Integrated Experimental and Theoretical Investigation of Copper Active Site Properties of a Lytic Polysaccharide Monooxygenase from Serratia marcescens.

In this paper, we employed a multidisciplinary approach, combining experimental techniques and density functional theory (DFT) calculations to elucidate key features of the copper coordination environment of the bacterial lytic polysaccharide monooxygenase (LPMO) from Serratia marcescens (SmAA10). The structure of the holo-enzyme was successfully obtained by X-ray crystallography. We then determined the copper(II) binding affinity using competing ligands and observed that the affinity of the histidine brace ligands for copper is significantly higher than previously described. UV-vis, advanced electron paramagnetic resonance (EPR), and X-ray absorption spectroscopy (XAS) techniques, including high-energy resolution fluorescence detected (HERFD) XAS, were further used to gain insight into the copper environment in both the Cu(II) and Cu(I) redox states. The experimental data were successfully rationalized by DFT models, offering valuable information on the electronic structure and coordination geometry of the copper center. Finally, the Cu(II)/Cu(I) redox potential was determined using two different methods at ca. 350 mV vs NHE and rationalized by DFT calculations. This integrated approach not only advances our knowledge of the active site properties of SmAA10 but also establishes a robust framework for future studies of similar enzymatic systems.

Median mandibular cleft in SAMS syndrome - A rare case report.

Rationale: SAMS syndrome is a rare genetic disorder characterized by midline facial clefting, skeletal anomalies, and other defects. Salient Features: Among the craniofacial manifestations of SAMS syndrome is the presence of a median mandibular cleft (MMC). MMC is a rare occurrence and in this syndrome, it poses a complex challenge for both functional and aesthetic reasons. Patient. Findings: This rare case report describes the successful correction of an MMC in an 18-month-old child diagnosed with SAMS syndrome. Treatment: This report describes the presentation, diagnosis and treatment. The surgical intervention involved a meticulous, single stage, osseous reconstruction. The mechanism of MMC in SAMS syndrome is discussed. Outcomes: Early intervention for MMC in SAMS syndrome patients can offer promising outcomes.

A Conserved Second Sphere Residue Tunes Copper Site Reactivity in Lytic Polysaccharide Monooxygenases.

Lytic polysaccharide monooxygenases (LPMOs) are powerful monocopper enzymes that can activate strong C-H bonds through a mechanism that remains largely unknown. Herein, we investigated the role of a conserved glutamine/glutamate in the second coordination sphere. Mutation of the Gln in NcAA9C to Glu, Asp, or Asn showed that the nature and distance of the headgroup to the copper fine-tune LPMO functionality and copper reactivity. The presence of Glu or Asp close to the copper lowered the reduction potential and decreased the ratio between the reduction and reoxidation rates by up to 500-fold. All mutants showed increased enzyme inactivation, likely due to changes in the confinement of radical intermediates, and displayed changes in a protective hole-hopping pathway. Electron paramagnetic resonance (EPR) and X-ray absorption spectroscopic (XAS) studies gave virtually identical results for all NcAA9C variants, showing that the mutations do not directly perturb the Cu(II) ligand field. DFT calculations indicated that the higher experimental reoxidation rate observed for the Glu mutant could be reconciled if this residue is protonated. Further, for the glutamic acid form, we identified a Cu(III)-hydroxide species formed in a single step on the H2O2 splitting path. This is in contrast to the Cu(II)-hydroxide and hydroxyl intermediates, which are predicted for the WT and the unprotonated glutamate variant. These results show that this second sphere residue is a crucial determinant of the catalytic functioning of the copper-binding histidine brace and provide insights that may help in understanding LPMOs and LPMO-inspired synthetic catalysts.

Adapting wine grape production to climate change through canopy architecture manipulation and irrigation in warm climates.

