Dr Value Research Articles

Solvent‐ or Base‐Controlled Diastereoselectivity and Chemoselectivity for the Reaction of Ketenimine Zwitterionic Salts

Comprehensive SummaryKetenimine zwitterionic salt (KZS), a novel and stable ketenimine precursor, is still underexplored in the realm of chemical synthesis. In this study, we demonstrate the transformation of pyrrole derivatives through the cyclization of KZS with α‐aminoketones. The diastereoselectivity of this reaction is influenced by the solvent, enabling the isolation of 3‐hydroxypyrrolidine diastereomers with the highest reported dr value of 21 : 1. Furthermore, the chemoselectivity is modulated by the choice of base, yielding 2‐aminopyrrole derivatives as the major products. This research offers a sustainable approach to harnessing the potential of KZS in organic synthesis, contributing to a greener chemical process.

Study on the Bearing Capacity of the Polyethylene Pipe–Cured-In-Place Pipe Liner Composite Structure under External Pressure

Cured-in-place pipe (CIPP) technology is used to repair deformed municipal polyethylene (PE) pipes caused by design flaws, construction issues, or external loads. However, research on CIPP for PE pipes is limited, restricting its broader application. This research focuses on the mechanical response characteristics and failure modes of the composite PE pipe–CIPP liner structure under external loads. Using experimental setups involving comparative test groups with different diameters and wall thickness ratios (DR values, defined as the ratio of the pipe’s outer diameter to its wall thickness), this study evaluates the effects of the liner’s elastic modulus, the bonding effectiveness at the PE pipe–CIPP liner interface, and the initial ovality of the pipes on the load-bearing capacity. The experimental results reveal that CIPP liners substantially enhance the stiffness and load-bearing capacity of PE pipes, with improvements ranging from 200% to nearly 500% depending on the pipe’s DR value. A novel ring stiffness prediction model is also introduced and validated against the experimental data. This model provides a theoretical framework for understanding the complex interactions at the PE pipe–CIPP liner interface and aids in designing more resilient urban drainage systems.

Effect of heat treatment on the radial structure of coaxial polyacrylonitrile/mesophase pitch composite fiber

AbstractCoaxial composite fibers with a cortex of polyacrylonitrile (PAN) and a core layer of mesophase pitch (MP) and PAN were prepared by wet spinning, then heat‐treated in air. The effects of heat treatment on the thermal reaction characteristics, pre‐oxidation degree, radial structure, and thermal stability of coaxial composite fibers were studied by differential scanning calorometry, Raman, and thermogravimetric analysis. As the heat treatment temperature increases, the coaxial composite fibers only undergo cyclization without oxidation, the peak temperature of the thermal reaction increases from 258 to 270°C, and the enthalpy increases from 19.66 to 237.82 J g−1, the heat mainly arises from the PAN component. The Dr value of the coaxial fiber skin layer increases from 0.193 to 0.255 (330°C) and then decreases to 0.236; the core layer Dr value increases from 0.353 to 0.392 (310°C) and then decreases to 0.368. The pre‐oxidation reaction leads to an increase in sp2‐hybridized carbons and an increase in pre‐oxidation degree. When the heat treatment temperature <310°C, the pre‐oxidation degree of the composite fibers increases, leading to formation of a more stable structure compared with that at lower temperatures and an increase in the carbon residue rate.

Alexithymia and Interoceptive Confusion in Covid-19 Pandemic Distress.

Alexithymic traits are associated with the difficulty of perceiving 'non-affective interoceptive signals', and are related to a problematic management of stressful life events (SLEs). The main purpose of this study was to quantify the psychological response of the general population to COVID-19 pandemic stress and to evaluate potential correlations with the presence of 'alexithymic traits' and 'interoceptive confusion' (study protocol # 0077794/2022). 175 subjects from general population were assessed with the Toronto-Alexithymia Scale (TAS-20), the Event-Revised Impact Scale (IES-R), the Interoceptive Accuracy Scale (IAS), and the Interoceptive Confusion Questionnaire (ICQ). a significant relationship emerged between alexithymic traits (assessed with the TAS-20), the ICQ 'interoceptive confusion', and the domain of 'hyper-arousal' as assessed with IES-R. Logistic regression model showed that ICQ-Total Score and IES-R 'hyper-arousal' domain were significantly correlated with TAS-20 total score, with DR value (R2 corrected) explaining the 36.8% of the variability (standard error: 10.7). This study, albeit with the limitations of a cross-sectional experimental design with self-evaluation tools in a general population sample, showed a vulnerability to COVID-19 pandemic stress due to high levels of hyper-arousal in subjects with alexithymic traits and interoceptive confusion.

