Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
10 result(s) for "Kishk, Ahmed Mustafa"
Sort by:
Combined transcranial and sacral magnetic stimulation in primary monosymptomatic nocturnal enuresis: a randomized controlled study
BackgroundPrimary nocturnal enuresis (PNE) is defined as recurrent voiding of urine into bed or clothing, causing distress or impairment in social, academic, or other critical areas. Despite neuroimaging data and brain models, targeted therapeutic approaches are lacking. Magnetic stimulation, including transcranial and direct sacral stimulation, could be a potential treatment for nocturnal enuresis. Results40 patients with PNE were recruited and randomly distributed into 2 groups. Group (I): 22 patients received real magnetic stimulation (transcranial and direct sacral root stimulation) and Group (II): 18 patients received sham stimulation as a control group. Patients were evaluated before, immediately after the sessions, 1 and 3 months after sessions, assessing frequency of wet nights, quality of life according to International Consultation on Incontinence Questionnaire–Lower Urinary Tract Symptom Quality of Life (ICIQ–LUTS qol) score and motor threshold (MT) as a measure for brain excitability and neuronal integrity. There was a substantial reduction in the frequency of wet nights per week for the treatment group compared to the control group, with a significant difference observed after 1 month (P value 0.086) and 3 months (P value < 0.001). MT assessment showed alterations in cortical excitability, with a significant difference observed at dates 2, 3 (P value 0.044, < 0.001). The clinical improvement was associated with correlated improvement in the quality of life, although it was not significantly observed immediately after the sessions. The International Children’s Continence Society (ICCS) criteria response rate showed a higher response rate for the real stimulation with no significant adverse effects. ConclusionsThe research highlights the effectiveness and safety of using both transcranial and sacral magnetic stimulation in treating pediatric patients with PMNE. To maximize therapeutic success in this patient population, more research is required to clarify the mechanisms of action and improve therapy regimens.
Olfactory dysfunction in essential tremor versus tremor dominant Parkinson disease
•Essential tremor and tremor dominant Parkinson disease variant constitute the main causes of geriatric tremor.•Olfactory dysfunction is a consistent non-motor manifestations (NMM) of PD and and additional sign in ET patients.•Sniffin’ Sticks test as well as Olfactory bulb volume are valuable biomarkers that differentiate doubtful TDPD and ET cases. Essential tremor (ET) and tremor dominant Parkinson disease (TDPD) variant constitute the main causes of geriatric tremor which differentiation is not always an easy mission. The objective of this work was to study the olfactory performance in ET and PD patients for possible consideration as a differentiating biomarker. This study was performed on 36ET, 22 TDPD variant and 24 healthy controls subjects (HCS) submitted to extended n-butanol Sniffin’ Sticks test (SST) and olfactory bulbs volumetry (OBV). There were significant decreases in SST threshold, discrimination, identification and TDI variables in TDPD patients compared to ET and HCS. ET patients showed significant decrease in the same variables compared to HCS. Regarding OBV, there were significant decreases in TDPD patients compared to ET and HCS with nonsignificant difference between the 2-latter groups. Our results showed that TDI score of 25 can differentiate between TDPD and ET patients with sensitivity and specificity (94 %, 91 %) respectively. Olfactory assessment is a rapid, safe, and easily applicable biomarker that could differentiate TDPD from ET in doubtful cases.
Spontaneous posterior fossa hemorrhage: profile and functional outcome in patients attending Tanta stroke unit
BackgroundThe most dangerous and least curable type of stroke is spontaneous intracerebral hemorrhage (ICH), and prognosis is highly correlated with location and size in the posterior fossa. The objective of this work was to estimate the frequency of posterior fossa hemorrhage (PFH) in Tanta University Hospitals, as well as identify functional outcomes and mortality in PFH.MethodsThis study was performed on 33 posterior fossa hemorrhagic patients and 119 posterior ischemic stroke patients (PCIS) submitted to the CT brain and the MRI brain, using the following scales: GCS and NIHSS, and the intracerebral hemorrhage scale (ICH score).ResultsPosterior fossa hemorrhage (PFH) represents 16.83% of total hemorrhagic stroke in the ER. Vertigo and DCL are more common in PFH (60.6%, 48.4%) than in PCIS. 82% of PFH patients had hypertension (HTN) hemorrhage. The cerebellum is the most common site for PFH (48%), pontine (24%), thalamic (18%), and midbrain (9%). PFH had unfavorable outcomes in 55% of the studied patients; the MRS mean was 4; and 39% died in the follow-up.ConclusionPosterior fossa hemorrhage is a potentially serious neurovascular emergency associated with complex symptomatology. PFH demonstrates diverse prognoses depending on the location of the intracerebral hemorrhage and the size of the hematoma.
