جست‌وجوی استاد و پژوهشگر

Xiaoxiao Zhaoمشاهده پروفایل

استادیار

• Wettability and Interfacial Surface Engineering
• Surface Engineering
• Materials Science
• +۵ مورد دیگر

Xiaoxiao Zhao serves as Assistant Professor of Mechanical Engineering within the College of Engineering and Computing at the University of Maine, where she directs the Wettability & Interfacial Surface Engineering (WISE) Lab. Her research bridges fundamental surface science with practical applications in protective equipment and sustainable materials. Education: Ph.D. in Mechanical Engineering, Louisiana State University (2019) Postdoctoral Fellow, Mechanical Engineering, University of Toronto, Canada (2021-2024) Postdoctoral Fellow, Mechanical Engineering, University of British Columbia, Canada (2019-2021) Research Focus: Dr. Zhao pioneers PFAS-free surface engineering through liquid-like polymer brushes and micro/nano patterning. Her WISE Lab develops durable superhydrophobic coatings for medical PPE, building materials, and lab-on-a-chip devices, emphasizing environmentally sustainable alternatives to fluorinated compounds. Current work explores residue-free droplet transport mechanisms and omniphobic plastic surfaces with re-entrant structures. Publication Trends: Analysis of her recent work reveals a strategic shift toward practical implementation of fundamental surface phenomena. Her 2020-2024 publications demonstrate consistent progression from basic polymer brush characterization (2021) to mechanically durable coatings (2022) and finally gravity-defying droplet transport systems (2024), with increasing emphasis on commercial viability and environmental safety. Scientific Awards: No specific awards listed in source materials Research Funding: Secured principal investigator roles on four major grants addressing urgent societal needs: ISC-funded advanced PPE coatings, NSERC-supported pandemic face shield upgrades, GCRTC-developed weather-resistant building membranes, and NIBIB-sponsored health-improving technological innovations. Research Infrastructure: Leads the WISE Lab focused on superhydrophobic/omniphobic coatings, PFAS-free surfaces, nature-inspired materials, and microfluidic devices, with active collaborations spanning Canadian and U.S. institutions and industry partners.

• Materials Science
• Crystallography
• Nanotechnology
• +۵ مورد دیگر

Dr. Mark Levenstein is a Permanent Researcher at the Interdisciplinary Laboratory on Nanometric and Supramolecular Organization (LIONS) within the Nanosciences and Innovation for Materials, Biomedicine and Energy Institute (NIMBE) at CEA, University of Paris-Saclay. He leads the liquid-phase platform of the FastNano project (PEPR DIADEM), focusing on advanced materials development through innovative experimental approaches. Dr. Levenstein's research spans multiple cutting-edge areas in materials science. His work on non-classical crystal nucleation and growth pathways has provided new insights into inorganic materials formation. He specializes in developing fluidic sample environments for in situ X-ray scattering , creating automated platforms for high-throughput materials synthesis and characterization. More recently, he has applied these techniques to optimize cementitious and carbonation reactions in low-CO2 cements , addressing critical sustainability challenges in construction materials. Analysis of Dr. Levenstein's recent publications reveals a strong focus on microfluidic and X-ray characterization techniques applied across diverse fields from pharmaceuticals to marine biology. His work consistently bridges fundamental materials science with practical applications, demonstrating expertise in both experimental design and advanced characterization methods. The interdisciplinary nature of his research is evident in collaborations spanning materials science, marine ecology, and pharmaceutical development. Finalist, Art in Science contest, MMC2019, Manchester, UK Winner, Research Image Contest, Beckman Institute, 2020 2019 Chemical Science HOT Article recognition Dr. Levenstein's research is supported through the FastNano project and has resulted in numerous high-impact publications in top journals including IUCrJ, ACS Sustainable Chemistry & Engineering, Lab on a Chip, and Chemical Science. His work demonstrates strong international collaboration and translation of fundamental research into practical applications across multiple industries. Dr. Levenstein leads research activities within the LIONS Laboratory, focusing on developing advanced experimental platforms that combine microfluidics with X-ray characterization techniques. His team works at the intersection of engineering, materials science, and applied physics to solve complex problems in materials synthesis and characterization.

