Validation of a Spanish version of the Health Assessment Questionnaire-II to assess Mexican patients’ physical function with rheumatoid arthritis
Publication date: Available online 6 June 2021Source: Reumatología Clínica (English Edition)Author(s): Gabriel Horta-Baas (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - June 7, 2021 Category: Rheumatology Source Type: research

Relationship of IP-10 gene expression to systemic lupus erythematosus activity
Publication date: Available online 3 June 2021Source: Reumatología Clínica (English Edition)Author(s): Julián Torres-Vázquez, Martín Uriel Vázquez-Medina, David Alberto Comoto-Santacruz, Mariano Emilio Pradillo-Macias, Omar Eloy Muñoz-Monroy, Adriana Martínez-Cuazitl (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - June 3, 2021 Category: Rheumatology Source Type: research

Ocular cicatricial pemphigoid: Methotrexate as an initial treatment?
Publication date: Available online 2 June 2021Source: Reumatología Clínica (English Edition)Author(s): Andrea María Smichowski, Victor Daniel Caputo, Cecilia Romeo, Estela Rivero, Natalia Soledad Morales, Gustavo Casado (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - June 2, 2021 Category: Rheumatology Source Type: research

Impact of the COVID-19 pandemic on rheumatology nursing consultation
Publication date: Available online 2 June 2021Source: Reumatología Clínica (English Edition)Author(s): Susana P. Fernández Sánchez, Fermín Rodríguez Muñoz, Ana Laiz, Ivan Castellví, Berta Magallares, Héctor Corominas (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - June 2, 2021 Category: Rheumatology Source Type: research

Tele-Rheumatology during the COVID-19 pandemic
Publication date: Available online 2 June 2021Source: Reumatología Clínica (English Edition)Author(s): Jesús Tornero-Molina, Fernando Sánchez-Alonso, Manuel Fernández-Prada, María-Luisa Bris-Ochaita, Alberto Sifuentes-Giraldo, Javier Vidal-Fuentes (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - June 2, 2021 Category: Rheumatology Source Type: research

Cost evolution of biological drugs in rheumatoid arthritis patients in a tertiary hospital: Influential factors on price
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Mariángeles González Fernández, Elena Villamañán, Inmaculada Jiménez-Nácher, Francisco Moreno, Chamaida Plasencia, Francisco Gayá, Alicia Herrero, Alejandro Balsa (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Definition of Remission and Disease Activity Assessment in Psoriatic Arthritis: Evidence and Expert-Based Recommendations
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Raquel Almodóvar, Juan D. Cañete, Eugenio de Miguel, José Antonio Pinto, Rubén Queiro (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Clinical and sociodemographic factors associated with lupus nephritis in Colombian patients: A cross-sectional study
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Juan C. Díaz-Coronado, Adriana Rojas-Villarraga, Deicy Hernandez-Parra, Laura Betancur-Vásquez, Jorge Lacouture-Fierro, Daniel Gonzalez-Hurtado, Juanita González-Arango, Laura Uribe-Arango, Maria C. Gaviria-Aguilar, Ricardo A. Pineda-Tamayo (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Is Botulinum Toxin Useful in Systemic Sclerosis Related Peripheral Vasculopathy? A Literature Review
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Miguel Gomes Guerra, Diogo Guimarães da Fonseca, Beatriz Samões, Taciana Videira, Patrícia Pinto (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Remission of Rheumatoid Arthritis and Primary Biliary Cholangitis After Treatment With Tocilizumab
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Soraia Azevedo, Joana Sousa-Neves, Joana Ramos Rodrigues, Daniela Peixoto, José Tavares-Costa, Filipa Teixeira (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Schwannomas mimicking rheumatologic conditions
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Joana Silva-Dinis, Ana Valido, Joaquim Polido-Pereira, Nikita Khmelinskii (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Growth factors: Do they play a role in entheseal involvement in psoriatic arthritis and undifferentiated spondyloarthritis patients?
Publication date: June–July 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 6Author(s): Cinzia Rotondo, Daniela Cici, Francesco Paolo Cantatore (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 23, 2021 Category: Rheumatology Source Type: research

