due to either SCI or MS who manage their bladder with indwelling catheters (SCI, n = 306; MS, n = 8), or by voiding (SCI, n = 103; MS, n = 383). A total of n = 381 USQNB-IDC respondents (five control groups), and 351 USQNB-V respondents (four control groups), contributed to our convergent and divergent validity evidence. METHODS: Data were collected online to estimate key aspects of psychometric validity (content, reflection of the construct to be measured; face, recognizability of the contents as representing the construct to be measured; structural, the extent to which the instrument captures recognizable dimensions of the construct to be measured). Divergent and convergent validity evidence was derived from multiple control groups, while evidence of criterion validity was derived from attribution of each item to their experience "with a UTI". RESULTS: Evidence of face, content, criterion, convergent, and divergent validity was compiled for each instrument. CONCLUSIONS: The instruments demonstrate adequate, multi-dimensional, validity evidence to recommend their use for decision-making by patients, clinicians, and researchers.

Clinical Profiles and Symptom Burden Estimates to Support Decision-Making Using the Urinary Symptom Questionnaire for People with Neurogenic Bladder (USQNB) using Intermittent Catheters.

OBJECTIVE: To describe the scoring approach, considering interpretability, validity, and use, of a new patient-centered patient reported outcome (PRO), the Urinary Symptom Questionnaire for Neurogenic Bladder-Intermittent Catheter version (USQNB-IC). DESIGN: Subject matter experts (researchers, clinicians, a consumer, a psychometrician) classified USQNB-IC items. Profiles were then composed based on self-management decisions made by patients; patient management decisions made by clinicians; and research-oriented decisions made by investigators. Participants in an 18-month pilot study completed the USQNB-IC every week. Differences in decisions based on traditional 'total scores' and profiles were examined. Validity was defined based on alignment of scoring method with decisions. SETTING: A new set of patient-centered PROs enable monitoring and decision-making around urinary signs and symptoms among people with neurogenic bladder (NB). PARTICIPANTS: Classifications of USQNB-IC items by subject matter experts. Utility of the classifications and profiles that were created was assessed using weekly responses from the 6-month baseline period from 103 participants in a pilot study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Classification of the 29 symptoms resulted in four categories with exchangeability within-category and nonexchangeability across categories. The burden of each symptom type is one approach to scoring the USQNB-IC. Five profiles, based on these categories, emerged based on, and supportive of, decisions to be made according to symptoms, representing a categorical approach to scoring the USQNB-IC. RESULTS: USQNB-IC items are not all exchangeable. Four symptom classifications comprise within-class exchangeable items. Five profiles emerged to summarize these items to promote decision-making and identification of change over time. Both ways to "score" the USQNB-IC are described and discussed. CONCLUSIONS: "Profiling" promotes valid and interpretable decisions by patients and clinicians, based on a patient's urinary symptoms with the USQNB-IC cross-sectionally and longitudinally. Alternatively, four subsets of the 29 USQNB-IC symptoms can be used as continuous outcomes representing "burden" in clinical management or research.

Effects of Intravesical Lactobacillus Rhamnosus GG on Urinary Symptom Burden in People with Neurogenic Lower Urinary Tract Dysfunction.

OBJECTIVE: To test the effectiveness of intravesical Lactobacillus rhamnosus GG (LGG) to reduce the burden of urinary symptoms for individuals with spinal cord injury and disease (SCI/D) with neurogenic lower urinary tract dysfunction (NLUTD) who manage their bladders with intermittent catheterization (IC). DESIGN: A three-phase study (6 months each in baseline, intervention, and washout). Participants self-managed following the Self-Management Protocol using Probiotics (SMP-Pro), completing the online Urinary Symptom Questionnaire for Neurogenic Bladder-IC version (USQNB-IC) weekly. SETTING: Nationwide (United States). PARTICIPANTS: Ninety-six adults and seven children with SCI/D. INTERVENTIONS: In response to one or both of the SMP-Pro trigger urinary symptoms, "cloudier" or "foul smelling" urine, participants self-administered using a clean urinary catheter an LGG+ Normal Saline instillate once or twice in a 30-hour period. MAIN OUTCOME MEASURES: Change in USQNB-IC burden was adjusted individually according to the previous phase for four symptom types. Adjusted changes in burden between the intervention and washout phases were analyzed using one-sample t-tests. Holm correction was applied for the four types of symptoms: A, clinically actionable; B1, bladder function; B2, urine quality; and C, other. RESULTS: During the intervention phase, participants met SMP-Pro instillation criteria 3.83 times on average (range 1-20). An average of 5.6 doses of LGG were instilled. For those who instilled at least once, burdens of type A and B2 symptoms were significantly improved at washout (both adjusted P < .05). CONCLUSIONS: Self-instilled LGG seemed to improve "clinically actionable" (A) and "urine quality" (B2) symptom burden. No changes were observed for those who did not instill. This first-in-human clinical trial supports ongoing research of intravesical LGG, and the SMP-Pro for urinary symptoms.

