Redox-active ligands - a viable route to reactive main group metal compounds.

Anionic redox-active ligands such as o-amidophenolates, catecholates, dithiolenes, 1,2-benzendithiolates, 2-amidobenzenethiolates, reduced α-diimines, ferrocenyl and porphyrinates are capable of reversible oxidation and thus have the ability to act as sources of electrons for metal centres. These and other non-innocent ligands have been employed in coordination complexes of base transition metals to influence their redox chemistry and afford compounds with useful catalytic, optical, magnetic and conducting properties. Despite the focus in contemporary main group chemistry on designing reactive compounds with potential catalytic activity, comparatively few studies exploring the chemistry of main group metal complexes incorporating redox-active ligands have been reported. This article highlights relevant chemical reactivity and electrochemical studies that probe the oxidation/reduction of main group metal compounds possessing redox-active ligands and comments on the prospects for this relatively untapped avenue of research.

Acoustic ducting by shelf water streamers at the New England shelfbreak.

Greater sound speed variability has been observed at the New England shelfbreak due to a greater influence from the Gulf Stream with increased meander amplitudes and frequency of Warm Core Ring (WCR) generation. Consequently, underwater sound propagation in the area also becomes more variable. This paper presents field observations of an acoustic near-surface ducting condition induced by shelf water streamers that are related to WCRs. The field observations also reveal the subsequent disappearance of the streamer duct due to the passage of a WCR filament. These two water column conditions are investigated with sound propagation measurements and numerical simulations.

Brain PET and SPECT imaging and quantification: a survey of the current status in the UK.

OBJECTIVES: With disease-modifying therapies in development for neurological disorders, quantitative brain imaging techniques become increasingly relevant for objective early diagnosis and assessment of response to treatment. The aim of this study was to evaluate the use of Brain SPECT and PET scans in the UK and explore drivers and barriers to using quantitative analysis through an online survey. METHODS: A web-based survey with 27 questions was used to capture a snapshot of brain imaging in the UK. The survey included multiple-choice questions assessing the availability and use of quantification for DaTscan, Perfusion SPECT, FDG PET and Amyloid PET. The survey results were reviewed and interpreted by a panel of imaging experts. RESULTS: Forty-six unique responses were collected and analysed, with 84% of responses from brain imaging sites. Within these sites, 88% perform DaTscan, 50% Perfusion SPECT, 48% FDG PET, and 33% Amyloid PET, while a few sites use other PET tracers. Quantitative Brain analysis is used in 86% of sites performing DaTscans, 40% for Perfusion SPECT, 63% for FDG PET and 42% for Amyloid PET. Commercial tools are used more frequently than in-house software. CONCLUSION: The survey showed variations across the UK, with high availability of DaTscan imaging and quantification and lower availability of other SPECT and PET scans. The main drivers for quantification were improved reporting confidence and diagnostic accuracy, while the main barriers were a perception of a need for an appropriate database of healthy controls and a lack of training, time, and software availability.

High-Risk Features Are Prognostic in dMMR/MSI-H Stage II Colon Cancer.

BACKGROUND: High-risk features, such as T4 disease, bowel obstruction, poorly/undifferentiated histology, lymphovascular, perineural invasion, and <12 lymph nodes sampled, indicate poor prognosis and define high-risk stage II disease in proficient mismatch repair stage II colon cancer (CC). The prognostic role of high-risk features in dMMR/MSI-H stage II CC is unknown. Similarly, the role of adjuvant therapy in high-risk stage II CC with dMMR/MSI-H (≥1 high-risk feature) has not been studied in prospective trials. The aim of this analysis of the National Cancer Database is to evaluate the prognostic value of high-risk features in stage II dMMR/MSI-H CC. METHODS: Univariate (UVA) and multivariate (MVA) Cox proportional hazards (Cox-PH) models were built to assess the association between clinical and demographic characteristics and overall survival. Kaplan-Meier survival curves were generated with log-rank tests to evaluate the association between adjuvant chemotherapy in high-risk and low-risk cohorts separately. RESULTS: A total of 2,293 stage II CC patients have dMMR/MSI-H; of those, 29.5% (n = 676) had high-risk features. The high-risk dMMR/MSI-H patients had worse overall survival [5-year survival and 95%CI, 73.2% (67.3-78.1%) vs. 80.3% (76.7-83.5%), p = 0.0001]. In patients with stage II dMMR/MSI-H CC, the high-risk features were associated with shorter overall survival (OS) along with male sex, positive carcinoembryonic antigen, Charlson-Deyo score >1, and older age. Adjuvant chemotherapy administration was associated with better OS, regardless of the high-risk features in dMMR/MSI-H (log-rank test, p = 0.001) or not (p = 0.0006). When stratified by age, the benefit of chemotherapy was evident only in patients age ≥65 with high-risk features. CONCLUSION: High-risk features are prognostic in the setting of dMMR/MSI-H stage II CC. Adjuvant chemotherapy may improve survival specifically in patients ≥65 years and with high-risk features.

