Journal of Surgical Research

Article	Citations
Cover 4: AAS Join Journal Ad	269
AAS Join Journal Ad Print	70
Letter Regarding: Perioperative Music Therapy in Colorectal Surgery: A Review of Cost-Effectiveness and Clinical Impact	65
Increased Hospital System Utilization After Gastrostomy in Children Is Related to Neighborhood	54
Discharge to Skilled Nursing Facility Is a Risk Factor for Readmission: A Nationwide Propensity-Matched Study	47
Adapting Surgical Coaching: Feasibility and Perceptions of Intraoperative Resident Peer Coaching	42
Letter Regarding: Long-Term Outcomes of Cricothyroidotomy Versus Endotracheal Intubation in Military Personnel: A Retrospective Comparative Analysis Cohort Study	36
Looking Beyond Hospital Discharge: One-Year Mortality Following Tracheostomy Creation in Traumatically Injured Older Adults	35
To Operate or Not to Operate? A Script Concordance Study of Resident Preoperative Decision-Making	35
Young Age as a Predictor of Chemotherapy Recommendation and Treatment in Breast Cancer: A National Cancer Database Study	33
Letter Regarding: Comparing How Three Frailty Scales Predict Negative Outcomes in Trauma Patients With Rib Fractures	33
Scoping Review of Operative Management of Thoracic Malignancies in Patients With Psychiatric Comorbidities	30
Can Artificial Intelligence Coach Faculty to Utilize Growth Mindset Language? A Qualitative Analysis of Feedback Statements	29
Qualitative Analysis of Program Director Perspectives on Conscientious Objection Policies to Gender-Affirming Care	29
Pharmacological Approaches for the Prevention of Breast Implant Capsular Contracture	29
Letter Regarding: Surgery Interest Groups in Medical Schools: Mentoring Factory	28
Firearm Violence Surrounding the COVID-19 Pandemic: A Reopening Phenomenon	27
Annual Structured Communication Skills Training for Surgery Residents	26
Outcomes of Transfusion With Whole Blood, Component Therapy, or Both in Adult Civilian Trauma Patients: A Systematic Review and Meta-Analysis	26
Female Patient Perceptions on Financial Incentives to Promote Follow-Up After Bariatric Surgery	25
A Statewide Analysis of Pediatric Liver Injuries Treated at Adult Versus Pediatric Trauma Centers	25
Association of Economic Recession and Social Distancing With Pediatric Non-accidental Trauma During COVID-19	25
Benefit of Kidney Transplantation for Post Lung Transplantation Renal Failure	24
Referral of Burn Patients in the Absence of Guidelines: A Rwandan Study	24
Peritoneal Metastases After Intraductal Papillary Mucinous Neoplasm Resection: How Common are They?	24

Law Enforcement and Patient Privacy Among Survivors of Violence: A Nationwide Mixed-Methods Study	24
Featured Articles	23
Serum Amyloid P Attenuates Hypertrophic Scarring in Large Animal Models	23
COVID Stressed, but Not due to the Virus	23
Evaluation of Medicare Reimbursement and Surgical Patterns for Male and Female Colorectal Surgeons	22
Instilling Resiliency in Surgical Education: The Benefits of Longitudinal Medical Student Learning	22
Incidence and Mortality of Pediatric Abdominal Compartment Syndrome	21
Management of the Pregnant Trauma Patient: A Systematic Literature Review	21
Identification of Clinical Risk Factors Affecting Patient-Physician Communication	21
Characterization of Epidural Analgesia Interruption and Associated Outcomes After Esophagectomy	21
Assessment of Conflicts of Interest in the Transcarotid Artery Revascularization Literature	20
Editorial Board	20
Manipulation of Nitric Oxide Levels via a Modified Hydroxyethyl Starch Molecule	20
The Prevalence of Benign Pathology Following Major Pulmonary Resection for Suspected Malignancy	20
Development and Feasibility Testing of a Decision Aid for Acute Appendicitis	20
The Impact of COVID-19 Pandemic Upon Non-elective Admissions and Surgery at a Safety-Net Hospital	20
Assessing the Association Between Endoscopic Tattooing and Lymph Node Yield in Rectal Cancer	20
