News for Healthier Living

New Analysis Shows That Uterus Transplants Help Women Achieve Successful Pregnancies

A decade of uterus transplantation in the United States has resulted in dozens of healthy births and steadily improving surgical outcomes, according to a new national review led by researchers from the Perelman School of Medicine at the University of Pennsylvania.

September 24, 2026

October 5 2026

• Nearly Twice as Many People Quit Smoking When Offered Cash Rewards
• Digital Alerts Support Timely Treatment Decisions of Critically Ill Cardiac Patients
• Managing Misfolded Proteins to Prevent Parkinson's Disease
• Immune Cells Support Early Placental Development
• Regular Walking Is Good for People with COPD, Even if They Live in Areas with Higher Air Pollution
• Smart Gene Circuits Could Future-Proof Horticultural Crops

October 2 2026

• Research Tip Sheet: Radiation, Stroke Tied to Heart Dangers
• Chemo as a Booster of Cancer Vaccines
• New Insights Into Fetal DNA Could Improve Prenatal Testing
• JMIR News: PMOS Care, Smart Textiles, Online Research Ethics, and the TEMPO Pilot
• Hackensack Meridian Health Kicks Off Breast Cancer Awareness Month With Pink Event At Several Campuses
• Interview Prep and Media Training for Experts - Best Practices Webinar
• Large Scandinavian Trial Finds No Benefit of Aspirin After Treatment of Colorectal Cancer Liver Metastases
• Colouring on Devices Can Improve Student Wellbeing, Study Finds
• KAIST Identifies a "Hidden Amplification Switch" in Lymphangiogenic Signaling, with Implications for Lymphedema and Cancer Metastasis
• Kennesaw State Researcher Receives NIH Grant to Study Sleep Apnea
• Stem Cell-Derived Brain Models Offer a New Window Into How Anesthesia Works

October 1 2026

• Inflammation and the heart: A new approach to cardiovascular disease prevention
• Cellular Recycling Changes with Age, but Not How We Expected
• Less Can Be More: How Breast Cancer Surgery is Becoming Less Invasive
• Less Can Be More: How Breast Cancer Surgery is Becoming Less Invasive
• American Joint Replacement Registry becomes first registry to accept patient data through Epic's cloud-based Community Registries
• Busier People Tend to Be Less Depressed, Perform Better, Study Shows
• Before the First Bite: A Missing Gut Protein May Set the Stage for Peanut Allergy
• Young RWJBarnabas Health Patients Celebrate Disease-Free Milestone Following Advanced Sickle Cell Treatments
• UTSW Research Briefs: Heart Failure, Diet's Impact on Aging, and MS Drugs
• How Robotic Surgery Helped Tackle a Rare Pediatric Lung Tumor
• Cedars-Sinai Guerin Children's Experts Available for Interviews at AAP 2026
• Mayo Clinic Researchers Report Early Results From Therapy Designed for a Single Patient with Rare Genetic Form of ALS
• Novel Treatment Combination Improves Progression-Free Survival in Most Common Form of Metastatic Breast Cancer
• Mount Sinai Study Uncovers How Loss of the Critical Tumor Suppressor p53 Enables Mutant Cells to Expand Through Normal Tissue
• Research Uncovers How Bacteria Fight Viruses, Opening the Door to Better Virus-Based Antibiotics
• Young RWJBarnabas Health Patients Celebrate Disease-Free Milestone Following Advanced Sickle Cell Treatments
• Targeted Cancer Therapy Gets a Sharper Focus
• How Gut Bacteria Can Shape the Brain's Response to Stroke
• How the Biological Clock Regulates Phases of Wakefulness
• Mount Sinai Researchers Identify a Brain Circuit That Remembers Stresses to Help Shape Reaction to Them
• Sudden Back Pain: It Can Develop for Several Reasons, Expert Explains
• Cultivating HPV to Improve Vaccine Development
• Initiative Standardizes Evaluation of ICU Discharge Readiness
• Children with Common Genetic Variant May Have More Inflammation in Response to Asthma Drug
• After 20 Miscarriages, Mom Prepares to Celebrate Healthy Baby's First Birthday

