Resumo O presente estudo teve como objetivo investigar a relação entre polimorfismos em genes desintoxicantes (GSTM1, GSTT1 e GSTP1) e sua associação com câncer colorretal (CCR) em tabagistas da etnia pashtun. Os polimorfismos nos genes selecionados foram genotipados em um estudo de caso-controle composto por 100 pacientes do sexo masculino com CCR, confirmados histologicamente, e 100 controles saudáveis, pareados por ano de nascimento e sexo usando o método PCR-RFLP. Os genótipos GSTM1 nulo e GSTT1 nulo contribuíram significativamente para o risco de CCR nos casos (OR = 3,131, IC 95%: 1,451-6,758, P = 0,004; OR = 3,541, IC 95%: 1,716-7,306, P = 0,001, respectivamente), enquanto a associação observada para GSTP1 Val/Val (1,139, IC 95%: 0,356-3,644, P = 0,826) não apresentou significância estatística. O GSTM1 nulo e o GSTT1 nulo combinados mostraram um risco 41 vezes maior (IC 95%: 4,945-351,950, P = 0,001) para CCR, enquanto os genótipos GSTM1 nulo e GSTP1 Ile/Val ou Val/Val combinados apresentaram risco cerca de 3 vezes maior (IC 95%: 1,196-7,414, P = 0,019) para CCR. Da mesma forma, os genótipos combinados GSTT1 nulo e GSTP1 Ile/Val ou Val/Val tiveram um risco para CRC cerca de 3 vezes maior (95% CI: 1,285-8,101, P = 0,013). Na combinação de três genótipos GST, os genótipos GSTM1 nulo, GSTT1 nulo e GSTP1 Ile/Val ou Val/Val apresentaram um risco 22 vezes maior (IC 95%: 2,441-212,106, P = 0,006) para CRC. Nossos achados sugerem que o polimorfismo GSTM1 e GSTT1 e sua combinação com GSTP1 podem estar associados à suscetibilidade ao CRC da população pashtun de Khyber Pakhtunkhwa, Paquistão, viciada em Naswar.

Abstract The current study aimed to investigate the relationship between polymorphisms in detoxifying (GSTM1, GSTT1, and GSTP1) genes and their association with colorectal cancer (CRC) in tobacco addicts of Pashtun ethnicity. Polymorphisms in the selected genes were genotyped in a case-control study consisting of 100 histologically confirmed male CRC patients and 100 birth-year and gender-matched healthy controls using the PCR−RFLP method. The GSTM1 null, and GSTT1 null genotypes were significantly contributed to the risk of CRC in the cases (OR= 3.131, 95% CI: 1.451−6.758, P = 0.004, and OR= 3.541, 95% CI: 1.716−7.306, P = 0.001, respectively), whereas the association observed for GSTP1 Val/Val (1.139, 95% CI: 0.356−3.644, P = 0.826) did not show statistical significance. The combined GSTM1 null and GSTT1 null showed a 41-fold increased risk (95% CI: 4.945−351.950, P = 0.001), while, the combined GSTM1 null and GSTP1 Ile/Val or Val/Val variant genotypes exhibited about 3-fold (95% CI: 1.196−7.414, P = 0.019) increased risk to CRC. Similarly, the combined GSTT1 null and GSTP1 Ile/Val or Val/Val variant genotypes showed about a 3-fold (95% CI: 1.285−8.101, P = 0.013) increased risk of CRC. In the combination of three GST genotypes, the GSTM1 null, GSTT1 null, and GSTP1 Ile/Val or Val/Val variant genotypes demonstrated a more than a 22-fold (95% CI: 2.441−212.106, P = 0.006) increased risk of CRC. Our findings suggest that GSTM1 and GSTT1 polymorphism and its combination with GSTP1 may be associated with CRC susceptibility in the Naswar addicted Pashtun population of Khyber Pakhtunkhwa, Pakistan.