How Accurate Are Surgeons at Assessing the Quality of Their Critical View of Safety During Laparoscopic Cholecystectomy?	19
Subscription Information	19
Trends in Management of Index Adhesive Small Bowel Obstruction in Children	19
The Importance of General Surgery Residency Program’s Online Presence Varies Among Applicant Groups	19
Association Between Conduit Type and Outcomes After Open Repair of Popliteal Artery Aneurysms	19
Timing to Rib Fixation in Patients With Flail Chest	19
Erratum to “Prehospital Narrow Pulse Pressure Predicts Need for Resuscitative Thoracotomy and Emergent Intervention after Trauma” [Journal of Surgical Research 268 (2021) 284–290]	19
Platelet and White Cell Reactivity to Top-Load Intravenous Perfluorocarbon Infusion in Healthy Sheep	19
Implementation of a Breast Intraoperative Oncoplastic Form to Aid Management of Oncoplastic Surgery	19
Weekend Discharge Is Not Associated With Increased Readmission After Hyperthermic Intraperitoneal Chemotherapy	19
Quality Review Committee Audit Improves Thoracic Enhanced Recovery After Surgery Protocol Compliance	18
COLQ and ARHGAP15 are Associated with Diverticular Disease and are Expressed in the Colon	18
Are We Underestimating the Morbidity of Single Rib Fractures?	18
COVID-19 and Mortality in the Global Surgical Population: A Systematic Review and Meta-Analysis	18
Letter Regarding: Utilizing Relative Citation Ratio to Compare Academic Productivity by Gender in Plastic Surgery	17
Assessment of Amniotic Fluid as a Preservation Solution in Pig Livers Undergoing Machine Perfusion	17
Endovascular Perfusion Augmentation After Resuscitative Endovascular Balloon Occlusion of the Aorta Improves Renal Perfusion and Decreases Vasopressors	17
Is REBOA the Last Card to Control a Massive Gastrointestinal Bleeding?	17
Acute Pancreatitis: Presentation and Outcomes at a Safety Net Hospital	17
Drugs, Delirium, and Trauma: Substance Use and Incidence of Delirium After Traumatic Brain Injury	17
“The Itsy-Bitsy Water Bead Went Down the Baby's Mouth. Will Drinking Gastrografin Help to Flush It Out?”	17
Omission of Routine Chest X-Rays After Chest Tube Removal Is Safe and Feasible After Thoracic Surgery: A Single Institution Quality Improvement Initiative	17
Acquisition of Surgical Skills in Medical Students via Telementoring: A Randomized Controlled Trial	17
Analysis of Surgical Residents’ Salaries and Associated Funding During Eight Residency Training Cycles: Toward Improving Future Residents’ Benefits and Compensation	17
Complications Following Splenic Embolization for Trauma: Have Things Changed Over Time?	16
Determining Outcomes in Nonpenetrating Trauma With qSOFA	16
Bile Spillage as a Prognostic Factor for Gall Bladder Cancer: A Systematic Review and Meta-Analysis	16
A Comparative Analysis of Zip Code Discordance in Pediatric Gunshot Wounds	16
Association Between Race, Gender, and Pediatric Postoperative Outcomes: An Updated Retrospective Review	16
Overnight Decision-Making for Equivocal Appendicitis Often Involves Unnecessary Hospital Admissions	16
Assessing Fall Mortality by Field-Relevant Categories at an Urban Level I Trauma Center	16
Letter Regarding: The Use of Inflammatory Markers for Treatment Response Monitoring in Acute Cholangitis: A Retrospective Cohort Study	16
Exploring Limited English Proficiency in the Clinical Outcomes of Pediatric Burn Patients	16

Insurance Status and Travel Distance to Single Treatment Facility Predictive of Mastectomy	16
To PEG or Not to PEG: Trends in Gastrostomy Tube Needs in Patients Requiring Tracheostomy	16
Association of High BMI With Morbidity and Mortality in Common Emergency General Surgery Procedures	16
Vascular Graft Infections Treated With Bioabsorbable Antibiotic Beads	16
Investigating the Association Between Type 2 Diabetes Mellitus and Pathological Responses Among Breast Cancer Patients Receiving Neoadjuvant Chemotherapy	16