September 30 2026

• Fit for Life: Childhood Fitness Linked to Lower Risk of Adult Depression
• UCLA Research Team Awarded $1 Million to Develop New Approach for Detecting Lung Cancer
• How Family-Based Treatment Helps Children and Teens With Eating Disorders
• Novel CAR-T Therapy for Hard-to-Treat Multiple Myeloma Shows Promising Safety and Durable Responses
• How the Brain Learns to Predict What to Fear Based on Past Experiences
• First Health System on West Coast to Use New Brain Bleed Technologies
• Johns Hopkins Investigators Identify a Metabolic Weak Point in Exhausted Immune Cells in Head and Neck Cancer
• Combing Nature's Library for Answers to Prostate Cancer
• People With Long COVID Who Used a Noninvasive Magnetic Therapy Headset Show Improved Cognitive Function and Mood
• Maryland Family Warns of Firepit Dangers After Tragic Accident
• Gut mRNA Tech Supercharges Vaccine and GLP-1 Delivery
• Can Brain Activity Reveal What Surveys Miss?
• Engineers Connect Health Wearables and Implants Using the Body as the Network
• Insurance Barriers Limit Access to Blood Cancer Drugs
• Dana-Farber Research Reveals Possible New Target for Treatment of Sickle Cell and Beta Thalassemia
• Staples Lab Helps Nebraska Childcare Providers Implement Outdoor Learning
• Case Report Highlights Multidisciplinary Approach to Recurrent Prostate Cancer
• Decadelong Study Finds Smoking Worsens Sickle Cell Retinopathy
• New Framework Guides Doctor-Patient Discussions on AI Chatbot Use for Mental Health
• Higher GLP-1 Costs Lead to Lower Adherence
• Preventing Skin Cancer Among Local Firefighters Through Community Outreach
• FAU Study Uses Raman Spectroscopy and AI to Detect Skin Cancer
• The Medical Minute: Living Well with Heart Failure
• Researchers Find Benzodiazepine Prescriptions Drop Sharply in the U.S. Over the Past Decade
• Smartphones as Retinal Cameras: New Opportunities for Global Eye Care - International Review Led by Bonn-Based Researchers Assesses the Potential and Limitations of Smartphone-Based Retinal Imaging
• Living Environment and Lifestyle Factors May Accelerate Biological Ageing Already in Early Adulthood
• Childhood Family Environment and Number of Siblings May Affect Heart and Brain Health in Middle Age
• Pneumonia Can Reveal Undiagnosed Blood Cancer
• AI-Driven Analytics and Data-Mining Strategies for Drug Discovery
• Can AI-enabled A-Fib Detection Technology Confirm Diagnosis Faster Than Conventional Monitoring?
• Wearable AI Forecasts Prolonged Sitting in Women With Chronic Pelvic Pain

September 29 2026

• Honeybee Silk Could Power Smarter Wound Dressings
• Personalized Support and Navigation Increased Genetic Testing of Hereditary Cancers Among Immediate Family Members
• New AI Platform Could Help Cancer Survivors Get Personalized Support Between Doctor Visits
• Exercise Program Supports Better Attention and Slows Biological Aging in Breast Cancer Survivors
• Ohio State Study Finds Patients with Developmental Disabilities Still Face Kidney Transplant Disparities Despite State Laws
• Enhancing CAR-T Therapy: From Cancer to Autoimmune Diseases
• CHLA Experts to Present on AI, Sports Medicine, and More at 2026 American Academy of Pediatrics Meeting
• RWJBarnabas Health Shares 10 Facts Everyone Should Know about Addiction and Recovery
• Distinct Gut Microbiome Patterns Found in 5 Cancer Groups and in Early-Onset Cancers
• Sinai Hospital Begins Using First FDA-Authorized AI Diagnostic Tool for Sepsis
• Sudden, Unexpected Death on the Rise Among Infants Born to Black Mothers
• A Concussion Expert and Football Father Discusses Why He Values Teamwork Over Zero-Risk
• Menthol Enhances the Strength, Duration of Nicotine's Effects in Rats
• Microplastics Cause Fatty Liver Disease in Mice
• One in Nine Older Adults Who Use Cannabis Meet Criteria for Cannabis Use Disorder