Effectiveness of intravenous tocilizumab in routine clinical practice in a cohort of Costa Rican patients with rheumatoid arthritis
Publication date: Available online 10 May 2021Source: Reumatología Clínica (English Edition)Author(s): Mauricio Cordero-Alfaro, Carlos León-Céspedes, Allan Ramos-Esquivel (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 12, 2021 Category: Rheumatology Source Type: research

Economic impact of obstetric events on women of reproductive age living with psoriatic arthritis, rheumatoid arthritis, axial spondyloarthritis and psoriasis in Spain
Publication date: Available online 7 May 2021Source: Reumatología Clínica (English Edition)Author(s): Nuria Martínez, Olga Villar, Onica Armijo, María Castellanos, Natalia Marin Huarte, María Mareque, Miguel Ángel Casado, Julia Martínez-Barrio (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 7, 2021 Category: Rheumatology Source Type: research

Treatment of psoriatic arthritis: Challenges in Latin America
Publication date: Available online 7 May 2021Source: Reumatología Clínica (English Edition)Author(s): Wilson Bautista Molano (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 7, 2021 Category: Rheumatology Source Type: research

Organisational and clinical approach to osteoporosis in rheumatology: OP-SER-Excellence survey and consensus
Publication date: Available online 7 May 2021Source: Reumatología Clínica (English Edition)Author(s): Antonio Naranjo, Pilar Aguado, Javier de Toro, M. Dolores Toledo, Teresa González, José Rosas, Cristina Campos Fernández, Diana Gavilan, Grupo OsteoResSER (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 7, 2021 Category: Rheumatology Source Type: research

Clinical management and discontinuation of treatment in patients with recent onset rheumatoid arthritis in a rheumatology consultation
Publication date: Available online 7 May 2021Source: Reumatología Clínica (English Edition)Author(s): Zulema Rosales Rosado, Judit Font Urgelles, Isabel Hernández Rodríguez, Leticia León Mateos, Lydia Abásolo Alcázar, Juan Ángel Jover Jover (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 7, 2021 Category: Rheumatology Source Type: research

Validity of the Cushing’s syndrome severity index in patients with iatrogenic Cushing’s syndrome
Publication date: Available online 7 May 2021Source: Reumatología Clínica (English Edition)Author(s): Everardo Álvarez-Hernández, Graciela Mercado-Molina, Rosa Consuelo Barrera-Guerra (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 7, 2021 Category: Rheumatology Source Type: research

Expanded Mesenchymal Stromal Cells in knee osteoarthritis: A systematic literature review
Publication date: Available online 3 May 2021Source: Reumatología Clínica (English Edition)Author(s): Paloma Álvarez Hernández, José de la Mata Llord (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 4, 2021 Category: Rheumatology Source Type: research

PROCOAC (PROspective COhort of A Coruña) description: Spanish prospective cohort to study osteoarthritis
Publication date: Available online 3 May 2021Source: Reumatología Clínica (English Edition)Author(s): Natividad Oreiro-Villar, Ana C. Raga, Ignacio Rego-Pérez, Sonia Pértega, Maite Silva-Diaz, Mercedes Freire, Carlos Fernández-López, Francisco J. Blanco (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 4, 2021 Category: Rheumatology Source Type: research

Non-thermal atmospheric plasma generated with helium gas as a promoter of wound healing by salivary gland biopsy in Sjögren’s syndrome. Presentation two cases
Publication date: Available online 30 April 2021Source: Reumatología Clínica (English Edition)Author(s): Norma Guadalupe Ibáñez-Mancera, Víctor Hugo Toral-Rizo, Edith Lara-Carrillo, Régulo López-Callejas (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - May 1, 2021 Category: Rheumatology Source Type: research