Mortality and Morbidity in Rib Fracture Surgery: Pulmonary Contusion Versus Extrathoracic Trauma	16
Admission Triage With Pain, Inspiratory Effort, Cough Score can Predict Critical Care Utilization and Length of Stay in Isolated Chest Wall Injury	15
Prevalence of and Risk Factors for Incidental Colonic Diverticulosis	15
Documentation and Follow-Up of Incidental Findings Found on Trauma CT Scan Imaging: A Scoping Review	15
Combination Therapy of Niacin and Apocynin Attenuates Lung Injury During Sepsis in Rats	15
Response Regarding: Surgical Residencies Need in Person Interviews	15
Identifying Young Adults at High Risk for Weight Gain Using Machine Learning	15
The COVID-19 Era Is Associated With Delays in Esophageal Cancer Diagnosis and Treatment	15
Discreet Values of Shock Index Pediatric Age-Adjusted (SIPA) to Predict Intervention in Children With Blunt Organ Injuries	15
Prophylactic Sartorius Flap Reconstruction is Associated With Reduced Vascular Graft Infection	15
Antibiotic Prophylaxis in Breast Cancer Surgery: A Multicontinental Survey Study	15
The Impact of Concurrent Multi-Service Coverage on Quality and Safety in Trauma Care	15
Geriatric Motorcycle-Related Outcomes: A Pennsylvania Multicenter Study	15
On The Cover	15
A Nationwide Analysis of Outcomes, Healthcare Encounters, and Costs of Small Bowel Obstruction	15
Fibrinogen in Resuscitation of Older Adult Trauma Patients: Are They Too Old to Receive New Adjuncts?	15
Association Between Psychiatric Illness and Short-Term Outcomes Among Patients With Hepatobiliary and Pancreatic Cancer	15
Interests and Barriers to Medical Students Participation in a Dedicated Global Surgery Curriculum	15
Influence of Race, Insurance, and Rurality on Equity of Breast Cancer Care	15
Enhancing Surgical Teaching Effectiveness: A Needs Assessment Study Using a Modified Delphi Process	15
Readmissions After Surgical Aortic Valve Replacement: Influence of Prosthesis Type	14
Mortality Trends in Contemporary Abdominal Aortic Aneurysm Repairs Among Veterans	14
Editorial Board	14
Table of Contents	14
Ex Vivo Comparison of the Elastic Properties of Vascular Substitutes Used for Pulmonary Artery Replacement	14
Aspirin Administration Mitigates Platelet Hyperaggregability After Splenectomy in a Murine Model	14
Syndecan-1 as the Effect or Effector of the Endothelial Inflammatory Response?	14
Journal of Surgical Research	14
Using Human-Centered Design to Improve a Surgery Resident Well-Being Program	14
On the Cover	14
Accuracy of National Surgical Quality Improvement Program Risk Calculator Among Elderly Patients Undergoing Pancreas Resection	14
Overlapping Surgeries From the Patient's Perspective	14
Table of Contents	14
Postoperative Pancreatic Fistula Following Traumatic Splenectomy: A Morbid and Costly Complication	13
AAS Get involved JSR Ad	13
The Effect of Tension on Gene Expression in Primary Nerve Repair via the Epineural Suture Technique	13
Predictors of Cytomegalovirus Recurrence Following Cessation of Posttransplant Prophylaxis	13
Psychiatric Consults Associated With Longer Length of Stay in Trauma Patients—A Retrospective Study	13
Associations of Fatty Liver Disease With Recovery After Traumatic Injury	13
Screening for Intimate Partner Violence After Traumatic Injury: A Community-Based Participatory Qualitative Research Study	13
Nondestructive Evaluation of Mechanical and Histological Properties of the Human Aorta With Near-Infrared Spectroscopy	13
Pediatric Sickle Cell Disease Patients on Hydroxyurea Have Higher Rates of Surgical Splenectomy	13
Machine Learning to Predict Early Death Despite Pancreaticoduodenectomy	13
Pediatric Patient and Caregiver Agreement on Perioperative Expectations and Self-Reported Outcomes	13
Expression of the Calcium-Sensing Receptor on Normal and Abnormal Parathyroid and Thyroid Tissue	13
Insurance Not Socioeconomic Status is Associated With Access to Postacute Care After Injury: A Multicenter Cohort Study	13