September 28 2026

• Withdrawal Med Use Points to Increasing Danger of Medetomidine
• Researchers Suggest Tile-Based Radiation Therapy as Standard of Care to Lower Risk of Recurrence in Brain Metastases
• When Her Leukemia Didn't Respond to Chemotherapy, Megan Found a New Treatment at Children's Hospital Los Angeles
• Engineers Develop a Smart Shoe That Could Help Track Changes in How People Walk
• Modifying Heart Cell Metabolism Unlocks Self-Repair System After Heart Attack
• Study Shows Rising Rates of Reported Intentional Substance Exposures at School Among Elementary- and Middle-School-Aged Children
• Los Alamos Maps the Changing Sounds of the Arctic to Strengthen Global Monitoring
• California firm licenses 'potent' anti-measles antibodies from Vanderbilt Health for development, clinical testing
• UNC Neurologist Receives Inaugural Grant to Improve Hospital Care for People with Parkinson's Disease
• Mount Sinai Announces Collaborative Research Agreement to Evaluate Novel Liquid Radioembolic Agent for Brain Tumors
• Research Reveals a Specific Brain Circuit Implicated in OCD
• Study Finds Fractionated Radiosurgery Reduces Recurrence After Surgery for Brain Metastases, May Improve Survival
• Supervised Physical Therapy Improves Short-Term Knee Pain and Function After ACL Surgery in Young Adults
• Medical Cannabis Enrollment Surged Nationwide Over Past Decade, but Leveled Off as Recreational Access Expanded
• First National Estimate Identifies Nearly 110,000 Medical Cannabis Caregivers
• Former USPSTF Chair Warns Political Interference Is Threatening Evidence-Based Preventive Care
• Frequent Marijuana Use Tied To More Severe Epilepsy
• Raw Milk Cheese Recalled Nationwide After E. Coli Outbreak Sickens 13
• Risk Of Death, Major Disease High Following Type 2 Diabetes Diagnosis
• Early interventions for depression tied to better cancer survival
• Dr. Elizabeth Alpern Appointed Founders' Board Centennial Chair of the Department of Pediatrics at Lurie Children's
• Frequent Cannabis Use Tied to More Severe Epilepsy
• Blocking Immune Cells' Path Into Brain Limits Neurodegeneration
• Fractionated Radiosurgery Reduces Cancer Recurrence After Surgery for Large Brain Metastases
• Short-Course Radiation Therapy Better Preserves Physical Function Before Pancreatic Cancer Surgery
• Radiosurgery Linked to Longer Survival for Small Cell Lung Cancer with Brain Metastases
• Five-Treatment Radiation Therapy Offers Effective Nonsurgical Alternative for Localized Prostate Cancer
• Incisionless Radiosurgery Shows Promise for Severe, Treatment-Resistant Depression
• 1 In 5 Seniors At Risk For Dangerous Drug Interactions
• Exercise A Solid Prescription For Pain, Review Reports
• Could the Timing of Speech Practice Matter for Young People With Childhood Apraxia?
• Revive & Survive San Diego Trains 1 Million People in Hands-Only CPR
• Eliminating Ultra-Processed Food From School Cafeterias Will Be Costly, Complicated, Study Warns
• Abortion Is On The Ballot Again As Post-Roe Policies Continue To Evolve
• New UMSOM Research Shows Promising Results for Health Care Professionals Using Ketogenic Diet Therapy to Treat Mental Illness
• NUS Team Unveils Electronic Skin That Lets Users "See" Touch Instantly
• 15 Million Americans Live in a County With No General Surgeon
• Heredity Is More Than Just DNA
• Insomnia: Linked to a Higher Risk of Stroke
• New Study Sheds Light on QALY and Disability Debate
• Psycho-Cardiovascular Interaction Network Links Mental Health and Heart Disease
• Tailored ACT+ Therapy Helps Cancer Survivors Reconnect with Valued Living
• Physician Knowledge Could Strengthen BRCA Cascade Testing in Turkiye
• Five Symptom Clusters Reveal Hidden Burden of Pancreatic Cancer Chemotherapy
• Swedish Survey Exposes Gaps in Internal Lymphedema Care
• How One Plant Makes More Brain-Healthy Fat Than Its Cousin -- and What It Means for Farming

September 27 2026

• Real-World Data Indicate Lower Adherence Rates for Breast Cancer Endocrine Therapy When Radiation Therapy Is Omitted
• Low-Dose Radiation Therapy May Slow Progression of Knee Osteoarthritis, Long-Term Study Indicates
• Ultra-Low-Dose Radiation Therapy Relieves Bone Pain From Multiple Myeloma