BACKGROUND: Final-year nursing students are actively involved in the delivery of public immunisation programmes as part of workplace-based learning, and require adequate knowledge, clinical skills, and attitudes regarding vaccines. This study investigated the knowledge, attitudes and perceptions regarding vaccines of final year nursing students at a South African University METHODS: This cross-sectional study, through the use of an online survey questionnaire, assessed the knowledge, attitudes and perceptions regarding vaccines and the Expanded Programme of Immunization of final-year nursing students registered at a South African University during the 2021-2022 academic year RESULTS: There were 68 participants enrolled in the study (85% response rate). Participants displayed good knowledge regarding vaccines (average score of 52.54/70 ± 5.01 standard deviation [s.d.]), and overall positive perceptions of their training on vaccines and its safety. Knowledge gaps were identified in the mechanisms through which vaccines confer immunity in the human body and the cold chain requirements for the storage of vaccines. Of concern was the prevalent misconception among 78% of participants that vaccines are not effective CONCLUSION: The findings of this study indicate that final year nursing students at the University of KwaZulu-Natal, South Africa have good knowledge regarding vaccines. However, an improved understanding of the mechanism of vaccines will aid nursing students to confront and address misperceptions by clients thereby reducing improving vaccine uptake. Curriculum planners should also consider the inclusion of communication strategies to address vaccine hesitancy CONTRIBUTION: The study contributes to data on nurse education regarding vaccines in the African context, and identifies areas to improve vaccine uptake

ABSTRACT Endoscopy is a competitive field in clinical practice, in which skilled endoscopists are in high demand. The learning process for Junior Gastrointestinal Endoscopists (JGEs) is difficult, quite long, and technically demanding. This directs JGEs to seek additive learning sources, including online sources. The purpose of this study was to determine the frequency, context, attitudes, perceived benefits, drawbacks, and recommendations for using YouTube videos as an educational platform among JGEs from the uses'prespective. We disseminated a cross-sectional online questionnaire from January 15th to March 17th, 2022, and recruited 166 JGE from 39 different countries. The majority of surveyed JGEs (138, 85.2%) were already using YouTube as a learning tool. The majority of JGEs (97, 59.8%) reported gaining knowledge and applying it in their clinical practice, but 56 (34.6 %) reported gaining knowledge without application in real practice. Most participants (124, 76.5 %) reported missing procedure details in YouTube endoscopy videos. The majority of JGEs (110, 80.9%) reported that YouTube videos are provided by endoscopy specialists. Only one participant, 0.6% out of the 166 JGEs surveyed, disliked video records, including YouTube as a source of learning. Based on their experience, 106 (65.4%) of participants recommended YouTube as an educational tool for the coming generation of JGEs. We consider that YouTube represents a potentially useful tool for JGEs, supplying them with both knowledge and clinical practice tricks. However, many drawbacks could make the experience misleading and time-consuming. Consequently, we encourage educational providers on YouTube and other platforms to upload well-constructed, peer-reviewed, interactive educational endoscopy videos.

RESUMEN Antecedentes : La endoscopia es un campo competitivo en la práctica clínica en el que los endoscopistas calificados tienen una gran demanda. El proceso de aprendizaje para los endoscopistas gastrointestinales junior (JE) es difícil, bastante largo y técnicamente exigente. Esto dirige a los JE a buscar fuentes de aprendizaje adicionales, incluidas las fuentes en línea. El propósito de este estudio fue determinar la frecuencia, el contexto, las actitudes, los beneficios percibidos, los inconvenientes y las recomendaciones para el uso de videos de YouTube como una plataforma educativa entre los JE desde la perspectiva de los usuarios. Métodos: Se aplicó un cuestionario transversal en línea difundido del 15 de enero al 17 de marzo de 2022 reclutó a 166 endoscopistas gastrointestinales junior de 39 países diferentes. Resultados : La mayoría de los JE encuestados (138, 85,2%) ya utilizaban YouTube como herramienta de aprendizaje. La mayoría de los JE (97, 59,8 %) refirieron adquirir conocimientos y aplicarlos en su práctica clínica, pero 56 (34,6 %) informaron adquirir conocimientos sin aplicación en la práctica real. La mayoría de los participantes (124, 76,5 %) informó que faltaban detalles del procedimiento en los videos de endoscopia de YouTube. La mayoría de los JE (110, 80,9%) informaron que los videos de YouTube son proporcionados por especialistas en endoscopia. Solo a un participante, el 0,6% de los 166 JE encuestados, le disgustaron los registros de video, incluyendo a YouTube como fuente de aprendizaje. Según su experiencia, 106 (65,4 %) de los participantes recomendaron YouTube como una herramienta educativa para la próxima generación de JE. Conclusión: YouTube representa una herramienta potencialmente útil para los EJ, brindándoles tanto conocimientos como trucos para la práctica clínica. Sin embargo, muchos inconvenientes podrían hacer que la experiencia sea engañosa y consuma mucho tiempo. En consecuencia, alentamos a los proveedores de educación en YouTube y otras plataformas a subir videos de endoscopia educativos interactivos, bien construidos y revisados por pares.