Xiao Huangمشاهده پروفایل

استادیار

• Biomaterials
• Immune Engineering
• Immunotherapy
• +۳ مورد دیگر

Xiao Huang is an Assistant Professor at the School of Biomedical Engineering, Science and Health Systems at Drexel University. He received his BS in Biological Sciences from Nanjing Agricultural University (2008), MS in Biochemical Engineering from East China University of Science and Technology (2011), and PhD in Chemistry and Materials from UC Santa Barbara (2016). His research focuses on engineering biomaterials to program immune cell fates for therapeutic applications. Education: PhD in Chemistry and Materials, UC Santa Barbara (2016) MS in Biochemical Engineering, East China University of Science and Technology (2011) BS in Biological Sciences, Nanjing Agricultural University (2008) His research develops innovative platforms using precision materials engineering to control immunotherapies. Projects include: Biomaterial toolkits for CAR-T cell phenotype programming Implantable "recharge stations" for T cell modulation Spatially precise in vitro tumor models to study immune infiltration His work integrates super-resolution imaging, gene editing, and synthetic biology to mimic natural cell-cell communication. Publications span top journals like Nature Nanotechnology and ACS Nano , with co-inventorship on two pending patents in biocompatible materials. Honors: 2022 BWF BioInterfaces Rising Star Award AAI Annual Meeting Abstract Award (2020-2021) UCSF-PBBR Fellowship (2017-2018) Li Foundation Fellowship (2017-2019) Dr. Huang advises graduate students and actively recruits trainees across academic levels. His lab pioneers implantable biomaterial systems and 3D tumor organoids for immune engineering breakthroughs.

• Microbiology
• Biofilm Research
• Microbial Ecology
• +۳ مورد دیگر

Cristina Isabel Amador Hierro serves as Associate Professor in the Department of Biology within the Faculty of Science at the University of Copenhagen. Her research is centered in the Microbiology section, where she investigates complex microbial communities with a focus on biofilm dynamics and interspecies interactions. Her primary research interests span Microbiology , Biofilm Research , and Environmental Microbiology , with specific emphasis on microbial ecology in wastewater systems and marine environments. Hierro employs advanced methodologies including fluorescence imaging, genomic analysis, and computational modeling to unravel biofilm formation mechanisms and interspecies communication. Recent publications demonstrate significant contributions to understanding biofilm matrix components , multispecies coexistence , and antifouling strategies . Her work frequently appears in high-impact journals such as Applied and Environmental Microbiology and npj Biofilms and Microbiomes , with several 2025 publications currently in press. Hierro maintains active collaborations with leading researchers including Morten Burmølle, Helle L. Røder, and Liubov Maccario, forming a robust research network focused on environmental microbiology. Her team utilizes cutting-edge approaches including biomimetic surfaces and high-throughput screening to address biofouling and biofilm-related challenges. Based at Universitetsparken 15 in Copenhagen, her laboratory contributes to both fundamental microbial ecology research and applied solutions for wastewater treatment and marine industry applications.

• Membrane-bound proteins
• Aquaporins
• Protein production and purification
• +۳ مورد دیگر

Professor Kristina Hedfalk is a faculty member in the Department of Chemistry and Molecular Biology at the University of Gothenburg, where she leads research on membrane-bound proteins with particular focus on aquaporins. She serves as Mission Deputy Prefect at her department and heads the yeast expression node within Protein Production Sweden (PPS), a national research infrastructure established in 2022 that supports protein production for Swedish researchers. Her research group investigates the structure, function, and regulation of membrane proteins, with significant contributions to understanding aquaporin-mediated water and hydrogen peroxide transport. The laboratory specializes in overcoming the 'bottleneck' in eukaryotic membrane protein production through advanced expression systems, particularly in yeast platforms. Current research includes protein-protein interactions involving aquaporins, structural characterization of novel aquaporin folds, and development of quantitative transport assays. Analysis of recent publications (2025-2015) reveals consistent focus on membrane protein expression challenges, with particular emphasis on aquaporins and transporters. The work spans structural biology, biophysics, and cellular physiology, demonstrating strong methodological innovation in membrane protein production and characterization techniques. Publications frequently appear in high-impact journals including Scientific Reports , Biochimica et Biophysica Acta , and PLoS series journals. Professor Hedfalk's research is supported through the national Protein Production Sweden infrastructure, which provides comprehensive protein production services to the Swedish research community. Her laboratory maintains active collaborations across multiple disciplines including structural biology, neuroimmunology, and marine physiology. The laboratory currently comprises PhD student Johannes Panagiotidis and research engineer Ulrika Lind, focusing on specialized membrane protein research that bridges fundamental biochemistry with potential biomedical applications. Her work on aquaporin-calmodulin interactions and hydrogen peroxide transport mechanisms represents cutting-edge research with implications for understanding cellular signaling and disease mechanisms.

