• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4403-4407
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• 2011

The nucleophilic substitution reactions of dipropyl chlorothiophosphate (3) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The obtained deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are primary normal ($k_H/k_D$ = 1.11-1.35). A concerted mechanism involving predominant frontside nucleophilic attack is proposed on the basis of the primary normal DKIEs and selectivity parameters. Hydrogen bonded, four-center-type transition state is proposed. The steric effects of the two ligands on the anilinolysis rates of various substrates are discussed.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.7
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• pp.9-16
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• 1999

We have investigated effects of local damage accumulation for ultra-low energy As and B ion implant using highly efficient molecular dynamics(MD) scheme. We simulated ion implantation by MD simulation using recoil ion approximation (RIA) method and local cell damage accumulation (LCDA) model proposed in the paper. Local damage accumulation probability function consisted of deposited energy in a unit cell, implant dose rate, target material, projectile atom, and recoil event number. The simulated results were good agreement with the experimental and other simulated results. The MDRANGE results without damage accumulation were different from SIMS data in the tail region. We also simulated 2 dimensional dopant and damage profiles using the local damage accumulation model and recoil ion approximation method.

• Advances in Traditional Medicine
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• v.6 no.4
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• pp.355-360
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• 2006

Plants have been used in traditional medicinal system for centuries. Bangladeshi medicinal plants have received considerable attention from the researchers for evaluation of their bioactivity. As a part of our ongoing research of screening the Bangladeshi medicinal plants, the ethanolic extract of Dendrophthoe falcata have been chosen for the present study. The ethanolic extract of the leaves of the plant have been assessed for their antioxidant, antinociceptive, and general toxicity. The extract showed potent antioxidant activity ($IC_{50}5.1{\mu}g/ml$) using DPPH radical scavenging assay, which is comparable to the standard ascorbic acid ($IC_{50}4.6{\mu}g/ml$). The extract significantly and dose dependently inhibited the acetic acid induced writhing in mice (71.2%, P < 0.001 and 28.0%, P < 0.05 for 500 and 250 mg/kg body weight, respectively). A general toxicity was assessed by a simple and low cost assay using brine shrimp lethality as an indicator. The extract showed low level of toxicity ($LC_{50}100{\mu}g/ml$). Using different chromatographic techniques, quercitrin (quercetin 3-O-${\alpha}$-rhamnoside) was separated as the major component from the extract. The structure was elucidated by detailed 1D and 2D NMR and mass spectral analysis.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.81-81
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• 2001

초지 공정은 wire, roll, pump등의 회전체로 이루어진 공정이 거의 대부분이기 때문에 주기적으로 변동하는 성분들이 많고, QCS(Quality Control System) 및 DCS(Distributed Co n ntrol System)상에 서 의 자동 Control Logic에 의 한 불안정 (Fluctuation)요소도 내 재 되 어 있 어 이에 대한 분석이 필요하다. 이러한 주기적인 변동은 제품의 여러 물성(평량, 두께, 광택 도등) 에 영향을 미치게 되어 품질의 균일성이나 프로파일에 영향을 미치게 된다. 따라서 공정상이나 품질에서 주기적으로 변동하는 성분을 추출하여 공정 각 성분과 연관을 시키변 품질에 나타나는 주기적 성분의 요인이 어느 부분에서 기인하는 지를 직접적으로 찾아낼 수 있고 이의 개선을 통해 품질의 균일성 및 프로파일 향상을 꾀할 수 있다. 본 연구에서는 Air padded type 헤드박스 초지기에서 DAQ(Data Acquisition) System 을 이용하여 각 공정별로 MD(Machine Direction)방향으로의 변동을 측정하고 제품의 물성 변동과 비교하였다. DAQ System은 각 공정상의 전기적 신호를 높은 주파수 영역까지 다채널로 동시에 받 아 들일 수 있는 장치로 이 시스템을 활용하여 공정상의 Machine chest 농도, Stock box 유량 및 레벨, Fan pump RPM, Cleaner압력, Screen압력, H!B압력 및 레벨, Silo level등 공 정요소의 변동상태와 상호영향을 분석하였다. 이러한 공정 각 요소의 변동과 MD 방향의 제품 물성 값(Tapio, Paper Variation Analyzer에 대한 비교 분석결과 제품 평량에서 주기적인 변동성분을 확인할 수 있었고 이중 큰 비 중을 차지하는 것이 fνB 레벨 변동주기와 일치하는 것을 찾아낼 수 있었다. 이에 근거하여 D DCS system의 control 요소인 튜닝 parameter(P,I 값)들을 미 세 조정 하여 제 품의 MD방향 평량 변동 진폭을 기존 수준의 30% 수준으로 감소시킬 수 있었다. 그 결과 COV(표준편차/ 평량)값을 0.8-1.2%에서 0.6-0.8%수준으로 낮출 수 있었고 이에 따라 CD (Cross Direction) 방향의 제품 Profile도 함께 개선되는 효과를 거둘 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2097-2108
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• 2014

Chemical feature based quantitative pharmacophore models were generated using the HypoGen module implemented in DS2.5. The best hypothesis, Hypo1, which was characterized by the highest correlation coefficient (0.96), the highest cost difference (61.60) and the lowest RMSD (0.74), consisted of one hydrogen bond acceptor, one hydrogen bond donor, one hydrophobic and one ring aromatic. The reliability of Hypo1 was validated on the basis of cost analysis, test set, Fischer's randomization method and GH test method. The validated Hypo1 was used as a 3D search query to identify novel inhibitors. The screened molecules were further refined by employing ADMET, docking studies and visual inspection. Three compounds with novel scaffolds were selected as the most promising candidates for the designing of Mcl-1 antagonists. Finally, a 10 ns molecular dynamics simulation was carried out on the complex of receptor and the retrieved ligand to demonstrate that the binding mode was stable during the MD simulation.

