Metrical Parameters Research Articles

How Do Ring Size and π-Donating Thiolate Ligands Affect Redox-Active, α-Imino-N-heterocycle Ligand Activation?

Considerable effort has been devoted to the development of first-row transition-metal catalysts containing redox-active imino-pyridine ligands that are capable of storing multiple reducing equivalents. This property allows abundant and inexpensive first-row transition metals, which favor sequential one-electron redox processes, to function as competent catalysts in the concerted two-electron reduction of substrates. Herein we report the syntheses and characterization of a series of iron complexes that contain both π-donating thiolate and π-accepting (α-imino)-N-heterocycle redox-active ligands, with progressively larger N-heterocycle rings (imidazole, pyridine, and quinoline). A cooperative interaction between these complementary redox-active ligands is shown to dictate the properties of these complexes. Unusually intense charge-transfer (CT) bands, and intraligand metrical parameters, reminiscent of a reduced (α-imino)-N-heterocycle ligand (L•-), initially suggested that the electron-donating thiolate had reduced the N-heterocycle. Sulfur K-edge X-ray absorption spectroscopic (XAS) data, however, provides evidence for direct communication, via backbonding, between the thiolate sulfur and the formally orthogonal (α-imino)-N-heterocycle ligand π*-orbitals. DFT calculations provide evidence for extensive delocalization of bonds over the sulfur, iron, and (α-imino)-N-heterocycle, and TD-DFT shows that the intense optical CT bands involve transitions between a mixed Fe/S donor, and (α-imino)-N-heterocycle π*-acceptor orbital. The energies and intensities of the optical and S K-edge pre-edge XAS transitions are shown to correlate with N-heterocycle ring size, as do the redox potentials. When the thiolate is replaced with a thioether, or when the low-spin S = 0 Fe(II) is replaced with a high-spin S = 3/2 Co(II), the N-heterocycle ligand metrical parameters and electronic structure do not change relative to the neutral L0 ligand. With respect to the development of future catalysts containing redox-active ligands, the energy cost of storing reducing equivalents is shown to be lowest when a quinoline, as opposed to imidazole or pyridine, is incorporated into the ligand backbone of the corresponding Fe complex.

Dynamics Change of Vegetated Lands in A Highway Corridor during 37 Years (Case study of Jagorawi Toll Road, Jakarta-Bogor)

Recently, a highway development is required as a liaison between regions to support the economic development of the regions. Even the availability of highways give positive impacts, it also has negative impacts, especially related to the changes of vegetated lands. This study aims to determine the change of vegetation coverage in Jagorawi corridor Jakarta-Bogor during 37 years, and to analyze landscape patterns in the corridor based on distance factor from Jakarta to Bogor. In this study, we used a long-series of Landsat images taken by Landsat 2 MSS (1978), Landsat 5 TM (1988, 1995, and 2005) and Landsat 8 OLI/TIRS (2015). Analysis of landscape metrics was conducted through patch analysis approach to determine the change of landscape patterns in the Jagorawi corridor Jakarta-Bogor. Several parameters of landscape metrics used are Number of Patches (NumP), Mean Patch Size (MPS), Mean Shape Index (MSI), and Edge Density (ED). These parameters can be used to provide information of structural elements of landscape, composition and spatial distribution in the corridor. The results indicated that vegetation coverage in the Jagorawi corridor Jakarta-Bogor decreased about 48% for 35 years. Moreover, NumP value increased and decreasing of MPS value as a means of higher fragmentation level occurs with patch size become smaller. Meanwhile, The increase in ED parameters indicates that vegetated land is damaged annually. MSI parameter shows a decrease in every year which means land degradation on vegetated land. This indicates that the declining value of MSI will have an impact on land degradation.

Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst

The formally zero-valent Mn dimer [(Ph2PEtPDI)Mn]2 has been synthesized upon reducing (Ph2PEtPDI)MnCl2 with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(Ph2PEtPDI)Mn]2 possesses a κ4-PDI chelate about each Mn center, as well as η2-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = 1/2 Mn centers. At ambient temperature in the absence of solvent, [(Ph2PEtPDI)Mn]2 has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min–1 (4,950 min–1 per Mn). Moreover, the [(Ph2PEtPDI)Mn]2-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min–1 (165 min–1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylen...

An N-Tethered Uranium(III) Arene Complex and the Synthesis of an Unsupported U–Fe Bond

Amination of 2,2″-dibromo-p-terphenyl with 2,6-diisopropylaniline, through Pd mediated cross coupling, yields the p-terphenyl bis(aniline) ligand H2LAr. Deprotonation of H2LAr with excess KH generates the dianion [K(DME)2]2LAr as a dark red solid. Treatment of [K(DME)2]2LAr with UI3(dioxane)1.5 produces the mononuclear U(III) complex LArU(I)(DME) (1). Subsequent addition of the nucleophilic metal anion [CpFe(CO)2]− (Fp–) gives the bimetallic U(III) compound LArU(Fp) (2) in modest yield which features a rare instance of an unsupported U–M bond. Inspection of the metrical parameters of the solid-state structures of 1·DME and 2·0.5DME from X-ray crystallographic analyses show a seemingly η6-interaction between the uranium and the terphenyl ligand (1: U1–Ccentroid = 2.56 A; 2: U1–Ccentroid = 2.45 A), spatially imposed as a consequence of the anilide N-donor atom coordination. Furthermore, the U–Fe bond length in 2 (U1–Fe1 = 2.9462(3) A) is consistent with a metal–metal single bond. Notably, electronic structu...

Noninnocent β-Diiminate Ligands: Redox Activity of a Bis(alkylimidazole)methane Ligand in Cobalt and Zinc Complexes.

A new β-diiminate ligand (the bis(1-methyl-4,5-diphenyl-1H-imidazol-2-yl)methane anion, BMIMPh2- ) is introduced, in which the ligand framework bears an extended imidazole-based π-system in conjugation with a formal β-diketiminates (NacNac) backbone. Bis-ligated transition metal complexes (Co, Zn) featuring this anionic ligand undergo a series of four consecutive single-electron oxidations that are all ligand-based. The singly and doubly oxidized complexes can be synthesized on a preparative scale and have been fully characterized by various spectroscopic techniques. This is in sharp contrast to the corresponding NacNac-based complexes in which only singly oxidized complexes were isolated and characterized. Single crystal X-ray structure determination revealed a correlation between the intra-ligand metrical parameters and the oxidation state of BMIMPh2- . These structural changes in the ligand framework make BMIMPh2- as a perceptible non-innocent ligand in contrast to NacNac type ligands.

Synthesis, Structure, and Reactivity of the Sterically Crowded Th3+ Complex (C5Me5)3Th Including Formation of the Thorium Carbonyl, [(C5Me5)3Th(CO)][BPh4