Abstract Because of their immense economic, wellness, and remedial value, the seeds of palm (Phoenix dactylifera) were selected with synthesized silver nanoparticles (AgNPs) based on their properties for increasing the antibacterial efficacy of medical cotton. This study aimed to be contingent upon the characterisation of raw cotton fabrics treated by AgNPs with date seed extract (DSE) of P. dactylifera both individually and in combination and to investigate their antibacterial activity against various human pathogens. The prepared cotton materials with the synthesized AgNPs and/or DSE were described by both X-ray diffraction (XRD) and scanning electron microscope (SEM). At the same time, gas chromatography-mass spectrometry (GC-MS) and High-performance liquid chromatography (HPLC) were employed to determine the bioactive components in the aqueous date seed extract. The greater antibacterial activity was recorded by cotton treated with DSE and AgNPs mix, in which inhibition zones of all treatments were against Escherichia coli (8 cm), followed by Staphylococcus aureus (2.33-5.87cm) and Bacillus subtilis (2.17-4.63 cm), respectively. Overall, these findings indicate that treated cotton fabrics with synthesised AgNPs and DSE may be widely applied in various potential biological and medical applications, which could enhance environmental sustainability in closed production and consumption.

Resumo Devido ao imenso valor econômico, propriedades curativas e de bem-estar, as sementes de palmeira (Phoenix dactylifera) foram selecionadas com nanopartículas de prata sintetizadas (AgNPs), com base em suas propriedades, visando aumentar a eficácia antibacteriana do algodão medicinal. Este estudo teve como objetivo a caracterização de tecidos de algodão cru tratados por AgNPs com extrato de semente de tâmara (DSE) de P. dactylifera tanto individualmente quanto em combinação e investigar sua atividade antibacteriana contra vários patógenos humanos. Os materiais de algodão preparados com os AgNPs sintetizados e/ou DSE foram descritos por difração de raios-X (XRD) e microscópio eletrônico de varredura (SEM). Ao mesmo tempo, cromatografia gasosa-espectrometria de massa (GC-MS) e cromatografia líquida de alta eficiência (HPLC) foram empregadas para determinar os componentes bioativos no extrato aquoso de sementes de tâmaras. A maior atividade antibacteriana foi registrada pelo algodão tratado com mistura de DSE e AgNPs, em que os halos de inibição de todos os tratamentos foram contra Escherichia coli (8 cm), seguido por Staphylococcus aureus (2,33-5,87 cm) e Bacillus subtilis (2,17-4,63 cm), respectivamente. De modo geral, essas descobertas indicam que os tecidos de algodão tratados com AgNPs sintetizados e DSE podem ser amplamente aplicados em várias aplicações biológicas e médicas potenciais, o que pode aumentar a sustentabilidade ambiental na produção e consumo fechados.

