A new supporting ligand, t ris-2-(3-mesityl-imidazol-2-ylidene)methylamine (TIMMNMes), was developed and utilized to isolate an air-stable iron(V) complex bearing a terminal nitrido ligand, which ...was synthesized by one-electron oxidation from the iron(IV) precursor. Single-crystal X-ray diffraction analyses of both complexes reveal that the metal-centered oxidation is escorted by iron nitride (FeN) bond elongation, which in turn is accompanied by the accommodation of the high-valence iron center closer to the equatorial plane of a trigonal bipyramid. This contrasts with the previous observation of the only other literature-known Fe(IV)N/Fe(V)N redox pair, namely, PhB(tBuIm)3FeN0/+. On the basis of 57Fe Mössbauer, EPR, and UV/vis electronic absorption spectroscopy as well as quantum chemical calculations, we identified the lesser degree of pyramidalization around the iron atom, the Jahn–Teller distortion, and the resulting nature of the SOMO to be the decisive factors at play.
The reaction of the cobalt(I) complex (TIMMNmes)CoI(BPh4) (2) (TIMMNmes=tris‐2‐(3‐mesitylimidazolin‐2‐ylidene)methylamine) with 1‐adamantylazide yields the cobalt(III) imido complex ...(TIMMNmes)CoIII(NAd)(BPh4) (3) with concomitant release of dinitrogen. The N‐anchor in diamagnetic 3 features an unusual, planar tertiary amine, which results from repulsive electrostatic interaction with the filled d(z2)‐orbital of the cobalt ion and negative hyperconjugation with the neighboring methylene groups. One‐electron oxidation of 3 with FeCp2(OTf) provides access to the rare, high‐valent cobalt(IV) imido complex (TIMMNmes)CoIV(NAd)(OTf)2 (4). Despite a half‐life of less than 1 h at room temperature, 4 could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=1/2
, electron configuration. A computational analysis of 4 suggests high covalency within the CoIV=NAd bond with non‐negligible spin density located at the imido moiety, which translates into substantial triplet nitrene character.
Straightforward access to a cobalt(IV) terminal imido complex was provided by one‐electron oxidation of a cobalt(III) terminal imido precursor. The cobalt(IV) monoimido complex could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=1/2
, electron configuration.
3D building model reconstruction is of great importance for environmental and urban applications. Airborne light detection and ranging (LiDAR) is a very useful data source for acquiring detailed ...geometric and topological information of building objects. In this study, we employed a graph-based method based on hierarchical structure analysis of building contours derived from LiDAR data to reconstruct urban building models. The proposed approach first uses a graph theory-based localized contour tree method to represent the topological structure of buildings, then separates the buildings into different parts by analyzing their topological relationships, and finally reconstructs the building model by integrating all the individual models established through the bipartite graph matching process. Our approach provides a more complete topological and geometrical description of building contours than existing approaches. We evaluated the proposed method by applying it to the Lujiazui region in Shanghai, China, a complex and large urban scene with various types of buildings. The results revealed that complex buildings could be reconstructed successfully with a mean modeling error of 0.32 m. Our proposed method offers a promising solution for 3D building model reconstruction from airborne LiDAR point clouds.
The synthesis, characterization, and reactivity of a series of cobalt terminal imido complexes supported by an N-anchored tripodal tris(carbene) chelate is described, including a Co-supported ...singlet nitrene. Reaction of the CoI precursor (TIMMNmes)CoI(PF6) (TIMMNmes = tris-2-(3-mesityl-imidazolin-2-ylidene)-methylamine) with p-methoxyphenyl azide yields a CoIII imide (TIMMNmes)CoIII(NAnisole)(PF6) (1). Treatment of 1 with 1 equiv of FeCp2(PF6) at −35 °C affords a formal CoIV imido complex (TIMMNmes)Co(NAnisole)(PF6)2 (2), which features a bent Co–N(imido)–C(Anisole) linkage. Subsequent one-electron oxidation of 2 with 1 equiv of AgPF6 provides access to the tricationic cobalt imido complex (TIMMNmes)Co(NAnisole)(PF6)3 (3). All complexes were fully characterized, including single-crystal X-ray diffraction (SC-XRD) analyses, infrared (IR) vibrational, ultraviolet/visible (UV/vis) electronic absorption, multinuclear NMR, X-band electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR), and high-energy-resolution fluorescence-detected X-ray absorption spectroscopy (HERFD XAS). Quantum chemical calculations provide additional insight into the electronic structures of all compounds. The dicationic CoIV imido complex 2 exhibits a doublet ground state with considerable imidyl character as a result of covalent Co–NAnisole bonding. At room temperature, 2 readily converts to a CoII amine complex involving intramolecular C–H bond amination. Electronically, tricationic complex 3 can be understood as a singlet nitrene bound to CoIII with significant CoIV imidyl radical character. Verifying the pronounced electrophilicity, nucleophiles such as H2O and t BuNH2 add to 3analogous to the parent free nitrenein the para position of the aromatic substituent, thus, clearly corroborating singlet nitrene-type reactivity.