The Th3+ complex, (C5Me5)3Th, has been isolated despite the fact that tris(pentamethylcyclopentadienyl) complexes are highly reactive due to steric crowding and few crystallographically characterizable Th3+ complexes are known due to their highly reducing nature. Reaction of (C5Me5)2ThMe2 with [Et3NH][BPh4] produces the cationic thorium complex [(C5Me5)2ThMe][BPh4] that can be treated with KC5Me5 to generate (C5Me5)3ThMe, 1. The methyl group on (C5Me5)3ThMe can be removed with [Et3NH][BPh4] to form [(C5Me5)3Th][BPh4], 2, the first cationic tris(pentamethylcyclopentadienyl) metal complex, which can be reduced with KC8 to yield (C5Me5)3Th, 3. Complexes 1-3 have metrical parameters consistent with the extreme steric crowding that previously has given unusual (C5Me5)- reactivity to (C5Me5)3M complexes in reactions that form less crowded (C5Me5)2M-containing products. However, neither sterically induced reduction nor (η1-C5Me5)- reactivity is observed for these complexes. (C5Me5)3Th, which has a characteristic EPR spectrum consistent with a d1 ground state, has the capacity for two-electron reduction via Th3+ and sterically induced reduction. However, it reacts with MeI to make two sterically more crowded complexes, (C5Me5)3ThI, 4, and (C5Me5)3ThMe, 1, rather than (C5Me5)2Th(Me)I. Complex 3 also forms more crowded complexes in reactions with I2, PhCl, and Al2Me6, which generate (C5Me5)3ThI, (C5Me5)3ThCl, and (C5Me5)3ThMe, 1, respectively. The reaction of (C5Me5)3Th, 3, with H2 forms the known (C5Me5)3ThH as the sole thorium-containing product. Surprisingly, (C5Me5)3ThH is also observed when (C5Me5)3Th is combined with 1,3,5,7-cyclooctatetraene. [(C5Me5)3Th][BPh4] reacts with tetrahydrofuran (THF) to make [(C5Me5)3Th(THF)][BPh4], 2-THF, which is the first (C5Me5)3M of any kind that does not have a trigonal planar arrangement of the (C5Me5)- rings. It is also the first (C5Me5)3M complex that does not ring-open THF. [(C5Me5)3Th][BPh4], 2, reacts with CO to generate a product characterized as [(C5Me5)3Th(CO)][BPh4], 5, the first example of a molecular thorium carbonyl isolable at room temperature. These results have been analyzed using density functional theory calculations.

Protonation and Sulfido versus Oxo Ligation Changes at the Molybdenum Cofactor in Xanthine Dehydrogenase (XDH) Variants Studied by X-ray Absorption Spectroscopy.

Enzymes of the xanthine oxidase family are among the best characterized mononuclear molybdenum enzymes. Open questions about their mechanism of transfer of an oxygen atom to the substrate remain. The enzymes share a molybdenum cofactor (Moco) with the metal ion binding a molybdopterin (MPT) molecule via its dithiolene function and terminal sulfur and oxygen groups. For xanthine dehydrogenase (XDH) from the bacterium Rhodobacter capsulatus, we used X-ray absorption spectroscopy to determine the Mo site structure, its changes in a pH range of 5-10, and the influence of amino acids (Glu730 and Gln179) close to Moco in wild-type (WT), Q179A, and E730A variants, complemented by enzyme kinetics and quantum chemical studies. Oxidized WT and Q179A revealed a similar Mo(VI) ion with each one MPT, Mo═O, Mo-O-, and Mo═S ligand, and a weak Mo-O(E730) bond at alkaline pH. Protonation of an oxo to a hydroxo (OH) ligand (pK ∼ 6.8) causes inhibition of XDH at acidic pH, whereas deprotonated xanthine (pK ∼ 8.8) is an inhibitor at alkaline pH. A similar acidic pK for the WT and Q179A variants, as well as the metrical parameters of the Mo site and density functional theory calculations, suggested protonation at the equatorial oxo group. The sulfido was replaced with an oxo ligand in the inactive E730A variant, further showing another oxo and one Mo-OH ligand at Mo, which are independent of pH. Our findings suggest a reaction mechanism for XDH in which an initial oxo rather than a hydroxo group and the sulfido ligand are essential for xanthine oxidation.

A Combined Spectroscopic/Molecular Dynamic Study for Investigating a Methyl-Carboxylated PEI as a Potential Uranium Decorporation Agent.

