The effect of change of direction angle on kneeand hip biomechanics : implications foranterior cruciate ligament injury

ACL injuries have been referred to poor mechanics as they frequently occur without contact. Changes in the knee valgus (abduction) angle and knee valgus (external abduction) moment and limb asymmetry have been linked to greater risk of ACLinjury. Change of direction (COD) manoeuvres are important for many field sports, however they are unfortunately associated with non-contact anterior cruciate ligament (ACL) injuries. There is limited literature exploring the associations between lower-limb biomechanical variables during COD manoeuvre associated with ACL injuries. Although players frequently COD at >90° angles, limited knowledge is available on hip and knee joints kinematics and kinetics in term of limb asymmetry and differences between COD at 90° and 135° manoeuvres. In addition, high knee valgus angle and moment during COD manoeuvre is associated with joint positions including increased hip flexion, abduction and internal rotation angles. In addition, isometric hip muscle strength has been reported to predict ACL injuries, indicating that weakness in hip muscles is a modifiable risk factor of the non-contact ACLinjury. However, the relationship between knee valgus angle and moment with hip kinematics and muscle strength during COD at 90° and 135° manoeuvres still unknown. Currently, there has been no published research correlating the hip abductor, extensor, and external rotator strength on frontal plane hip and knee biomechanics during 90° and 135° COD manoeuvres. Therefore, the purposes of this thesis was to (1) determine whether asymmetry in knee and hip biomechanics kinematics and kinetics and hip muscle strength between preferred and nonpreferred limbs during COD manoeuvres at 90° and 135° angles exists, (2)determine whether differences in knee and hip biomechanics kinematics and kinetics between COD manoeuvres at 90° and 135° angles exists and (3) explore the relationships between ACL injury risk factors (knee valgus angle and moment) and hip kinematics and muscles strength during 90° and 135° COD manoeuvres.Three-dimensional (3D) motion analysis technique is a gold stander to assess biomechanical lower-limb during functional activities. In fact, the gold standard for examining lower limb biomechanics is 3D motion analysis system and allows researchers to calculate all three motion planes during dynamic manoeuvres. Inaddition, the isokinetic dynamometer has been considered as a gold standard measurement tool for assessing isometric hip muscle strength and become more popular in sport, research and clinic setting. Healthy male recreational soccer players performed COD manoeuvres at 90° and 135° angles and maximal voluntaryisometric contractions of the hip abductors, extensors, and external rotators. From recorded motion capture, ground reaction force data and hip and knee biomechanics as well as, hip muscles peak torque were calculated. To determine limb asymmetry,a paired sample t-test was conducted using a Holm method correction. Then, pearson’s correlation coefficient (r) was used to explore the relationships between hip kinematics and strength and knee valgus angle and moment. 36 individuals took part in the study (24.25 ±6.21 years, 1.72 ±0.06 m and 66.41 ±10.83 kg). At 135° COD, participants showed greater knee valgus angles at initialcontact and greater peak external knee abduction moments than at 90°. However, no effect of COD angles on knee flexion angle and peak vGRF were found. The results suggest that there were no differences between preferred and non-preferred limbs. Furthermore, the results highlight an important role the hip motion play in controlling kinematic and kinetic risk factors of ACL injury during COD manoeuvres. The findings provided some support that excessive knee valgus angle and moment is potentially associated with poor hip control in all planes. However, there were nosignificant correlation between hip muscles strength and knee frontal plane kinetics and kinematics. It can be concluded that different COD angles demand different hip and knee kinematics and kinetics. The results suggest that sharper COD angle place the knee at more risk for ACL injuries. COD manoeuvres at 90° may be useful for evaluating of individuals but may not be challenging enough to reveal poor neuromuscular control over hip and knee motion. Therefore, sharper angles of examination should be utilized in the evaluation of individuals. Moreover, these results may help provide an appropriate manipulation and intervention on COD manoeuvre to reduce the risk of ACL injury. The findings of this study will increase the knowledge base of ACL injury and can aid in the design of more appropriate neuromuscular and plyometrictraining protocols for injury prevention