Development and evaluation of an online monitoring single-particle optical particle counter with polarization detection

We developed a single-particle optical particle counter with polarization detection (SOPC) for the real-time measurement of the optical size and depolarization ratio (defined as the ratio of the vertical component to the parallel component of backward scattering) of atmospheric particles, the polarization ratio (DR) value can reflect the irregularity of the particles. The SOPC can detect aerosol particles with size larger than 500 nm and the maximum particle count rate reaches ∼1.8 × 105 particles per liter. The SOPC uses a modulated polarization laser to measure the optical size of particles according to forward scattering signal and the DR value of the particles by backward S and P signal components. The sampling rate of the SOPC was 106 #/(sec·channel), and all the raw data were processed online. The calibration curve was obtained by polystyrene latex spheres with sizes of 0.5-10 µm, and the average relative deviation of measurement was 3.96% for sub 3 µm particles. T-matrix method calculations showed that the DR value of backscatter light at 120° could describe the variations in the aspect ratio of particles in the above size range. We performed insitu observations for the evaluation of the SOPC, the mass concentration constructed by the SOPC showed good agreement with the PM2.5 measurements in a nearby state-controlled monitoring site. This instrument could provide useful data for source appointment and regulations against air pollution.

Financial performance of the aviation sector transportation during the covid-19 pandemic review from financial ratio

The purpose of this study was to determine the financial performance of the aviation sector transportation industry during the Covid-19 pandemic in terms of financial ratios at PT AirAsia Indonesia Tbk and PT Garuda Indonesia Tbk in 2020. This study used a analysis descriptive qualitative method using secondary data in the form of reports financial statements and annual reports of PT AirAsia Indonesia Tbk and PT Garuda Indonesia Tbk from 2016 to 2020. The results of the study show that the company's short-term liquidity capability is getting lower. Both companies experienced a decrease in solvency work which can be seen from the negative DER value and the DR value more than 1 time. Profitability conditions seen from ROI during the Covid-19 pandemic experienced a very high rate of increase in losses. But ROE during the Covid-19 pandemic was profitable. As the impact of Covid-19, in 2020 PT AirAsia Indonesia Tbk and PT Garuda Indonesia Tbk experienced a decrease in total asset turnover almost touching zero, which means that the effectiveness of the use of total assets in the company is not good or the company's financial performance is low.

Diastereoselective Access to Triazolo[1,2-a]indolines via a Bio-Inspired Oxidative Cyclization of NH-Indoles.

Establishing three-dimensional chemicals by using the C2-C3 π bond of indoles has always been a research hotspot in organic synthesis; however, employing the oxidative C2-C3 π bond of indoles to generate imine which would lead to the N1-C2 π bond cyclization under metal-free conditions is still rare. Here, we report a bio-inspired synthesis of triazolo[1,2-a]indolines by the oxidative cyclization between NH-indoles and azomethine imines with 3,3-dimethyldioxirane as the sole oxidant under metal-free and mild conditions. This finding represents an elegant instance of tri-functionalization of NH-indoles, which provides rapid access to a broad range of triazolo[1,2-a]indolines with tetrahydroisoquinolines in one single step. Up to 86% yield and above 20:1 dr value are observed. The radical mechanism and proton migration process have been speculated.