Natural uranium has a very limited radioactive dose impact, but its chemical toxicity due to chronic exposure is still a matter of debate. Once inside the human body, the soluble uranium, under its uranyl form (U(VI)), is quickly removed from the blood system, partially excreted from the body, and partially retained in targeted organs, that is, the kidneys and bone matrix essentially. It is then crucial to remove or prevent the incorporation of uranium in these organs to limit the long-term chronic exposure. A lot of small chelating agents such as aminocarboxylates, catecholamides, and hydroxypyridonates have been developed so far. However, they suffer from poor selectivity and targeting abilities. Macromolecules and polymers are known to present a passive accumulation (size related), that is, the so-called enhanced permeability and retention effect, toward the main organs, which can be used as indirect targeting. Very interestingly, the methyl carboxylated polyethylenimine (PEI-MC) derivative has been described as a potent sequestering agent for heavy metals. It would be therefore an interesting candidate to evaluate as a new class of decorporation agents with passive targeting capabilities matching uranium preferential sequestering sites. In the present work, we explored the ability of a highly functionalized (89% rate) PEI-MC to uptake U(VI) close to physiological pH using a combination of analytical and spectroscopic techniques (inductively coupled plasma optical emission spectrometry (ICP-OES); extended X-ray absorption fine structure (EXAFS); and Fourier transformed infrared (FT-IR)) together with molecular dynamics (MD) simulation. A maximum loading of 0.47 mg U(VI) per milligram of PEI-MC was determined by ICP-OES measurements. From FT-IR data, a majority of monodentate coordination of the carboxylate functions of the PEI-MC seems to occur. From EXAFS and MD, a mix of mono and bidentate coordination mode was observed. Note that agreement between the EXAFS metrical parameters and MD radial distribution functions is remarkable. To the best of our knowledge, this is the first comprehensive structural study of a macromolecular PEI-based agent considered for uranium decorporation purposes.

Synthesis and characterisation of p-block complexes of biquinoline at different ligand charge states.

The first examples of p-block coordination complexes of biquinoline, namely [(biq)BCl2]Cl and [(biq)BCl2]˙, were synthesized and structurally characterized. The acquired data allowed the estimation of the ligand charge state based on its metrical parameters. The subsequent use of this protocol, augmented with theoretical calculations, revealed ambiguities in the published data for transition metal complexes of biquinoline.

The Acquisition of Parameters for Word Stress Production and Perception among Iraqi EFL Learners: A Pilot Study

<div><p><em>This study investigates the acquisition of the parameters of word stress production and perception by 10 Iraqi learners of English as a foreign language (EFL)</em><em>. It aims at investigating Iraqi learners’ difficulties in resetting the parameters of word stress production and perception in L2. Two experiments are conducted to test the learners’ production and perception of word stress in isolation and in sentences. The first experiment is the production test and the second one is the perception test. The learners’ responses of word stress in both experimental tasks are elicited manually and analysed according to [7]</em><em> model of metrical parameters</em><em> which is used </em><em>to investigate</em><em> the acquisition of parameters of word stress production and perception by Iraqi learners</em><em>. The findings</em><em> reveal that </em><em>Iraqi EFL learners are able to reset the parameters of L2 but even though they failed in resetting all the parameters completely. Besides, the learners used more ranking level kinds of the parameters in the perception task than in the production task which may cause Iraqi learners assign wrongly the word stress placement.</em></p></div>

Examining the Effects of Ligand Variation on the Electronic Structure of Uranium Bis(imido) Species.