September 25 2026

• ASTRO: UT MD Anderson Highlights Advances in Radiation Oncology
• Mayo Clinic Experts Present Radiation Oncology Research at ASTRO 2026
• ASTRO: Targeted Radioactive Therapy for Prostate Cancer, New SBRT Approaches, Personalized Radiation and More
• New AI Tool Detects Widely Underdiagnosed Heart Condition
• Cancer Survivors Less Likely to Be Physically Active, Study Finds
• Additional Research Highlights From the 2026 ASTRO Annual Meeting
• 165,000+ Pounds Of Pork, Beef And Goat Recalled Over USDA Inspection Mark
• Loneliness, Isolation Can Strip Away Years Of Healthy Life, Large Study Finds
• Stroke Rates Nearly Double In Younger Adults
• UT MD Anderson Shares Latest Research Breakthroughs
• US Will Face a Shortage of Nearly 28,000 Surgeons by 2038, First Nationwide Study Finds
• E-Scooter Trauma Admissions Nearly Double as Youngest Riders Are Hurt Most Severely
• Metastatic Colorectal Cancer is More Advanced in Younger Patients than Older Ones, but They Survive Longer with the Disease, Study Finds
• Prostate Cancer Surgery and Radiation Have Different Long-Term Effects on Urinary, Sexual, and Survival Outcomes
• Deaths Linked to Treatable Emergency Surgical Conditions Are Rising in the US
• Artificial Intelligence Model Predicts Pancreatic Cancer Risk 3 Years Before Diagnosis
• Appendectomy for Appendicitis Associated with 58% Lower Colorectal Cancer Risk Than Antibiotics Alone
• Underweight Patients Face 92% Increased Odds of Death After Emergency General Surgery
• Urban Heat Islands Linked to Worse Recovery After Major Surgery
• JMIR News: Patient Simulator Robots, Participation Fraud in Online Research, and More
• Study Identifies Two Factors That May Help Patients Benefit From Off-the-Shelf CAR T Cell Therapies
• Dietary Supplement May Influence Lung Tumor Growth Differently in Females and Males, UCLA Study Finds
• How The MIND Diet Protects Aging Brains
• Keeping A Steady Job Might Help You Stay Sharp Later In Life
• Depressed? Try Cutting Back On Ultra-Processed Foods, Study Suggests
• As Health Insurance Costs Soar, Healthcare Workers Also Feel The Pinch
• Rethinking Triple-Negative Breast Cancer Treatment Through EGFR Co-Targeting and Nanotechnology
• Decoding a Molecular Dialogue: How Arginine Methylation and Ubiquitination Shape Cancer
• Metabolic Vulnerabilities Open New Therapeutic Possibilities in Clear Cell Renal Cell Carcinoma
• Drug Development and Promising Therapeutic Targets for Coronary Artery Disease: Current Landscape and Future Prospects
• Study Reveals Complex, Nonlinear Process of Health Behavior Change Among Women With Polycystic Ovary Syndrome
• Hidden Protein Helps Cells Divide Correctly
• Real-World FLOURISH Study Confirms Osimertinib Benefit in Chinese NSCLC