Pengaruh Tinggi Muka Air Terhadap Deformasi Tanah Terlikuefaksi

Liquefaction occurs in saturated loose sandy soils that experience an increase in pore water pressure due to the propagation of earthquake waves to the ground surface. This phenomenon raises various questions such as how the groundwater level can affect the occurrence of liquefaction events at different earthquake strengths. The purpose of this study was to determine the effect of groundwater level on liquefaction-prone soils at different seismic peak acceleration values and the effect of relative density (Dr) values on liquefaction-prone soils with variations in groundwater level and earthquake acceleration. In this study, a sample of Jono Oge sand soil was used from the occurrence of liquefaction that met the gradation criteria. The soil was separated through the #8 sieve and retained #100. The modeling technique is carried out with several variables such as the ratio of groundwater level (Hw/Hs) of 25%, 50%, 75%, and 90%, relative density (Dr) 30%-40% and 40%-50%, and at different peak accelerations of 0.3g and 0.4g. The modeling test uses a sieve shaker for earthquake vibrations.. The results of the study show that the difference in groundwater level affects the subsidence of liquefied soil where the settlement will be accure greater in the ratio of the groundwater level (Hw/Hs) and the peak acceleration is greater and vice versa, the difference in relative density (Dr) also affects the magnitude of the the settlement where the lower the Dr value for Hw/Hs and the greater the peak acceleration, the greater the settlement will be occure.

Enantioselective Synthesis of α-Alkenylated γ-Lactam Enabled by Ni-Catalyzed 1,4-Arylcarbamoylation of 1,3-Dienes

Enantioselective Synthesis of α-Alkenylated γ-Lactam Enabled by Ni-Catalyzed 1,4-Arylcarbamoylation of 1,3-Dienes

Grindability of titanium alloy using cryogenic nanolubricant minimum quantity lubrication

The defect suppression of titanium alloy disturbed by low thermal conductivity is an urgent problem in grinding. The existing green manufacturing processes such as Nanolubricant minimum quantity lubrication (NMQL) and cryogenic air cooling are unsatisfactory due to insufficient cooling or lubrication performance. Cryogenic NMQL (CNMQL) is a new approach that utilizes the heat transfer capacity of cryogenic air and antiwear/antifriction performance of nanolubricant. However, the lack of grindability analysis and in-depth mechanism explanation limits the optimization and application of CNMQL. In this research, the calculation formulas for the Energy ratio coefficient of the cooling medium (Rm) and Defect ratio (Dr) of workpiece surface were established to evaluate Ti-6Al-4V grindability based on other common parameters, including force, temperature, surface roughness, workpiece and debris morphology. Results show that the lowest grinding force (tangential force is 46.8 N, normal force is 61.4 N), grinding peak temperature (151.2 °C), and surface roughness value (Ra = 0.468 μm) are obtained by CNMQL, compared with NMQL and cryogenic air cooling. The Rm in CNMQL is 36.4 %, which is 68.5 % higher than that of NMQL. The Dr value under CNMQL is 2.67 %, which is 84.5 % lower than cryogenic air cooling and 69.2 % lower than NMQL. Cryogenic nanolubricant displays excellent grinding performance due to its higher viscosity and shows significant improvement of convective heat transfer capacity. The critical cutting depth and plastic accumulation are significantly reduced therefore resulting in fewer surface defects.

Galangal extract of an antimicrobial model for predicting the reduction in histamine concentration in minced pork

Histamine concentration increases in meats, such as fresh pork, when contaminated with some bacteria. Galangal extract, known for its antimicrobial properties, was studied to determine its effects in reducing bacteria in minced pork artificially inoculated with Histamine-Producing Bacteria (HPB) such as Lactobacillus plantarum and to predict the DR value for the Weibull model. Antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Galangal extract was prepared by ethanol distillation and used at 10% and 15% dilutions in distilled water. Bacterial inhibition was evaluated at 4 °C and 8 °C using filter papers soaked in the extract and placed on a minced pork surface. The extract at both concentrations effectively inhibited bacterial growth for 5 days. On the 6th day, the histamine levels detected in food samples stored at 8 °C and exposed to 10% and 15% extract dilutions were 0.9935 and 0.9825 μg/g, respectively. The DR value of the Weibull model, the concentration of galangal extract required for more than 90% reduction in HPB population in minced pork, was determined to be 2.3516 mg/mL (R2= 0.9793). The detected and predicted histamine levels in minced pork were safe. The findings of this study can be used to reduce HPB in food by galangal extract application in packaging and suggest histamine safety levels in pork.