Elderly Patients Benefit From Enhanced Recovery Protocols After Colorectal Surgery.

BACKGROUND: Enhanced recovery protocols (ERAS) aim to decrease physiological stress response to surgery and maintain postoperative physiological function. Proponents of ERAS state these protocols decrease lengths of stay (LOS) and complication rates. Our aim was to assess whether elderly patients receive the same benefit as younger patients using ERAS protocols. METHODS: We queried patients from 2015 to 2017 at our institution with Enhanced Recovery in Surgery (ERIN) variables from the targeted colectomy NSQIP database. The patients were divided into sextiles and analyzed for readmission, LOS, return of bowel function, tolerating diet, mobilization, and multimodal pain management comparing the youngest sextile to the oldest sextile. RESULTS: Two hundred sixty-two patients (73% colectomies) were enrolled in ERAS. When compared with the youngest sextile (age 19-43.8), the oldest sextile (age 71.4-92.5) had similar readmission rates at 9.8% versus 9.5% (P-value = 0.87), quicker return of bowel function, average 1.9 d versus 3.7 d (P-value < 0.01), and tolerated diet quicker, average POD 2.4 d versus 5.1 d (P-value < 0.01). There was a slight decrease in the use of multimodal pain management 88% versus 100% (P-value = 0.07), but mobilization on POD1 was slightly better in the elderly at 80% versus 78% (P-value = 0.76). Elderly patients enrolled in ERAS had an average LOS of 4.9 days versus 7.8 in the younger patients (P-value = 0.08). Among elderly non-ERAS patients average LOS was 14.6 days. CONCLUSION: Overall, elderly patients fared better or the same on the ERIN variables analyzed than the younger cohort. ERAS protocols are beneficial and applicable to elderly patients undergoing colorectal surgery.

Short-range quorum sensing controls horizontal gene transfer at micron scale in bacterial communities.

In bacterial communities, cells often communicate by the release and detection of small diffusible molecules, a process termed quorum-sensing. Signal molecules are thought to broadly diffuse in space; however, they often regulate traits such as conjugative transfer that strictly depend on the local community composition. This raises the question how nearby cells within the community can be detected. Here, we compare the range of communication of different quorum-sensing systems. While some systems support long-range communication, we show that others support a form of highly localized communication. In these systems, signal molecules propagate no more than a few microns away from signaling cells, due to the irreversible uptake of the signal molecules from the environment. This enables cells to accurately detect micron scale changes in the community composition. Several mobile genetic elements, including conjugative elements and phages, employ short-range communication to assess the fraction of susceptible host cells in their vicinity and adaptively trigger horizontal gene transfer in response. Our results underscore the complex spatial biology of bacteria, which can communicate and interact at widely different spatial scales.

Nutrient complexity triggers transitions between solitary and colonial growth in bacterial populations.

Microbial populations often experience fluctuations in nutrient complexity in their natural environment such as between high molecular weight polysaccharides and simple monosaccharides. However, it is unclear if cells can adopt growth behaviors that allow individuals to optimally respond to differences in nutrient complexity. Here, we directly control nutrient complexity and use quantitative single-cell analysis to study the growth dynamics of individuals within populations of the aquatic bacterium Caulobacter crescentus. We show that cells form clonal microcolonies when growing on the polysaccharide xylan, which is abundant in nature and degraded using extracellular cell-linked enzymes; and disperse to solitary growth modes when the corresponding monosaccharide xylose becomes available or nutrients are exhausted. We find that the cellular density required to achieve maximal growth rates is four-fold higher on xylan than on xylose, indicating that aggregating is advantageous on polysaccharides. When collectives on xylan are transitioned to xylose, cells start dispersing, indicating that colony formation is no longer beneficial and solitary behaviors might serve to reduce intercellular competition. Our study demonstrates that cells can dynamically tune their behaviors when nutrient complexity fluctuates, elucidates the quantitative advantages of distinct growth behaviors for individual cells and indicates why collective growth modes are prevalent in microbial populations.

Receipt of Adjuvant Chemotherapy in Stage II Colon Cancer and Overall Survival: A National Cancer Database Study.

