检索结果-南通市图书馆

Journal of World Architecture 2024年第2期8卷 96-107页

作者： m.zárate López A.Almejo Ornelas m.Sahagún Valenzuela Autonomous University of Baja California Mexico

This paper analyzes neighborhood conflicts arising from the condominium property regime,under which social housing promoted by mexican government institutions and private developers is *** regime has facilitated access to housing for the salaried population,but it is far from contributing to the attainment of the right to *** research takes as case studies housing complexes located in the city of Tijuana,Baja California,*** analysis included a mixed ***,similar case studies were analyzed;secondly,a review of the Condominium Property Regime Law was carried out in order to understand its *** view of the pandemic situation,a virtual survey was applied to the inhabitants of these areas,as well as interviews with presidents of neighborhood committees of these *** the above,it was found that this form of ownership generates conflicts,reflected in the dissatisfaction of the inhabitants with their housing,disagreements and controversies in their organization and *** inhabitants have to collectively solve the problems they face,related to the maintenance and use of common areas,insecurity,and cleanliness,among *** addition,there is a lack of support from local *** this,it is concluded that although the inhabitants have a space that solves their housing problem,it does not manage to be a space that adequately guarantees their right to housing.

关键词： Neighborhood conflicts Right to housing Condominium property Social interest Affordable housing

Effects of friction stir processing and nano-hydroxyapatite on the microstructure,hardness,degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2024年第1期12卷 209-224页

作者： Bo Wu Farazila Yusof Fuguo Li Huan miao A.R.Bushroa mohd Ridha Bin muhamad Irfan Anjum Badruddin mahmoud z.Ibrahim Department of mechanical Engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur 50603Malaysia Centre of advanced manufacturing and material Processing(AmmP Centre) Universiti MalayaKuala Lumpur 50603Malaysia Center of Foundation studies in Science Universiti MalayaKuala Lumpur 50603Malaysia State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China mechanical Engineering Department College of EngineeringKing Khalid UniversityAbha 61421Saudi Arabia Design and Production Engineering Faculty of EngineeringAin Shams UniversityCairo 11517Egypt

Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural ***,the rapid degradation of magnesium alloys in biological media hinders successful *** of microstructure,as well as reinforcement particles can significantly improve the degradation *** this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were *** subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three *** resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,*** is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation *** corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(mg24Y5and mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n ***,the growing Ca-P and mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation *** wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base ***,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three *** results raise that the grain refinement by FSP and introduction of n HA partic

关键词： Friction stir processing magnesium-based composite Nano-hydroxyapatite Corrosion behavior In-vitro bioactivity

Compressive property and energy absorption characteristic of interconnected porous mg-zn-Y alloys with adjusting Y addition

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2024年第1期12卷 171-185页

作者： J.A.Liu S.J.Liu B.Wang W.B.Sun X.J.Liu z.W.Han College of materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of Bionic Engineering(ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for Bionics-Jilin University Weihai 264205PR China

In this study,interconnected porous mg-2zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous mg-zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different mg-zn-Y ternary phases appear:I-phase(mg_(3)zn_(6)Y),W-phase(mg_(3)zn_(3)Y_(2)),and LPSO phase(mg_(12)znY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30mPa to 9.23 mPa,and the energy absorption capacity increases from 7.33 mJ/m^(3)to 10.97 mJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous mg-zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous mg-zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements microstructure Compressive behavior Energy absorption characteristic

Cost-Effectiveness Analysis of Renalof® versus Extracorporeal Shockwave Lithotripsy (ESWL) for the Treatment of Kidney Stones ≤ 1 cm in Nicaragua

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Health 2024年第7期16卷 674-687页

作者： mélida m. Aguilar Chamorro Sergio Vargas Collado Leslie Pérez Ruíz David márquez Soriano Jorge Luis Soriano García Clínica Senior Managua Nicaragua Centro de Inmunología molecular Havana Cuba Catalysis S.L. Madrid Spain