RESUMO Contexto: O papel dos alimentos lácteos na doença inflamatória intestinal (DII) tem sido controverso e é discutível se os pacientes com DII devem ou não evitar leite e laticínios, bem como a relação entre esses alimentos e sintomas nesta população. Objetivo: Estudo transversal multicêntrico foi projetado para avaliar se é realmente necessário privar os pacientes com DII do consumo desta classe de alimentos. Métodos: Um estudo multicêntrico com 12 centros de referência em gastroenterologia de quatro países foi projetado para avaliar sintomas gastrointestinais após o consumo de alimentos lácteos em todos os ambulatórios de DII durante seis meses e comparar pacientes tratados nos mesmos centros sem DII. Resultados: No total, foram incluídos 1888 casos (872 pacientes com DII e 1016 casos sem DII. 56,6% dos participantes eram do sexo feminino com idade média de 40,1 anos. 79,8% dos participantes eram caucasianos e originalmente eram cidadãos de 10 países. A prevalência relativa de DII foi maior em africanos e indianos e a prevalência mais frequente de intolerância a alimentos lácteos observada nos asiáticos. Entre os pacientes com DII, 571 casos foram diagnosticados como colite ulcerativa e 189 participantes como doença de Crohn. A duração média do diagnóstico como DII foi de 6,8 anos (de 2 meses a 35 anos). Os sintomas de gastrointestinais mais prevalentes após o consumo de todos os alimentos lácteos foram inchaço e dor abdominal. No total, a intolerância aos alimentos lácteos e a deficiência de lactase foi mais prevalente entre os pacientes com DII em comparação com os casos sem DII (65,5% vs 46,1%, P=0,0001). A taxa de queixas gastrointestinais entre os pacientes com DII que não tinham histórico familiar de deficiência de lactase, histórico de sensibilidade alimentar ou ambos foram de 59,91%, 52,87% e 50,33% respectivamente e semelhantes aos casos sem DII (P=0,68, 0,98 e 0,99, respectivamente). Conclusão: A taxa de intolerância de alimentos lácteos entre pacientes com DII sem histórico familiar de deficiência de lactase ou histórico de sensibilidade alimentar é semelhante aos casos sem DII e provavelmente não há razão para privá-los dessa importante fonte de cálcio dietético, vitamina D e outros nutrientes.

ABSTRACT Background: The role of dairy foods in inflammatory bowel disease (IBD) has been controversial and it is debatable if patients with IBD should avoid milk and dairy products or not, as well as the relationship between these foods and symptoms among those population. Objective: This multi centric cross-sectional study designed to evaluate if it is really necessary to deprive IBD patients from consumption of dairy foods. Methods: A multicenter study with 12 gastroenterology referral centers in four countries was designed to evaluate gastrointestinal (GI) symptoms after consumption of dairy foods from all outpatients with IBD during 6 months and to compare patients treated at the same centers without IBD (non IBD cases). Results: Overall 1888 cases included (872 IBD patients and 1016 non IBD cases). 56.6% of participants were female with average age of 40.1 years. Racially 79.8% participants were Caucasians and originally they were citizens of 10 countries. Relative prevalence of IBD was higher in Africans and Indians and the most frequent prevalence of dairy foods intolerance was seen in Asians. Among IBD patients, 571 cases diagnosed as ulcerative colitis and 189 participants as Crohn’s disease. Average duration of diagnosis as IBD was 6.8 years (from 2 months to 35 years). The most prevalent GI symptoms after consumption of all the dairy foods were bloating and abdominal pain. Totally, intolerance of dairy foods and lactase deficiency was more prevalent among IBD patients in comparison with non IBD cases (65.5% vs 46.1%, P=0.0001). But the rate of GI complains among IBD patients who had not any family history of lactase deficiency, history of food sensitivity or both were 59.91%, 52.87% & 50.33% respectively and similar to non IBD cases (P=0.68, 0.98 & 0.99 respectively). Conclusion: The rate of dairy foods intolerance among IBD patients without family history of lactase deficiency or history of food sensitivity is similar to non IBD cases and probably there is no reason to deprive them from this important source of dietary calcium, vitamin D and other nutrients.

ABSTRACT Introduction: The current coronavirus pandemic has greatly strained the limited resources that had previously maintained the sustainability of the high-cost cardiothoracic surgeries in low-income countries like Egypt. Methods: Hospital databases and patients’ records were reviewed to evaluate the impact of the pandemic on the workflow and waiting lists. Postoperative patients were contacted by telephone for follow-up, as well as preoperative patients whose operations were cancelled. Regular virtual meetings were held, and residents were asked to discuss the stresses, challenges, and their suggestions for the gradual resumption of services. Residents’ logbooks were evaluated to assess the disruption of the surgical exposure compared to 2019. Results: While thoracic surgeries have continued to thrive, cardiac surgeries have witnessed the worst consequences, including cancellation of all surgeries, expansion of waiting lists, patients’ non-compliance with follow-up, and impaired surgical exposure of junior residents. Conclusion: The gradual recovery of cardiac surgery services in Alexandria (Egypt) is being carefully planned, taking into consideration the backlog of cases and the shortage of screening kits. Careful tiering and triaging of patients by a multidisciplinary team, as well as seeking alternative assessment tools for trainees, are the main lines of our action plan.