Arylazide and diazene activation by highly reduced uranium(IV) complexes bearing trianionic redox-active pyridine(diimine) ligands, [CpPU(MesPDIMe)]2 (1-CpP), Cp*U(MesPDIMe)(THF) (1-Cp*) (CpP = 1-(7,7-dimethylbenzyl)cyclopentadienide; Cp* = η5-1,2,3,4,5-pentamethylcyclopentadienide), and Cp*U(tBu-MesPDIMe) (THF) (1-tBu) (2,6-((Mes)N═CMe)2-p-R-C5H2N, Mes = 2,4,6-trimethylphenyl; R = H, MesPDIMe; R = C(CH3)3, tBu-MesPDIMe), has been investigated. While 1-Cp* and 1-CpP readily reduce N3R (R = Ph, p-tolyl) to form trans-bis(imido) species, CpPU(NAr)2(MesPDIMe) (Ar = Ph, 2-CpP; Ar = p-Tol, 3-CpP) and Cp*U(NPh)2(MesPDIMe) (2-Cp*), only 1-Cp* can cleave diazene N═N double bonds to form the same product. Complexes 2-Cp*, 2-CpP, and 3-CpP are uranium(V) trans-bis(imido) species supported by neutral [MesPDIMe]0 ligands formed by complete oxidation of [MesPDIMe]3- ligands of 1-CpP and 1-Cp*. Variation of the arylimido substituent in 2-Cp* from phenyl to p-tolyl, forming Cp*U(NTol)2(MesPDIMe) (3-Cp*), changes the electronic structure, generating a uranium(VI) ion with a monoanionic pyridine(diimine) radical. The tert-butyl-substituted analogue, Cp*U(NTol)2(tBu-MesPDIMe) (3-tBu), displays the same electronic structure. Oxidation of the ligand radical in 3-Cp* and 3-tBu by Ag(I) forms cationic uranium(VI) [Cp*U(NTol)2(MesPDIMe)][SbF6] (4-Cp*) and [Cp*U(NTol)2(tBu-MesPDIMe)][SbF6] (4-tBu), respectively, as confirmed by metrical parameters. Conversely, oxidation of pentavalent 2-Cp* with AgSbF6 affords cationic [Cp*U(NPh)2(MesPDIMe)][SbF6] (5-Cp*) from a metal-based U(V)/U(VI) oxidation. All complexes have been characterized by multidimensional NMR spectroscopy with assignments confirmed by electronic absorption spectroscopy. The effective nuclear charge at uranium has been probed using X-ray absorption spectroscopy, while structural parameters of 1-CpP, 3-Cp*, 3-tBu, 4-Cp*, 4-tBu, and 5-Cp* have been elucidated by X-ray crystallography.

A Systematic Study of Structure and E-H Bond Activation Chemistry by Sterically Encumbered Germylene Complexes.

A series of new germylene compounds has been synthesized offering systematic variation in the σ- and π-capabilities of the α-substituent and differing levels of reactivity towards E-H bond activation (E=H, B, C, N, Si, Ge). Chloride metathesis utilizing [(terphenyl)GeCl] proves to be an effective synthetic route to complexes of the type [(terphenyl)Ge(ERn )] (1-6: ERn =NHDipp, CH(SiMe3 )2 , P(SiMe3 )2 , Si(SiMe3 )3 or B(NDippCH)2 ; terphenyl=C6 H3 Mes2 -2,6=Ar(Mes) or C6 H3 Dipp2 -2,6=Ar(Dipp) ; Dipp=C6 H3 iPr2 -2,6, Mes=C6 H2 Me3 -2,4,6), while the related complex [{(Me3 Si)2 N}Ge{B(NDippCH)2 }] (8) can be accessed by an amide/boryl exchange route. Metrical parameters have been probed by X-ray crystallography, and are consistent with widening angles at the metal centre as more bulky and/or more electropositive substituents are employed. Thus, the widest germylene units (θ>110°) are found to be associated with strongly σ-donating boryl or silyl ancillary donors. HOMO-LUMO gaps for the new germylene complexes have been appraised by DFT calculations. The aryl(boryl)-germylene system [Ar(Mes) Ge{B(NDippCH)2 }] (6-Mes), which features a wide C-Ge-B angle (110.4(1)°) and (albeit relatively weak) ancillary π-acceptor capabilities, has the smallest HOMO-LUMO gap (119 kJ mol(-1) ). These features result in 6-Mes being remarkably reactive, undergoing facile intramolecular C-H activation involving one of the mesityl ortho-methyl groups. The related aryl(silyl)-germylene system, [Ar(Mes) Ge{Si(SiMe3 )3 }] (5-Mes) has a marginally wider HOMO-LUMO gap (134 kJ mol(-1) ), rendering it less labile towards decomposition, yet reactive enough to oxidatively cleave H2 and NH3 to give the corresponding dihydride and (amido)hydride. Mixed aryl/alkyl, aryl/amido and aryl/phosphido complexes are unreactive, but amido/boryl complex 8 is competent for the activation of E-H bonds (E=H, B, Si) to give hydrido, boryl and silyl products. The results of these reactivity studies imply that the use of the very strongly σ-donating boryl or silyl substituents is an effective strategy for rendering metallylene complexes competent for E-H bond activation.