TREO Aortic Endograft Demonstrates Superior Aneurysmal Sac Regression Over Mid-Term Follow-Up	13
Timing of Pediatric Incarcerated Inguinal Hernia Repair: A Review of Nationwide Readmissions Data	13
Mild and Severe Blood Alcohol Concentration Effects on Trauma and Traumatic Brain Injury Outcomes	13
Protective Effect of Topiroxostat on Myocardial Injury Induced by Lipopolysaccharide	13
The Relationship Between Nodal Metastases and Primary Location in Stage I Non-Small Cell Lung Cancer	13
How to Optimize Your Research During a Pandemic – A Summary of Discussions From the Association for Academic Surgery Town Hall and Lessons Learned From 2020	13
Lyticase Facilitates Mycobiome Resolution Without Disrupting Microbiome Fidelity in Primates	13
Telestration With Augmented Reality in Surgery: A Comprehensive Systematic Review and Meta-analysis	12
Predictors of Receiving Mental Health Services in Trauma Patients With Positive Drug Screen	12
Renal Dysfunction at Discharge and Long-Term Survival in Acute Type A Aortic Dissection	12
Oncologic Efficacy of Robotic Compared to Open Total Pancreatectomy for Pancreatic Cancer	12
Letter Regarding: Adenosine 2A Receptor Agonism Improves Survival in Extracorporeal Cardiopulmonary Resuscitation	12
Predictive Modeling for One-Year Lower Extremity Endovascular Revascularization Failure in Black Persons	12
The Alarming Surge of Driving Under the Influence-Related Motor Vehicle Crashes	12
Predicting Survivability of Noncardiac Pediatric Patients Requiring Extracorporeal Cardiopulmonary Resuscitation	12
Tolerance and Outcomes of Neoadjuvant Chemotherapy in Geriatric Breast Cancer Patients	12
Trisomy 21 Children With Duodenal Atresia or Anorectal Malformation: NSQIP-P Surgical Outcomes Study	12
Implementation Requires Evaluation of Adoption: Lessons From a Multimodal Pain Regimen Order Set	12
Implementation of an Intensive Surgical Simulation Week for Medical Students in Rwanda	12
Comparison of Adjunctive Anesthesia Within an ERAS Protocol: A Retrospective Cohort Study	12
Distribution and Application of Antineutrophil Cytoplasmic Antibodies in Patients With Macrovascular Diseases	12
Surgical Residents’ Experience With a Perinatal Resident Policy: A Qualitative Study	12
Understanding EPA Micro-Assessment Quality and Entrustability: Impact of Gender and Experience Level	12
Complication Timing, Failure to Rescue, and Readmission After Inpatient Pediatric Surgery	12
ASC 2026 Save the Date Journal Ad	12
Correlation Between Postoperative Complications and Number of Colorectal Liver Metastases Resected	12
Predicting Unilateral Aldosterone Secretion in Primary Aldosteronism	12
Cardiothoracic Surgery Interviews and Selection in a Pandemic Era – Lessons to Learn	12
Surgical Stress and Liver Response: Injury, Regeneration, and Protection	12

Getting Started in Leadership: Mindsets and Skillsets for Leading in Complex Systems	11
Do Perioperative Probiotics/Synbiotics Reduce Postoperative Infection Rates Following Elective Colorectal Surgery? A Systematic Review and Meta-Analysis	11
Corrigendum to “Gender Parity Among Vascular Surgeons: Progress and Attrition” [Journal of Surgical Research, Volume 303 (2024) P281-286]	11
Occupational Exposures During Emergency Department Thoracotomies	11
Guess Who's Coming to Clinic? Companions in a Pediatric Urology Clinic	11
Comparison of Instructor-Led and Video-Based Instruction in Teaching Suturing to Medical Students	11
The Correlation Between Altmetric Score and Traditional Bibliometrics in Orthopaedic Literature	11
Implantation of an Impedance Sensor for Early Detection of Gastrointestinal Anastomotic Leaks	11
Does Long-Term Bowel Function Change After Colectomy for Colon Malignancy?	11
AI-Based Video Segmentation: Procedural Steps or Basic Maneuvers?	11
Are 99mTC-Sestamibi Single Photon Emission Computed Tomography Scan Results Associated to the Parathyroid Cell Type in Primary Hyperparathyroidism?	11
AAS Join Journal Ad 2025	11