Objectives: To assess the efficiency in terms of cost-effectiveness (CE) of oral Renalof® treatment versus extracorporeal shockwave lithotripsy (ESWL) in the treatment of kidney stones ≤ 1 cm in Nicaragua. methods: A cost-effectiveness economic evaluation was carried out based on the results obtained in the randomised, prospective, observational, single-blind, prospective, phase 2 clinical trial. Cost-effectiveness and the incremental cost-effectiveness ratio (ICER) were calculated. Economic data were obtained from the Economics Department of Clínica Senior in managua, Nicaragua. The monetary cost was expressed in US dollars (USD). Results: Treatment with Renalof® yielded a CE of $1,323.08/% remission, while ESWL was $9,498.54/% remission. The ICER shows that, in order to achieve a high percentage of kidney stone remission with ESWL, an extra $4,734.70 per patient must be invested. Conclusions: The use of Renalof® is shown to be a more cost-effective option than ESWL. It is recommended for the treatment of kidney stones ≤ 1 cm in size.

关键词： Economic Evaluation Pharmacoeconomics Renalof® Extracorporeal Shockwave Lithotripsy Kidney Stones

China-Caribe:más cerca que nunca

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

今日中国（西文版） 2024年第3期 34-35页

作者： mICHAEL zÁRATE 不详

Effects of exosomes from mesenchymal stem cells on functional recovery of a patient with total radial nerve injury: A pilot study

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

World Journal of Stem Cells 2024年第1期16卷 19-32页

作者： ErdinçCivelek Serdar Kabatas Eyüp Can Savrunlu Furkan Diren Necati Kaplan Demet Ofluoğlu Erdal Karaöz Department of Neurosurgery University of Health SciencesGaziosmanpaşa Training and Research HospitalGaziosmanpaşa 34255IstanbulTurkey Department of Neurosurgery University of Health Sciences TurkeyGaziosmanpaşa Training and Research HospitalGaziosmanpaşa 34255IstanbulTurkey Center for Stem Cell&Gene Therapy Research and Practice University of Health Sciences TurkeyGaziosmanpaşa 34255IstanbulTurkey Department of Neurosurgery Nevşehir State HospitalNevşehir 50300Turkey Department of Neurosurgery Istanbul Rumeli UniversityÇorlu Reyap HospitalÇorlu 59860TekirdağTurkey Department of Physical medicine and Rehabilitation Ofluoğlu KlinikGöztepe 34728IstanbulTurkey Liv Hospital Center for Regenerative Medicine and Stem Cell Research&Manufacturing(LivMedCell)Beşiktaş34340IstanbulTurkey Department of Histology and Embryology Istinye UniversityFaculty of MedicineZeytinburnu 34010IstanbulTurkey Istinye University Center for Stem Cell and Tissue Engineering Research and PracticeBeşiktaş34340IstanbulTurkey

BACKGROUND Peripheral nerve injury can result in significant clinical complications that have uncertain ***,there is a lack of effective pharmacological interventions for nerve damage,despite the existence of several small compounds,Despite the objective of achieving full functional restoration by surgical intervention,the persistent challenge of inadequate functional recovery remains a significant concern in the context of peripheral nerve *** To examine the impact of exosomes on the process of functional recovery following a complete radial nerve *** A male individual,aged 24,who is right-hand dominant and an immigrant,arrived with an injury caused by a knife *** cut is located on the left arm,specifically below the *** neurological examination and electrodiagnostic testing reveal evidence of left radial nerve *** sural autograft was utilized for repair,followed by the application of 1 mL of mesenchymal stem cell-derived exosome,comprising 5 billion *** exosome was split into four equal volumes of 0.25 mL each and delivered microsurgically to both the proximal and distal stumps using the subepineural *** patient was subjected to a period of 180 d during which they had neurological examination and electrodiagnostic *** The duration of the patient’s follow-up period was 180 *** increasing Tinel’s sign and sensory-motor recovery were detected even at the 10th wk following nerve *** the conclusion of the 6-mo post-treatment period,an evaluation was conducted to measure the extent of improvement in motor and sensory functions of the *** assessment was based on the British medical Research Council scale and the mackinnon-Dellon *** results indicated that the level of improvement in motor function was classified as m5,denoting an excellent ***,the level of improvement in sensory function was classified as S3+,indicating a good *** is

