Correspondence on "Beyond the Dimer and Trimer: Tetraspiro[2.1.25.1.29.1.213.13]hexadecane-1,3,5,7-tetraone - the Cyclic Tetramer of Carbonylcyclopropane".

The International Union of Pure and Applied Chemistry (IUPAC) name given in the title is incorrect. The correct IUPAC name for this molecule is tetraspiro[2.1.25.1.29.1.213.13]hexadecane-4,8,12,16-tetraone. The incorrect name given in the title, unfortunately, makes the carbon atom hexavalent at two different (3 and 5) positions. In addition, the two other keto groups (at positions 1 and 7) would appear on two of the cyclopropane rings if one adopts to the incorrect name. Nevertheless, this wrong name is a good example to discuss the importance of IUPAC nomenclature in the classroom with students.

Ulnar Buttress Arthroplasty without Ulnar Stump Stabilization for Giant Cell Tumor of Distal Ulna.

Purpose Reconstruction and stabilization of ulnar stump after distal ulna tumor resection is still a matter of debate. We present the outcomes of ulnar buttress arthroplasty without stabilization of the ulna stump in giant cell tumor of bone (GCTB) of the distal ulna. Methods Evaluation of functional outcome was performed using Musculoskeletal Tumor Society 93 (MSTS93) score, Modified Mayo Wrist score (MMWS), and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. We also assessed the hand grip strength, range of motion at the wrist, and ulnar carpal translation. Results The study included 8 patients with Campanacci grade 3 GCTB of the distal ulna with a mean follow-up of 35.5 ± 9.1 months. The mean resection length was 7.7 ± 1.3 cm. The mean hand grip strength on the operated side was noted to be 90 ± 0.04% of the contralateral side. Mean MSTS93 score was 27.9 ± 1.25, mean MMWS was 86.9 ± 4.58%, and the mean DASH score was 4.9 ± 1.67, depicting a good to excellent functional outcome with low degree of disability. No radiocarpal instability, ulnar carpal translation, prominence, or instability of the proximal ulnar stump was noted in any patient. Conclusion Reconstruction of the distal radioulnar joint using iliac crest bone graft for ulnar buttress without stabilization of the ulnar stump after resection of the distal ulna is an effective reconstruction option with good functional outcome and preservation of good hand grip strength. Level of Evidence Level IV, Therapeutic study.

Novel approach to the derivation of dam breach parameters in 2D hydrodynamic modeling of earthquake induced dam failures.

Current methods of dam breach analyses adopt a deterministic approach. Applying these methods to Concrete Faced Rockfill Dams (CFRD) is fraught with huge levels of uncertainty, especially in the context of natural hazards. The frequency and magnitude of rainfall and earthquakes are higher in today's world. In the literature, the complete collapse of dams is modelled on dam breach parameters that define the dam break outflow but are not related to the return periods of natural hazards. As more new dams are constructed to control the floods in intra-plate seismic regions, this study presents a novel approach to the derivation of generalized dam break parameters for CFRD based on the structural analysis of Finite Element Model (FEM) simulations for peak ground accelerations corresponding to 475 and 2475 year return periods. Furthermore, the occurrence of rainfall and earthquake for different return periods are modelled using 2D hydrodynamic simulations. Results show the significance of generalized dam breach parameters for planning and managing CFRDs during earthquakes. The study emphasizes the utilization of structural analysis outputs for the hydraulic modeling of dam breaks, which will result in more specific and accurate dam break parameters. Additionally, the study has shown that the flood risk and the severity will increase with the intensity of earthquake and rainfall magnitudes. Disaster mitigation strategies can be optimized by considering the integrated occurrence of rainfall and earthquakes based on the probability of occurrence, demonstrated using a case-study dam. Another significant outcome of the study is the effect of soil saturation condition during a dam break, which reveals that areas within 40 km of the dam breach location might be worst affected.

Energetic and Spectroscopic Properties of Astrophysically Relevant MgC4H Radicals Using High-Level Ab Initio Calculations.