Grape growing regions are facing constant warming of the growing season temperature as well as limitations on ground water pumping used for irrigating to overcome water deficits. Trellis systems are utilized to optimize grapevine production, physiology, and berry chemistry. This study aimed to compare 6 trellis systems with 3 levels of applied water amounts based on different replacements of crop evapotranspiration (ETc) in two consecutive seasons. The treatments included a vertical shoot position (VSP), two modified VSPs (VSP60 and VSP80), a single high wire (SH), a high quadrilateral (HQ), and a Guyot pruned VSP (GY) combined with 25%, 50%, and 100% ETc water replacement. The SH had greater yields, whereas HQ was slower to reach full production potential. At harvest in both years, the accumulation of anthocyanin derivatives was enhanced in SH, whereas VSPs decreased them. As crown porosity increased (mostly VSPs), berry flavonol concentration and likewise molar % of quercetin in berries increased. Conversely, as leaf area increased, total flavonol concentration and molar % of quercetin decreased, indicating a preferential arrangement of leaf area along the canopy for overexposure of grape berry with VSP types. The irrigation treatments revealed linear trends for components of yield, where greater applied water resulted in larger berry size and likewise greater yield. 25% ETc was able to increase berry anthocyanin and flavonol concentrations. Overall, this study evidenced the efficiency of trellis systems for optimizing production and berry composition in Californian climate, also, the feasibility of using flavonols as the indicator of canopy architecture.

Idiopathic bilateral mandibular condylar resorption causing anterior open bite - A case report.

Introduction: Mandibular condylar resorption (MCR) is a rare pathological entity, often affecting young females. Patient Concerns: It is accompanied by pain, malocclusion and compromised quality of life including aesthetic perception. Due to this multiplicity of features, the diagnosis, treatment and management of MCR are always a challenge. Diagnosis: This article reports a 25-year-old female suffering from progressive temporomandibular joint pain and compromised aesthetics. This article describes the clinical and radiological findings of this case. Treatment: The possible aetiopathogenesis and treatment are described.

Distinct C4 sub-types and C3 bundle sheath isolation in the Paniceae grasses.

In C4 plants, the enzymatic machinery underpinning photosynthesis can vary, with, for example, three distinct C4 acid decarboxylases being used to release CO2 in the vicinity of RuBisCO. For decades, these decarboxylases have been used to classify C4 species into three biochemical sub-types. However, more recently, the notion that C4 species mix and match C4 acid decarboxylases has increased in popularity, and as a consequence, the validity of specific biochemical sub-types has been questioned. Using five species from the grass tribe Paniceae, we show that, although in some species transcripts and enzymes involved in multiple C4 acid decarboxylases accumulate, in others, transcript abundance and enzyme activity is almost entirely from one decarboxylase. In addition, the development of a bundle sheath isolation procedure for a close C3 species in the Paniceae enables the preliminary exploration of C4 sub-type evolution.

Single-Step Sulfur Insertions into Iron Carbide Carbonyl Clusters: Unlocking the Synthetic Door to FeMoco Analogues.

The one-step syntheses, X-ray structures, and spectroscopic characterization of synthetic iron clusters, bearing either inorganic sulfides or thiolate with interstitial carbide motifs, are reported. Treatment of iron carbide carbonyl clusters [Fen (µn -C)(CO)m ]x (n=5,6; m=15,16; x=0,-2) with electrophilic sulfur sources (S2 Cl2 , S8 ) results in the formation of several µ4 -S dimers of clusters, and moreover, iron-sulfide-(sulfocarbide) clusters. The core sulfocarbide unit {C-S}4- serves as a structural model for a proposed intermediate in the radical S-adenosyl-L-methionine biogenesis of the M-cluster. Furthermore, the electrophilic sulfur strategy has been extended to provide the first ever thiolato-iron-carbide complex: an analogous reaction with toluylsulfenyl chloride affords the cluster [Fe5 (µ5 -C)(SC7 H7 )(CO)13 ]- . The strategy described herein provides a breakthrough towards developing syntheses of biomimetic iron-sulfur-carbide clusters like FeMoco.