Myopia progression in school children with prolonged screen time during the coronavirus disease confinement

Background: Myopia, the most common refractive error, is a global public health problem with substantial visual impairment if left untreated. Several studies have investigated the association between increased near-work and restricted outdoor activities in children with myopia; however, such studies in children without myopia are scarce. We aimed to monitor the effect of the coronavirus disease-2019 (COVID-19) home confinement and mandatory virtual learning on myopic progression among myopic and non-myopic school-aged children. Methods: We conducted a retrospective chart review of children aged 6 – 12 years attending regular visits to the pediatric ophthalmology clinic in a tertiary eye hospital in Eastern Province, Saudi Arabia. Cycloplegic refraction was determined from three visits at least six months apart: two visits before the start of the COVID-19 pandemic and one during the COVID-19 home confinement. Parents were asked about the time spent in near-work and outdoor activities, the devices used during virtual learning, and the demographic characteristics of the children. Statistical analyses were conducted to compare myopia progression before and during the COVID-19 home confinement. Results: A total of 160 eyes of 80 children were analyzed. The boy (n = 46) to girl (n = 34) ratio was 1.4:1. The hyperopia (n = 131 eyes) to myopia (n = 29 eyes) ratio was 4.5:1. Most eyes exhibited a hyperopic shift before the confinement; however, all eyes displayed a myopic shift during the confinement. When comparing both eyes of the same individual, the more myopic or less hyperopic eye in the same child had a significantly greater myopic shift than the fellow eye (both P < 0.05). Children who used tablets showed a significant myopic shift (P < 0.05). Likewise, children in both age categories (less than or equal to 8 and > 8 years), boys, those living in an apartment, and those having parents with bachelor’s degrees experienced a significant myopic shift during COVID-19 home confinement compared to before (all P < 0.05). The mean myopic shift was greater in children aged > 8 years than in those aged less than or equal to 8 years. Children with and without a family history of myopia had a myopic shift in the mean spherical equivalent during COVID-19 home confinement; however, that of children with no family history was statistically significant (P < 0.05). Conclusions: Progression of myopia accelerated in children during the COVID-19 pandemic. Excessive time spent on digital screen devices at near distances is considered a substantial environmental contributor to myopic shift in children. Further multicenter studies with extended follow-up periods are needed to assess the factors contributing to myopic progression in our population

What do non-ophthalmic health professionals know about retinoblastoma: a survey in Saudi Arabia

Background: The aim of the study is to estimate the level of knowledge about retinoblastoma (Rb) and its determinants among non-ophthalmic health professionals of Qassim region of Saudi Arabia.Methods: This cross-sectional survey was held in 2016 in primary health centres (PHC) and general hospitals in the study area. In addition to demography like age, gender, education, place of work, participants replied to five questions related to Rb with close-ended questions to respond. They were matched to the expert group's answers to estimate the level of knowledge.Results: One hundred and fifty-two non-ophthalmic doctors participated in the survey. The excellent grade of knowledge of Rb was in 66 [43.3% (95% confidence interval 35.5-51.3)] of participants. Very poor level of knowledge was noted in 13 [8.6% (95% CI 4.1-13.0)] participants. Male gender (P = 0.02) and physician category (P = 0.02) were significantly associated with the excellent grade of Rb related knowledge. The participant’s response by type of questions varied significantly (P<0.001).Conclusions: More than half of the non-ophthalmic health professionals had less than desired knowledge about Rb. Health education about Rb to health professionals could be gender sensitive and based on the type of profession. Increasing the awareness about retinoblastoma among non-ophthalmic health professional is important

The reliability of lower limb 3D gait analysis variables during a change of direction to 90- and 135-degree manoeuvres in recreational soccer players