Intravesical Lactobacillus rhamnosus GG is safe and well tolerated in adults and children with neurogenic lower urinary tract dysfunction: first-in-human trial.

BACKGROUND: Urinary symptoms are common for people with neurogenic lower urinary tract dysfunction (NLUTD). No nonprescription approach has been proven safe and effective for self-management of urinary symptoms. Our objective was to describe the safety and tolerability of Lactobacillus rhamnosus GG (LGG®) instilled intravesically for self-management of inflammatory urinary symptoms in adults and children with NLUTD due to spinal cord injury or disease (SCI/D) and who use intermittent catheterization (IC). METHODS: A total of 103 individuals with SCI/D enrolled in an 18-month study consisting of three 6-month stages: baseline (weekly observation of urinary symptoms); intervention (self-instilled intravesical LGG® in response to more cloudy or foul-smelling urine); and washout (weekly observation of urinary symptoms). Urinary symptoms were assessed using the Urinary Symptom Questionnaire for people with neurogenic bladder using intermittent catheters (USQNB-IC). Safety was based on serious adverse events and adverse events (S/AEs) and trends in symptoms. Tolerability was defined as the independence of AE experience and willingness to use/pay for this intervention. RESULTS: A total of 74 (77%) adults and 6 (86%) of children completed the study, of whom 64 instilled LGG® for a total of 357 instillations (range 1-41 per person). There were 59 S/AEs, 44% (26/59) of which were categorized as infectious genitourinary. There was no statistical relationship between S/AEs and use or dose of the intervention. CONCLUSIONS: One or two doses of self-instilled intravesical LGG® in response to more cloudy or foul-smelling urine was safe and well tolerated among this sample of adults and children with SCI/D who have NLUTD and use IC.

Differential responses of amphibian and reptile assemblages to size of riparian buffers within managed forests.

Streamside management zones (i.e., riparian buffers; SMZs) are commonly implemented within managed forests to protect water quality but may also provide habitat for riparian-associated wildlife. Yet, little research has rigorously addressed the value of SMZs for wildlife, particularly for cryptic species such as amphibians and reptiles. Previous studies of herpetofauna within SMZs have focused on one or a few stream-associated species, and questions remain regarding variation among species or guilds and what role SMZs serve toward conservation of herpetofaunal diversity in managed forests. However, recent statistical advances have improved our ability to analyze large multi-species presence-absence data sets, accounting for low detection rates typical for some herpetofaunal species. Our study represents an extensive landscape-scale examination of herpetofaunal communities within SMZs using a multi-species occupancy approach. We conducted four replicate surveys at 102 headwater streams, spanning a gradient of SMZ widths and adjacent forest stand ages, within the Ouachita Mountains, Arkansas, USA. We used a hierarchical Bayesian community occupancy model to estimate species richness and species-specific occupancy responses to SMZ and overstory characteristics, accounting for variation in occupancy and detection attributable to site and sampling covariates. We documented high richness (37 species) within SMZs. Across the herpetofaunal community, occupancy and species richness were consistently positively associated with SMZ width, with maximum predicted richness of 30 species occurring at sites with buffers extending 51 m on either side of the stream. However, we documented considerable variation among groups and species within groups, underscoring the potential for different responses to forest management among taxa. Reptile predicted richness increased more rapidly up to SMZs of ~35 m, whereas maximum salamander predicted richness was not seen until an SMZ width of 55 m. Estimated salamander richness was highest within SMZs embedded in mature managed pine stands and was higher in SMZs comprised of a deciduous or mixed overstory vs. a pine overstory. Compared to salamanders, more anuran species showed high mean estimated occupancy (>75%) at narrower SMZs (<30 m). Collectively, our results indicate that SMZs surrounding small first-order streams in intensively managed forests not only protect water quality, but also can support diverse amphibian and reptile communities.

Left Ventricular Pseudoaneurysm Following Surgical Repair of Ventricular Septal Defect in an Infant.

Left ventricular pseudoaneurysm (LV-PSA) is a rare complication following cardiac surgery, let alone in the pediatric population. Other known causes of LV-PSA are trauma, percutaneous cardiac intervention, and infections. This report describes the development of LV-PSA following surgical repair of ventricular septal defect (VSD) and coarctation of aorta (CoA) in an infant.

Anti-Ma2-antibody-associated encephalitis: An atypical paraneoplastic neurologic syndrome.