Considering the importance of magnesium-bearing hydrocarbon molecules (MgCnH; n = 2, 4, and 6) in the carbon-rich circumstellar envelopes (e.g., IRC+10216), a total of 28 constitutional isomers of MgC4H have been theoretically investigated using density functional theory (DFT) and coupled-cluster methods. The zero-point vibrational energy corrected relative energies at the ROCCSD(T)/cc-pCVTZ level of theory reveal that the linear isomer, 1-magnesapent-2,4-diyn-1-yl (1, 2Σ+), is the global minimum geometry on the MgC4H potential energy surface. The latter has been detected both in the laboratory and in the evolved carbon star, IRC+10216. The calculated spectroscopic data for 1 match well with the experimental observations (error ∼ 0.78%) which validates our theoretical methodology. Plausible isomerization processes happening among different isomers are examined using DFT and coupled-cluster methods. CASPT2 calculations have been performed for a few isomers exhibiting multireference characteristics. The second most stable isomer, 1-ethynyl-1λ3-magnesacycloprop-2-ene-2,3-diyl (2, 2A1, µ = 2.54 D), is 146 kJ mol-1 higher in energy than 1 and possibly the next promising candidate to be detected in the laboratory or in the interstellar medium in future.

Theoretical Studies on the Isomerization Kinetics of Low-Lying Isomers of the SiC4H2 System.

The low-lying isomers of SiC4H2 are investigated to understand the kinetics of isomerization pathways using density functional theory. In our earlier work, we studied the various possible isomers (J. Phys. Chem. A, 2020, 124, 987-1002) and the chemical bonding of low-lying isomers of SiC4H2 (J. Phys. Chem. A, 2022, 126, 9366-9374). Among them, four isomers, 1-ethynyl-3-silacycloprop-1-en-3-ylidene (1), 3-silapent-1,4-diyn-3-ylidene (2), 1-silapent-1,2,3,4-tetraen-1-ylidene (4), and 1-silapent-2,4-diyn-1-ylidene (5) have already been identified in the laboratory. The previously known theoretical isomer 2-methylene-1-silabicyclo[1.1.0]but-1(3)-en-4-ylidene (3) and the newly identified unknown isomer through the present kinetic studies 5-silabicyclo[2.1.0]pent-1(4),2-dien-5-ylidene (N6) remain elusive in the laboratory to date. The isomerization pathways of the low-lying isomers of SiC4H2 are predicted through the transition state structures. Intrinsic reaction coordinate analysis identifies the minimum energy reaction pathways connecting the transition state from one isomer to another of the investigated system. The present kinetic data reveal the isomerization of global minimum energy isomer 1 to thermodynamically stable low-lying isomers, 2 and 5. Interestingly, isomer 3 interconverts to the experimentally known low-energy isomer 4, the second most thermodynamically stable isomer among them. The thermodynamic and kinetic parameters of the low-lying isomers of SiC4H2 are also documented in this work. The rate coefficient and equilibrium constant for isomerization reactions are calculated using the Rice-Ramsperger-Kassel-Marcus theory. The equilibrium constant delineates the difficulties in forming N6 and 3 through the isomerization pathways. Furthermore, ab initio molecular dynamics studies dictate the stability of low-lying isomers of SiC4H2 within the time scale of the simulation.

CCSD(T) Rotational Constants for Highly Challenging C5H2 Isomers-A Comparison between Theory and Experiment.

We evaluate the accuracy of CCSD(T) and density functional theory (DFT) methods for the calculation of equilibrium rotational constants (Ae, Be, and Ce) for four experimentally detected low-lying C5H2 isomers (ethynylcyclopropenylidene (2), pentatetraenylidene (3), ethynylpropadienylidene (5), and 2-cyclopropen-1-ylidenethenylidene (8)). The calculated rotational constants are compared to semi-experimental rotational constants obtained by converting the vibrationally averaged experimental rotational constants (A0, B0, and C0) to equilibrium values by subtracting the vibrational contributions (calculated at the B3LYP/jun-cc-pVTZ level of the theory). The considered isomers are closed-shell carbenes, with cumulene, acetylene, or strained cyclopropene moieties, and are therefore highly challenging from an electronic structure point of view. We consider both frozen-core and all-electron CCSD(T) calculations, as well as a range of DFT methods. We find that calculating the equilibrium rotational constants of these C5H2 isomers is a difficult task, even at the CCSD(T) level. For example, at the all-electron CCSD(T)/cc-pwCVTZ level of the theory, we obtain percentage errors ≤0.4% (Ce of isomer 3, Be and Ce of isomer 5, and Be of isomer 8) and 0.9-1.5% (Be and Ce of isomer 2, Ae of isomer 5, and Ce of isomer 8), whereas for the Ae rotational constant of isomers 2 and 8 and Be rotational constant of isomer 3, high percentage errors above 3% are obtained. These results highlight the challenges associated with calculating accurate rotational constants for isomers with highly challenging electronic structures, which is further complicated by the need to convert vibrationally averaged experimental rotational constants to equilibrium values. We use our best CCSD(T) rotational constants (namely, ae-CCSD(T)/cc-pwCVTZ for isomers 2 and 5, and ae-CCSD(T)/cc-pCVQZ for isomers 3 and 8) to evaluate the performance of DFT methods across the rungs of Jacob's Ladder. We find that the considered pure functionals (BLYP-D3BJ, PBE-D3BJ, and TPSS-D3BJ) perform significantly better than the global and range-separated hybrid functionals. The double-hybrid DSD-PBEP86-D3BJ method shows the best overall performance, with percentage errors below 0.5% in nearly all cases.