Spectroscopic X-ray and Mössbauer Characterization of M6 and M5 Iron(Molybdenum)-Carbonyl Carbide Clusters: High Carbide-Iron Covalency Enhances Local Iron Site Electron Density Despite Cluster Oxidation.

The present study employs a suite of spectroscopic techniques to evaluate the electronic and bonding characteristics of the interstitial carbide in a set of iron-carbonyl-carbide clusters, one of which is substituted with a molybdenum atom. The M6C and M5C clusters are the dianions (Et4N)2[Fe6(µ6-C)(µ2-CO)2(CO)14] (1), [K(benzo-18-crown-6)]2[Fe5(µ5-C)(µ2-CO)1(CO)13] (2), and [K(benzo-18-crown-6)]2[Fe5Mo(µ6-C)(µ2-CO)2(CO)15] (3). Because 1 and 2 have the same overall cluster charge (2-) but different numbers of iron sites (1: 6 sites → 2: 5 sites), the metal atoms of 2 are formally oxidized compared to those in 1. Despite this, Mössbauer studies indicate that the iron sites in 2 possess significantly greater electron density (lower spectroscopic oxidation state) compared with those in 1. Iron K-edge X-ray absorption and valence-to-core X-ray emission spectroscopy measurements, paired with density functional theory spectral calculations, revealed the presence of significant metal-to-metal and carbide 2p-based character in the filled valence and low-lying unfilled electronic manifolds. In all of the above experiments, the presence of the molybdenum atom in 3 (Fe5Mo) results in somewhat unremarkable spectroscopic properties that are essentially a "hybrid" of 1 (Fe6) and 2 (Fe5). The overall electronic portrait that emerges illustrates that the central inorganic carbide ligand is essential for distributing charge and maximizing electronic communication throughout the cluster. It is evident that the carbide coordination environment is quite flexible and adaptive: it can drastically modify the covalency of individual Fe-C bonds based on local structural changes and redox manipulation of the clusters. In light of these findings, our data and calculations suggest a potential role for the central carbon atom in FeMoco, which likely performs a similar function in order to maintain cluster integrity through multiple redox and ligand binding events.

Body Mass Index From Early-, Mid-, and Older-Adulthood and Risk of Heart Failure and Atherosclerotic Cardiovascular Disease: MESA.

Background Obesity contributes significantly to risk of atherosclerotic cardiovascular disease (ASCVD) and especially for heart failure (HF). An elevated body mass index (BMI) in older adults might not carry the same risk as in younger adults, but measured weights at other lifetime points are often not available. We determined the associations of self-reported weights from early- and mid-adulthood, after accounting for measured weight at older age, with incident HF/ASCVD risk. Methods and Results We studied 6437 MESA (Multi-Ethnic Study of Atherosclerosis) participants (aged 45-84, free of baseline HF/ASCVD) with self-reported weights at ages 20 and 40 years (by questionnaire), measured weights at up to 5 in-person examinations (2000-2012), and follow-up for adjudicated HF/ASCVD events. Participant mean±SD age at the baseline examination was 62.2±10.2 years. Over median follow-up of 13 years, 290 HF and 828 ASCVD events occurred. After adjustment for cardiovascular risk factors and baseline BMI, higher self-reported weights at ages 20 and 40 years were independently associated with increased risk of incident HF with hazard ratios (95% confidence interval) of 1.27 (1.07-1.50) and 1.36 (1.18-1.57), respectively, per 5-kg/m2 higher BMI. For incident ASCVD, only higher BMI at age 20 years was associated after accounting for current BMI (1.13 [1.01-1.26] per 5 kg/m2). Obesity during follow-up examinations was also associated with incident HF (1.72 [1.21-2.45]) but not ASCVD. Conclusions Self-reported lifetime weight is a low-tech tool easily utilized in any clinical encounter. Although subject to recall bias, self-reported weights may provide prognostic information about future HF risk, incremental to current BMI, in a multiethnic cohort of middle-aged to older adults. Clinical Trial Registration URL: http://www.clinicaltrials.gov . Unique identifier: NCT00005487.