A Dipolar Cyclization/Fragmentation Strategy for the Catalytic Asymmetric Synthesis of Chiral Eight-Membered Lactams

A Dipolar Cyclization/Fragmentation Strategy for the Catalytic Asymmetric Synthesis of Chiral Eight-Membered Lactams

Photoneutron-induced damage reduction for cardiac implantable electronic devices using neutron-shielding sheets in high-energy X-ray radiotherapy: A phantom study.

To evaluate damage reduction in cardiac implantable electronic devices (CIEDs) caused by photoneutrons in high-energy X-ray radiotherapy using a neutron-shielding sheet (NSS). The NSS consists of a bolus with a thickness of 1 or 2cm (Bls1 or Bls2) as a moderator and several absorbers (20%, 50%, or 80% B4C silicone sheet [B4C20, B4C50, or B4C80] or a 40% LiF silicone sheet [LiF40]). First, a linear accelerator (LINAC) with a water-equivalent phantom was modeled in the simulation and measured experimentally. Several NSSs were placed on the phantom, a Eu:LiCaAlF6 scintillator was placed between the phantom and the NSS, and X-rays were irradiated. The relative counts (Cr=counts when placing the NSS or Bls2) were compared between the experiment and simulation. Second, CIED damage was evaluated in the simulation. The relative damage (Dr=damage when placing or not placing the NSS) was compared among all the NSSs. In addition, the γ-ray and leaking X-ray dose from B4C was measured using a dosimetric film. After determining the optimal NSS combination,Dr value analysis was performed by changing the length of one side and the thickness. The Cr values of the simulation and experiment agreed within a 30% percentage difference, except for Bare or LiF40-only. The Dr value was reduced by 43% when Bls2+B4C80 was applied. The photon dose wasless than5cGy/1500 MU. The Dr values were smaller for the smaller lengths of one side of B4C80 and decreased as the M-layer thickness increased. The CIED damage induced by photoneutrons generated by a LINAC was effectively reduced by applying the optimal NSS.

The combined use of temporal dominance of sensations (TDS) and discrete time-intensity (DTI) to describe the dynamic sensory profile of alcoholic cocktails

Time Intensity (both continuous-TI and discontinuous-DTI) and Temporal Dominance of Sensations (TDS) represent the main methodologies for describing the temporal evolution of the different sensations developing during food consumption. Sensory description from these methods relies on different aspects of perception, time-intensity covers the time course of selected sensation intensity while TDS describes the profile in terms of dominant sensations and their temporal sequence. Data collection on both these aspects would provide a more comprehensive description of the dynamic sensory profile. In this work, a new approach combining TDS and DTI methodologies is presented with the aim to: 1) describe the time course of dominant sensations and their relevant intensities in alcoholic beverages; 2) propose new graphical tools to facilitate the observation of changes in the intensities of dominant sensations over time within and between products. The TDS profile of alcoholic cocktails was described by trained assessors. TDS curves of each product were visually inspected, the significantly dominant attributes were selected considering three evaluation intervals: attack 0–30 s; evolution 31–60 s; finishing 61–90 s. Meaningful points for intensity evaluation were identified considering the times at which the dominant attributes were close to their maximum DR value in each time interval. The same panel was further trained to perform the DTI task consisting in the evaluation of the intensity of the dominant attributes at the selected time points. The proposed approach described the product dynamic profiles in terms of the time course of dominant attributes intensities. The dynamic spider plot was proposed as a new graphic representation to illustrate and compare the evolution of the intensity of dominant attributes along attack, evolution, and finishing within and across products.