BACKGROUND: There are variations in the use of adjuvant chemotherapy (AC) in stage II colon cancer (CRC). We sought to determine which patients received chemotherapy, what factors were associated with receipt of AC, and how this impacted overall survival. METHODS: Using the National Cancer Database, patients with stage II CRC who underwent surgical resection were selected; patients who received radiation or neoadjuvant chemotherapy were excluded. High-risk features (HRFs) were defined as pathological tumor stage IV, positive surgical margins, and perineural or lymphovascular invasion. Multivariable and subgroup analysis with eight subgroups stratified in the presence of HRFs, age, and the Charlson-Deyo score was performed. RESULTS: Of 77,739 patients identified with stage II CRC, 18.3% received AC. Younger, healthier patients with HRFs had the highest chemotherapy receipt rate (46.7%), whereas patients without HRFs, ≥ 75 y, and with the Charlson-Deyo score of 2+ had the lowest rate (2.1%). Community cancer centers were more likely to initiate AC (odds ratio = 1.24 P < 0.01) especially among healthy HRF-negative patients and younger patients. No significant racial differences in AC use were observed. AC was associated with improved overall survival in subgroups with HRFs (hazard ratio [HR]: 0.81 P < 0.001; HR: 0.75 P < 0.001; HR: 0.65 P = 0.03; HR: 0.55, P < 0.001) but not in patients without HRFs. CONCLUSIONS: AC receipt rates differed depending on patient age and type of institution delivering care. AC was associated with survival benefits only in patients with HRFs regardless of age. These findings are clinically relevant to inform appropriate use of AC in stage II CRC.

Phenotypic variation in spatially structured microbial communities: ecological origins and consequences.

Microbial cells in nature live within dense multispecies conglomerates, forming a self-organizing ecosystem. In such assemblies, genotypes interact with each other in a myriad of ways, driving community dynamics and functionalities. The role of interactions between genotypes and their consequences for spatial structure and functional outcomes are being increasingly studied to understand the ecology and evolution of microbial communities. An increasing body of work with simple microbial populations has elucidated that phenotypic variation, that is, differences within isogenic cells can have important consequences for population dynamics and evolution. However, the role of individual level behavioral differences for community level dynamics is relatively unknown. I argue that it is necessary to study phenotypic variation and microscale processes in order to understand the emergence and consequences of interactions within microbial communities. I highlight possible explanations that can explain the emergence of variation in multi-genotypic assemblages and propose possible consequences on community dynamics.

A Collaborative Approach to Pain Control Reduces In-hospital Opioid Use and Improves Range of Motion following Total Knee Arthroplasty.

INTRODUCTION: Opioid pain medications are commonly prescribed following orthopedic procedures, with overprescribing of these pain medications implicated as a driver of the current opioid epidemic. In an effort to reduce reliance on opioid pain medications, surgeons are relying on periarticular injections or peripheral nerve blocks. The purpose of this study was to compare numerical rating scale (NRS) pain scores and oral morphine equivalents (OMEs) in patients who underwent primary total knee arthroplasty (TKA) with a periarticular injection alone to those who underwent a collaborative approach with a periarticular injection in the posterior tissue and an adductor canal catheter for anterior knee analgesia. METHODS: In this study, 236 patients underwent a primary TKA between December 2017 and April 2018. Forty patients received an adductor canal catheter and 196 underwent a periarticular injection alone. RESULTS: We found no difference in patient demographics between the cohorts (p>0.05). The patients that underwent the collaborative approach with a periarticular injection and adductor canal catheter had lower NRS pain scores on post-operative day 0, 1, and 2 (all P≤0.033). These patients demonstrated a reduction of 43% in opioid consumption during the hospitalization (P<0.001). These patients also demonstrated improved range of motion (ROM) (96 vs. 92 degrees) on the day of discharge (P=0.013). CONCLUSION: This study provides strong evidence that in patients undergoing TKA, the collaborative approach with the adductor canal catheter and periarticular injection is associated with lower post-operative pain scores, fewer total OMEs per hospital day, and a greater ROM arc prior to discharge compared to patients receiving a periarticular injection alone.

Synthesis and crystal structure of bis-(µ-2-methyl-benzene-thiol-ato-κ2S:S)bis-[meth-yl(2-methyl-benzene-thiol-ato-κS)indium(III)].

The dinuclear title compound, [In2(CH3)2(C7H7S)4] or [Me(2-MeC6H4S)In-µ-(2-MeC6H4S)2InMe(2-MeC6H4S)], was prepared from the 1:2 reaction of Me3In and 2-MeC6H4SH in toluene. Its crystal structure exhibits a four-membered In2S2 ring core via bridging (2-MeC6H4S) groups. The dimeric units are further associated into a one-dimensional polymeric structure extending parallel to the a axis via inter-molecular In⋯S contacts. The In atoms are then in distorted trigonal-bipyramidal CS4 bonding environments.