Crystal structure of bis-(aceto-nitrile-κN)(4,4'-di-tert-butyl-2,2'-bi-pyridine-κ2N,N')platinum(II) bis-(tetra-fluorido-borate) packing as head-to-head dimers.

The crystal structure of a platinum(II) supra-molecular building block, [Pt(dbbpy)(NCCH3)2](BF4)2 (dbbpy = 4,4'-di-tert-butyl-2,2'-bi-pyridine, C18H24N2) is an example of a rare head-to-head dimer, even with the bulky tert-butyl groups of the bi-pyridine. This packing motif still enables significant π-π inter-actions between two pyridyl groups, and may result from the close proximity of the tetra-fluorido-borate ions to the platinum(II) complexes, resulting in intra-molecular H⋯F distances between 2.156 and 2.573 Å.

Obstetric admissions to tertiary level intensive care unit - Prevalence, clinical characteristics and outcomes.

BACKGROUND AND AIMS: Obstetric admissions to the intensive care unit (ICU) are a subject of increasing interest, as it is an indirect indicator of maternal morbidity and mortality. The studies from areas reported to have a higher maternal mortality rate are lacking. Thus, we undertook this study to determine the prevalence pattern, clinical characteristics and outcome of obstetric patients admitted to the ICU of a tertiary care hospital. METHODS: All obstetric patients (up till 42 days of delivery) admitted to the ICU from 1st October 2015 to 30th September 2016 and from 1st October 2010 to 30th September 2015 were included. Data collected for our study included demographic characteristics, Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II score at the time of admission, obstetric and medical history, provisional diagnosis, the reason for ICU admission, interventions required in ICU and the outcome. RESULTS: The third trimester (46.79%) and postpartum period (40.37%) were the most common time of admission with conditions such as severe pre-eclampsia, eclampsia, HELLP syndrome (Haemolysis, elevated liver enzymes, low platelet count), antepartum haemorrhage, postpartum haemorrhage and anaemia. The mean APACHE II score was 16.89 ± 7.48 with a mortality rate of 17.76%. The mean length of stay in ICU was 3.47 ± 3.16 days, and mean length of stay in our hospital was 8.78 ± 6.76 days. CONCLUSION: Obstetric patients recover well if treated early. A good ICU care with monitoring can save a young productive life.

Fe5Mo Cluster with Iron-Carbide and Molybdenum-Carbide Bonding Motifs: Structure and Selective Alkyne Reductions.

Herein we report the synthesis, X-ray structure, and characterization of the title pentairon (molybdo)carbido cluster. The reaction of the pentairon (µ5-carbido) dianion [Fe5(µ6-C)(µ2-CO)2(CO)12]2- (1) with [Mo(CO)3(chpt)] (chpt = cycloheptatriene) forms the heterohexanuclear cluster [K(benzo-18-crown-6)]2[Fe5Mo(µ6-C)(µ2-CO)3(CO)14] (2). The dianion exhibits a Fe5Mo(µ6-C) core structure supported by three bridging (νCO = 1788 cm-1) and terminal (νCO = 1943 cm-1) CO ligands. Cluster 2 provides the selective reduction of diphenylacetylene to cis-diphenylethylene via a spectroscopically observed cluster-hydride intermediate (1H NMR: δ -26).

Structures, Interconversions, and Spectroscopy of Iron Carbonyl Clusters with an Interstitial Carbide: Localized Metal Center Reduction by Overall Cluster Oxidation.