In Silico Drug Design and Analysis of Dual Amyloid-Beta and Tau Protein-Aggregation Inhibitors for Alzheimer's Disease Treatment.

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder that gradually leads to the state of dementia. The main features of AD include the deposition of amyloid-beta peptides (Aß), forming senile plaques, and the development of neurofibrillary tangles due to the accumulation of hyperphosphorylated Tau protein (p-tau) within the brain cells. In this report, seven dual-inhibitor molecules (L1-7) that can prevent the aggregation of both Aß and p-tau are suggested. The drug-like features and identification of the target proteins are analyzed by the in silico method. L1-7 show positive results in both Blood-Brain Barrier (BBB) crossing and gastrointestinal absorption, rendering to the results of the permeation method. The molecular docking test performed for L1-7 shows binding energies in the range of -4.9 to -6.0 kcal/mol towards Aß, and -4.6 to -5.6 kcal/mol for p-tau. The drug's effectiveness under physiological conditions is assessed by the use of solvation models on the investigated systems. Further, the photophysical properties of L1-3 are predicted using TD-DFT studies.

An in silico discovery of potential 3CL protease inhibitors of SARS-CoV-2 based upon inactivation of the cysteine 145-Histidine 41 catalytic dyad.

Coronavirus disease 19 (COVID19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, several countries are at risk of the pandemic caused by this virus. In the absence of any vaccine or virus-specific antiviral treatments, the need is to fast track search for potential drug candidates to combat the virus. Though there are known drugs that are being repurposed to fight against the SARS-CoV-2, there is a requirement for the virus-specific drugs at the earliest. One of the main drug targets of SARS-CoV-2 is an essential non-structural protein, 3CL protease, critical for the life cycle of the virus. We have used molecular docking studies to screen a chemically diverse set of small molecules to identify potential drug candidates to target this protein. Of the 22,630 molecules from varied small molecule libraries, based on the binding affinities and physicochemical properties, we finalized 30 molecules to be potential drug candidates. Eight of these molecules bind in a manner allowing for the scope of a nearly orthogonal backside nucleophilic attack on their suitably placed electrophilic carbonyl groups by the thiol group of cysteine residue 145, while remaining inside a 4 Ǻ distance range. It is interesting since carbonyl groups are known to be attacked in a similar fashion by external nucleophiles and can be relevant when considering these molecules as potential mechanism-based irreversible inhibitors of the 3CLPro. Further, ADMET analysis and Molecular dynamics simulations and available bioactive assays led to the identification of three molecules with high potential to be explored as drug candidates/lead molecules to target 3CLPro of SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

A Clinico Epidemiological Study of Adverse Cutaneous Manifestations on Using Personal Protective Equipment Among Health Care Workers During Covid Pandemic in a Tertiary Care Centre.