September 24 2026

• New Analysis Shows That Uterus Transplants Help Women Achieve Successful Pregnancies
• Anesthesia Training in the Age of AI
• AI Model Uses Routine Imaging to Identify Patients at Risk for Serious Treatment-Induced Lung Inflammation
• Walking Reduces Fatigue for Colorectal Cancer Survivors
• Navigating the Confusing Maze of Breast Cancer Screening Guidelines
• Wistar Scientists Identify Connection Between Nervous System and Aggressive Prostate Cancer
• Contaminated Soil Poses Hidden Lead Threat Inside Homes
• Mount Sinai Study Identifies Why Some Patients Develop Severe Intestinal Inflammation After CAR-T Therapy
• Multiple Childhood Traumas Tied to Worse Young Adult Outcomes
• Blood Proteins Reveal Effects of Alzheimer's Drug
• MedStar Health is First System in Maryland to Use New AI-Powered Tool for Cardiac Catheterization
• FDA Panel Narrowly Backs Multi-Cancer Blood Test Despite Doubts It Works
• VIDEO AVAILABLE: Reporter Boot Camps, In-Person Visits, and Science Comms Training - Best Practices Webinar
• 'Reporter Game' Might Help Autistic Kids Manage Sensory Overload
• Sugar Exposure In Early Life Linked To Anxiety Risk In Adulthood
• Mount Sinai Researchers Identify How APOE4 Gene Damages Brain Blood Vessels in Alzheimer's Disease
• 2 In 5 College Athletes Have Considered Suicide, Survey Finds
• Weight-Loss Meds Lead To Nutritional Deficits For Many Kids And Teens, Study Finds
• Cancer Twice As Common Among Those With Type 2 Diabetes, Study Finds
• Study Examines Racial Disparities in Patients' Adherence to Their Diabetes Medications
• Nursing Home Beds Are Becoming More Scarce
• AI Model Combining Ultrasound and Digital Breast Tomosynthesis Improves Specificity in Breast Cancer Triage
• Chronic Stress Linked to Differences in Cognitive Decline Across Certain Demographic Groups, Study Finds
• Starving Cancer's Fuel Source Could Boost Treatment Effectiveness
• New Evidence of How Hormones Alter Women's Mood
• Birmingham Researchers Find New Approach to Detect Infections Causing Meningitis and Encephalitis
• Probiotics Linked to Fewer Deaths in Premature Babies
• Effects of Obesity Decoded - Bonn Study: Immune Cells in Adipose Tissue Require the Enzyme ACC1 to Maintain Metabolic Health
• New Mathematical Modeling Breakthrough in Cancer Radiotherapy

September 23 2026

• A Pediatric Cardiologist's Battle with Heart Failure and How It Transformed Her Approach to Care
• Exercise Keeps Astronauts' Hearts Strong Enough for Flight to Mars
• AAOS Releases 2026 Shoulder & Elbow Registry Annual Report
• Study: Enzyme May Help Protect Against Severe Liver Disease
• Nebraska Is Among First to Earn New Carnegie Sustainability Classification
• CIMS Harnesses National Labs to Accelerate Adoption of Computing in Energy-Intensive Industries
• 3D-Printed, Solid-State Bioreactor Converts Methane Waste to Useful Chemicals
• Genetic Clues Help Reveal Kids' Cancer Risk
• Less Is More: Exercise Rivals Common Pain Meds
• More Young Adults Are Having Strokes Than Three Decades Ago
• Transient Ischemic Attack Associated with Increased Risk of Dementia
• Organic Applesauce Recalled Over High Levels Of Mold Toxin
• Anti-Trans Laws Fuel Nationwide Stress, U.S. Study Finds
• Chiropractic Neck Adjustments Do Not Raise Risk Of Rare Artery Tear, Study Finds
• Nine Studies Led By Mount Sinai Investigators Featured in Coordinated Collection of Papers That Map the Molecular and Cellular Architecture of Brain Disorders
• Study Identifies Potential RAS Inhibitor-Immunotherapy Strategy for Pancreatic Cancer
• UTHealth Houston Database Fills Gap in Long COVID Surveillance
• Replacement Joints Might Affect A Person's Brain, Study Finds
• Abnormally Large Breasts Linked To Range Of Headache And Pain Disorders
• Kids' Vaccinations Don't Have To Be Scary Or Painful, New Guidelines Argue
• McMaster Researchers Uncover What Could Make Some Bacteria-Killing Viruses More Effective Than Others
• It's Hard To Predict Who Will Be Suicidal. It's Easier To Ensure People Can't Shoot Themselves
• Pivotal SPRAY-CB Trial of RejuvenAir(r) Published in American Journal of Respiratory and Critical Care Medicine
• People with Dementia Want to Participate in Research: Novel Law Clinic Study Was Found to Be Meaningful and Empowering