The syntheses, interconversions, and spectroscopic properties of a set of iron carbonyl clusters containing an interstitial carbide are reported. This includes the low temperature X-ray structures of the six-iron clusters (Y)2[Fe6(µ6-C)(µ2-CO)4(CO)12] (1a-c; where Y = NMe4, NEt4, PPh4); the five-iron cluster [Fe5(µ5-C)(CO)15] (3); and the novel formulation of the five-iron cluster (NMe4)2[Fe5(µ5-C)(µ2-CO)(CO)13] (4). Also included in this set is the novel charge-neutral cluster, [Fe6(µ6-C)(CO)18] (2), for which we were unable to obtain a crystallographic structure. As synthetic proof for the identity of 2, we performed a closed loop of interconversions within a family of crystallographically defined species (1, 3, and 4): [Fe6]2- → [Fe6]0 → [Fe5]0 → [Fe5]2- → [Fe6]2-. The structural, spectroscopic, and electronic properties of this "missing link" cluster 2 were investigated by IR, Raman, XPS, and Mössbauer spectroscopies-as well as by DFT calculations. A single νCO feature (1965 cm-1) in the IR spectrum of 2, as well as a prominent Raman feature (νsymm = 1550 cm-1), are consistent with the presence of terminal carbonyls and a {(µ6-C)Fe6} arrangement of iron centers around the central carbide. The XPS of 2 exhibits a higher energy Fe 2p3/2 feature (707.4 eV) as compared to that of 1 (705.5 eV), consistent with the two-electron oxidation induced by treatment of 1 with two equivalents of [Fc](PF6) under CO atmosphere (for the two added CO ligands). DFT calculations indicate two axial and four equatorial Fe sites in 1, all of which have the same or similar oxidation states, for example, two Fe(0) and four Fe(+0.5). These assignments are supported by Mössbauer spectra for 1, which exhibit two closely spaced quadrupole doublets with δ = 0.076 and 0.064 mm s-1. The high-field Mössbauer spectrum of 2 (4.2 K) exhibits three prominent quadrupole doublets with δ = -0.18, -0.11, and +0.41 mm s-1. This indicates three pairs of chemically equivalent Fe sites. The first two pairs arise from irons of a similar oxidation state, while the last pair arises from irons in a different oxidation state, indicating a mixed-valent cluster. Variable field Mössbauer spectra for 2 were simulated assuming these two groups and a diamagnetic ground state. Taken together, the Mössbauer results and DFT calculations for 2 indicate two axial Fe(II) sites and four equatorial sites of lower valence, probably Fe(0). In the DFT optimized pentagonal bipyramidal structure for 2, the Fe(II)-Ccarbide distances are compressed (∼1.84 Å), while the Fe(0)-Ccarbide distances are elongated (∼2.05 Å). Analysis of the formulations for 1 (closo-square bipyramid) and 2 (nido-pentagonal bipyramid) is considered in the context of the textbook electron-counting rules of 14n+2 and 14n+4 for closo and nido clusters, respectively. This redox-dependent intracluster disproportionation of Fe oxidation states is concluded to arise from changes in bonding to the central carbide. A similar phenomenon may be promoted by the central carbide of the FeMoco cluster of nitrogenase, which may in turn stimulate N2 reduction.

Associations Between At-Risk Alcohol Use, Substance Use, and Smoking with Lipohypertrophy and Lipoatrophy Among Patients Living with HIV.