Several biomechanical outcomes are being used to monitor the risk of injuries; therefore, their reliability and measurement errors need to be known. To measure the reliability and measurement error in lower limb 3D gait analysis outcomes during a 90∘ and 135∘ change of direction (COD) manoeuvre. A test re-test reliability study for ten healthy recreational players was conducted at seven-day intervals. Kinematics (Hip flexion, adduction, internal rotation angles and knee flexion abduction angles) and kinetics (Knee abduction moment and vertical ground reaction force) data during cutting 90∘ and 135∘ were collected using 3D gait analysis and force platform. Five trials for each task and leg were collected. Standard error of measurement (SEM) and the intraclass correlation coefficient (ICC) were calculated form the randomised leg. The ICC values of the kinematics, kinetics, and vertical ground reaction force (VGRF) outcomes (90∘ and 135∘) ranged from 0.85 to 0.95, showing good to excellent reliability. The SEM for joint angles was less than 1.69∘. The VGRV showed a higher ICC value than the other outcomes. The current study results support the use of kinematics, kinetics, and VGRF outcomes for the assessment of knee ACL risk in clinic or research. However, the hip internal rotation angle should be treated with caution since the standard measurement error exceeded 10% compared to the mean value. The measurement errors provided in the current study are valuable for future studies

Glycine-betaine induced salinity tolerance in maize by regulating the physiological attributes, antioxidant defense system and ionic homeostasis

The plants are exposed to different abiotic stresses, including the salinity stress (SS) that negatively affect the growth, metabolism, physiological and biochemical processes. Thus, this study investigated the effect of diverse levels of foliar-applied GB (0 control, 50 mM and 100 mM) on maize growth, membrane stability, physiological and biochemical attributes, antioxidant enzymes and nutrients accumulation under different levels of SS (i.e., control, 6 dS m-1, 12 dS m-1). Salt stress diminished the root and shoot length, root and shoot biomass, chlorophyll contents, photosynthetic rate (Pn), stomatal conductance (gs), relative water contents (RWC), soluble proteins (SP) and free amino acids; (FAA); and increased activities of antioxidant enzymes, electrical conductivity (EC) and accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), Na+ and Cl− ions. GB application significantly increased root and shoot growth, leaves per plant, shoots length, chlorophyll contents, gs, Pn and membrane stability by reducing MDA and H2O2 accumulation. Moreover, GB also increased the SP, FAA accumulation, activities of antioxidant enzymes and Na+ and Cl- exclusion by favouring Ca2+ and K+ accumulation. In conclusion, the foliar-applied GB increased Pn, gs, ant-oxidants activities, and accumulation of SP and FAA; and reduced the accretion of Na+ and Cl− by favouring the Ca2+ and K+ accretion which in turns improved growth under SS

Challenges of Autism Spectrum Disorders Families Towards Oral Health Care in Kingdom of Saudi Arabia

Objective: To assess the knowledge, attitudes, and practice regarding oral health care among parents of autistic children and also the challenges faced by them in providing dental care for their Autism Spectrum Disorders (ASD) children’s in four regions of Kingdom of Saudi Arabia. Material and Methods:&nbsp; In total, 263 parents of autistic children participated in this cross-sectional study who were enrolled from 4 major regions of Kingdom of Saudi Arabia. A self-administered questionnaire formulated in simple Arabic was distributed to parents of children diagnosed with autism or any form of ASD. The questionnaires consisted of demographic questions and also to assess their knowledge on oral health, child’s oral hygiene practices and visits to their dentist, oral hygiene, experience and challenges in waiting room area before the dental treatment, acceptance of treatment or rejection, accessibility to find non-dental centers either government or private for treatment and their recommendations. Results: All the parents brushed their child’s teeth using a toothbrush and fluoridated toothpaste. A total of 29.7% of the parents informed that their child never brushes teeth. A total of 41.4% of the parents visit the dental clinic when the child complains about dental problems and 54% find difficulty in locating appropriate dental clinic to deal with their ASD children. Most parents reported taking their child to a private office (38.8%). Only 3.8% of parents reported that their children had seizures during dental procedures. Conclusion:&nbsp; The knowledge toward oral health was found to be inadequate among the majority of the parents. Parents of ASD children need to be educated about the consequences of oral health neglect and the importance of regular check-ups

