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Jörg Wulff, Kilian-Simon Baumann, Nico Gerd Verbeek, Christian Baeumer, Beate Timmermann, Klemens Zink
Geant4 - as used in TOPAS - is one of the major general purpose codes suitable for investigation of ionization chambers in proton beams. To provide reliable results, the impact of parameter settings and possible limitations of the underlying condensed history (CH) algorithm need to be known.
 A version of the Fano cavity test was implemented in Geant4 (10.03.p1) for protons, which allows comparison of calculation with expected result for a typical ionization chamber-like geometry. Parameters of the CH implementation in the EMStandardOpt4 physics-list were tested...
May 8, 2018: Physics in Medicine and Biology
Igor L Fedushkin, Anton N Lukoyanov, Evgeny V Baranov
The reduction of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-Bian) with an excess of La metal in the presence of iodine (dpp-Bian/I2 = 2/1) in tetrahydrofuran (thf) or dimethoxyethane (dme) affords lanthanum(III) complexes of dpp-Bian dianion: deep blue [(dpp-Bian)2- LaI(thf)2 ]2 (1, 84%) was isolated by crystallization of the product from hexane, while deep green [(dpp-Bian)LaI(dme)2 ] (2, 93%) precipitated from the reaction mixture in the course of its synthesis. A treatment of complex 1 with 0...
March 21, 2018: Inorganic Chemistry
Yan Liu, Ling Zhang, Li-Na Niu, Tao Yu, Hockin H K Xu, Michael D Weir, Thomas W Oates, Franklin R Tay, Ji-Hua Chen
OBJECTIVES: To evaluate the bonding performance, antibacterial activity, and remineralization effect on enamel of the orthodontic adhesive containing MAE-DB and NACP. METHODS: Eighty non-carious human premolars were divided into 3 groups: Transbond XT (TB), PEHB + 5% MAE-DB (PD), and PEHB + 40% NACP + 5% MAE-DB (PND). Premolars were bonded with orthodontic brackets, the first subgroup (n = 10) and the second subgroup (n = 10) were subjected to shear bond strength testing after immersed in water for 1 day and in demineralization solution for 28 days respectively and then tested surface roughness, while the third subgroup (n = 6) was used for microhardness evaluation after aged in demineralization solution for 28 days...
March 10, 2018: Journal of Dentistry
Yousif A Al-Dulaijan, Lei Cheng, Michael D Weir, Mary Anne S Melo, Huaibing Liu, Thomas W Oates, Lin Wang, Hockin H K Xu
OBJECTIVE: Rechargeable calcium phosphate (CaP) composites were developed recently. However, none of the rechargeable CaP composites was antibacterial. The objectives of this study were to develop the first rechargeable CaP composite that was antibacterial, and to investigate the effects of adding dimethylaminohexadecyl methacrylate (DMAHDM) into rechargeable CaP composite on ion rechargeability and re-release as well as biofilm properties. METHODS: DMAHDM was synthesized via a Menschutkin reaction...
May 2018: Journal of Dentistry
Kedar Mehta, Ajay M V Kumar, Sudhir Chawla, Paragkumar Chavda, Kalaiselvi Selvaraj, Kalpita S Shringarpure, Dipak M Solanki, Pramod B Verma, B B Rewari
BACKGROUND: In 2016, the National AIDS Control Programme (NACP) in Gujarat, India implemented an innovative intervention called 'M-TRACK' (mobile phone reminders once every week for four weeks after diagnosis and electronic patient tracking tool) to reduce pre-treatment loss to follow-up (LFU) among people living with HIV (PLHIV) in Vadodara district while other districts received standard of care. OBJECTIVES: To assess the effectiveness of M-TRACK in reducing pre-treatment LFU (proportion of diagnosed PLHIV not registering for HIV care by four weeks after diagnosis) and to explore the implementation enablers and challenges from health care providers' and PLHIV perspective...