关键词： mesenchymal stem cell Exosomes Radial nerve Sural nerve

STCF conceptual design report (Volume 1): Physics & detector

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第1期19卷 1-154页

作者： m.Achasov X.C.Ai L.P.An R.Aliberti Q.An X.z.Bai Y.Bai O.Bakina A.Barnyakov V.Blinov V.Bobrovnikov D.Bodrov A.Bogomyagkov A.Bondar I.Boyko z.H.Bu F.m.Cai H.Cai J.J.Cao Q.H.Cao X.Cao z.Cao Q.Chang K.T.Chao D.Y.Chen H.Chen H.X.Chen J.F.Chen K.Chen L.L.Chen P.Chen S.L.Chen S.m.Chen S.Chen S.P.Chen W.Chen X.Chen X.F.Chen X.R.Chen Y.Chen Y.Q.Chen H.Y.Cheng J.Cheng S.Cheng T.G.Cheng J.P.Dai L.Y.Dai X.C.Dai D.Dedovich A.Denig I.Denisenko J.m.Dias D.z.Ding L.Y.Dong W.H.Dong V.Druzhinin D.S.Du Y.J.Du z.G.Du L.m.Duan D.Epifanov Y.L.Fan S.S.Fang z.J.Fang G.Fedotovich C.Q.Feng X.Feng Y.T.Feng J.L.Fu J.Gao Y.N.Gao P.S.Ge C.Q.Geng L.S.Geng A.Gilman L.Gong T.Gong B.Gou W.Gradl J.L.Gu A.Guevara L.C.Gui A.Q.Guo F.K.Guo J.C.Guo J.Guo Y.P.Guo z.H.Guo A.Guskov K.L.Han L.Han m.Han X.Q.Hao J.B.He S.Q.He X.G.He Y.L.He z.B.He z.X.Heng B.L.Hou T.J.Hou Y.R.Hou C.Y.Hu H.m.Hu K.Hu R.J.Hu W.H.Hu X.H.Hu Y.C.Hu J.Hua G.S.Huang J.S.Huang m.Huang Q.Y.Huang W.Q.Huang X.T.Huang X.J.Huang Y.B.Huang Y.S.Huang N.Hüsken V.Ivanov Q.P.Ji J.J.Jia S.Jia z.K.Jia H.B.Jiang J.Jiang S.z.Jiang J.B.Jiao z.Jiao H.J.Jing X.L.Kang X.S.Kang B.C.Ke m.Kenzie A.Khoukaz I.Koop E.Kravchenko A.Kuzmin Y.Lei E.Levichev C.H.Li C.Li D.Y.Li F.Li G.Li G.Li H.B.Li H.Li H.N.Li H.J.Li H.L.Li J.m.Li J.Li L.Li L.Li L.Y.Li N.Li P.R.Li R.H.Li S.Li T.Li W.J.Li X.Li X.H.Li X.Q.Li X.H.Li Y.Li Y.Y.Li z.J.Li H.Liang J.H.Liang Y.T.Liang G.R.Liao L.z.Liao Y.Liao C.X.Lin D.X.Lin X.S.Lin B.J.Liu C.W.Liu D.Liu F.Liu G.m.Liu H.B.Liu J.Liu J.J.Liu J.B.Liu K.Liu K.Y.Liu K.Liu L.Liu Q.Liu S.B.Liu T.Liu X.Liu Y.W.Liu Y.Liu Y.L.Liu z.Q.Liu z.Y.Liu z.W.Liu I.Logashenko Y.Long C.G.Lu J.X.Lu N.Lu Q.F.Lü Y.Lu Y.Lu z.Lu P.Lukin F.J.Luo T.Luo X.F.Luo Y.H.Luo H.J.Lyu X.R.Lyu J.P.ma P.ma Y.ma Y.m.ma F.maas S.malde D.matvienko z.X.meng R.mitchell A.Nefediev Y.Nefedov S.L.Olsen Q.Ouyang P.Pakhlov G.Pakhlova X.Pan Y.Pan E.Passemar Y.P.Pei H.P.Peng L.Peng X.Y.Peng X.J.Peng K.Peters S.Pivovarov E.Pyata B.B.Qi Y.Q.Qi W.B.Qian Y.Qian C.F.Qiao J.J.Qin J.J.Qin L.Q.Qin X.S.Qin T.L.Qiu J.Rademacker C.F.Redmer H.Y.Sang Anhui University Hefei 230039China Beihang University Beijing 100191China Budker Institute of Nuclear Physics Novosibirsk 630090Russia CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Cavendish Laboratory University of CambridgeJJ Thomson AveCambridge CB30HEUnited Kingdom Central China Normal University Wuhan 430079China Central South University Changsha 410083China China University of Geosciences Wuhan 430074China China University of mining and Technology Xuzhou 221116China École Polytechnique Fédérale de Lausanne(EPFL) LausanneSwitzerland Fudan University Shanghai 200433China Goethe University Frankfurt D-60325 Frankfurt am MainGermany Guangxi Normal University Guilin 541004China Guangxi Uninversity Nanning 530004China Hangzhou Institute for advanced Study UCASHangzhou 310024China Hebei Normal University Shijiazhuang 050024China Hebei University Baoding 071002China Hefei University of Technology Hefei 230601China Helmholtz Institute mainz Staudinger Weg 18D-55099 MainzGermany Henan Normal University Xinxiang 453007China Henan University Kaifeng 475004China High Energy Physics Center Chung-Ang UniversitySeoul 06974Korea Higher School of Economy 11 Pokrovsky Bulvar Moscow 109028Russia Huangshan University Huangshan 245000China Hubei University of Automotive Technology Shiyan 442002China Hunan Normal University Changsha 410081China Hunan University of Science and Technology Xiangtan 411201China Hunan University Changsha 410082China Indiana University BloomingtonIndiana 47405USA Inner mongolia University Hohhot 010021China Institute of advanced Science Facilities Shenzhen 518107China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Institute of modern Physics Chinese Academy of SciencesLanzhou 730000China Institute of Physics Academia SinicaTaipeiTaiwan 11529China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China Jilin University Changch