September 22 2026

• Multicancer Blood Test Detects 17 Cancer Types in Large Prospective Study
• Individual IR focus and Evaluation and Management Services Facilitate Higher Complexity IR Practice
• Patrick Kirby's Journey From Heart Defect to Recovery
• Molecular biologist and neuroscientist Catherine Dulac wins the 2026 Pearl Meister Greengard Prize
• Surgery Gives NBA Pro a Second Shot
• Longtime Microbiology Chair, Vaccine Researcher, and Academic Leader James B. Kaper, PhD, Retires After Four Decades
• Researchers Uncover Dual Role of B7-H3 in Tumor Immune Suppression
• High Speed, Low Light Conditions Tied to Unbuckled Driving
• Blood-Brain Barrier Modulation Stimulates Myelin-Producing Cells
• What The Data Say About GLP-1 Drugs and Vision Loss
• New Study Helps Explain How Endometriosis Causes Pain
• A Shorter, Better-Tolerated Treatment for Chagas Disease Is Possible
• Support for Research Is a Class Act
• What Happens When You Can’t See A Family Doctor Regularly?
• Kratom Cases Climb Sharply Across The US
• Cardiovascular Health And Exercise: How Much Aerobic Activity Do You Really Need?
• Mindfulness, Tai Chi Can Ease Pain, Fatigue Among Cancer Survivors
• MIND Diet May Help Support Cognition Through Healthier Arteries
• Interest In Dementia Vaccine High In U.S., Survey Finds
• Marathons Safe For People With Type 1 Diabetes, Study Says
• Parents Say They Don't Know Much About E-Bikes, Poll Finds
• Women with Enlarged Breast Tissue More Likely to Experience Chronic Migraine, Neck Pain and Sleep Apnea, Study Finds
• The Drugs And Devices Have Been On The Market For Years. But FDA-Ordered Studies Still Aren't Done.
• When Health Uncertainty Follows You to Work: The Hidden Labor of Staying Functional
• The Menopause Movement Is Making Waves
• When Health Uncertainty Follows You to Work: The Hidden Labor of Staying Functional
• Sugar Exposure in Early Life Linked to Anxiety in Adulthood
• Changes in Retinal Dopamine Balance During Inherited Retinal Degenerations
• Mpox: More Than a Third of Positive Tests May Have Been False Diagnoses
• Simple Cleaning Reduced Bacteria on Single-Use Medical Devices
• Inequality of Health Chances is More than a Question for Health Systems
• Marine Carbohydrate Therapeutics: From Structural Diversity to Clinical Translation
• SKKU Research Team Led by Professor Inki Kim Develops Ultra-Sensitive Nanoplasmonic Biochip Housing Parkinson's Patient-Derived "Mini-Brain"
• 4D fMRI CrossFormer: Toward Explainable and Trustworthy AI for Brain Disorder Diagnosis

September 21 2026

• From Lab to Living Room: Revolutionary Utah Bionic Arm Enters First Home Trial
• Teaching Autistic Children to 'Think Like a Reporter' Calms Overly Sensitive Brain Activity
• GLP-1s Linked to Nutritional Deficiencies in Children
• Stomach Flu vs. Foodborne Illness in Kids: How to Tell the Difference
• A Tiny Worm Helps Scientists Unravel a Genetic Clue to Kidney Disease
• Cleveland Clinic Children's Expands Newborn Screening to Identify Virus that Can Lead to Hearing Loss and Developmental Delays
• During Falls Prevention Awareness Week, AAOS Orthopaedic Experts Share Practical Ways to Reduce Fall Risks at Home
• Scientists Discover Why High Levels of the Amino Acid Cysteine Are Toxic to Cells
• U.S. Alcohol Use Falls for First Time Since the COVID-19 Pandemic, but Remains Above Pre-Pandemic Levels
• Gen Z and Millennials Drove Recent Drop in Alcohol Use, Study Shows
• New VA/DoD Guideline Recommends Varenicline and Combination Nicotine Replacement Therapy as Preferred Treatments for Tobacco Use
• Wildfire Smoke Might Be More Toxic Than Other Air Pollution, Studies Say
• Vitamin D Levels May Raise Preterm Birth Risk
• JMIR News: Deepfake Physician Scams and Nursing Robotics
• Beyond Raw Brainpower: New Study Reveals Best Ways to Train AI for Clinical Care
• Social Media Posts Mislead About Blood Tests For Alzheimer's
• Most Sports Parents Say There's More Good Than Harm In Youth Sports, Survey Finds
• Engineered Nanoparticles Sensitize Gliomas to Radiotherapy
• Lupus Patients Can Lower Their Heart Disease Risk By Sticking To One Common Treatment, Study Says
• 3 Common Drugs Older Adults Might Be Overusing
• Efficacy of Commercial Disinfectants Virkon(r)S and Microchem Plus Against Poliovirus