Preferences in Suture Skills Instruction: Virtual Versus In-Person Instruction	11
Clinical Comparative Analyses of Thymectomy Between Subxiphoid and Subcostal Arch Thoracoscopic Resection and Median Sternotomy for the Treatment of Thymoma With Myasthenia Gravis in Chinese Patients	11
Modern Impact of Surgery Journals: Associations Between Impact Factor, H5-Index, and Altmetric Score	11
Key Indicators Associated With Survival in Pediatric Trauma Massive Transfusion Protocol	11
Colon Cancer Survival Among South Asian Americans: A Cross-Sectional Analysis of a National Dataset	11
Avoiding Overtreatment of Women ≥70 With Early-Stage Breast Cancer: A Provider-Level Deimplementation Strategy	11
Alcohol-Containing Versus Aqueous-Based Solutions for Skin Preparation in Abdominal Surgery: A Systematic Review and Meta-analysis	11
Immersive Virtual Reality for Surgical Training: A Systematic Review	11
A Prescribing Guideline Decreases Postoperative Opioid Prescribing in Emergency General Surgery	11
Trends in Integrated Plastic Surgery Applicant, Resident, and Junior Attending Research Productivity	11
Registration and Reporting Quality of Systematic Reviews on Surgical Intervention: A Meta-epidemiological Study	11
Letter Regarding: An In-Depth Analysis of the State Laws That License International Medical Graduates Without American Residency Training	11
Associations of Well-being Measures With Suicidal Ideation in Surgeons	11
Age-Adjusted Modified Frailty Index: Association With Hip Fracture Discharge Functional Dependence	11
Adverse Effects of Chronic Steroid use Following Thyroidectomy	11
Effects of Lycopene in Intestinal Ischemia Reperfusion Injury via Intestinal Immunoglobulin A	11
Early Tracheostomy in Older Trauma Patient Is Associated With Comparable Outcomes to Younger Cohort	10
Extracorporeal Membrane Oxygenation Before 34 Wks’ Gestation: A Single-Center Experience	10
Novel Application of Hydrodissection in Laparoscopic Cholecystectomy for Gangrenous Gallbladders	10
dV-Trainer vs. da Vinci Simulator: Comparison of Virtual Reality Platforms for Robotic Surgery	10
Cover 4: AAS_Job_Board_ad for JSR_2022	10
Journal of Surgical Research	10
Clinical Presentation Patterns and Survival Outcomes of Hispanic Patients With Gastric Cancer	10
Featured Articles 4C	10
Subscription Information	10
Experiences of Acute Surgical Care During the Coronavirus Disease 2019 Pandemic Among Patients and Their Next of Kin	10
Depression Is Associated With Non-Home Discharge After Coronary Artery Bypass Graft	10
Lack of Enteral Feeding Associated with Mortality in Prematurity and Necrotizing Enterocolitis	10
Pilot Cross-Sectional Quality of Life Study of a Diverse Endocrine Surgery Patient Population	10
Rhabdomyolysis After Tracheobronchoplasty: Incidence, Predictors, and Association With Postoperative Outcomes	10
Propranolol Reduces p-tau Accumulation and Improves Behavior Outcomes in a Polytrauma Murine Model	10
Long-Term Opioid Use After Colon and Rectal Surgery	10
Treatment of Severe Blunt Splenic Injury Varies Across Race and Insurance Type of Pediatric Patients	10
Angioembolization in Severe Pelvic Trauma is Associated with Venous Thromboembolism	10
Wide Provider Variation in Cost for Thyroidectomy: Potential Benefits of Standardizing Practice?	10
Letter Regarding: “Alcohol-Containing Versus Aqueous-Based Solutions for Skin Preparation in Abdominal Surgery”	10
Cover 1: Update	10
Thyroid Cancer–Related Fear & Anxiety in Patients With Benign Thyroid Nodules: A Mixed-Methods Study	10
Use of Erector Spinae Fascial Plane Blocks in Enhanced Recovery for Open Abdominal Surgery	10
Fragmentation of Care After Admissions for Burn: An Analysis of the National Readmissions Database	10
Systematic Literature Review of Health-Related Quality-of-Life Measures for Caregivers of Older Adult Trauma Patients	10
Emergency Department Shock Index Outperforms Prehospital and Delta Shock Indices in Predicting Outcomes of Trauma Patients	10