Teleconsultation of infant rheumatology in Covid-19 time
Publication date: Available online 27 April 2021Source: Reumatología Clínica (English Edition)Author(s): Juan Carlos Nieto-González, Indalecio Monteagudo (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 28, 2021 Category: Rheumatology Source Type: research

Autoantibodies to extractable nuclear antigens (ENAs) pattern in rheumatoid arthritis patients: Relevance and clinical implications
Publication date: May 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 5Author(s): Yasser Emad, Yasser Ragab, Nevin Hammam, Nashwa El-Shaarawy, Ossama Ibrahim, Rania M. Gamal, Magdy Abd-Elsalam, Reem H.A. Mohammed, Mona Hawass, Johannes J. Rasker (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 22, 2021 Category: Rheumatology Source Type: research

Proposal for the use of anakinra in acute respiratory distress secondary to COVID-19
Publication date: Available online 12 April 2021Source: Reumatología Clínica (English Edition)Author(s): Alejandro Muñoz-Jiménez, Esteban Rubio-Romero, José Luis Marenco de la Fuente (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 13, 2021 Category: Rheumatology Source Type: research

Rheumatological therapy in Prehispanic Mesoamerica
Publication date: Available online 8 April 2021Source: Reumatología Clínica (English Edition)Author(s): Juan Manuel Miranda Limón (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 9, 2021 Category: Rheumatology Source Type: research

Current state, control, impact and management of rheumatoid arthritis according to patient: AR 2020 national survey
Publication date: Available online 7 April 2021Source: Reumatología Clínica (English Edition)Author(s): Laly Alcaide, Antonio I. Torralba, José Eusamio Serre, Carlos García Cotarelo, Estíbaliz Loza, Francisca Sivera (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 7, 2021 Category: Rheumatology Source Type: research

Prospective multicentre study of experience in real-world clinical practice in monitoring reported outcome measures (PROMs) of patient with a diagnosis of psoriatic and/or spondyloarthritis and initiating treatment with secukinumab
Publication date: Available online 7 April 2021Source: Reumatología Clínica (English Edition)Author(s): Juan José Lerma Garrido, Antonio Gracia Pérez, Antonio Pérez Torres, Amalia Rueda Cid, Clara Molina Almela, María Dolores Pastor Cubillo, Cristina Campos Fernández, Isabel Balaguer Trull, Loreto Carmona, Javier Calvo Catalá (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 7, 2021 Category: Rheumatology Source Type: research

Development and feasibility of 4 checklists for the evaluation of comorbidity in patients with rheumatoid arthritis, axial spondyloarthritis and psoriatic arthritis: GECOAI Project
Publication date: Available online 7 April 2021Source: Reumatología Clínica (English Edition)Author(s): Santos Castañeda, Carlos González, Virginia Villaverde, Cristina Lajas Petisco, María Carmen Castro, Fernando Jirout, Juan Carlos Obaya, Juan Carlos Hermosa, Carmen Suárez, Silvia García, María Rodero, Leticia León, Amparo López Esteban, Milena Gobbo, Laly Alcaide, Juan Carlos Torre-Alonso (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 7, 2021 Category: Rheumatology Source Type: research

