Mesoionic carbene-based self-assembled monolayers on gold.

N-Heterocyclic carbenes (NHC) have been widely studied as ligands for surface chemistry, and have shown advantages compared to existing ligands (e.g. thiols). Herein, we introduce mesoionic carbenes (MICs) as a new type of surface ligand. MICs exhibit higher σ-donor ability compared to typical NHCs, yet they have received little attention in the area of surface chemistry. The synthesis of MICs derived from imidazo[1,2-a]pyridine was established and fully characterized by spectroscopic methods. The self-assembly of these MICs on gold was analyzed by X-ray photoelectron spectroscopy (XPS). Additionally, XPS was used to compare bonding ability in MICs compared to the typical NHCs. These results show that MIC overlayers on gold are robust, resistant to replacement by NHCs, and may be superior to NHCs for applications that require even greater levels of robustness.

Non-operative Management of a Rare Segmental Clavicle Fracture in an Adolescent Patient: A Case Report.

A 12-year-old Caucasian male presented to the clinic with a displaced, segmental left clavicle fracture involving the distal clavicle after falling from a zip line. He was treated non-operatively in a sling and returned to normal activities without restrictions after three months. At one year, the patient was able to maintain his pre-injury baseline function without limitations of his left shoulder. While no clear guidelines for operative treatment of segmental clavicle fractures in the adolescent population exist in the current literature, this report illustrates an excellent patient outcome following conservative therapy of a segmental clavicle fracture involving the middle one-third and distal clavicle in a young adolescent with open physis.

Factors that Influence Acquisition of Lower Extremity Braces in the Pediatric Orthopaedic Population.

BACKGROUND: Lower extremity brace-wear compliance has been studied in pediatrics, but failure to acquire a prescribed brace has not been included. The purpose of this study was to evaluate brace acquisition as a component of brace-wear compliance. METHODS: Records of patients (0 to 21 y) prescribed lower extremity braces from 2017 to 2019 were reviewed. Diagnoses included cerebral palsy, spina bifida, short Achilles tendon, clubfoot, and other. Brace type was categorized as clubfoot foot abduction orthosis, ankle-foot orthosis, knee, hip, or custom/other braces. Brace prescription and acquisition dates were recorded. Insurance was classified as government, private, or uninsured. Patient demographics included age, sex, race, and calculated area deprivation index. RESULTS: Of the 1176 prescribed lower extremity braces, 1094 (93%) were acquired while 82 (7%) were not. The odds ratios (OR) of failure to acquire a prescribed brace in Black and Hispanic patients were 1.64 and 2.71 times that in White patients, respectively (95% confidence interval: 1.01-2.71, P=0.045; 1.23-5.6, P=0.015); in patients without insurance, the OR was 8.48 times that in privately insured patients (95% confidence interval: 1.93-31.1, P=0.007). The ORs of failure to acquire were 2.12 (P=0.003) in patients 4 years or more versus 0 to 3 years, 4.17 (P<0.0001) in cerebral palsy versus clubfoot, and 4.12 (P=0.01) in short Achilles tendon versus clubfoot. There was no significant association between sex or area deprivation index and failure of brace acquisition. CONCLUSIONS: In our cohort, 7% of prescribed braces were not acquired. Black or Hispanic race, lack of insurance, and older age were associated with failure to acquire prescribed braces. Braces prescribed for clubfoot were acquired more often than for cerebral palsy or short Achilles tendon. Brace-wear compliance is an established factor in treatment success and recurrence. This study identified risk factors for failed brace acquisition, a critical step for improving compliance. These results may help effect changes in the current system that may lead to more compliance with brace wear. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Competing Effects of Chlorination on the Strength of Te⋠⋠⋠O Chalcogen Bonds Select the Structure of Mixed Supramolecular Macrocyclic Aggregates of Iso-Tellurazole N-Oxides.

Chlorination of 3-methyl-5-phenyl-1,2-tellurazole-2-oxide yielded the λ4 Te dichloro derivative. Its crystal structure demonstrates that the heterocycle retains its ability to autoassociate by chalcogen bonding (ChB) forming macrocyclic tetramers. The corresponding Te⋅⋅⋅O ChB distances are 2.062 Å, the shortest observed to date in aggregates of this type. DFT-D3 calculations indicate that while the halogenated molecule is stronger as a ChB donor it also is a weaker ChB acceptor; the overall effect is that the ChBs in the chlorinated homotetramer are not significantly stronger. However, partial halogenation or scrambling selectively yield the 2 : 2 heterotetramer with alternating λ4 Te and λ2 Te centers, which calculations identified as the thermodynamically preferred arrangement.

Factors affecting egg production in the selfing mangrove rivulus (Kryptolebias marmoratus).

The mangrove rivulus, Kryptolebias marmoratus, is one of two known vertebrate species with preferentially self-fertilizing hermaphrodites. Males also exist, and can outcross with hermaphrodites. Outcrossing events vary across wild populations and occur infrequently in laboratory settings. This study sought to add dimension to our understanding of mangrove rivulus reproductive habits by probing the effects of male presence on hermaphroditic unfertilized egg production. Specifically, we quantified egg production of solitary hermaphrodites compared to hermaphrodites exposed to males and exposed to other hermaphrodites. Hermaphrodites tended to produce more fertilized eggs in the presence of males but unfertilized eggs were produced relatively rarely and did not vary significantly among treatments. The probability that hermaphrodites would produce eggs changed as a function of genetic dissimilarity with their partner and in a season-dependent manner. In the fall, the probability of laying eggs decreased as a function of increased genetic dissimilarity, regardless of the sex of the partner. In the winter/spring, however, the probability of laying eggs increased markedly with increased genetic dissimilarity, regardless of the sex of the partner. Our findings indicate that reproductive decisions are modulated by factors beyond male presence, and we discuss a number of alternative hypotheses that should be tested in future studies.