The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics *** is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or *** STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard *** STCF project in China is under development with an extensive R&D *** document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.

关键词： electron–positron collider tau-charm region high luminosity STCF detector conceptual design

Integrated Approaches of mechanical Barrier, Insecticide and Botanicals against mango mealybug (Drosicha mangiferae)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

advances in Entomology 2024年第3期12卷 195-202页

作者： N. Akhter m. z. Alam m. A. Rahaman m. R. U. miah I. H. mian m. A. Latif Department of Entomology Faculty of Agriculture Sher-e-Bangla Agricultural University Dhaka Bangladesh Department of Entomology Faculty of Agriculture Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur Bangladesh Department of Plant Pathology Faculty of Agriculture Sher-e-Bangla Agricultural University Dhaka Bangladesh Department of Plant Pathology Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur Bangladesh

An experiment was conducted to test the efficacy of a mechanical barrier around the tree trunk with one spray of Cypermethrin @ 1 ml/l and turmeric powder extract @ 15 g/500ml of water applied in integrated approaches against mango mealybug on mango tree. There were 7 treatments including a control. The treatments were mechanical barrier, Cypermethrin spray @ 1 ml/l, Turmeric powder spray @ 15 g/500ml of water, Cypermethrin spray + Turmeric spray, Cypermethrin spray + mechanical barrier, Turmeric + mechanical barrier and untreated control. Three-year-old mango plants grafted from a 5-year-old mango tree (Variety Amropali) and planted in pots were used in the experiment. The treatment, Cypermethrin spray + mechanical barrier gave the highest reduction of mango mealybug population 87.06% to 93.90% followed by Turmeric spray + mechanical barrier and showed 81.13% to 86.04% and mechanical barrier alone showed 81.13% to 84.59% population reduction. Turmeric powder extract showed only (8.42% to 23.77%) population reduction of mango mealybug which was lowest compared to other treatments.