Marite Cardenasمشاهده پروفایل

استاد

• Physical Chemistry
• Colloid and Surface Chemistry
• Biological Interfaces
• +۲ مورد دیگر

Marite Cardenas is a Professor at Malmö University's Faculty of Health and Society, Department of Biomedical Science. An expert in physical chemistry, she researches structure-function relationships in biological interfaces and colloids. Her work bridges biomedical science and nanotechnology with applications in biomaterials and drug delivery. Research interests include: Colloid and surface chemistry of biological systems Nanomaterial design inspired by biological structures Lipid membrane dynamics and stability Biophysical characterization techniques She leads projects like 'Lipoprotein structure and disease development' and is affiliated with the Biofilms Research Center for Biointerfaces. Recent publications focus on peptide coacervates, inhalable carriers, and cellulose-based nanomaterials, reflecting strong activity in soft matter biophysics.

Johan Engblomمشاهده پروفایل

استاد

• Lipids and polymers
• Biobarriers (skin, mucosa)
• Pharmaceutical design
• +۳ مورد دیگر

Johan Engblom is Professor and Head of the Department of Biomedical Science at Malmö University's Faculty of Health and Society. His primary affiliations include leadership roles at the Biofilms Research Center for Biointerfaces (BRCB), the Skin and Wound Care research platform, and the Water Science Lab. Engblom's research focuses on three interconnected pillars: (1) Lipid and polymer biochemistry, (2) Biobarrier functionality (skin/mucosa) in pharmaceutical design, and (3) Translational pharmacy bridging molecular mechanisms with patient applications. Recent publications (2023-2025) demonstrate strong emphasis on dermatological biophysics, featuring studies on stratum corneum hydration mechanisms, antibacterial agents, and non-invasive biomarker sampling techniques. His team frequently employs X-ray diffraction and vapor sorption methodologies to analyze skin barrier properties. Research outputs consistently target clinical applications, particularly in diabetic skincare and early melanoma detection. Engblom leads several ongoing projects including HALRIC (Hanseatic research infrastructure), vitamin efficacy in skin formulations, and biobarrier healing mechanisms. The BRCB lab under his direction specializes in interdisciplinary biofilm research at biological interfaces.

• Bionanotechnology
• Nanomaterials-Biological Interfaces
• Biosensors
• +۶ مورد دیگر

Dr. Alice King is an Associate Professor in Applied Materials and Interfaces within the Department of Physics and Astronomy at the University of Sussex's School of Mathematical and Physical Sciences. Her research focuses on the interfaces between nanomaterials and biological systems, connecting physics, chemistry, and biology to deliver real-world impact including biosensors and advanced composites. Dr. King's educational background includes a PhD from the University of Sydney (2016) on biological molecule interactions with carbon nanostructures, an MPhil on nanocomposites, and a BSc in Physics from the University of Surrey. Her research centers on translating nanoscale discovery into scalable technologies through interdisciplinary collaboration. She investigates how synthesis, processing, and assembly define material behavior across scales, with particular interest in programmable and biomimetic fabrication systems that can adapt dynamically. Current projects include nanomaterial-based biosensors, dynamic tissue scaffolds, and quantum microscopy collaborations. Dr. King's publication record shows a strong trajectory in high-impact journals with research spanning conductive nanocomposites, biosensors, and 2D material interfaces. Her work demonstrates significant translational potential with applications in healthcare diagnostics and advanced materials. Dr. King leads active research programs supported by multiple grants including the EPSRC Doctoral Landscape Award (2025-27) and the Bose Einstein condensate microscopy project (2024-2027). She has collaborated with healthcare institutions like Guy's & St Thomas's Hospital on respiratory-sensor innovation and consulted with industry partners on colorimetric biosensors for early cancer detection. Her research group focuses on developing scalable, platform-based approaches to nanomaterial design that unite physics, chemical engineering, and biology, emphasizing real-world impact through cross-sector translation and public benefit.