Background: COVID-19 (Coronavirus Disease 2019) pandemic was caused by a novel coronavirus. The frontline health care workers (HCW), wearing personal protective equipment (PPE) for a longer duration can result in a spectrum of adverse skin reactions. Recognizing occupationally induced adverse skin manifestations from PPE is necessary to avoid skin damage and risk of infections and to maintain compliance. Aim: This study aimed to determine the prevalence, clinical characteristics of adverse cutaneous manifestations due to PPE, and also the contributing epidemiological factors among HCW in a tertiary care institute. Materials and Methods: This cross-sectional study was conducted for a period of one month. Four hundred fifteen health care workers who used PPE continuously for >4 hours voluntarily participated in this study. By using a self-administered online questionnaire, the information and clinical photographs were collected. Results: The prevalence of adverse skin manifestations was 62.1% (258). The prevalence was more common in females. Mask-related facial skin problems were most commonly reported. Of 74 participants with pre-existing acne lesions, 35 (8.4%) reported acne flare-ups after using PPE. Increased sweating (22.6%) and itching (11%) were the most commonly noted symptoms. Conclusion: This study provides an insight into the prevalence of adverse skin reactions due to prolonged PPE usages, such as N95 masks and latex gloves in particular. Hence dermatological screening of HCW at regular intervals is inevitable to facilitate early management and prevent inadvertent protocol breaches. Further, it proposes the importance of raising proper safety measures to effectively reduce the COVID positivity rate among HCW by minimizing and preventing occupationally induced dermatosis.

E6C15 (E = Si-Pb): polycyclic aromatic compounds with three planar tetracoordinate carbons.

A systematic exploration of the potential energy surface reveals two global minima with three planar tetra coordinate carbons (ptCs) and two global minima with three quasi-ptCs for E6C15 (E = Si-Pb) combinations. These consist of aromatic polycyclic templates suitable for further design of different materials without hindering the ptC texture.

Planar pentacoordinate carbon in [XC7H2]2+ (X = Be and Mg) and its derivatives.

The planar pentacoordinate carbon (ppC) atom is theoretically established here in [XC7H2]2+ and [XSi2C5H2]2+, where X = Be and Mg, using density functional theory. Inclusion compounds with alkali and alkaline earth metal ions are identified with the monomer units of tricyclic C7H2 and Si2C5H2 isomers with a planar tetracoordinate carbon (ptC) atom. While all alkali and some alkaline earth metals (Ca2+, Sr2+, and Ba2+) stabilize the ptC isomer in both cases, Be2+ and Mg2+ ions form a bond directly with the ptC atom, thus making it a ppC atom. The theoretical binding energies computed at the PBE0-D3/def2-TZVP level of theory are ∼-9.68, -10.42, -5.85, and -5.47 eV for [BeC7H2]2+, [BeSi2C5H2]2+, [MgC7H2]2+, and [MgSi2C5H2]2+, respectively.

New Carbenes and Cyclic Allenes Energetically Comparable to Experimentally Known 1-Azulenylcarbene.

1-Azulenylcarbene (18; 0 kJ mol-1) is experimentally known as the key reactive intermediate for the rearrangement reactions of aryl carbenes in the laboratory. Here, using coupled-cluster methods up to the fc-CCSD(T)/cc-pVTZ//fc-CCSD(T)/cc-pVDZ level, thirteen new carbenes and one new cyclic allene are theoretically identified within the C11H8 elemental composition that either energetically lie below or very close to 18. While the cyclic allene, bicyclo[5.4.0]undeca-2,3,5,7,9,11-hexene (1; -166 kJ mol-1), is the experimentally known lowest energy isomer, three other cyclic allenes, bicyclo[5.4.0]undeca-1,2,4,6,8,10-hexene (2; -100 kJ mol-1), bicyclo[5.4.0]undeca-1,3,4,6,8,10-hexene (3; -97 kJ mol-1), and bicyclo[6.3.0]undeca-1,2,4,6,8,10-hexene (13; -42 kJ mol-1), demand new experimental studies. In total, thirty-one isomers are studied in this work (within -166 to +15 kJ mol-1 from 18) and all are found to be polar (µ ≠ 0). Among these, 1H-benzo[7]annulen-1-ylidene (17; -4 kJ mol-1; µ = 5.24 D), bicyclo[5.4.0]undeca-2,4,6,8,11-pentaene-10-ylidene (24; 13 kJ mol-1; µ = 7.59 D), 5-methylene-naphthalen-1-ylidene (26; 15 kJ mol-1; µ = 5.32 D), 6-methylene-naphthalen-2-ylidene (27; -43 kJ mol-1; µ = 6.60 D), and 8-methylene-naphthalen-2-ylidene (28; -39 kJ mol-1; µ = 5.55 D) are competitively polar compared to 18 (µ = 5.39 D). Therefore, these carbene molecules are potential targets for rotational spectroscopists and radioastronomers. Considering the importance of naphthyl and azulenylcarbenes in reactive intermediate chemistry, mechanisms of different rearrangement reactions and plausible formation pathways of some of these new carbenes are studied in this work using density functional theory.