关键词： mango mealybug Integrated management

Higgs-like(pseudo)scalars in adS_(4),marginal and irrelevant deformations in CFT_(3),and instantons on S^(3)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第4期48卷 68-81页

作者： m.Naghdi Department of Physics Faculty of Basic SciencesUniversity of IlamIlamIran

Employing a 4-form ansatz of 11-dimensional supergravity over a non-dynamical adS_(4)×S^(7)/z_(k)background and setting the internal space as an S1 Hopf fibration on CP3,we obtain a consistent ***(pseudo)scalars,in the resulting scalar equations in Euclidean adS_(4)space,may be considered to arise from(anti)m-branes wrapping around the internal directions in the(Wick-rotated)skew-whiffed m2-brane background(as the resulting theory is for anti-m2-branes),thus realizing the modes after swapping the three fundamental representations 8_(s),8_(c),and 8_(v) of SO(8).Taking the backreaction on the external and internal spaces,we obtain the massless and massive modes,corresponding to exactly marginal and marginally irrelevant deformations on the boundary CFT3,***,we obtain a closed solution for the bulk equation and compute its correction with respect to the background ***,considering the Higgs-like(breathing)mode m^(2)=18,having all supersymmetries as well as parity and scale-invariance broken,solving the associated bulk equation with mathematical methods,specifically the adomian decomposition method,and analyzing the behavior near the boundary of the solutions,we realize the boundary duals in the SU(4)×U(1)-singlet sectors of the ABJm ***,introducing the new dual deformationΔ_(+)=3,6 operators made of bi-fundamental scalars,fermions,and U(1)gauge fields,we obtain the SO(4)-invariant solutions as small instantons on a three-sphere with the radius at infinity,which correspond to collapsing bulk bubbles leading to big-crunch singularities.

关键词： adS_(4)/CFT_(3)correspondence scalar equations in adS_(4) instantons marginal and irrelevant operators (anti)m-branes

An integrated microfluidic platform for nucleic acid testing

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

microsystems & Nanoengineering 2024年第3期10卷 181-194页

作者： Antao Sun Petra Vopařilová Xiaocheng Liu Bingqian Kou TomášŘezníček TomášLednický Sheng Ni JiříKudr Ondřej zítka zdenka Fohlerová Petr Pajer Haoqing zhang Pavel Neužil ministry of Education Key Laboratory of micro and Nano Systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi’anShaanxi 710072P.R.China Department of Chemistry and Biochemistry Mendel University in BrnoZemědělská161300 BrnoCzech Republic ITD Tech s.r.o Osvoboditelů100573581 BohumínCzech Republic Central European Institute of Technology Brno University of TechnologyPurkyňova 123Brno 61200Czech Republic Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong SARChina Department of microelectronics Faculty of Electrical Engineering and CommunicationBrno University of TechnologyTechnická3058/10Brno 61600Czech Republic military Health Institute U Vojenskénemocnice 120016200 Praha 6Czech Republic The Key Laboratory of Biomedical Information Engineering of ministry of Education School of Life Science and TechnologyXi’an Jiaotong UniversityXi’anShaanxi 710049P.R.China Bioinspired Engineering and Biomechanics Center(BEBC) Xi’an Jiaotong UniversityXi’an 710049P.R.China

This study presents a rapid and versatile low-cost sample-to-answer system for SARS-CoV-2 *** system integrates the extraction and purification of nucleic acids,followed by amplification via either reverse transcriptionquantitative polymerase chain reaction(RT–qPCR)or reverse transcription loop-mediated isothermal amplification(RT–LAmP).By meeting diverse diagnostic and reagent needs,the platform yields testing results that closely align with those of commercial RT-LAmP and RT‒qPCR *** advantages of our system include its speed and *** assay is completed within 28 min,including sample loading(5 min),ribonucleic acid(RNA)extraction(3 min),and RT-LAmP(20 min).The cost of each assay is≈$9.5,and this pricing is competitive against that of Food and Drug administration(FDA)-approved commercial *** some RNA loss during on-chip extraction is observed,the platform maintains a potential limit of detection lower than 297 *** makes the system particularly useful in environments where centralized laboratories are either unavailable or inconveniently *** key feature is the platform’s versatility,allowing users to choose between RT‒qPCR or RT‒LAmP tests based on specific requirements.

关键词： testing maintain versatile