Normal growth, altered growth? Study of the relationship between harris lines and bone form within a post-medieval plague cemetery (Dendermonde, Belgium, 16th Century).

Harris lines (HLs) are defined as transverse, mineralized lines associated with temporary growth arrest. In paleopathology, HLs are used to reconstruct health status of past populations. However, their etiology is still obscure. The aim of this article is to test the reliability of HLs as an arrested growth marker by investigating their incidence on human metrical parameters. The study was performed on 69 individuals (28 adults, 41 subadults) from the Dendermonde plague cemetery (Belgium, 16th century). HLs were rated on distal femora and both ends of tibiae. Overall prevalence and age-at-formation of each detected lines were calculated. ANOVA analyses were conducted within subadult and adult samples to test if the presence of HLs did impact size and shape parameters of the individuals. At Dendermonde, 52% of the individuals had at least one HL. The age-at-formation was estimated between 5 and 9 years old for the subadults and between 10 and 14 years old for the adults. ANOVA analyses showed that the presence of HLs did not affect the size of the individuals. However, significant differences in shape parameters were highlighted by HL presence. Subadults with HLs displayed slighter shape parameters than the subadults without, whereas the adults with HLs had larger measurements than the adults without. The results suggest that HLs can have a certain impact on shape parameters. The underlying causes can be various, especially for the early formed HLs. However, HLs deposited around puberty are more likely to be physiological lines reflecting hormonal secretions. Am. J. Hum. Biol. 29:e22885, 2017. © 2016 Wiley Periodicals, Inc.

Fe(IV) alkylidenes are actually Fe(II), and a related octahedral Fe(II) “alkylidene” is a conjugated vinyl complex

Electronic structure calculations on previously synthesized [mer-{κ-C,N,C-(2-C6H4)CHN(1,2-C6H4)C(iPr)}Fe(PMe3)3][BArF4] (1) and mer,trans-{κ-C,N,C-(2-C6H4)CH(Bn)N(1,2-C6H4)C(iPr)}Fe(PMe3)2N2 (4-Bn) reveal that 1 is best interpreted as Fe(II) bound to a carbenium ion, while 4-Bn has an imino-vinyl unit bound to a ferrous center. Attempts to prepare LnFeCHR species capable of olefin metathesis or carbene transfer were obviated by alternative reactivity, although precursors mer,trans-{κ3-N,N,C-(2-py)CHNCH2CHCH}Fe(PMe3)2CH3 (6), [mer,trans-{κ3-N,N,C-2-py-CHNCH2CHCH}Fe(PMe3)2CH3] [PF6−] (8), mer,trans-{κ3-N,N,C-2-py-CHNCH2CHCH}Fe(PMe3)2I (9), mer-{κ3-N,N,C-(2-pyridyl) CHNCHCHCH}Fe(PMe3)3 (11), and mer-{κ3-C,N,C-(2-C6H4)CHNCH2CHCH}Fe(PMe3)3 (12) were prepared. Related phenyl derivatives, mer,trans-{κ3-N,N,C-(2-py)CHNC(Me)2CHCH}Fe(PMe3)2CH3 (13) and [mer,trans-{κ3-N,N,C-(2-py)CHNC(Me)2CHCH}Fe(PMe3)2N2][BArF4] (15) were prepared to test additional stability issues. Compounds 9 and 11 were structurally characterized, and metrical parameters of the latter, in addition to electronic structure calculations, suggest that it is not an alkylidene, but an Fe(II) center coordinated by a conjugated vinyl ligand with extensive delocalization in its π-system.