2018: Global Health Action
Jaegi Lee, Sung-Joon Ye
Magnetic resonance imaging-guided radiotherapy provides real-time imaging with a superior soft-tissue contrast without radiation exposure. Recently, several groups have been developing such a new technology. Strong magnetic fields can influence trajectories of the secondary electrons by the Lorentz force. The reference dosimetry using an ion-chamber in magnetic fields needs additional correction factors [1]. In this study, we calculated magnetic field correction factors by the Monte Carlo method for the reference dosimetry using a parallel-plate ion-chamber...
January 2018: Physica Medica: PM
Kunneng Liang, Shimeng Xiao, Junling Wu, Jiyao Li, Michael D Weir, Lei Cheng, Mark A Reynolds, Xuedong Zhou, Hockin H K Xu
OBJECTIVE: Previous studies investigated short-term dentin remineralization; studies on long-term dentin remineralization after fluid challenges mimicking fluids in oral environment are lacking. The objective of this study was to develop a long-term remineralization method to via poly(amido amine) (PAMAM) and rechargeable composite containing nanoparticles of amorphous calcium phosphate (NACP) after fluid challenges for the first time. METHODS: NACP composite was immersed at pH 4 to exhaust its calcium (Ca) and phosphate (P) ions, and then recharged with Ca and P ions, to test the remineralization of the exhausted and recharged NACP composite...
April 2018: Dental Materials: Official Publication of the Academy of Dental Materials
Jorge D Machicado, Suresh T Chari, Lawrence Timmons, Gong Tang, Dhiraj Yadav
BACKGROUND: Based on reports from tertiary care centers, chronic pancreatitis (CP) is considered to be a painful and debilitating disease frequently requiring invasive interventions. Our primary aim was to assess the natural course of CP in a population-based cohort using endoscopic and surgical interventions as surrogates for disease aggressiveness. METHODS: We identified all patients (n = 89, alcoholic [ACP = 46], non-alcoholic [NACP] = 43) with newly diagnosed definite CP from Olmsted County, Minnesota between 1977 and 2006...
January 2018: Pancreatology: Official Journal of the International Association of Pancreatology (IAP) ... [et Al.]
Kunneng Liang, Shimeng Xiao, Michael D Weir, Chongyun Bao, Huaibing Liu, Lei Cheng, Xuedong Zhou, Jiyao Li, Hockin H K Xu
Patients with dry mouth often have an acidic oral environment lacking saliva to provide calcium (Ca) and phosphate (P) ions. There has been no report on tooth remineralization in acidic pH4 and CaP ion-lacking solutions. The objective of this study was to develop a novel method of combining poly(amido amine) (PAMAM) with adhesive containing nanoparticles of amorphous calcium phosphate (NACP) for dentin remineralization in pH4 and CaP-lacking solution for the first time. Demineralized dentin was tested in four groups: (1) dentin control, (2) dentin with PAMAM, (3) dentin with NACP adhesive, (4) dentin with PAMAM + NACP adhesive...
November 28, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Safaa H Ali, Glen B Deacon, Peter C Junk, Shima Hamidi, Michal Wiecko, Jun Wang
Pseudo-Grignard reagents PhLnI (Ln=Yb, Eu), readily prepared by the oxidative addition of iodobenzene to ytterbium or europium metal at -78 °C in tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME), react with a range of bulky N,N'-bis(aryl)formamidines to generate an extensive series of LnII or more rarely LnIII complexes, namely [Eu(DippForm)I(thf)4 ]⋅thf (1), [{EuI2 (dme)2 }2 ] (2), [Eu(XylForm)I(dme)2 ]⋅0.5 dme (3 a), [Eu(XylForm)I(dme)(μ-dme)]n (3 b), [{Eu(XylForm)I(μ-OH)(thf)2 }2 ] (4), [Yb(DippForm)I(thf)3 ]⋅thf (5 a), [Yb(DippForm)I2 (thf)3 ]⋅2 thf (5 b), [{Yb(MesForm)I(thf)2 }2 ] (6), [{Yb(XylForm)I(thf)2 }2 ] (7 a), and [Yb(XylForm)2 I(dme)]⋅dme (7 b) {(Form=ArNCHNAr; XylForm (Ar=2,6-Me2 C6 H3 ), MesForm (Ar=2,4,6-Me3 C6 H2 ), DippForm (Ar=2,6-iPr2 C6 H3 )}...