Crystal structure of dimethyl-1κ(2) C-bis(µ-4-methylphenolato-1:2κ(2) O:O)(N,N,N',N'-tetramethylethylenediamine-2κ(2) N,N')indium(III)lithium(I).

The mixed bimetallic title compound, [InLi(CH3)2(C7H7O)2(C6H16N2)] or [(tmeda)Li-µ-(4-MeC6H4O)2InMe2] (tmeda is N,N,N',N'-tetra-methyl-ethylenedi-amine), exhibits a four-membered LiO2In ring core via bridging 4-methyl-phenolate groups. The Li and In atoms are in distorted tetra-hedral N2O2 and C2O2 bonding environments, respectively. The Li atom is further chelated by a tmeda group, yielding a spiro-cyclic structure.

Structural variation in ethylenediamine and -diphosphine adducts of (2,6-Me2C6H3S)2Pb: a single crystal X-ray diffraction and 207Pb solid-state NMR spectroscopy study.

Coordination complexes of (2,6-Me2C6H3S)2Pb (1) with flexible bidentate ligands have been prepared to explore new bonding environments for Pb(II) thiolates. The reaction of 1 with a series of ethylenediamine and ethylenediphosphine ligands resulted in isolation of the adducts [(2,6-Me2C6H3S)2Pb]2(tmeda) (9), [(2,6-Me2C6H3S)2Pb]3(dmpe) (10) and [(2,6-Me2C6H3S)2Pb]2(dppe) (11) [tmeda = N,N,N',N'-tetramethylethylenediamine; dmpe = bis(dimethylphosphino)ethane; dppe = bis(diphenylphosphino)ethane]. The X-ray crystal structure of 9 shows a dinuclear species in which tmeda is chelating a ψ-trigonal bipyramidal S2N2 Pb centre via axial and equatorial sites. The structure of 10 displays a trinuclear structural unit in which dmpe is chelating a ψ-trigonal bipyramidal S2P2 Pb centre via equatorial sites. Compounds 9 and 10 also contain a second unique metal centre with ψ-tetrahedral S3Pb bonding motifs. The structure of 11 shows the dppe ligand bridging two Pb ψ-tetrahedral S2P metal bonding environments. Static (207)Pb solid-state NMR (SSNMR) spectra of 9-11 and [Ph4As][(PhS)3Pb] (12) were acquired with cross polarization (CP)-CPMG and frequency swept pulse (WURST)-CPMG pulse sequences, and the efficiencies of these pulse sequences are compared. The (207)Pb SSNMR spectra reveal that the lead chemical shift anisotropies (CSA) vary greatly between the different Pb sites, and are generally large in magnitude. DFT calculations are utilized to relate the orientations of the (207)Pb nuclear magnetic shielding tensors to the molecular structures, and to aid in spectral assignment where multiple Pb centres are present. The combination of X-ray diffraction, (207)Pb SSNMR and DFT is shown to be invaluable for the structural characterization of these important structural motifs, and should find wide-ranging application to numerous lead coordination compounds.

catena-Poly[bis-[dimeth-yl(pyridine-κN)indium(III)]-µ4-benzene-1,3-diolato-bis-[di-methyl-indium(III)]-µ4-benzene-1,3-diolato].

The title compound, [In2(CH3)4(C6H4O2)(C5H5N)] or [{(CH3)2In}(1,3-O2C6H4){In(CH3)2(py)}] n , (py = pyridine) contains two crystallographically unique In(III) ions which are in distorted tetra-hedral C2O2 and distorted trigonal-bipyramidal C2O2N coordination environments. The In(III) coordination centers are bridged head-to-head via In-O bonds, yielding four-membered In2O2 rings and zigzag polymeric chains along [001].

Direct interaction between the Gulf Stream and the shelfbreak south of New England.

Sea surface temperature imagery, satellite altimetry, and a surface drifter track reveal an unusual tilt in the Gulf Stream path that brought the Gulf Stream to 39.9°N near the Middle Atlantic Bight shelfbreak--200 km north of its mean position--in October 2011, while a large meander brought Gulf Stream water within 12 km of the shelfbreak in December 2011. Near-bottom temperature measurements from lobster traps on the outer continental shelf south of New England show distinct warming events (temperature increases exceeding 6°C) in November and December 2011. Moored profiler measurements over the continental slope show high salinities and temperatures, suggesting that the warm water on the continental shelf originated in the Gulf Stream. The combination of unusual water properties over the shelf and slope in late fall and the subsequent mild winter may affect seasonal stratification and habitat selection for marine life over the continental shelf in 2012.