Why Are MgC3H Isomers Missing in the Interstellar Medium?

Considering the recent findings of linear doublet (2Σ+) MgCnH isomers (n = 2, 4, and 6) in the evolved carbon star IRC+10216, various structural isomers of MgC3H and MgC3H+ are theoretically investigated here. For MgC3H, 11 doublet and 8 quartet stationary points ranging from 0.0 to 71.8 and 0.0 to 110.1 kcal mol-1, respectively, have been identified initially at the UωB97XD/6-311++G(2d,2p) level. To get accurate relative energies, further energy evaluations are carried out for all isomers with coupled cluster methods and thermochemical modules such as G3//B3LYP, G4MP2, and CBS-QB3 methods. Unlike the even series, where the global minima are linear molecules with a Mg atom at one end, in the case of MgC3H, the global minimum geometry turns out to be a cyclic isomer, 2-magnesabicyclo[1.1.0]but-1,3,4-triyl (1, C2v, 2A1). In addition, five low-lying isomers, magnesium-substituted cyclopropenylidene (2, Cs, 2A'), 1-magnesabut-2,3-dien-1-yl-4-ylidene (3, Cs, 2A″), 1-magnesabut-2-yn-1-yl-4-ylidene (4, Cs, 2A″), 2λ3-magnesabicyclo[1.1.0]but-1,3-diyl-4-ylidene (5, C2v;, 2A1), and 1-magnesabut-2,3-dien-2-yl-4-ylidene (6, C∞v, 2Σ+), were also identified. The doublet linear isomer of MgC3H, 1-magnesabutatrienyl (10, C∞v, 2Σ+) turns out to be a minimum but lies 54.1 kcal mol-1 above 1 at the ROCCSD(T)/cc-pVTZ level. The quartet (4Σ+) electronic state of 10 was also found to be a minimum, but it lies 8.0 kcal mol-1 above 1 at the same level. Among quartets, isomer 10 is the most stable molecule. The next quartet electronic state (of isomer 11) is 34.4 kcal mol-1 above 10, and all other quartet electronic states of other isomers are not energetically close to low-lying doublet isomers 2 to 6. Overall, the chemical space of MgC3H contains more cyclic isomers (1, 2, and 3) on the low-energy side unlike their even-numbered MgCnH counterparts (n = 2, 4, and 6). Though the quartet electronic state of 10 is linear, it is not the global minimum geometry on the MgC3H potential energy surface. Isomerization pathways among the low-lying isomers (doublets of 1-4 and a quartet of 10) reveal that these molecules are kinetically stable. For the cation, MgC3H+, the cyclic isomers (1+, 2+, and 3+) are on the low-energy side. The singlet linear isomer, 10+, is a fourth-order saddle point. The low-lying cations are quite polar, with dipole moment values of >7.00 D. The current theoretical data would be helpful to both laboratory astrophysicists and radioastronomers for further studies on the MgC3H0/+ isomers.

Why an integrated approach between search algorithms and chemical intuition is necessary?

Though search algorithms are appropriate tools for identifying low-energy isomers, fixing several constraints seems to be a fundamental prerequisite to successfully running any structural search program. This causes some potential setbacks as far as identifying all possible isomers, close to the lowest-energy isomer, for any elemental composition. The number of explored candidates, the choice of method, basis set, and availability of CPU time needed to analyze the various initial test structures become necessary restrictions in resolving the issues of structural isomerism reasonably. While one could arrive at new structures through chemical intuition, reproducing or achieving those exact same structures requires increasing the number of variables in any given program, which causes further constraints in exploring the potential energy surface in a reasonable amount of time. Thus, it is emphasized here that an integrated approach between search algorithms and chemical intuition is necessary by taking the C12O2Mg2 system as an example. Our initial search through the AUTOMATON program yielded 1450 different geometries. However, through chemical intuition, we found eighteen new geometries within 40.0 kcal mol-1 at the PBE0-D3/def2-TZVP level. These results indirectly emphasize that an integrated approach between search algorithms and chemical intuition is necessary to further our knowledge in chemical space for any given elemental composition.