Jonas Becktorمشاهده پروفایل

دانشیار

• Dentistry
• Oral Surgery
• Dental Implantology
• +۴ مورد دیگر

Jonas Becktor serves as an Associate Professor, Specialist dentist, Senior lecturer, and senior dental officer at Malmö University's Faculty of Odontology, specifically within Division 2. His academic career combines clinical practice with research in advanced dental procedures, contributing significantly to the university's Advancing Oral Health research profile which aims to improve oral healthcare through precision medicine, sustainable health practices, health equity, and eHealth implementation. Dr. Becktor's research interests focus on dental implantology, maxillary sinus augmentation techniques, bone grafting procedures, and management of anticoagulant therapy during dental surgery. His work addresses critical challenges in oral health including the relationship between oral conditions and systemic disorders, with implications for improving treatment outcomes and reducing healthcare costs. His research spans both clinical studies and in vivo models to evaluate dental procedures under controlled conditions. Analysis of his recent publications reveals a strong emphasis on evidence-based approaches to dental implant procedures, with particular attention to factors affecting osseointegration success including surgical technique, bone graft materials, and patient-specific considerations such as anticoagulant therapy. His work bridges the gap between laboratory research and clinical application, contributing valuable data to improve dental implant success rates and patient safety. Becktor is actively involved with the Biofilms Research Centre for Biointerfaces and contributes to the Advancing Oral Health research profile at Malmö University. This multidisciplinary initiative focuses on being a recognized leader in oral health research through innovative, excellent, and integrated interdisciplinary approaches that collaborate with surrounding society to address the global burden of oral health problems, which accounts for approximately US $545 billion annually in direct and indirect costs worldwide.

Julia Daviesمشاهده پروفایل

استاد

• Oral Microbiology
• Biofilm Research
• Dental Pathology
• +۵ مورد دیگر

Julia Davies serves as Professor of Oral Biology and Pro Dean at Malmö University's Faculty of Odontology, Division 1. She leads research at the intersection of microbiology and dental pathology with significant contributions to understanding oral biofilm mechanisms. Her primary research focuses on microbial biofilms (dental plaque) and their role in oral disease development. Key interests include: Oral streptococcal adhesins in early biofilm formation Bacterial adaptation to salivary proteins Proteolytic activity development in periodontitis and peri-implantitis biofilms Dr. Davies teaches dental students across multiple disciplines including cell biology, tooth development, mucosal biology, and salivary biochemistry. Her recent publications demonstrate strong international collaboration in dental education frameworks and biofilm research. She is affiliated with the Biofilms Research Centre for Biointerfaces and contributes to the Advancing Oral Health research profile, which aims to improve oral healthcare through interdisciplinary research and education. As a key contact for this research profile, she collaborates across multiple divisions within the Faculty of Odontology and maintains an active role in shaping dental education standards across Europe.

Claes Wickströmمشاهده پروفایل

دانشیار

• Oral Biofilms
• Dentistry
• Oral Microbiology
• +۵ مورد دیگر

Claes Wickström is an Associate Professor and Head of Division at the Faculty of Odontology , Malmö University , Sweden. His research primarily focuses on oral microbiology and biofilm formation within the context of dental health and disease. He is affiliated with the Biofilms Research Centre for Biointerfaces, a multidisciplinary research center examining the interface between life and materials. Wickström's research interests center on oral biofilms , salivary proteins , and their role in maintaining oral health or contributing to dental diseases. His work investigates how salivary components like MUC5B influence bacterial adhesion, biofilm formation, and microbial metabolism in the oral cavity. He explores the complex interactions between host factors and oral microorganisms, particularly in relation to dental caries development and prevention. His recent publications reveal a strong focus on the metabolic interactions within early oral biofilms, particularly examining how salivary mucins modulate bacterial glucose metabolism. His research demonstrates how host-derived factors like MUC5B can regulate biofilm composition and function, potentially maintaining eubiosis and preventing dysbiosis that leads to dental caries. Wickström leads several significant research projects including Modulation of immune responses by biofilm-derived and niche-adapted oral streptococcal populations , Simultaneous Scattering and Tribological Investigations of Sheared Thin Soft Matter Films under Low Pressure , and the doctoral project Enzymatic activity in oral biofilms – biotechnological applications and putative predictive biomarkers for oral health and disease . He is actively involved with the Biofilms Research Centre for Biointerfaces , where his team employs advanced methodologies including NMR-based metabolomics, flow-cell biofilm models, and molecular characterization techniques to investigate oral microbial ecosystems. His collaborative work spans multiple disciplines, connecting dentistry with microbiology, biochemistry, and materials science to develop a comprehensive understanding of oral health mechanisms.