Aryl-substituted BIAN complexes of iron dibromide: Synthesis, X-ray and electronic structure, and catalytic hydrosilylation activity

Anhydrous iron dibromide complexes bearing bidentate α-diimine ligands ArNC(Me)(Me)CNAr and ArBIAN (BIAN=bis(imino)acenaphthene; Ar=dpp and Mes; dpp=2,6-diisopropylphenyl; Mes=2,4,6-trimethylphenyl) have been prepared and characterized by 1H NMR spectroscopy. The aryl-substituted BIAN complexes were structurally characterized by single-crystal X-ray diffraction, and their metrical parameters are consistent with a redox-innocent chelating ligand. A high-spin iron(II) electronic structure description for the ArBIAN iron complexes is supported by Mössbauer spectroscopy, solution state magnetic measurements, and quantum-chemical calculations. Upon reduction, the iron complexes promote catalytic hydrosilylation of 1-hexene with phenylsilane at 22°C. Under optimized conditions, 1 mol% of the dppBIANFeBr2 precatalyst was activated in situ to produce 1-hexylphenylsilane in high yield from a 1:1 ratio of 1-hexene:PhSiH3 in solvent-free conditions at 22°C in 24h.

Synthesis and Reactivity of a U(IV) Dibenzyne Complex

Reaction of UCl4 with 6 equiv of 2-Li-C6H4CH2NMe2 affords the U(IV) dibenzyne complex [Li]2[U(2,3-C6H3CH2NMe2)2(2-C6H4CH2NMe2)2] (1), which can be isolated as a dark blue solid in 40% yield. Complex 1 represents a rare example of a structurally characterized dibenzyne complex, and its solid-state metrical parameters suggest that the two benzyne ligands are best described with the dianionic metallacyclopropene resonance form. The reactivity of 1 with a variety of electrophiles and oxidants, including benzophenone, 1-azidoadamantane, and benzonitrile, was also explored. Reaction of 1 with 2 equiv of benzophenone affords the insertion product [Li][U(2-C6H3CH2NMe2-3-COPh2)2(2-C6H4CH2NMe2)] (3) as a red-orange solid in 61% yield, concomitant with formation of 1 equiv of 2-Li-C6H4CH2NMe2. Reaction of 1 with 2 equiv of PhCN also affords an insertion product, [Li][Li(Et2O)][U(2,3-C6H3CH2NMe2)(2-C6H3CH2NMe2-3-C(Ph)═N)(2-C6H4CH2NMe2)2] (4), as a green-brown crystalline solid in 21% yield. In an attempt to oxidize 1...

Sex determination of human mandible using metrical parameters by computed tomography: A prospective radiographic short study

Introduction: Sex determination of unidentified human remains is very important in forensic medicine, medicolegal cases, and forensic anthropology. The mandible is the largest and hardest facial bone that commonly resists postmortem damage and forms an important source of personal identification. Additional studies have demonstrated the applicability of facial reconstruction using three-dimensional computed tomography scan (3D-CT) for the purpose of individual identification. Aim: To determine the sex of human mandible using metrical parameters by CT. Materials and Methods: The study included thirty subjects (15 males and 15 females), with age group ranging between 10 and 60 years obtained from the outpatient department of Oral Medicine and Radiology, Narsinhbhai Patel Dental College and Hospital. CT scan was performed on all the subjects, and the data obtained were reconstructed for 3D viewing. After obtaining 3D-CT scan, a total of seven mandibular measurements, i.e., gonial angle (G-angle), ramus length (Ramus-L), minimum ramus breadth and gonion-gnathion length (G-G-L), bigonial breadth, bicondylar breadth (BIC-Br), and coronoid length (CO-L) were measured; collected data were analyzed using SPSS statistical analysis program by Student's t-test. Results: The result of the study showed that out of seven parameters, G-angle, Ramus-L, G-G-L, BIC-Br, and CO-L showed a significant statistical difference (P < 0.05), with overall accuracy of 86% for males and 82% for females. Conclusion: Personal identification using mandible by conventional methods has already been proved but with variable efficacies. Advanced imaging modalities can aid in personal identification with much higher accuracy than conventional methods.