Paraneoplastic syndromes are a heterogeneous group of conditions affecting cancer patients, where the signs and symptoms are not owing to the local effects of the tumour but instead owing to humoral or immunologic effects. We describe an unusual presentation of a paraneoplastic neurologic syndrome presenting with predominant involvement of the hypothalamus and deep grey nuclei secondary to an anterior mediastinal germinoma and associated with anti-Ma2 antibody.

Prospects for 207Pb solid-state NMR studies of lead tetrel bonds.

The feasibility and value of 207Pb solid-state NMR experiments on compounds featuring lead tetrel bonds is explored. Although the definition remains to be formalized, lead tetrel bonds may be qualitatively described as existing when there is evidence of a net attractive interaction between an electrophilic region associated with lead in a molecular entity and a nucleophilic region in another, or the same, molecular entity. Unambiguous identification of lead tetrel bonds can be challenging due to the hypervalent tendency of lead. We report here a series of 207Pb solid-state NMR experiments on five metal-organic frameworks featuring lead coordinated to hydrazone-based ligands. Such frameworks may be held together in part by lead tetrel bonds. The acquisition of 207Pb solid-state NMR spectra for such materials is feasible and is readily accomplished using a combination of magic-angle spinning and Carr-Purcell-Meiboom-Gill methods in moderate to low applied magnetic fields. The lead centres are characterized by 207Pb isotropic chemical shifts ranging from -426 to -2591 ppm and chemical shift tensor spans ranging from 910 to 2681 ppm. Careful inspection of the structures of the compounds and the literature 207Pb NMR data may suggest that a tetrel bond to lead results in chemical shift parameters which are intermediate between those which are characteristic of holodirected and hemidirected lead coordination geometries. Challenges associated with DFT computations of the 207Pb NMR parameters are discussed. In summary, the 207Pb data for the compounds studied herein show a marked response to the presence of non-coordinating electron-rich moieties in close contact with the electrophilic surface of formally hemidirectionally coordinated lead compounds.

Multinuclear solid-state magnetic resonance study of oxo-bridged diniobium and quadruply-bonded dimolybdenum carboxylate clusters.

Carboxylate paddlewheels and their oxo-bridged analogues constitute ideal building blocks for the assembly of two- and three-dimensional framework materials. Here, we present a multinuclear (1H, 13C, 93Nb, 95Mo) magnetic resonance study of solid samples of Nb2OCl6(O2Ph)2 (1), Mo2(O2CMe)4 (2), and Mo2(O2CCHF2)4 (3). High-resolution proton and 13C CP/MAS NMR spectra provide valuable information on structure and crystal symmetry and on cocrystallized solvent. 93Nb solid-state NMR spectra of 1 provide quadrupolar coupling constants and chemical shift tensors which are characteristic of the axially asymmetric Nb-O-Nb bridging environment. 95Mo solid-state NMR spectra of 2 and 3 provide quadrupolar coupling constants and chemical shift tensors which are directly characteristic of the molybdenum-molybdenum quadruple bonds in these compounds. The quadruple bonds are characterized by particularly large 95Mo chemical shift tensor spans on the order of 5500ppm. Density functional theoretical computations provide good agreement with the 93Nb and 95Mo experimental data, with some exceptions noted. This work demonstrates possible NMR approaches to characterize more complex framework materials and provides key insight into the Mo-Mo quadruple bond.

Rational serendipity: "undirected" synthesis of a large {MnCu} complex from pre-formed MnII building blocks.

Use of an aminopolyalcohol-based MnII complex in solvothermal CuII chemistry leads to a rare example of a high nuclearity heterometallic {MnCu} system, in which four CuII(H1Edte) units trap an inner {MnCuII} oxide core.

From discrete molecule, to polymer, to MOF: mapping the coordination chemistry of Cd(II) using (113)Cd solid-state NMR.

Studies of three related Cd(II) systems (a discrete [Cd(II)2] unit, a one-dimensional [Cd(II)2]n coordination polymer and a Cd(II)-based MOF) all derived from the ligand 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine, reveal an exceptionally rare example of (113)Cd-(113)Cd J coupling in the polymer that is detectable by solid-state NMR ((2)JCd-Cd = ∼65 Hz).

Pediatric Thoracic Organ Transplantation: Current Indications, Techniques, and Imaging Findings.

In the past decade, with improved surgical technique and knowledge of immunosuppression, pediatric lung and heart transplantation have been established as viable therapeutic interventions for pediatric patients with end-stage cardiopulmonary disease from various underlying congenital and acquired disorders. Although outcomes for pediatric patients are similar to those for adult patients, thoracic organ transplantation in this special age group carries unique challenges for preoperative and postoperative imaging evaluation. The article provides an up-to-date review of the postoperative transplant anatomy, imaging techniques, and complications of pediatric lung and heart transplantation.