Solar energy, as a clean and renewable resource is becoming increasingly important in the global context of climate change and energy crisis. Utilization of solar energy in urban areas is of great ...importance in urban energy planning, environmental conservation, and sustainable development. However, available spaces for solar panel installation in cities are quite limited except for building roofs. Furthermore, complex urban 3D morphology greatly affects sunlit patterns on building roofs, especially in downtown areas, which makes the determination of roof solar energy potential a challenging task. The object of this study is to estimate the solar radiation on building roofs in an urban area in Shanghai, China, and select suitable spaces for installing solar panels that can effectively utilize solar energy. A Graphic Processing Unit (GPU)-based solar radiation model named SHORTWAVE-C simulating direct and non-direct solar radiation intensity was developed by adding the capability of considering cloud influence into the previous SHORTWAVE model. Airborne Light Detection and Ranging (LiDAR) data was used as the input of the SHORTWAVE-C model and to investigate the morphological characteristics of the study area. The results show that the SHORTWAVE-C model can accurately estimate the solar radiation intensity in a complex urban environment under cloudy conditions, and the GPU acceleration method can reduce the computation time by up to 46%. Two sites with different building densities and rooftop structures were selected to illustrate the influence of urban morphology on the solar radiation and solar illumination duration. Based on the findings, an object-based method was implemented to identify suitable places for rooftop solar panel installation that can fully utilize the solar energy potential. Our study provides useful strategic guidelines for the selection and assessment of roof solar energy potential for urban energy planning.
The effects of dulaglutide and a calorie-restricted diet (CRD) on visceral adipose tissue (VAT) and metabolic profiles in polycystic ovary syndrome (PCOS) have not been extensively investigated. In ...this study, we investigated whether dulaglutide combined with CRD could further reduce VAT and promote clinical benefits as compared with a CRD regimen alone in overweight or obese PCOS-affected women. Between May 2021 and May 2022, this single-center, randomized, controlled, open-label clinical trial was conducted. Overall, 243 participants with PCOS were screened, of which 68 overweight or obese individuals were randomly randomized to undergo dulaglutide combined with CRD treatment (
= 35) or CRD treatment alone (
= 33). The duration of intervention was set as the time taken to achieve a 7% weight loss goal from baseline body weight, which was restricted to 6 months. The primary endpoint was the difference in the change in VAT area reduction between the groups. The secondary endpoints contained changes in menstrual frequency, metabolic profiles, hormonal parameters, liver fat, and body composition. As compared with the CRD group, the dulaglutide + CRD group had a considerably shorter median time to achieve 7% weight loss. There was no significant between-group difference in area change of VAT reduction (-0.97 cm
, 95% confidence interval from -14.36 to 12.42,
= 0.884). As compared with CRD alone, dulaglutide + CRD had significant advantages in reducing glycated hemoglobin A1c and postprandial plasma glucose levels. The results of the analyses showed different changes in menstruation frequency, additional metabolic profiles, hormonal markers, liver fat, and body composition between the two groups did not differ significantly. Nausea, vomiting, constipation, and loss of appetite were the main adverse events of dulaglutide. These results emphasize the value of dietary intervention as the first line of treatment for PCOS-affected women, while glucagon-like peptide 1 receptor agonist therapy provides an efficient and typically well tolerated adjuvant therapy to aid in reaching weight targets based on dietary therapy in the population of overweight/obese PCOS-affected women.
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•Introducing pendant donors changes electronic and steric features of β-diketiminates.•Some challenging rare-earth metal complexes were synthesized by using these ligands.•Hemilabile ...property of pendant arms balances complexes’ stabilization and reactivity.