Prevalence of osteoporosis in Colombia: Data from the National Health Registry from 2012 to 2018
Publication date: Available online 5 April 2021Source: Reumatología Clínica (English Edition)Author(s): Daniel G. Fernández-Ávila, Santiago Bernal-Macías, María J. Parra, Diana N. Rincón, Juan M. Gutiérrez, Diego Rosselli (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Human papilloma virus screening: evaluation of testing and surveillance in rheumatoid arthritis, psoriatic arthritis and systemic lupus erythematosus
Publication date: Available online 5 April 2021Source: Reumatología Clínica (English Edition)Author(s): Blanca Vidal Alejandre, Ernesto Tovar Sugrañes, Raquel López Poza, Mariano Andrés, María Paz Martínez-Vidal (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Prolotherapy with dextrose to reduce pain in osteoarthritis of the knee
Publication date: Available online 5 April 2021Source: Reumatología Clínica (English Edition)Author(s): Sandra Martínez-Pizarro (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Digital ischemia as the initial presentation of catastrophic antiphospholipid syndrome
Publication date: Available online 6 April 2021Source: Reumatología Clínica (English Edition)Author(s): Laura Martín Pedraz, Rocío Galindo Zavala, Francisco Nieto Vega, Irene Sánchez Bazán, Esmeralda Núñez Cuadros (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Diffuse alveolar haemorrhage in systemic lupus erythematosus patients
Publication date: Available online 6 April 2021Source: Reumatología Clínica (English Edition)Author(s): Alejandro Antonio Reibaldi, Lorena Sager, Romina Calvo, Alberto Ortiz, Susana Roverano, Sergio Paira, Elena Fernández de Carrera (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Hemorrhagic bullous IgA vasculitis (Schönlein-Henoch purpura), does it have a worse prognosis?
Publication date: Available online 6 April 2021Source: Reumatología Clínica (English Edition)Author(s): Julia Alonso de la Hoz, Carmen Eugenia Martínez Antequera, Beatriz Fernández Manso, Lucía Llorente Otones, Jaime de Inocencio Arocena (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Reply
Publication date: Available online 6 April 2021Source: Reumatología Clínica (English Edition)Author(s): Alejandro Olive Marqués (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - April 6, 2021 Category: Rheumatology Source Type: research

Pregnancy control in patients with systemic lupus erythematosus/antiphospholipid syndrome. Part 3: Childbirth. Puerperium. Breastfeeding contraception. Newborn
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): Paloma Delgado, Ángel Robles, Juan Antonio Martínez López, Luis Sáez-Comet, Esther Rodríguez Almaraz, Nuria Martínez-Sánchez, Amaia Ugarte, Paloma Vela-Casasempere, Beatriz Marco, Gerard Espinosa, Maria Galindo, Manel Casellas, Guillermo Ruiz-Irastorza, Victor Martínez-Taboada, Jose Luis Bartha (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Role of Inflammasome Activation in Systemic Lupus Erythematosus: Are Innate Immune Cells Activated?
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): Rodolfo Perez-Alamino, Raquel Cuchacovich, Luis R. Espinoza, Constance P. Porretta, Arnold H. Zea (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Comparison of disease activity in patients with ankylosing spondylitis under TNFi or NSAID treatment, is there any difference? An observational study
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): Mireia Moreno, Marta Arévalo, Marc Zamora, Caridad Pontes, Juan Carlos Oliva, Jordi Gratacós (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Development of a risk indicator score for the identification of interstitial lung disease in patients with rheumatoid arthritis
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): Francisco Paulin, Tracy Jennifer Doyle, Juan Francisco Mercado, Leandro Fassola, Martín Fernández, Fabián Caro, María Laura Alberti, María Elena Crespo Espíndola, Emilio Buschiazzo (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Treat-to-target strategy in patients with rheumatoid arthritis: Audit of adherence from real world clinical data
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): José-Luis Andréu, María Auxiliadora Martín, Héctor Corominas, José Javier Pérez-Venegas, José Andrés Román-Ivorra, Fernando Sánchez-Alonso, Ángel Gil de Miguel (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Unusual presentation of IgG4-related disease
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): Jonathan Franco Vanegas, Martí Esteban i Fernández, Jordi Robert Olalla (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Ultrasound features in patients with gout: A comparative analysis with matched controls
Publication date: April 2021Source: Reumatología Clínica (English Edition), Volume 17, Issue 4Author(s): Joana Leite Silva, Daniela Santos-Faria, Marcos Cerqueira, Joana Sousa-Neves, Daniela Peixoto, Filipa Teixeira (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 25, 2021 Category: Rheumatology Source Type: research