Insights into Bacterial Community Involved in Bioremediation of Aged Oil-Contaminated Soil in Arid Environment
Soil contamination by hydrocarbons due to oil spills has become a global concern and it has more implications in oil producing regions. Biostimulation is considered as one of the promising remediation techniques that can be adopted to enhance the rate of degradation of crude oil. The soil microbial consortia play a critical role in governing the biodegradation of total petroleum hydrocarbons (TPHs), in particular polycyclic aromatic hydrocarbons (PAHs). In this study, the degradation pattern of TPHs and PAHs of Kuwait soil biopiles was measured at three-month intervals. Then, the microbial consortium associated with oil degradation at each interval was revealed through 16S rRNA based next generation sequencing. Rapid degradation of TPHs and most of the PAHs was noticed at the first 3 months of biostimulation with a degradation rate of pyrene significantly higher compared to other PAHs counterparts. The taxonomic profiling of individual stages of remediation revealed that, biostimulation of the investigated soil favored the growth of Proteobacteria, Alphaprotobacteria, Chloroflexi, Chlorobi, and Acidobacteria groups. These findings provide a key step towards the restoration of oil-contaminated lands in the arid environment.
Joint Uplink and Downlink EMF Exposure: Performance Analysis and Design Insights
Installing more base stations (BSs) into the existing cellular infrastructure is an essential way to provide greater network capacity and higher data rate in the 5th-generation cellular networks (5G). However, a non-negligible amount of population is concerned that such network densification will generate a notable increase in exposure to electric and magnetic fields (EMF) over the territory. In this paper, we analyze the downlink, uplink, and joint downlink&uplink exposure induced by the radiation from BSs and personal user equipment (UE), respectively, in terms of the received power density and exposure index. In our analysis, we consider the EMF restrictions set by the regulatory authorities such as the minimum distance between restricted areas (e.g., schools and hospitals) and BSs, and the maximum permitted exposure. Exploiting tools from stochastic geometry, mathematical expressions for the coverage probability and statistical EMF exposure are derived and validated. Tuning the system parameters such as the BS density and the minimum distance from a BS to restricted areas, we show a trade-off between reducing the population's exposure to EMF and enhancing the network coverage performance. Then, we formulate optimization problems to maximize the performance of the EMF-aware cellular network while ensuring that the EMF exposure complies with the standard regulation limits with high probability. For instance, the exposure from BSs is two orders of magnitude less than the maximum permissible level when the density of BSs is less than 20 BSs/km2.
Joint Coverage and Electromagnetic Field Exposure Analysis in Downlink and Uplink for RIS-assisted Networks
Reconfigurable intelligent surfaces (RISs) have shown the potential to improve signal-to-interference-plus-noise ratio (SINR) related coverage, especially at high-frequency communications. However, assessing electromagnetic filed exposure (EMFE) and establishing EMFE regulations in RIS-assisted large-scale networks are still open issues. This paper proposes a framework to characterize SINR and EMFE in such networks for downlink and uplink scenarios. Particularly, we carefully consider the association rule with the presence of RISs, accurate antenna pattern at base stations (BSs), fading model, and power control mechanism at mobile devices in the system model. Under the proposed framework, we derive the marginal and joint distributions of SINR and EMFE in downlink and uplink, respectively. The first moment of EMFE is also provided. Additionally, we design the compliance distance (CD) between a BS/RIS and a user to comply with the EMFE regulations. To facilitate efficient identification, we further provide approximate closed-form expressions for CDs. From numerical results of the marginal distributions, we find that in the downlink scenario, deploying RISs may not always be beneficial, as the improved SINR comes at the cost of increased EMFE. However, in the uplink scenario, RIS deployment is promising to enhance coverage while still maintaining EMFE compliance. By simultaneously evaluating coverage and compliance metrics through joint distributions, we demonstrate the feasibility of RISs in improving uplink and downlink performance. Insights from this framework can contribute to establishing EMFE guidelines and achieving a balance between coverage and compliance when deploying RISs.
Unveiling Passive and Active EMF Exposure in Large-Scale Cellular Networks
With the development of fifth-generation (5G) networks, the number of user equipments (UE) increases dramatically. However, the potential health risks from electromagnetic fields (EMF) tend to be a public concern. Generally, EMF exposure-related analysis mainly considers the passive exposure from base stations (BSs) and active exposure that results from the user's personal devices while communicating. However, the passive radiation that is generated by nearby devices of other users is typically ignored. In fact, with the increase in the density of UE, their passive exposure to human bodies can no longer be ignored. In this work, we propose a stochastic geometry framework to analyze the EMF exposure from active and passive radiation sources. In particular, considering a typical user, we account for their exposure to EMF from BSs, their own UE, and other UE. We derive the distribution of the Exposure index (EI) and the coverage probability for two typical models for spatial distributions of UE, i.e., \\textit{i)} a Poisson point process (PPP); \\textit{ii)} a Matern cluster process. Also, we show the trade-off between the EMF exposure and the coverage probability. Our numerical results suggest that the passive exposure from other users is non-negligible compared to the exposure from BSs when user density is \\(10^2\\) times higher than BS density, and non-negligible compared to active exposure from the user's own UE when user density is \\(10^5\\) times the BS density.