Pyrethroid resistance and selection against Trogoderma granarium (Everts) in Punjab, Pakistan

Current study was designed to investigate the current susceptibility levels of field collected strains of T. granarium (Everts) from Punjab, Pakistan. T. granarium populations were collected from different areas of Punjab i.e., Lahore, Sheikhupura, Gujranwala, Bahawalpur, Bhakkar and Faisalabad, were evaluated for their relative resistance or susceptibility in comparison to laboratory reared strain against pyrethroids. Filter paper impregnation method was used to assess the contact toxicity of pyrethroids (technical grade deltamethrin, α-cypermethrin, cypermethrin and bifenthrin) against 4th instar larval stage of T. granarium. Mortality responses were evaluated under constant temperature and relative humidity (r.h.) at 32 ± 2 °C and 65 ± 5 r.h. respectively. Data was recorded after 24, 48 and 72 h of treatment and completely randomized design (CRD) were used with four replications. Experiments were conducted in Grain Research Training and Storage management cell, University of Agriculture, Faisalabad, Pakistan during year 2018–19. Bioassays showed that field collected strains were resistant to all test insecticides. Very low to moderate level of resistance was found in field strains. Bahawalpur strain showed highest resistance ratios of up-to 12.7, 18.9, 4.63 and 8.27 for deltamethrin, bifenthrin, α-cypermethrin and cypermethrin respectively, after 72 h of exposure to treatment. Bhakkar strain also showed moderate resistance following Bahawalpur strain. Lahore and Faisalabad collected strains were susceptible as compared to other field strains. In-vitro selection for deltamethrin revealed increase in resistance up-to 18.7 folds after selection for 7 generations by maintaining selection pressure at 80% mortality. Reversion in resistance occurred when strain was again reared for next 5 generations without insecticide exposure and resistance values decreased to 7.74 folds at G12. DR value for change in resistance was -0.07. The effectiveness of commonly used pyrethroids for the management of T. granarium was significantly reduced in the field populations exhibiting low to moderate resistance. Long-term use of insecticides with similar mode of action could be the reason for the development of resistance. Multi-tactical approach with integrated pest management (IPM) framework may prolong the effectiveness of pyrethroids in the T. granarium management.

Organocatalytic Stereoselective [8+2] Cycloaddition of Tropones with Azlactones

Organocatalytic Stereoselective [8+2] Cycloaddition of Tropones with Azlactones

Calibration-based minimalistic multi-exposure digital sensor camera robust linear high dynamic range enhancement technique demonstration

Demonstrated for a digital image sensor-based camera is a calibration target optimized method for finding the Camera Response Function (CRF). The proposed method uses localized known target zone pixel outputs spatial averaging and histogram analysis for saturated pixel detection. Using the proposed CRF generation method with a 87 dB High Dynamic Range (HDR) silicon CMOS image sensor camera viewing a 90 dB HDR calibration target, experimentally produced is a non-linear CRF with a limited 40 dB linear CRF zone. Next, a 78 dB test target is deployed to test the camera with this measured CRF and its restricted 40 dB zone. By engaging the proposed minimal exposures, weighting free, multi-exposure imaging method with 2 images, demonstrated is a highly robust recovery of the test target. In addition, the 78 dB test target recovery with 16 individual DR value patches stays robust over a factor of 20 change in test target illumination lighting. In comparison, a non-robust test target image recovery is produced by 5 leading prior-art multi-exposure HDR recovery algorithms using 16 images having 16 different exposure times, with each consecutive image having a sensor dwell time increasing by a factor of 2. Further validation of the proposed HDR image recovery method is provided using two additional experiments, the first using a 78 dB calibrated target combined with a natural indoor scene to form a hybrid design target and a second experiment using an uncalibrated indoor natural scene. The proposed technique applies to all digital image sensor-based cameras having exposure time and illumination controls. In addition, the proposed methods apply to various sensor technologies, spectral bands, and imaging applications.

Diastereoselective synthesis of chiral 3-substituted isoindolinones via rhodium(III)-catalyzed oxidative C-H olefination/annulation.