V-ATPase V1 sector is required for corpse clearance and neurotransmission in Caenorhabditis elegans.

The vacuolar-type ATPase (V-ATPase) is a proton pump composed of two sectors, the cytoplasmic V(1) sector that catalyzes ATP hydrolysis and the transmembrane V(o) sector responsible for proton translocation. The transmembrane V(o) complex directs the complex to different membranes, but also has been proposed to have roles independent of the V(1) sector. However, the roles of the V(1) sector have not been well characterized. In the nematode Caenorhabditis elegans there are two V(1) B-subunit genes; one of them, vha-12, is on the X chromosome, whereas spe-5 is on an autosome. vha-12 is broadly expressed in adults, and homozygotes for a weak allele in vha-12 are viable but are uncoordinated due to decreased neurotransmission. Analysis of a null mutation demonstrates that vha-12 is not required for oogenesis or spermatogenesis in the adult germ line, but it is required maternally for early embryonic development. Zygotic expression begins during embryonic morphogenesis, and homozygous null mutants arrest at the twofold stage. These mutant embryos exhibit a defect in the clearance of apoptotic cell corpses in vha-12 null mutants. These observations indicate that the V(1) sector, in addition to the V(o) sector, is required in exocytic and endocytic pathways.

On whether azimuthal isotropy and alongshelf translational invariance are present in low-frequency acoustic propagation along the New Jersey shelfbreak.

To understand the issues associated with the presence (or lack) of azimuthal isotropy and horizontal (along isobath) invariance of low-frequency (center frequencies of 600 Hz and 900 Hz) acoustic propagation in a shelfbreak environment, a series of experiments were conducted under the Autonomous Wide-Aperture Cluster for Surveillance component of the Shallow Water 2006 experiment. Transmission loss data reported here were from two mobile acoustic sources executing (nearly) circular tracks transmitting to sonobuoy receivers in the circle centers, and from one 12.5 km alongshelf acoustic track. The circle radii were 7.5 km. Data are from September 8, 2006. Details of the acoustic and environmental measurements are presented. Simple analytic and computer models are used to assess the variability expected due to the ocean and seabed conditions encountered. A comparison of model results and data is made, which shows preliminary consistency between the data and the models, but also points towards further work that should be undertaken specifically in enlarging the range and frequency parameter space, and in looking at integrated transmission loss.

Long distance passive localization of vocalizing sei whales using an acoustic normal mode approach.

During a 2 day period in mid-September 2006, more than 200, unconfirmed but identifiable, sei whale (Balaenoptera borealis) calls were collected as incidental data during a multidisciplinary oceanography and acoustics experiment on the shelf off New Jersey. Using a combined vertical and horizontal acoustic receiving array, sei whale movements were tracked over long distances (up to tens of kilometers) using a normal mode back propagation technique. This approach uses low-frequency, broadband passive sei whale call receptions from a single-station, two-dimensional hydrophone array to perform long distance localization and tracking by exploiting the dispersive nature of propagating normal modes in a shallow water environment. The back propagation approach is examined for accuracy and application to tracking the sei whale vocalizations identified in the vertical and horizontal array signals. This passive whale tracking, combined with the intensive oceanography measurements performed during the experiment, was also used to examine sei whale movements in relation to oceanographic features observed in this region.

catena-Poly[[bis(pyridine)-lead(II)]bis(µ-penta-fluoro-benzene-thiol-ato)].

The title compound, [Pb(C(6)F(5)S)(2)(C(5)H(5)N)(2)](n), shows the Pb(II) atom in a ψ-trigonal bipyramidal S(2)N(2) bonding environment. Pyridine N atoms occupy axial sites, while thiol-ate S atoms and a stereochemically active lone pair occupy equatorial sites. Very long inter-molecular Pb⋯S inter-actions [3.618 (4) and 3.614 (4) Å] yield a weakly associated one-dimensional polymeric structure extending parallel to [010].

Bis(µ-diethyl-phosphido-κP:P)bis-[bis(2,4,6-trimethyl-phen-yl)indium(III)].

The title compound, [In(2)(C(9)H(11))(4)(C(4)H(10)P)(2)], contains a centrosymmetric In(2)P(2) core with short inter-molecular In-P bonds. This core has acute P-In-P and obtuse In-P-In bond angles compared with other [R(2)InPR'(2)](2) analogues, due to the presence of the bulky aromatic substituents on the In atom and the non-sterically demanding ethyl substituents on the P atom.