Langerhans cell histiocytosis presenting as a blueberry muffin rash

Langerhans cells, often referred to as the “macrophages of the skin”, are dendritic cells that normally reside in the epidermis and papillary dermis. Just like macrophages, they function as antigen-presenting cells that activate naive T cells. Certain mutations such as those involving the BRAF gene can cause unopposed production of Langerhans Cells, which is known as Langerhans Cell Histiocytosis (LCH). LCH triggers an inflammatory immune response that causes systemic manifestations such as fever and fatigue, as well as other manifestations depending on the affected organs. The pathogenesis behind LCH remains poorly understood. It is still unknown whether it is a neoplastic process or a reactive cancer-mimicking illness. Diagnosis of LCH is confirmed by biopsy, and treatment is largely dependent on the extent and severity of the disease. Common treatments include corticosteroids, excision, radiation, and chemotherapy. We present a case of a 1-year-old Saudi male with LCH

Enhancing antioxidant defense system of mung bean with a salicylic acid exogenous application to mitigate cadmium toxicity

Cadmium (Cd) accumulation is an emerging environmental hazard and has detrimental effects on plant growth and development. Salicylic acid (SA) is a well-known plant growth regulator that can initiate various molecular pathways to ameliorate Cd toxicity. The experiment was executed to scrutinize the mediatory role of SA to accelerate the defensive mechanism of mung bean in response to Cd stress. Mung bean plants were exposed to 0, 5, 10 and 15 mg Cd kg-1 of soil. Exogenous application of SA 0, 10-6 and 10-3 M was added prior flowering. Results exhibited that Cd stress considerably reduced the growth-related attributes i.e. shoot length, root length, fresh and dry biomass, total soluble protein, total amino acids, relative water contents and photosynthetic pigments. Cadmium stress showed a significant increase in antioxidants levels such as peroxidase (POD), ascorbate peroxidase (APX), ascorbic acid (AsA), and catalase (CAT) and promoted the accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. However, exogenously applied SA significantly improved plant biomass and photosynthetic pigments under Cd stress. Moreover, SA improved the defensive system by enhancing antioxidants’ activities under the increasing concentration of Cd stress. Furthermore, SA reduced the Cd uptake, membrane damage and, H2O2 and MDA accumulation. The study's findings concluded that exogenous-applied SA enhanced plant growth, promoted the antioxidant activities, and reduced the oxidative damage in mung bean seedlings under Cd stress

CleanET: enabling timing validation for complex automotive systems

Timing validation for automotive systems occurs in late integration stages when it is hard to control how the instances of software tasks overlap in time. To make things worse, in complex software systems, like those for autonomous driving, tasks schedule has a strong event-driven nature, which further complicates relating those task-overlapping scenarios (TOS) captured during the software timing budgeting and those observed during validation phases. This paper proposes CleanET, an approach to derive the dilation factor r caused due to the simultaneous execution of multiple tasks. To that end, CleanET builds on the captured TOS during testing and predicts how tasks execution time react under untested TOS (e.g. full overlap), hence acting as a mean of robust testing. CleanET also provides additional evidence for certification about the derived timing budgets for every task. We apply CleanET to a commercial autonomous driving framework, Apollo, where task measurements can only be reasonably collected under 'arbitrary' TOS. Our results show that CleanET successfully derives the dilation factor and allows assessing whether execution times for the different tasks adhere to their respective deadlines for unobserved scenarios.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under grant TIN2015- 65316-P, the SuPerCom European Research Council (ERC) project under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 772773), and the HiPEAC Network of Excellence. MINECO partially supported Jaume Abella under Ramon y Cajal postdoctoral fellowship (RYC-2013-14717).Peer ReviewedPostprint (author's final draft