OBJECTIVE: To examine associations between lipohypertrophy and lipoatrophy and illicit drug use, smoking, and at-risk alcohol use among a large diverse cohort of persons living with HIV (PLWH) in clinical care. METHODS: 7,931 PLWH at six sites across the United States completed 21,279 clinical assessments, including lipohypertrophy and lipoatrophy, drug/alcohol use, physical activity level, and smoking. Lipohypertrophy and lipoatrophy were measured using the FRAM body morphology instrument and associations were assessed with generalized estimating equations. RESULTS: Lipohypertrophy (33% mild, 4% moderate-to-severe) and lipoatrophy (20% mild, 3% moderate-to-severe) were common. Older age, male sex, and higher current CD4 count were associated with more severe lipohypertrophy (p values <.001-.03). Prior methamphetamine or marijuana use, and prior and current cocaine use, were associated with more severe lipohypertrophy (p values <.001-.009). Older age, detectable viral load, and low current CD4 cell counts were associated with more severe lipoatrophy (p values <.001-.003). In addition, current smoking and marijuana and opiate use were associated with more severe lipoatrophy (p values <.001-.03). Patients with very low physical activity levels had more severe lipohypertrophy and also more severe lipoatrophy than those with all other activity levels (p values <.001). For example, the lipohypertrophy score of those reporting high levels of physical activity was on average 1.6 points lower than those reporting very low levels of physical activity (-1.6, 95% CI: -1.8 to -1.4, p < .001). CONCLUSIONS: We found a high prevalence of lipohypertrophy and lipoatrophy among a nationally distributed cohort of PLWH. While low levels of physical activity were associated with both lipohypertrophy and lipoatrophy, associations with substance use and other clinical characteristics differed between lipohypertrophy and lipoatrophy. These results support the conclusion that lipohypertrophy and lipoatrophy are distinct, and highlight differential associations with specific illicit drug use.

Development of a new diabetes risk prediction tool for incident coronary heart disease events: the Multi-Ethnic Study of Atherosclerosis and the Heinz Nixdorf Recall Study.

OBJECTIVE: We develop a new diabetes CHD risk estimator using traditional risk factors plus coronary artery calcium (CAC), ankle-brachial index (ABI), high sensitivity C-reactive protein, family history of CHD, and carotid intima-media thickness and compared it with United Kingdom Prospective Diabetes study (UKPDS), Framingham risk and the NCEP/ATP III risk scores in type 2 diabetes mellitus (T2DM). METHODS AND RESULTS: We combined data from T2DM without clinical CVD in the Multi-Ethnic Study of Atherosclerosis (MESA) and the Heinz Nixdorf Recall Study (N = 1343). After a mean follow-up of 8.5 years, 85 (6.3%) participants had incident CHD. Among the novel risk markers, CAC best predicted CHD independent of the FRS [hazard ratio: HR (95% CI): log (CAC +25):1.69 (1.45-1.97), p < 0.0001; CAC categories: CAC ≤ 25 as reference, >25 and ≤125:2.29 (0.87-5.95), >125 and ≤400: 3.87 (1.57-9.57), >400: 5.97 (2.57-13.84), respectively). The MESA-HNR diabetes CHD risk score has better accuracy for the main outcome versus the FRS or UKPDS [area under curve (AUC) of 0.76 vs. 0.70 and 0.69, respectively; all p < 0.05]. The MESA-HNR risk score improved risk classification versus the FRS (net reclassification improvement (NRI) = 0.19 and integrated discrimination improvement (IDI) = 0.046, p < 0.05) and UKPDS (NRI = 0.215 and IDI = 0.046, p < 0.05). Compared with the ATP III guidelines, the MESA-HNR score has an NRI of 0.74 for the main outcome. CONCLUSIONS: This new CHD risk estimator has better discriminative ability for incident CHD than the FRS, UKPDS, and the ATP III/NCEP recommendations in a multi-ethnic cohort with T2DM.

Implementation of resource management plans: identifying keys to success.

One of the primary challenges in resource and environmental planning is successful implementation of plans. Plan implementation is a complex process influenced by many factors. This study identifies 19 criteria affecting implementation success and tests the impact of these criteria through a case study of collaborative plan implementation in British Columbia, Canada. The significance of criteria and degree to which they are met is assessed by a survey of senior officials responsible for plan implementation. An implementation evaluation index (IEI) is constructed to assess the quality of plan implementation systems and best practices for effective implementation are identified.