Purpose The purpose of this paper is to investigate the rheological characteristics of graphene nanoplatelets (GNPs) and hybridized nanocomposite consisting of multi-walled carbon nanotubes (MWCNTs) and GNPs as an additive on lithium-based grease. The experiments of nanogrease are examined in different values of shear stress, apparent viscosity, temperature and shear rate using Brookfield Programmable Rheometer DV-III ULTRA and characterized by high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD). Design/methodology/approach First, GNPs was mixed well with lithium grease using mechanical stirring at 3,500 rpm for 15 min at room temperature to form a homogenous composite at different concentrations (0.5, 1, 1.5, 2 and 2.5 Wt.%). Afterwards, MWCNTs and GNPs are mixed and dispersed well in the lithium grease using a sonication path for 30 min and mechanical stirring at 3,500 rpm for 15 min at 28°C to form a homogenous nanocomposite. Findings The results indicated that 1 Wt.% of GNPs is the optimum concentration. Subsequently, the weight percentage of additives varying between MWCNTs and GNPs are tested, and the result indicate that the grease containing GNPs had a 75 per cent increase in shear stress and 93.7 per cent increase in apparent viscosity over ordinary grease. Originality/value This work describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.Purpose The purpose of this paper is to investigate the rheological characteristics of graphene nanoplatelets (GNPs) and hybridized nanocomposite consisting of multi-walled carbon nanotubes (MWCNTs) and GNPs as an additive on lithium-based grease. The experiments of nanogrease are examined in different values of shear stress, apparent viscosity, temperature and shear rate using Brookfield Programmable Rheometer DV-III ULTRA and characterized by high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD). Design/methodology/approach First, GNPs was mixed well with lithium grease using mechanical stirring at 3,500 rpm for 15 min at room temperature to form a homogenous composite at different concentrations (0.5, 1, 1.5, 2 and 2.5 Wt.%). Afterwards, MWCNTs and GNPs are mixed and dispersed well in the lithium grease using a sonication path for 30 min and mechanical stirring at 3,500 rpm for 15 min at 28°C to form a homogenous nanocomposite. Findings The results indicated that 1 Wt.% of GNPs is the optimum concentration. Subsequently, the weight percentage of additives varying between MWCNTs and GNPs are tested, and the result indicate that the grease containing GNPs had a 75 per cent increase in shear stress and 93.7 per cent increase in apparent viscosity over ordinary grease. Originality/value This work describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

OBJECTIVES: The aim of the present work was to explore the perspectives of Egyptian Rheumatology staff members as regards the coronavirus disease-19 (COVID-19) vaccine.

METHODS: The survey is composed of 25 questions. Some questions were adapted from the global rheumatology alliance COVID-19 survey for patients.

RESULTS: 187 rheumatology staff members across Egypt from 18 universities and authorizations actively participated with a valid response. The mean time needed to complete the survey was 17.7 ± 13 min. Participants were 159 (85%) females (F:M 5.7:1). One-third agreed that they will be vaccinated once available, 24.6% have already received at least one dose, 29.4% are unsure while 16% will not take it. Furthermore, 70.1% agreed that they will recommend it to the rheumatic diseases (RD) patients once available, 24.1% are not sure while 5.9% will not recommend it. RD priority to be vaccinated against COVID-19 in descending order include SLE (82.9%), RA (55.1%), vasculitis (51.3%), systemic sclerosis (39.6%), MCTD (31.6%), Behcet's disease (28.3%). The most common drugs to be avoided before vaccination included biologics (71.7%), DMARDs (44.4%), biosimilars (26.7%), IVIg (17.1%) and NSAIDs (9.1%).

CONCLUSIONS: The results of the study and specifically the low rate of acceptability are alarming to Egyptian health authorities and should stir further interventions to reduce the levels of vaccine hesitancy. As rheumatic disease patients in Egypt were not systematically provided with the vaccine till present, making the vaccine available could as well enhance vaccine acceptance. Further studies to investigate any possible side effects, on a large scale of RD patients are warranted.