January 2, 2018: Chemistry: a European Journal
Eric Y Tenkorang, Adobea Y Owusu, Amos K Laar, Eric H Yeboah
As part of providing comprehensive HIV/AIDS services, the Ghana National AIDS Control Programme (NACP) and Ministry of Health recommend that Persons Living with HIV/AIDS (PLWHAs) receive psychosocial support and follow-up visits that ensure medical and drug adherence assistance. The successful implementation of these support services requires patients to have stable and quality housing, yet studies that examine associations between housing, psychosocial support, and adherence counseling among PLWHAs in Ghana and sub-Saharan Africa are limited...
October 18, 2017: Health Promotion International
Silvia Vargas Castrillón, Francisco Cutanda Henríquez
The International Atomic Energy Agency Technical Reports Series-398 code of practice for dosimetry recommends measuring photon percentage depth dose (PDD) curves with parallel-plate chambers. This code of practice was published before flattening filter-free (FFF) beams were widely used in clinical linear accelerators. The choice of detector for PDD measurements needs to be reassessed for FFF beams given the physical differences between FFF beams and flattened ones. The present study compares PDD curves for FFF beams of nominal energies 6 MV, 6 FFF, 10 MV, and 10 FFF from a Varian TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, USA) acquired with Scanditronix photon diodes, two scanning type chambers (both PTW 31010 Semiflex), two small volume chambers (Wellhofer CC04 and PTW 31016 PinPoint 3D), PTW 34001 Roos, Scanditronix Roos, and NACP 02 parallel-plate chambers...
July 2017: Journal of Medical Physics
Benjamin A Clough, Simona Mellino, Andrey V Protchenko, Martin Slusarczyk, Laura C Stevenson, Matthew P Blake, Bowen Xie, Eric Clot, Philip Mountford
We report a combined experimental and computational study of the synthesis and electronic structure of titanium borylimido compounds. Three new synthetic routes to this hitherto almost unknown class of Group 4 imide are presented. The double-deprotonation reaction of the borylamine H2 NB(NAr'CH)2 (Ar' = 2,6-C6 H3 i Pr2 ) with Ti(NMe2 )2 Cl2 gave Ti{NB(NAr'CH)2 }Cl2 (NHMe2 )2 , which was easily converted to Ti{NB(NAr'CH)2 }Cl2 (py)3 . This compound is an entry point to other borylimides, for example, reacting with Li2 N2 pyr NMe to form Ti(N2 pyr NMe ){NB(NAr'CH)2 }(py)2 and with 2 equiv of NaCp to give Cp2 Ti{NB(NAr'CH)2 }(py) (23)...
September 5, 2017: Inorganic Chemistry
Shimeng Xiao, Kunneng Liang, Michael D Weir, Lei Cheng, Huaibing Liu, Xuedong Zhou, Yi Ding, Hockin H K Xu
Objectives. The objectives of this study were to: (1) develop a bioactive multifunctional composite (BMC) via nanoparticles of amorphous calcium phosphate (NACP), 2-methacryloyloxyethyl phosphorylcholine (MPC), dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of silver (NAg); and (2) investigate the effects of combined BMC + poly (amido amine) (PAMAM) on remineralization of demineralized root dentin in a cyclic artificial saliva/lactic acid environment for the first time. Methods. Root dentin specimens were prepared and demineralized with 37% phosphoric acid for 15 s...
January 22, 2017: Materials
Michael D Weir, Jianping Ruan, Ning Zhang, Laurence C Chow, Ke Zhang, Xiaofeng Chang, Yuxing Bai, Hockin H K Xu
OBJECTIVE: Secondary caries is a primary reason for dental restoration failures. The objective of this study was to investigate the remineralization of human dentin lesions in vitro via restorations using nanocomposites containing nanoparticles of amorphous calcium phosphate (NACP) or NACP and tetracalcium phosphate (TTCP) for the first time. METHODS: NACP was synthesized by a spray-drying technique and incorporated into a resin consisting of ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM)...