Aerial Base Stations Deployment in 6G Cellular Networks using Tethered Drones: The Mobility and Endurance Trade-off
Airborne base stations (carried by drones) have a great potential to enhance coverage and capacity of cellular networks. Multiple scenarios and use cases will highly benefit from such technology such as (i) offloading terrestrial base stations (BSs) in dense and urban areas, and (ii) providing coverage for rural areas. However, one of the main challenges facing the deployment of airborne BSs is the limited available energy at the drone, which limits the flight time. In fact, most of the currently used unmanned aerial vehicles (UAVs) can only operate for one hour maximum. This limits the performance of the UAV-enabled cellular network due to the need to frequently visit the ground station to recharge, leaving the UAV's coverage area temporarily out of service. In this article, we propose a new UAV-enabled cellular network setup based on tethered UAVs (TUAVs). In the proposed setup, the TUAV is connected to a ground station (GS) through a tether, which provides the TUAV with both energy and data. This enables a flight that can stay for days. We describe in detail the components of the proposed system. Furthermore, we enlist the main advantages of a TUAV-enabled cellular network compared to typical untethered UAVs. Next, we discuss the potential applications and use cases for TUAVs. Finally, we discuss the challenges, design considerations, and future research directions to realize the proposed setup.
On the 3-D Placement of Airborne Base Stations Using Tethered UAVs
One of the main challenges slowing the deployment of airborne base stations (BSs) using unmanned aerial vehicles (UAVs) is the limited on-board energy and flight time. One potential solution to such problem, is to provide the UAV with power supply through a tether that connects the UAV to the ground. In this paper, we study the optimal placement of tethered UAVs (TUAVs) to minimize the average path-loss between the TUAV and a receiver located on the ground. Given that the tether has a maximum length, and the launching point of the TUAV (the starting point of the tether) is placed on a rooftop, the TUAV is only allowed to hover within a specific hovering region. Beside the maximum tether length, this hovering region also depends on the heights of the buildings surrounding the rooftop, which requires the inclination angle of the tether not to be below a given minimum value, in order to avoid tangling and ensure safety. We first formulate the optimization problem for such setup and provide some useful insights on its solution. Next, we derive upper and lower bounds for the optimal values of the tether length and inclination angle. We also propose a suboptimal closed-form solution for the tether length and its inclination angle that is based on maximizing the line-of-sight probability. Finally, we derive the probability distribution of the minimum inclination angle of the tether length. We show that its mean value varies depending on the environment from 10 degrees in suburban environments to 31 degrees in high rise urban environments. Our numerical results show that the derived upper and lower bounds on the optimal values of the tether length and inclination angle lead to tight suboptimal values of the average path-loss that are only 0-3 dBs above the minimum value.
On the Capacity of the Underwater Acoustic Channel with Dominant Noise Sources
This paper provides an upper-bound for the capacity of the underwater acoustic (UWA) channel with dominant noise sources and generalized fading environments. Previous works have shown that UWA channel noise statistics are not necessary Gaussian, especially in a shallow water environment which is dominated by impulsive noise sources. In this case, noise is best represented by the Generalized Gaussian (GG) noise model with a shaping parameter \\(\\beta\\). On the other hand, fading in the UWA channel is generally represented using an \\(\\alpha\\)-\\(\\mu\\) distribution, which is a generalization of a wide range of well known fading distributions. We show that the Additive White Generalized Gaussian Noise (AWGGN) channel capacity is upper bounded by the AWGN capacity in addition to a constant gap of \\(\\frac{1}{2} \\log \\left(\\frac{\\beta^{2} \\pi e^{1-\\frac{2}{\\beta}} \\Gamma(\\frac{3}{\\beta})}{2(\\Gamma(\\frac{1}{\\beta}))^{3}} \\right)\\) bits. The same gap also exists when characterizing the ergodic capacity of AWGGN channels with \\(\\alpha\\)-\\(\\mu\\) fading compared to the faded AWGN channel capacity. We justify our results by revisiting the sphere-packing problem, which represents a geometric interpertation of the channel capacity. Moreover, UWA channel secrecy rates are characterized and the dependency of UWA channel secrecy on the shaping parameters of the legitimate and eavesdropper channels is highlighted.