A new method for the direct and stereoselective synthesis of 3-substituted isoindolinones via Rh(iii)-catalyzed chiral N-sulfinyl amide directed asymmetric [4 + 1] annulation of benzamides with acrylic esters has been developed. The reaction proceeded through an oxidative C-H olefination and a subsequent cyclization by intramolecular aza-Michael addition, producing a series of diastereoisomeric chiral isoindolinones (20 examples) in generally good yields with a dr value up to 5.5 : 1. The absolute configurations of the newly formed C-stereocenters in the major and minor diastereomers of the catalysis product have been determined by X-ray crystal diffraction analysis to be S and R, respectively. The separation of the major diastereoisomers from the catalysis products and subsequent removal of the N-sulfinyl chiral auxiliary afforded enantiomerically pure (S)-isoindolinones. The application of the obtained (S)-isoindolinones in the synthesis of several biologically active isoindolinones such as (S)-PD172938, (S)-pazinaclone and (S)-pagoclone is presented.

Theoretical investigation on the mechanism and enantioselectivity of organocatalytic asymmetric Povarov reactions of anilines and aldehydes

AbstractThe mechanism is investigated for organocatalytic asymmetric Povarov reaction of anilines and aldehydes using M06‐2X functional. Two molecule of aldehyde condense with aniline and catalyst giving N‐arylimine and enamine. The reaction is stepwise involving [2 + 2] cycloaddition and ring‐opening/cyclization. Four competitive paths exist in step 1 leading to isomers of quaternary nitrogen heterocycle as cycloadduct. Step 2 is sequential with proton transfer and concerted ring‐opening/cyclization in two feasible orders. Each path in step 1 divides into two in step 2 producing isomers of tetrahydroquinoline (THQ) bonded with catalyst as cyclization product. The reactive nucleophilic adduct with two charge centers in step 1 supports the recovery of catalyst and generation of aldehyde assisted by water. THQ alcohol is obtained in the following intramolecular Friedel–Crafts reaction. The enantio‐ and diastereoselectivity are both thermodynamic control with preferred path yielding the most stable isomer with 2S3S or 1R2S3S configuration. The path bias is in line with the reduction degree of energy barrier in solvent compared with gas phase. Our conclusion is verified by Multiwfn analysis and the predicted ee, dr value of THQ scaffold in experiment.

Evaluation of nine reference evapotranspiration models in Traghen region, Southwest of Libya

This research was carried out to evaluate nine reference evapotranspiration, and find out an alternative models to the standard FAO Penman-Monteith model in Traghen region southwest of Libya. The models applied were standard FAO Penman-Monteith, FAO Radiation, FAO Blaney-Criddle, Hargreaves-Samani, Priestley-Taylor, Makkink, Turc, Thornthwaite, Kharrufa and McCloud. The models were compared with the FAO Penman-Monteith model using root mean square error (RMSE) , mean bias error (MBE), Pearson type goodness of fit index (R2), refined index of agreement (dr), modeling efficiency (Ef) and t-test. Results showed that FAO Radiation and FAO Blaney-Criddle models overestimated ETo by values ranged from 0.64% to 16.06%. However, Kharrufa and McCloud models overestimated ETo in some months and underestimated ETo in some other months. Whereas, the other models underestimated ETo by values ranged from -86.69 % to -6.02%. The FAO radiation model gave the highest dr (0.892) and Ef (0.951) values, and the lowest RMSE (0.534 mm/day), indicating that this model was the best alternative to the FAO Penman-Monteith model in the study region, followed by FAO Blaney-Criddle model with dr value of 0.851, Ef value of 0.878, and RMSE value of 0.845 mm/day. In addition, FAO radiation model showed the second best R2 and MBE values at 0.993 and 0.473, respectively Also, FAO Blaney-Criddle model showed the third best R2 value at 0.989. Therefore, FAO radiation model is ranked the first and FAO Blaney-Criddle model is ranked the second. According to the statistical measures stated above, Turc model ranked the third, Kharrufa model ranked forth. Models of Hargreaves-Samani, Makkink, Priestley-Taylor, McCloud and Thornthwaite ranked fifth, sixth, seventh, eighth and ninth, respectively. T-test analysis at 5% level of significance indicated that there is a significant difference between the FAO Penman-Monteith model and all models except Kharrufa and McCloud models.