ABSTRACT Background Peritoneal carcinomatosis (PC) is a lethal regional progression in patients with colorectal cancer (CRC). Treatment with complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) achieves better local control than systemic palliative chemotherapy. Objectives To assess the efficacy on the prognosis of CRS and HIPEC compared with CRS only and to identify possible clinicopathological factors associated with the recurrence of PC. Methods The present retrospective study included all colorectal carcinoma cases with PC subjected to CRS with or without HIPC from January 2009 to June 2018 at the National Cancer Institute (NCI), Cairo University, Cairo, Egypt. The outcome is evaluated in terms of recurrence-free survival (RFS) and its predictors. Results Out of the 61 patients, 45 patients (73.8%) underwent CRS plus HIPEC, and 16 (26.2%) underwent CRS alone. The 1-year RFS was 55.7%, with a median of 12 months. The risk factors for recurrence identified in the univariate analysis were T4 primary tumor, high-grade, positive lymphovascular invasion (LVI), positive extracapsular nodal spread, and patients treated with CRS only, without HIPEC. In the multivariate analysis, the independent risk factors for recurrence were high grade and patients treated with CRS only. Conclusion T4 primary tumor, high grade, positive LVI, and positive extracapsular nodal spread seemed to be important predictors of recurrence following the treatment of PC. Our study also demonstrated that the addition of HIPEC to CRS improved the RFS.

ABSTRACT A total of 593 samples of Lethrinus lentjan (Lacepede, 1802) were collected from the Red Sea, Jeddah, Saudi Arabia, to study their productive biology and spawning season of the local population. Sampling was carried out on a monthly basis for a period of one year. The monthly sex ratios indicated that females were dominant throughout the study period, with an overall male:female sex ratio of 1:7.98, although males were larger than females. The highest monthly performance maturation index (PMI), as well as the male and female gonadosomatic index (GSI) and ovarian maturation rate (OMR) were observed in February and March. Histological examination of the gonads confirmed the process of sexual transformation in this fish species, wherein individuals mature first as female, and then change sex to male (protogynous hermaphroditism). Histological sections also showed that the sexual maturation of males of L. lenjtan comprised three main stages, while the sexual development of females could be classified into four main stages. Extended spawning in the form of batches released during different months throughout the year were recorded for this fish species, with the main spawning season in February and March, and an additional, shorter spawning season in September.

Resumo Introdução e objetivos O termo colite inespecífica (CI) refere-se a uma condição inflamatória do cólon que microscopicamente não apresenta características de qualquer forma específica de colite; é comumente observada em relatórios patológicos de biópsias de colonoscopia. De fato, tem-se questionado se esta seria uma entidade patológica separada ou apenas um estágio intermediário no curso da DII. Este estudo foi realizado para estimar a prevalência de CI entre pacientes com colite e caracterizar seu curso durante um período de seis meses. Pacientes e métodos O estudo incluiu 80 pacientes adultos que se apresentaram para colonoscopia. Na análise, os pacientes foram divididos em dois grupos: grupo A (CI) e grupo B (DII) Todos os pacientes foram submetidos a anamnese completa, exame clínico completo e investigações laboratoriais que incluíram análise de fezes, PCR, VHS, colonoscopia completa e biópsias aleatórias de cólon para exame histopatológico. Resultados Do total de pacientes, 67 foram alocados no grupo A (83,75%) e 13 (16,25%) no grupo B. Os pacientes com DII apresentavam sinais clínicos e laboratoriais de inflamação significativamente maiores do que o observado em pacientes com CI. Seis pacientes (8,95%) do grupo CI desenvolveram características histológicas de DII florida após seis meses. Não foram identificados preditores independentes para essa conversão. Conclusão Entre os 80 pacientes submetidos a colonoscopia e biópsia, o diagnóstico de CI foi feito em 67 (83,75%); destes, seis pacientes (8,95%) foram reexaminados após seis meses e apresentaram DII, sendo que essa conversão não foi associada a fatores preditivos.