September 2017: Dental Materials: Official Publication of the Academy of Dental Materials
Matthew C Leclerc, Bulat M Gabidullin, Jason G Da Gama, Stephanie L Daifuku, Theresa E Iannuzzi, Michael L Neidig, R Tom Baker
Herein, a recently reported polyfluoroalkenyl imidazolium salt is shown to react with nitrogen-, oxygen- and sulfur-based nucleophiles at the C β position in a stereoselective and regioselective fashion, without the use of a transition metal. In contrast, reactivity with 1-methylimidazole demonstrates net substitution at C α . This product reacts quantitatively with water, affording clean transformation of a difluoromethylene group to give an α , β -unsaturated trifluoromethyl ketone. Further reactivity studies demonstrate that the difluoromethyl fragment of an N-heterocyclic fluoroalkene is capable of direct C-C bond formation with NaCp through loss of sodium fluoride and double C-F bond activation (Cp = cyclopentadienide)...
February 27, 2017: Organometallics
Yansong Ma, Ning Zhang, Michael D Weir, Yuxing Bai, Hockin H K Xu
OBJECTIVES: White spot lesions due to biofilm acid-induced enamel demineralization are prevalent in orthodontic treatments. The aim of this study was to develop a novel bioactive multifunctional cement with protein-repellent, antibacterial and remineralizing capabilities, and investigate the effects on enamel hardness and lesion depth in vitro for the first time. MATERIALS AND METHODS: 2-Methacryloyloxyethyl phosphorylcholine (MPC), dimethylaminohexadecyl methacrylate (DMAHDM), and nanoparticles of amorphous calcium phosphate (NACP) were incorporated into a resin-modified glass ionomer (RMGI)...
September 2017: Journal of Dentistry
Reshu Agarwal, Bharat Bhushan Rewari, Suresh Shastri, Sharath Burugina Nagaraja, Abhilakh Singh Rathore
Competing domestic health priorities and shrinking financial support from external agencies necessitates that India's National AIDS Control Programme (NACP) brings in cost efficiencies to sustain the programme. In addition, current plans to expand the criteria for eligibility for antiretroviral therapy (ART) in India will have significant financial implications in the near future. ART centres in India provide comprehensive services to people living with HIV (PLHIV): those fulfilling national eligibility criteria and receiving ART and those on pre-ART care, i...
April 2017: WHO South-East Asia Journal of Public Health
Bharat Bhushan Rewari, Reshu Agarwal, Suresh Shastri, Sharath Burugina Nagaraja, Abhilakh Singh Rathore
The therapeutic and preventive benefits of early initiation of antiretroviral therapy (ART) for HIV are now well established. Reflecting new research evidence, in 2015 the World Health Organization (WHO) recommended initiation of ART for all people living with HIV (PLHIV), irrespective of their clinical staging and CD4 cell count. The National AIDS Control Programme (NACP) in India is currently following the 2010 WHO ART guidelines for adults and the 2013 guidelines for pregnant women and children. This desk study assessed the number of people living with HIV who will additionally be eligible for ART on adoption of the 2015 WHO recommendations on ART...
April 2017: WHO South-East Asia Journal of Public Health
Kunneng Liang, Han Zhou, Michael D Weir, Chongyun Bao, Mark A Reynolds, Xuedong Zhou, Jiyao Li, Hockin H K Xu
OBJECTIVE: Patients with dry mouth often have an acidic oral environment lacking saliva that provides calcium (Ca) and phosphate (P) ions. However, there has been no study on dentin remineralization by placing samples in an acidic solution without Ca and P ions. Previous studies used saliva-like solutions with neutral pH and Ca and P ions. Therefore, the objective of this study was to investigate a novel method of combining poly(amido amine) (PAMAM) with a composite of nanoparticles of amorphous calcium phosphate (NACP) on dentin remineralization in an acidic solution without Ca and P ions for the first time...
July 2017: Dental Materials: Official Publication of the Academy of Dental Materials
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