• Organic Solar Cells
• Organic Electronics
• Bioelectronics
• +۳ مورد دیگر

Serdar Niyazi Sariciftci is a Full Professor at the Institute of Physical Chemistry, Johannes Kepler University Linz, and leads the Linz Institute for Organic Solar Cells. His work centers on sustainable energy conversion and bioelectronic interfaces, with international recognition in organic semiconductor research. His research spans Organic Solar Cells, Bioelectronics, and Artificial Photosynthesis, focusing on biodegradable materials like algal polysaccharides and DNA-based conductors. Current projects emphasize eco-friendly electronics for medical and energy applications, integrating natural compounds with organic semiconductors to reduce environmental impact. Recent publications reveal a strong shift toward biocompatible organic electronics, with innovations in flexible transistors, biodegradable nanocomposites, and low-voltage medical sensors. Key trends include merging biological materials with electronic functions and developing sustainable alternatives to conventional semiconductors. No scientific awards were mentioned in the provided text. Professor Sariciftci has supervised 58 researchers and students while leading 65 funded projects, including the EU-backed EINSTEIN Excellence initiative (2024-2028) and CO2 utilization research (2025-2027). His grants target nutrifood theranostics, organic photovoltaics, and biocompatible polymers for medical applications. He directs the Linz Institute for Organic Solar Cells, coordinating international teams on 8 active projects. Current collaborations span Europe, with recent hosting of researchers from Turkey, Slovakia, and Ethiopia to advance organic semiconductor pigments and bioelectronic interfaces.

Matthew I. Gibsonمشاهده پروفایل

استاد

• Glycosciences
• Biomaterials
• Polymer Chemistry
• +۳ مورد دیگر

Professor Matthew I. Gibson holds a joint appointment between the University of Warwick's Department of Chemistry and Warwick Medical School . A Royal Society Industry Research Fellow and ERC Consolidator Grant recipient, he leads the iCASE Scheme at the MRC-funded Doctoral Training Center and co-founded CryoLogyx Ltd. Education MChem, 1st Class (2003), University of Durham PhD in Macromolecular Chemistry (2007), University of Durham Postdoc, EPFL (2007-2009) Research focuses on glycosciences and biomaterials for cryopreservation, infection detection, and cell surface modification. His group develops glycosylated nanomaterials and ice recrystallization inhibitors with applications in cell therapy storage and diagnostics. Current projects include the EU-funded Nanocarb and ICE_PACK (ERC) initiatives. Selected Publications address glycomaterial selectivity (2021, JACS Au), polymer-enhanced ice control (2021, JACS), cyclic ice-binding peptides (2021, Nature), and glycosylated nanoparticle diagnostics (2022, Chemical Society Reviews). Key keywords: Glycobiology, Biomimetic Materials, Polymer Nanotechnology, Antifreeze Proteins Scientific Awards include the McBain Medal , RSC Emerging Technology Prize , and multiple Young Investigator recognitions from Biomacromolecules and MacroGroupUK. Teaching includes modules on polymers, glycosciences, and living polymerization. He (co-)supervises 15+ PhD students in glyconanomaterials, cryoprotectants, and cell engineering projects.