Pregnancy and systemic lupus erythematosus in Spain: Has anything changed in the 21st century?
Publication date: Available online 24 March 2021Source: Reumatología Clínica (English Edition)Author(s): Manuel de la Hera Madrazo, Pedro Muñoz Cacho, Leyre Riancho Zarrabeitia, Lorena Álvarez Rodríguez, Ana Haya, Marcos López-Hoyos, Víctor M. Martínez-Taboada (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 24, 2021 Category: Rheumatology Source Type: research

Safety in the use of ultrasound in rheumatology during the COVID-19 Pandemic. Spanish Society of Rheumatology positioning paper
Publication date: Available online 22 March 2021Source: Reumatología Clínica (English Edition)Author(s): Lucía Mayordomo, Juan Molina Collada, Félix M. Francisco Hernández, Ángel Bueno, Santos A. Insua Vilariño, Francisco Gabriel Jiménez-Núñez, Rosalía Martínez Pérez, Ingrid Möller, Jacqueline Usón Jaeger, José Francisco García-Llorente, José M. Álvaro-Gracia, Eduardo Aparicio Ruiz, Liliana Asaro Daverio, Esperanza Naredo, Grupo de Trabajo de Ecografía de la Sociedad Española de R...
Source: Reumatologia Clinica - March 23, 2021 Category: Rheumatology Source Type: research

Experts document about an adequate utilization of SYSADOAs in controversial clinical situations
Publication date: Available online 19 March 2021Source: Reumatología Clínica (English Edition)Author(s): Jordi Monfort, Xavier Carné, Benjamín Abarca, Sergio Giménez, Montserrat Romera, Ingrid Möller, Marco Bibas, Marianna Vitaloni, Aina Batlle, Josep Vergés (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 19, 2021 Category: Rheumatology Source Type: research

Serum immunoglobulin levels, complement components 3 and 4, HLA-B27 allele and spondyloarthropathy in patients with non-infectious anterior uveites
Publication date: Available online 18 March 2021Source: Reumatología Clínica (English Edition)Author(s): Bárbara Torres Rives, Goitybell Martínez Téllez, Minerva Mataran Valdés, Teresa Collazo Mesa, Rosa Colás González, Isabel Frutos Ambou (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 18, 2021 Category: Rheumatology Source Type: research

Massive osteolysis in a patient with Gorham-Stout syndrome
Publication date: Available online 16 March 2021Source: Reumatología Clínica (English Edition)Author(s): Irene María López García, María Teresa Lorenzo Domínguez, Ana María Fernández Martínez, María Teresa Cuesta Marcos (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 17, 2021 Category: Rheumatology Source Type: research

Management of pregnancy in patients with systemic lupus erythematosus/antiphospholipid syndrome. Part 3: Childbirth. Puerperium. Breastfeeding contraception. Newborn
Publication date: Available online 17 March 2021Source: Reumatología Clínica (English Edition)Author(s): Paloma Delgado, Ángel Robles, Juan Antonio Martínez López, Luis Sáez-Comet, Esther Rodríguez Almaraz, Nuria Martínez-Sánchez, Amaia Ugarte, Paloma Vela-Casasempere, Beatriz Marco, Gerard Espinosa, Maria Galindo, Manel Casellas, Guillermo Ruiz-Irastorza, Victor Martínez-Taboada, Jose Luis Bartha (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 17, 2021 Category: Rheumatology Source Type: research

Rheumatology manpower in the public system in Catalonia (Spain)
Publication date: Available online 15 March 2021Source: Reumatología Clínica (English Edition)Author(s): Dolors Grados Canovas, Melania Martínez-Morillo, Alejandro Olivé Marques, Alexandra Retamero, Joan M. Nolla, Núria Guanyabens (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 17, 2021 Category: Rheumatology Source Type: research

Increasing trend in mortality from systemic lupus erythematosus in Latin America as an expression of social disparities in health
Publication date: Available online 15 March 2021Source: Reumatología Clínica (English Edition)Author(s): Halbert Hernández-Negrín, David Padilla-Cueto, Onan Martínez Morales (Source: Reumatologia Clinica)
Source: Reumatologia Clinica - March 17, 2021 Category: Rheumatology Source Type: research