Application of Component Separation and Short-Term Outcomes in Ventral Hernia Repairs	10
Comparison of Antimicrobial Activity Between Bacitracin-Soaked Sutures and Triclosan Coated Suture	10
Diagnostic Impact of Adrenal Vein Sampling in Adrenal Cushing's Syndrome	10
Prevalence of Work-related Musculoskeletal Pain Among Plastic Surgeons: A Systematic Review and Meta-analysis	10
Assessment of MRI and Ultrasound Screening for Tethered Cord Syndrome in Patients Diagnosed With Esophageal Atresia/Tracheoesophageal Fistula	10
Junior Doctor Experiences and Challenges in Obtaining Surgical Informed Consent: A Qualitative Systematic Review and Meta-Ethnography	10
The Mediating Effect of Operative Approach on Racial Disparities in Bariatric Surgery Complications	10
On The Cover	10
Journal of Surgical Research	10
Specificity of Presepsin as a Biomarker of Bacterial Infection in Mouse Sepsis Models	10
Feasibility of Low-Volume Atomized Povidone-Iodine as a Peritoneal Antiseptic in Complicated Appendicitis	10
Letter Regarding: Academic Global Surgery Curricula: Current Status and a Call for a More Equitable Approach	10
Design and Development of a Clot Burst Pressure Device to Investigate Resuscitation Strategies	10
Increased Complications of Emergent Surgical Procedures During the First Wave of COVID-19	10
Text Messaging, Telephone, or In-Person Outpatient Visit to the Surgical Clinic: A Randomized Trial	10
Racial Disparities in Surgical Outcomes of Acute Diverticulitis: Have We Moved the Needle?	10
Modeling the COVID Pandemic: Do Delays in Surgery Justify Using Stereotactic Radiation to Treat Low-Risk Early Stage Non–Small Cell Lung Cancer?	10
Assessing Adequacy: A Meta-Analysis of Rapid Onsite Evaluation of Thyroid Nodules	10
Factors Affecting Peripheral Intravenous Catheter Placement During Pediatric Trauma Resuscitation	10
Hernia Recurrence Risk Matters More Than Mesh Type to Patients Undergoing Ventral Hernia Repair	10
ASC 2026 Save the Date Journal Ad	9
Melanoma Deaths by Thickness: Most Melanoma Deaths Are Not Attributable to Thin Melanomas	9
Short-Term Prognostic Effect of Comprehensive Complication Index in Patients With Gastric Cardia Adenocarcinoma	9
AAS Fall Courses JSR Ad 2025	9
Intravenous Versus Intraosseous Use of Tranexamic Acid in Patients With Traumatic Brain Injury	9
Therapeutic Use of Carbon Monoxide in Ex-Vivo Lung Perfusion in Donor With Prolonged Cold Ischemia	9
Outcomes Following Implementation of an Electronic Model for Perioperative Hematologic Consultation	9
Assessment of Attitudes Toward Initiation of Immediate Adjuvant Chemotherapy for Colon Cancer	9
Sugammadex in Colorectal Surgery: A Systematic Review and Meta-analysis	9
Association of Sex Differences on Weight Loss and Complications Following Bariatric Surgery	9
The Volume of Thoracic Irrigation Is Associated With Length of Stay in Patients With Traumatic Hemothorax	9
Comparing Provider and Adolescent Estimates of Postoperative Opioid Use	9
Resident Race and Operative Experience in General Surgery Residency: A Mixed-Methods Study	9
Fatal Pediatric Firearm Injuries: When and Where Are Children at Risk?	9
Impact of Medicaid Expansion on Abdominal Surgery Morbidity, Mortality, and Hospital Readmission	9
Why Potentially Elective General Surgery Becomes Emergent: A Multi-Methods Approach	9
Preclinical Immersion Experiences Improve Medical Student Perceptions of Surgery	9
Alemtuzumab Associated With Higher Mortality Than Basiliximab in Older Kidney Transplant Recipients	9
Development of a Venous Thromboembolism Prophylaxis and Pain Medication Pathway in Thoracic Surgery Enhanced Recovery After Surgery Program	9
Challenging Dogma by Skipping the Emergency Department Thoracotomy: A Propensity Score Matched Analysis of the Trauma Quality Improvement Database	9
Gender Differences With Ibutilide Effectiveness and Safety in Cardioversion of Atrial Fibrillation	9