The Metrical Parameters of Word Stress Production and Perception among Iraqi English as a Foreign Language (EFL) Learners

The Metrical Parameters of Word Stress Production and Perception among Iraqi English as a Foreign Language (EFL) Learners

A Mathematical Model for Evaluating the Functional Connectivity Strongness in Healthy People.

The human brain is a really complex organization of connectivity whose principal elements are neurons, synapses and brain regions. Up to now this connectivity is not fully understood, and recent impulse in investigating its structure has been given by Graph Theory. However, some points remain unclear, mainly due to possible mismatching between the Mathematical and the Neuroscientific approach. It is known that neural connectivity is classified into three categories: structural (or anatomical) connectivity, functional connectivity and effective connectivity. The point is that these categories demand different kinds of graphs, except in the case of the resting state, and sometimes topological and metrical parameters are involved simultaneously, without a specific distinction of their roles. In this paper we propose a mathematical model for treating the functional connectivity, based on directed graphs with weighted edges. The function W(i,j,t), representing the weight of the edge connecting nodes i,j at time t, is obtained by splitting the model in two parts, where different parameters have been introduced step by step and rigorously motivated. In particular, there is a double role played by the notion of distance, which, according to the different parts of the model, assumes a discrete or an Euclidean meaning. Analogously, the time t appears both from a local and from a global perspective. The local aspect relates to a specific task submitted to an health volunteer (in view of possible future applications also to subjects affected by neurological diseases), while the global one concerns the different periods in the human life that characterize the main changes in the neural brain network. In the particular case of the resting state, we have shown that W reduces to the usually employed probabilistic growth laws for the edge formation. We tested the correctness of our model by means of synthetic data, where the selection of all involved parameters has been motivated according to what is known from the available literature. It turns out that simulated outputs fit well with the expected results, which encourages further analysis on real data, and possible future applications to neurological pathologies.

FORMATION OF THE ANTHROPOMETRICAL STATUS DURINFG PHYSICAL DEVELOPMENT PHASE

In this work we’ve defined one-measured statistical analyses of antropometrical parameters of men and women (age of 7-18 y. old). These data were defined on basis of growth and differentiation of the most informative of metrical signs including physical development. In order to determine the most informative metrical parameters belonging to people while growth phase, 10 examples of absolute size, body mass and 3 indexes have been examined among people who live in Western region of Ukraine.Together with public health services, for purposes of preventive supervision 360 male and female persons aged 7-18 years have been examined (i.e. students of secondary school). Anthropometrical parameters were determined according to the accepted medical anthropology’ methodology: trunk length, shoulders’ breadth, pelvis breadth, longitudinal head diameter, the most diametrical head diameter; head, armlet, thigh and shin circumference; body mass. Indexes were figured out according to trunk length(IRLT), shoulders’ breadth(IRBS) and pelvis. These parameters formed %(percentage) of correlation between corresponding proportions and height.Analysis of indications system which marks the anthropometrical status is enough to be able to determine (by means of the factorial criterion of sex) the index of relative trunk length at the age of 7, 13, 14, 15, 17, 18 years (Р&lt;0,01 – 0,001). This analysis also helped to prove the comparison of all total indexes while second childhood phase (Р&gt;0,05) and to determine the importance of sex trend in antroph-amorphous status formation at the age periods of 13-16 and 17-18 years: according to the index of pelvis breadth – 12, 13 years (Р&lt;0,05),14, 15 years (Р&lt;0,001) and index of the relative shoulders’ breadth - 15, 17, 18 years (Р&lt;0,01 – 0,001).While adolescence, particularly at the age of 16 in female, more rapid body growth in height in comparison with trunk length is registered. It causes the decrease in IRLT indexes from 30,0% while childhood up to 27,5% at the age period of 13-18 years. On the contrary, IRBS index increases from 21,0% (childhood) to 22,0% (adolescence) and up to 23,5% (teenagers) in maleand from 20,6% to 21,3%and 22,5% in female persons in accordance with growth impairment.On the basis ofanthropometrical parameters’ indexes in male and female persons and taking into consideration their annual age appliance while growth phase, charts of the most veritable metrical parameters have been formed.