Two factor authentication protocol for IoT based healthcare monitoring system.

In the last few years, technological advancement has led to the use of wearable body sensors for gathering patient information. Wireless body area networks played an essential role in the modern medical era. Through wearable body sensors, patient data are sent to medical professionals in real-time without any hindrance. This information moves through the public channel, and thus proper security and protection are needed because of its sensitiveness. Many authentication protocols proposed for solving these issues were neither secure nor cost-effective. This paper proposed an authentication protocol using certificateless cryptography for wireless body area networks to resolve the associated security concerns. A formal security analysis is done using the Burrows-Abadi-Needham logic shows that the proposed protocol is resilient against prevailing attacks. Additionally, we employ the Real-or-Random model for mathematical proof and Automated Verification Security Protocol and Analysis simulation tool for security analysis. A detailed comprehensive comparison with the existing protocols indicates that the proposed protocol is cost-effective with improved functionality.

From Molecules with a Planar Tetracoordinate Carbon to an Astronomically Known C5H2 Carbene.

Ethynylcyclopropenylidene (2), an isomer of C5H2, is a known molecule in the laboratory and has recently been identified in Taurus Molecular Cloud-1 (TMC-1). Using high-level coupled-cluster methods up to the CCSDT(Q)/CBS level of theory, it is shown that two isomers of C5H2 with a planar tetracoordinate carbon (ptC) atom, (SP-4)-spiro[2.2]pent-1,4-dien-1,4-diyl (11) and (SP-4)-spiro[2.2]pent-1,4-dien-1,5-diyl (13), serve as the reactive intermediates for the formation of 2. Here, a theoretical connection has been established between molecules containing ptC atoms (11 and 13) and a molecule (2) that is present nearly 430 light years away, thus providing evidence for the existence of ptC species in the interstellar medium. The reaction pathways connecting the transition states and the reactants and products have been confirmed by intrinsic reaction coordinate calculations at the CCSDT(Q)/CBS//B3LYP-D3BJ/cc-pVTZ level. While isomer 11 is non-polar (µ = 0), isomers 2 and 13 are polar, with dipole moment values of 3.52 and 5.17 Debye at the CCSD(T)/cc-pVTZ level. Therefore, 13 is also a suitable candidate for both laboratory and radioastronomical studies.

Leaving half the acetabulum in pelvic resections improves hip function. Is there a need to revisit conventional pelvic resections?

BACKGROUND: Conventional periacetabular pelvic resections are associated with poor functional outcomes. Resections through surgical corridors beyond the conventional margins may be helpful in retaining greater function without compromising the oncological margins. METHODS: The study included a retrospective review of 82 cases of pelvic resections for pelvic tumors. Outcomes of acetabulum preservation (Group A) were compared with complete acetabular resection (Group B). Also, we compared outcomes of Type I + half resections (Group 1) with Type I + II resections (Group 2), and Type III + half resections (Group 3) with Type II + III resections (Group 4). RESULTS: Group A (n = 44) had significantly better functional outcome than Group B (n = 38) with average MSTS93 score 22.3 versus 20.1 and average HHS 91.3 versus 82.5 (p < 0.001). Group 1 (n = 14) and Group 2 (n = 12) had similar functional outcomes (mean MSTS93 score 22.07 vs. 21.58 [p = 0.597] and mean HHS 90.37 vs. 86.51 [p = 0.205]). Group 3 (n = 11) had significantly better functional outcome than Group 4 (n = 17), with mean MSTS93 score 22.8 versus 19.7 (p < 0.001) and mean HHS 92.3 versus 80.1 (p < 0.001). Oncological outcomes were similar among the groups. CONCLUSION: Transacetabular pelvic resections provide functional benefit over conventional resections without compromising oncological margins. There is a need to revisit and revise the pelvic resection planes.

Surgical phocomelia or phoco-reduction as a method of limb salvage for sarcomas of the upper limb: A suitable alternative to amputation.