By using the β-diketiminato ligands bearing pendant nitrogen or oxygen donors, a series of rare-earth metal complexes containing reactive metal-bound functionalities have been synthesized. The most notable is the synthesis of subvalent scandium complex, scandium terminal imido complexes, four-coordinate scandium phosphinidene complex, non-pincer-type mononuclear scandium alkylidene complexes, scandium nitrilimine complex, yttrium hydride-PhSiH3 complex, and dialkyl complexes with larger rare-earth metal ions. The reactivity and catalytic activity of rare-earth metal complexes of β-diketiminato ligands bearing pendant donors are also briefly reviewed.
Objective
In the initial assessment of thyroid nodules, thyrotropin (TSH) has very low sensitivity for assessing functional thyroid nodules (FTNs). The false negativity in FTNs and the false ...positivity in non-FTNs misinterpreted by TSH will raise unnecessary assessment costs. Therefore, the aim of this study is to explore the values of the TSH and color flow Doppler sonography (CFDS) combined strategies in reducing the unnecessary assessment costs.
Methods
2383 patients with thyroid nodules were retrospectively analyzed, including 107 FTNs and 2276 non-FTNs. Four strategies including TSH, CFDS, Combination 1 (TSH+/CFDS+, TSH+/CFDS−, and TSH−/CFDS+ defined as positive; TSH−/CFDS− defined as negative) and Combination 2 (TSH+/CFDS+ defined as positive; TSH+/CFDS−, TSH−/CFDS+, and TSH−/CFDS− defined as negative) were separately used for initial assessment. The four strategies were compared using the testing cost ratio of fine-needle aspiration (FNA) to thyroid scintigraphy (TS) (marked as C
FNA/TS
) as main outcome measure.
Results
Compared with TSH, Combination 1 prevented 15.89 % of FTNs from unnecessary FNA, but increased the number of non-FTNs subjected to unnecessary
99m
Tc-TS by 9.31 %. Combination 2 prevented 5.32 % of non-FTNs from unnecessary TS, but increased the number of FTNs subjected to unnecessary FNA by 18.69 %. When C
FNA/TS
was <6.05, the lowest total cost was found in Combination 2. The TSH and Combination 1 were optimal at 6.05 ≤ C
FNA/TS
≤ 12.47 and C
FNA/TS
> 12.47, respectively.
Conclusions
The combined strategies can be used to supplement TSH in the initial assessment of thyroid nodules in iodine-adequate areas, depending on the testing costs of FNA and TS.
The first phosphoniomethylidene complexes of scandium and lutetium, LLn(CHPPh3)X (L = MeC(NDIPP)CHC(NDIPP)Me−; Ln = Sc, X = Me, I, TfO; Ln = Lu, X = CH2SiMe3), have been synthesized and fully ...characterized. DFT calculations clearly demonstrate the presence of an allylic Ln, C, P π-type interaction in these complexes. X-ray diffraction indicates that the scandium iodide complex has the shortest Sc–C bond length to date (2.044(5) Å). These phosphoniomethylidene complexes readily convert into the ylide complexes, and the reactivity is affected by both X– anion and Ln3+ ion. The reaction of lutetium complex with imine shows a rapid insertion of imine into the Lu–C(alkylidene) bond. DFT calculations indicate that, although the bonding situation seems similar to that of the scandium analog, the strong negative charge at the alkylidene carbon is not sufficiently screened by one hydrogen in the lutetium complex because of a more ionic bonding, and therefore, the reactivity of the lutetium complex is much higher.
•A new indicator named Floor Green View Index (FGVI) is proposed for quantifying visual amenity of urban vegetation.•FGVI is defined as the area of visible urban vegetation observed from a certain ...floor in a building.•New methods are proposed for calculating the indicators.•FGVI of over 100 buildings in the Lujiazui region, Shanghai, are calculated and analysed.•FGVI can be used to facilitate the assessment and planning of urban construction projects.
Vegetation provides many environmental benefits to the city, and daily access to vegetation contributes to the well-being and psychological status of urban residents. Understanding and measuring urban dwellers’ view-based exposure to greenery has become an important and much needed task for assessing the quality of urban life. This paper presents a new quantitative and objective indicator, the Floor Green View Index (FGVI). It is defined as the area of visible urban vegetation on a particular floor of a city building. The method for estimating FGVI consists of three steps: creating observation points and setting observation platform for each detected floor, conducting viewshed analysis and extracting visible urban green space, and computing the Floor Green View Index. The method is proposed and tested through a case study of the Lujiazui region, Shanghai, China, using airborne Light Detection and Ranging (LiDAR) data and aerial photographs. The new indicator and methods can be used as powerful quantitative tools for urban design, landscape architecture, urban green planning and management.
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