Among 42 plant species representing the flora of north Sinai, two possessed sand grain sheath encasing the roots. They are Panicum turgidum Forssk. and Stipagrostis scoparia (Trin.and Rupr.) deWinter. Rhizosheaths, compared to surrounding free sand, accommodated higher population density of microorganisms including associative diazotrophs. Isolates secured belonged to the species of Bacillus circulans, Paenib. macerans (Bacillus macerans), Enterobacter agglomerans, Agrobacterium radiobacter and Chryseomonas luteola (Pseudomonos luteola). The rhizosheath potentiality in re-vegetating sand dunes and arid lands, through nitrogen fixation, plant-water relationship and root continuity for nutrient uptake, are discussed. © 2004 Elsevier GmbH. All rights reserved.

Abstract Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of inherited retinal degenerations that is estimated to affect more than 1.5 million people worldwide. RP is characterized by retinal pigment deposits visible on fundus examination, abnormal electroretinogram and progressive retinal dysfunction. The present work aimed to identify the possible mutations in the rhodopsin gene (RHO) among Egyptian RP patients as well as identifying the different inheritance patterns of those patients. Thirty diagnosed retinitis pigmentosa patients were enrolled in the study. Inheritance forms of RP were identified by recording full family history, the coding regions of the rhodopsin gene were sequenced using blood-derived genomic DNA samples donated by patients and fifteen healthy controls. A high percentage of autosomal recessive cases was reported. Also a high parental consanguinity rates were evident. Sequencing of rhodopsin gene revealed no mutations among the study population. Rhodopsin mutations are scarcely associated with the autosomal recessive RP, suggesting that wide scale studies are needed to determine the genetic variations involved in RP and particularly in the autosomal recessive inheritance.

OBJECTIVE: Inflammation has been associated with an increased risk for cancer development, while innate immune system activation could counteract the risk for malignancies. Familial Mediterranean fever (FMF) is a severe systemic inflammatory condition and also represents the archetype of innate immunity deregulation. Therefore, the aim of this study is to investigate the risk for cancer development in FMF.

METHODS: The risk ratio (RR) for malignancies was separately compared between FMF patients and fibromyalgia subjects, Still's disease patients and Behçet's disease patients. Clinical variables associated with cancer development in FMF patients were searched through binary logistic regression.

RESULTS: 580 FMF patients and 102 fibromyalgia subjects, 1012 Behçet's disease patients and 497 Still's disease patients were enrolled. The RR for the occurrence of malignant neoplasms was 0.26 (95% Confidence Interval [CI.] 0.10-0.73, p=0.006) in patients with FMF compared to fibromyalgia subjects; the RR for the occurrence of malignant cancer was 0.51 (95% CI. 0.23-1.16, =0.10) in FMF compared to Still's disease and 0.60 (95% CI. 0.29-1.28, =0.18) in FMF compared to Behçet's disease. At logistic regression, the risk of occurrence of malignant neoplasms in FMF patients was associated with the age at disease onset (β1 = 0.039, 95% CI. 0.001-0.071, =0.02), the age at the diagnosis (β1 = 0.048, 95% CI. 0.039-0.085, =0.006), the age at the enrolment (β1 = 0.05, 95% CI. 0.007-0.068, =0.01), the number of attacks per year (β1 = 0.011, 95% CI. 0.001- 0.019, =0.008), the use of biotechnological agents (β1 = 1.77, 95% CI. 0.43-3.19, =0.009), the use of anti-IL-1 agents (β1 = 2.089, 95% CI. 0.7-3.5, =0.002).

CONCLUSIONS: The risk for cancer is reduced in Caucasic FMF patients; however, when malignant neoplasms occur, this is more frequent in FMF cases suffering from a severe disease phenotype and presenting a colchicine-resistant disease.