• The korean journal of orthodontics
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• v.52 no.4
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• pp.287-297
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• 2022

Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent two-jaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four time-points (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.

• Bulletin of the Korean Chemical Society
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• v.7 no.5
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• pp.367-371
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• 1986

Dynamic and equilibrium properties of n-alkane chains immersed in solvent molecules have been investigated by a molecular dynamics method. The n-alkane chain is assumed to be a chain of elements (CH$_2$) interconnected by bonds having a fixed bond length and bond angle, but each bond of the chain is allowed to execute hindered internal rotation. We studied the effect of the number of the chain elements (N$_c$ = 10, 15 and 20) on the equilibrium properties of the system, e.g., the pair correlation functions between a chain element and solvent molecules, g$_{cs}$(r), and between the chain elements, g$_{cc}$(r), and the configurational properties such as the mean-square end-to-end distance < R$^2$ >, the mean-square radius of gyration < S$^2$ >, and the eigenvalues of the moment-of-inertia tensor < S$_i^2$ > / < S$^2$ > (i = 1, 2 and 3). We also studied the dynamic properties of the system, e.g., the autocorrelation function C(A;t) where A = R$^2$(t), = S$^2$(t), or = ${\vec{V}}(t)({\vec{V}}$ = velocity of the center of mass), and the diffusion coefficient D. The g$_{cs}$(r)'s are almost equal irrespective of the change of Nc while g$_{cc}$(r) becomes larger as N$_c$ increases; The MD computed configurational properties < R$^2$2 > and < S$^2$ > were found to be a little different from the values calculated from the statistical equations of < R$^2$ > and < S$^2$ >, it may be due to the fact that our model for the MD simulations includes a long-range volume effect. From the < S$_i^2$ > / < S$^2$ >, it is found that the chain molecule has a nearly spherical shape irrespective of the variation of N$_c$. For the dynamic properties we found that the C(R$^2$;t) and C(S$^2$;t) of lower N$_c$ decay faster than those of higher N$_c$, while the C($\vec V$;t) of the center of mass in the chain is weakly dependent on the N$_c$. The center of mass diffusion coefficient D$_c$ decreases as N$_c$ increases while the end point diffusion coefficient D$_e$ is nearly equal irrespective of the change of N$_c$.

• Advances in nano research
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• v.2 no.3
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• pp.157-172
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• 2014

The three-dimensional Nano-Electronic Modeling toolkit (NEMO 3-D) is an open source software package that allows the atomistic calculation of single-particle electronic states and optical response of various semiconductor structures including bulk materials, quantum dots, impurities, quantum wires, quantum wells and nanocrystals containing millions of atoms. This paper, first, describes a software module introduced in the NEMO 3-D toolkit for the calculation of electronic bandstructure and interband optical transitions in nanowires having wurtzite crystal symmetry. The energetics (Hamiltonian) of the quantum system under study is described via the tight-binding (TB) formalism (including $sp^3$, $sp^3s^*$ and $sp^3d^5s^*$ models as appropriate). Emphasis has been given in the treatment of surface atoms that, if left unpassivated, can lead to the creation of energy states within the bandgap of the sample. Furthermore, the developed software has been validated via the calculation of: a) modulation of the energy bandgap and the effective masses in [0001] oriented wurtzite nanowires as compared to the experimentally reported values in bulk structures, and b) the localization of wavefunctions and the optical anisotropy in GaN/AlN disk-in-wire nanowires.

• Natural Product Sciences
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• v.27 no.2
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• pp.61-67
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• 2021

Since ancient times, various herbal medicines have been used in folk medicine to treat a variety of diseases. While the majority of drugs belong to the Kingdom of Plantae, some drugs from the Kingdom of Animalia are listed in various Materia medica of alternative medicines. Animal-derived drugs are mentioned in the Unani system of Medicine (USM) and have been used successfully to treat a variety of diseases. Marjān (Corallium rubrum) is a vital marine drug of animal origin that has been used in USM since ancient times and continues to be used today. It possesses a variety of beneficial pharmacological properties, including tonic effects on the heart, brain, stomach, and eyes, pregnancy protection, expectorant, and hemostyptic properties. It is used to treat hemoptysis, palpitation, bleeding piles, hemiplegia, heart failure, and general weakness. It is also an ingredient in a variety of Unani formulations with pharmacological significance. Unani physicians expanded the uses of Marjan and successfully used it to treat a variety of new diseases. There is a dearth of scientific research on its pharmacological and medicinal properties. The urgent need is to validate the Unani claims about its beneficial cardiac and nervine actions, as well as other significant actions mentioned in the Unani literature.

• Journal of Forest and Environmental Science
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• v.26 no.3
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• pp.161-170
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• 2010

A study was conducted for indentifying the floral biodiversity of woody species by calculating four diversity indices using data collected from 4 stands of different age groups and disturbance regimes in two areas of Madhupur tract. Results showed that highest species diversity in the old growth secondary coppice forest (>60 years) under moderate anthropogenic disturbances of Madhupur National Park area (delete (D=0.74, H'=3.36) followed by old growth secondary forest stands (>40 years) under moderate disturbances at Bhawal National Park area (D=0.65, H'=2.81). Plant species diversity of the young enrichment plantations (<20 years and <15 years) under high anthropogenic disturbances in both the areas are much low (D=0.54 and H'=2.16 and D=0.52 and H'=1.92 respectively), which indicate high anthropogenic disturbances coupled with introduction of invasive exotics that are rival for endemic species are detrimental for conservation of biological diversity of tropical moist deciduous forests of Madhupur tract in Bangladesh.