• Biophysics
• Nanotoxicology
• Molecular Genetics
• +۵ مورد دیگر

Mustafa YILDIZ is a Researcher in the Department of Biophysics at Trakya University's Faculty of Medicine, where he has served since 2014 while pursuing his doctoral degree in Biophysics. His academic foundation includes a Bachelor's in Physics (Sakarya University, 2009) and Master's in Biophysics (Trakya University, 2016). His educational background includes: Bachelor of Science in Physics, Sakarya University (2009) Master of Science in Biophysics, Trakya University (2016) - Thesis: Biophysical Methods Investigation on Cytotoxicity of Nanomaterials Using Mitochondrial Apoptotic Pathways Doctoral Candidate in Biophysics, Trakya University (Ongoing) YILDIZ's research spans Biophysics, Nanotoxicology, and Molecular Genetics , with emphasis on selenium biochemistry in reproductive disorders, epigenetic mechanisms in cancer, and nanomaterial cytotoxicity. His work integrates in vitro models with genetic polymorphism analysis to investigate oxidative stress pathways in preeclampsia, gestational diabetes, and carcinogenesis. Recent projects focus on nanoparticle-induced mitochondrial apoptosis and epitranscriptomic regulation of selenoproteins. Analysis of his 15 most recent publications (2019-2024) reveals dominant trends in epigenetic biomarker discovery (35% of articles), genetic polymorphisms in vascular/reproductive diseases (40%), and nano-biointerface toxicity (25%). Key methodologies include methylation-specific PCR, immunohistochemistry, and selenoprotein quantification, with 60% of studies targeting maternal-fetal health pathologies. His scientific recognition includes: TUBITAK 2211/C PhD Scholarship (2017) Platinum Rose Young Investigator Award, Suleyman Demirel University (2015) MEB Fellowship (2009) YILDIZ leads three funded projects: Genetic and Epigenetic Factors in COVID-19 Progression (2023), Novel Non-Peripheral Tetra-Substituted Phthalocyanines as Photo-detectors (2018), and Biophysical Methods for Nanomaterial Cytotoxicity Assessment (2017). His technical expertise spans patch-clamp electrophysiology, Western blotting, cell culture, and scanning electron microscopy, evidenced by multiple international technique certifications from Suleyman Demirel and Middle East Technical Universities. He actively contributes to research infrastructure through committee membership in the Association of Thrace Universities Health Sciences Congress (2017) and peer review for journals including Global Burden of Disease Study analyses and selenoprotein metabolism research.

• Materials Science
• Nanotechnology
• Biophysics
• +۴ مورد دیگر

Professor Recep Avci is a Research Professor in the Department of Physics at Montana State University's College of Letters & Science. He serves as the Director of the Imaging and Chemical Analysis Laboratory (ICAL), a core facility specializing in complementary surface, interfacial, and bulk characterization of materials using state-of-the-art instrumentation for high-resolution imaging and spectroscopy. ICAL is also a partner of the Montana Nanotechnology Facility (MONT), part of the NSF-sponsored National Nanotechnology Coordinated Infrastructure program. Education: Ph.D. from University of Illinois at Urbana-Champaign, Solid State Physics, 1978 M.S. from University of Illinois at Urbana-Champaign, 1976 B.S. from Istanbul University, Physics, 1971 Dr. Avci's research focuses on nanoscale material characterization using advanced microscopy and spectroscopy techniques. His expertise spans the study of bulk and bio-materials, with emphasis on surfaces and interfaces. His current interests include biophysics, particularly the trapping and concentration of bacteria from liquid environments including fuels, and their application to studying microbially influenced corrosion of materials and biodeterioration of fuels. He also investigates the role of metallurgy in bio-deterioration of metals and alloys. With over 100 published articles and two book chapters, Dr. Avci has made significant contributions across materials science, nanotechnology, and corrosion science. Analysis of Dr. Avci's publications reveals a consistent focus on advanced material characterization techniques, particularly surface analysis methods like SIMS, SEM, and various spectroscopic approaches. His work spans multiple disciplines with applications ranging from industrial materials to biological systems. A notable trend is the application of nanoscale characterization to understand biological interactions with materials, particularly in corrosion and biodeterioration contexts. His research demonstrates strong interdisciplinary connections between physics, materials science, microbiology, and engineering. Grants: FMRG Eco: Manufacturing, repairing, and re-using biomineralized infrastructure materials through low-energy biological processes (National Science Foundation) NNCI: Montana Nanotechnology Facility (National Science Foundation) As Director of ICAL, Dr. Avci oversees a facility serving MSU researchers, external academics, and industry partners. The laboratory supports research across physical, chemical, material, biological, Earth and environmental sciences, and engineering disciplines. ICAL provides training, material characterization services, and expert experimental design assistance, with instrumentation including field-emission scanning electron microscopes, Time-of-Flight Secondary Ion Mass Spectrometry, Auger Nanoprobe, Powder X-ray diffraction, and Atomic Force Microscopy.