BACKGROUND: Reconstruction following resection of sarcomas of the upper extremity with methods described in the prevalent literature may not be possible in few selected cases. We describe surgical phocomelia or phoco-reduction as a method of limb salvage in such cases of extensive sarcomas of the upper limb with its functional and oncological outcomes. METHODS: Evaluation of functional and oncological outcomes was performed for 11 patients who underwent surgical phocomelia or phoco-reduction for extensive sarcomas of the upper limb between 2010 and 2019. RESULTS: The mean follow-up period in the study was 27.8 months. Five patients required a segmental resection including the entire humerus while six patients underwent segmental resection around the elbow with a mean resection length of 21.5 cm. Mean Musculoskeletal Tumor Society 93 score was 22 depicting a good functional outcome. Mean handgrip strength on the operated side was 62% of the contralateral side with preservation of useful hand function. Meantime to humeroulnar union was 6.7 months. Radial nerve palsy and implant failure occurred in one patient each. No patient developed local recurrence while three patients died of metastasis. CONCLUSION: Surgical phocomelia is a prudent alternative to severely incapacitating amputations in situations where other reconstruction methods are not feasible.

Cross-covariance based affinity for graphs.

The accuracy of graph based learning techniques relies on the underlying topological structure and affinity between data points, which are assumed to lie on a smooth Riemannian manifold. However, the assumption of local linearity in a neighborhood does not always hold true. Hence, the Euclidean distance based affinity that determines the graph edges may fail to represent the true connectivity strength between data points. Moreover, the affinity between data points is influenced by the distribution of the data around them and must be considered in the affinity measure. In this paper, we propose two techniques, C C G A L and C C G A N that use cross-covariance based graph affinity (CCGA) to represent the relation between data points in a local region. C C G A L also explores the additional connectivity between data points which share a common local neighborhood. C C G A N considers the influence of respective neighborhoods of the two immediately connected data points, which further enhance the affinity measure. Experimental results of manifold learning on synthetic datasets show that CCGA is able to represent the affinity measure between data points more accurately. This results in better low dimensional representation. Manifold regularization experiments on standard image dataset further indicate that the proposed CCGA based affinity is able to accurately identify and include the influence of the data points and its common neighborhood that increase the classification accuracy. The proposed method outperforms the existing state-of-the-art manifold regularization methods by a significant margin.

Six Low-Lying Isomers of C11H8 Are Unidentified in the Laboratory-A Theoretical Study.

Isomers of C11H8 have been theoretically examined using density functional theory and coupled-cluster methods. The current investigation reveals that 2aH-cyclopenta[cd]indene (2), 7-ethynyl-1H-indene (6), 4-ethynyl-1H-indene (7), 6-ethynyl-1H-indene (8), 5-ethynyl-1H-indene (9), and 7bH-cyclopenta[cd]indene (10) remain elusive till date in the laboratory. The puckered low-lying isomer 2 lies at 9 kJ mol-1 below the experimentally known molecule, cyclobuta[de]naphthalene (3), at the fc-CCSD(T)/cc-pVTZ//fc-CCSD(T)/cc-pVDZ level of theory. 2 lies at 36 kJ mol-1 above the thermodynamically most stable and experimentally known isomer, 1H-cyclopenta[cd]indene (1), at the same level. It is identified that 1,2-H transfer from 1 yields 2H-cyclopenta[cd]indene (14) and subsequent 1,2-H shift from 14 yields 2. Appropriate transition states have been identified, and intrinsic reaction coordinate calculations have been carried out at the B3LYP/6-311+G(d,p) level of theory. Recently, 1-ethynyl-1H-indene (11) has been detected using synchrotron-based vacuum ultraviolet ionization mass spectrometry. 2-Ethynyl-1H-indene (4) and 3-ethynyl-1H-indene (5) have been synthetically characterized in the past. While the derivatives of 7bH-cyclopenta[cd]indene (10) have been isolated elsewhere, the parent compound remains unidentified till date in the laboratory. Although C11H8 is a key elemental composition of astronomical interest for the formation of polycyclic aromatic hydrocarbons in the interstellar medium, none of its low-lying isomers have been characterized by rotational spectroscopy though they are having a permanent dipole moment (µ ≠ 0). Therefore, energetic and spectroscopic properties have been computed, and the present investigation necessitates new synthetic studies on C11H8, in particular 2, 6-10, and also rotational spectroscopic studies on all low-lying isomers.