Abstract Background and study aim The term non-specific colitis refers to an inflammatory condition of the colon that microscopically lacks the characteristic features of any specific form of colitis and is commonly seen in pathology reports of colonoscopy biopsies. In fact, it has been questioned whether it is a separate pathological entity or it is merely an intermediate stage in the course of inflammatory bowel disease. This study was conducted to estimate the prevalence of non-specific colitis among patients with colitis and characterize its natural history over a 6 months year period. Patients and methods Eighty adult patients presented for colonoscopy were enrolled. In the final analysis they were divided into Group A; the non-specific colitis Group and Group B; the inflammatory bowel disease Group. All patients were subjected to: full history taking, full clinical examination, laboratory investigations: which included stool analysis, CRP, ESR, complete colonoscopy and entire random colon biopsies for histopathological examination. Results Group A included 67 patients (83.75%) while Group B included 13 (16.25%) patients. Patients with IBD had clinical and laboratory features of inflammation significantly higher than patients with non-specific colitis. Six patients (8.95%) of non-specific colitis group developed histologic features of florid inflammatory bowel disease after 6 months. There were no independent predictors of this conversion. Conclusion Among our 80 patients with colonoscopy and biopsy 67 (83.75%) were diagnosed as non-specific colitis and out of them 6 patients (8.95%) were reexamined after 6 months and proved to have inflammtory bowel disese this change was not linked to predictive factors.

Abstract The study aims to determine the dynamic properties of high volume fly ash nanosilica (HVFANS) concrete exposed to strain rates between 30.12 to 101.42 s-1 and temperatures of 25, 400, and 700 oC by using split Hopkinson pressure bar (SHPB) machine. The static and dynamic compressive strengths of HVFANS concrete were slightly lower than plain concrete (PC) at room temperature, while its values were higher at 400 and 700 o C. The results proved that the CEB model of dynamic increase factor is more reliable to estimate the behaviour of HVFANS concrete at studied temperatures. The toughness, critical strain, and damage of HVFANS concrete recorded a superior performance than PC under studied strain rates and temperatures that would reflect the possibility of use HVFANS concrete in structures to improve its resistant of fire and impact loads, as well as to decrease the demand on Portland cement which could lead to restrict the risks of liberated gases during cement production. Furthermore, equations were proposed to estimate the dynamic increase factor, toughness, and critical strain of both concretes under investigated conditions.

Abstract Aim: To investigate the effect of implant-abutment angulation and crown material on stress distribution of central incisors. Finite element method was used to simulate the clinical situation of a maxillary right central incisor restored by two different implant-abutment angulations, 15° and 25°, using two different crown materials (IPS E-Max CAD and zirconia). Methods: Two 3D finite element models were specially prepared for this research simulating the abutment angulations. Commercial engineering CAD/CAM package was used to model crown, implant abutment complex and bone (cortical and spongy) in 3D. Linear static analysis was performed by applying a 178 N oblique load. The obtained results were compared with former experimental results. Results: Implant Von Mises stress level was negligibly changed with increasing abutment angulation. The abutment with higher angulation is mechanically weaker and expected to fail at lower loading in comparison with the steeper one. Similarly, screw used with abutment angulation of 25° will fail at lower (about one-third) load value the failure load of similar screw used with abutment angulated by 15°. Conclusions: Bone (cortical and spongy) is insensitive to crown material. Increasing abutment angulation from 15° to 25°, increases stress on cortical bone by about 20% and reduces it by about 12% on spongy bone. Crown fracture resistance is dramatically reduced by increasing abutment angulation. Zirconia crown showed better performance than E-Max one.

Studying the flow patterns and behaviour of double baffled gates under different flow heads is important to improve their performance, which could help in widening the range of their application. In the present study, physical and numerical investigations were conducted on the double baffled gate. A 3D Acoustic Doppler Velocity Meter (ADV) was used for laboratory measurements of the instantaneous velocity fields in the physical gate model. In parallel with this, the CFD Fluent package was adopted to carry out a sensitivity analysis for a matrix of geometric parameters of the double baffled gate. The outcomes of the laboratory and CFD numerical investigations were incorporated in a spreadsheet with the purpose of informing the design of double baffled gates under conditions of non-submergence.

The methanolic extract of the root wood of Michelia compressa (Maxim.) Sargent showed cytotoxicity against MCF-7, NCI-H460 and SF-268 cancer cell lines. Bioassay-guided fractionation of the chloroform-soluble layer led to the isolation of costunohde and liriodenine with cytotoxic activities, along with the isolation of twenty-seven known compounds. The active costunohde existed as major constituent in this study.