COVID-19 and Diabetes Mellitus: A Complex Interplay

COVID-19 pandemic, which caused by the newly emerged severe acute respiratory syndrome coronavirus-2 (SARS- CoV-2), puts the entire world in an unprecedented crisis, leaving behind huge human losses and serious socio-economical damages. The clinical spectrum of COVID-19 varies from asymptomatic to multi-organ manifestations. Diabetes mellitus (DM) is a chronic inflammatory condition, which associated with metabolic and vascular abnormalities, increases the risk for SARS-CoV-2 infection, severity and mortality. Due to global prevalence, DM effect on COVID-19 outcomes as well as the potential mechanisms by which DM modulates the host-viral interactions and host-immune responses are discussed in this review. This review also highlights the effects of anti-diabetic drugs on treatment of SARS-CoV-2 infection and vice versa.

Linking the Rapid Cascade of Visuo-Attentional Processes to Successful Memory Encoding

While it is broadly accepted that attention modulates memory, the contribution of specific rapid attentional processes to successful encoding is largely unknown. To investigate this issue, we leveraged the high temporal resolution of electroencephalographic recordings to directly link a cascade of visuo-attentional neural processes to successful encoding: namely (1) the N2pc (peaking ~200 ms), which reflects stimulus-specific attentional orienting and allocation, (2) the sustained posterior-contralateral negativity (post-N2pc), which has been associated with sustained visual processing, (3) the contralateral reduction in oscillatory alpha power (contralateral reduction in alpha > 200 ms), which has also been independently related to attentionally sustained visual processing. Each of these visuo-attentional processes was robustly predictive of successful encoding, and, moreover, each enhanced memory independently of the classic, longer-latency, conceptually related, difference-due-to memory (Dm) effect. Early latency midfrontal theta power also promoted successful encoding, with at least part of this influence being mediated by the later latency Dm effect. These findings markedly expand current knowledge by helping to elucidate the intimate relationship between attentional modulations of perceptual processing and effective encoding for later memory retrieval.

The effect of dark matter on stars at the Galactic center: The paradox of youth problem

Stars that evolve near the Galactic massive black hole show strange behaviors. The spectroscopic features of these stars show that they must be old. But their luminosities are much higher than the amounts that are predicted by the current stellar evolutionary models, which means that they must be active and young stars. In fact, this group of stars shows signatures of old and young stars, simultaneously. This is a paradox known as the “paradox of youth problem” (PYP). Some people tried to solve the PYP without supposing dark matter (DM) effects on stars. But, in this work, we implemented Weakly Interacting Massive Particles (WIMPs) annihilation as a new source of energy inside such stars. This implementation is logical for stars that evolve at high DM density environments. The new source of energy causes stars to follow different evolutionary paths on the H-R diagram in comparison with classical stellar evolutionary models. Increasing DM density in stellar evolutionary simulations causes the deviations from the standard H-R diagrams becomes more pronounced. By investigating the effects of WIMPs density on stellar structures and evolutions, we concluded that by considering DM effects on stars at the Galactic center, it is possible to solve the PYP. In addition to DM effect, complete solutions to PYP must consider all extreme and unique physical conditions that are present near the Galactic massive black hole.

Diabetic Patients Knowledge and Practice Regarding Annual Visual Checking

Background: Diabetes mellitus (DM) is a significant cause of visual impairment; many diabetics do not have regular eye examinations, although it is known that early diagnosis and reduces the risk of blindness. There were many barriers that prevent diabetics from attending eye clinics. Objectives: To assess knowledge, and practice about ocular complications among diabetic patients and to determine barriers preventing the diabetic patients annual visual checking Methods: A cross-sectional study involving the interview was conducted among 300 diabetic patients attending out patient in Ibn Al Haitham Teaching Ophthalmology Hospital between November 2017 and June 2018. Results: The vast majority of patients (95%) believe that; diabetes could affect their eyes. 67% have their eyes checked up after being diagnosed with diabetes, of which only 33% they examined their eyes if vision got poor. Majority of patients believe that; controlling their blood sugar levels can help preserve their vision (84%). 72% of the total has good knowledge of DM effect on the eye. 55% of patients obtained their knowledge from the doctor and only 2% having obtained this knowledge from Television. Unfortunately only 3% of them check their vision annually 37 % they don’t know treatments available for diabetic retinopathy. Conclusion: Diabetic patients’ knowledge of ocular manifestations and the practice of diabetic patients towards eye examination were low, thus required to improve practice towards eye care to prevent visual impairment.

Ferroelectricity and magnetic orderings in Delafossite family compounds

Since discovery of the ferroelectric polarization induced by magnetic field in CuFeO2, delafossite family compounds have attracted much attention, because some theoretical formula, which had been presented, could not explain the ferroelectric polarization of CuFeO2. We have been investigating correlation among their magnetic orderings, lattice symmetry and ferroelectric polarization in AFeO2 (A=Cu, Ag, Na) systems. In CuFeO2, the ferroelectric polarization is induced by chemical substitutions for Fe sites in CuFe1-xBxO2 (B=Al, Ga, Rh, Mn) as well as magnetic field. The magnetic structure in the ferroelectric phase is proper screw type with magnetic point group 21' determined by the neutron diffraction experiments.[1] The ferroelectric polarization parallel to the propagation vector in CuFeO2 can be explained by both extended inverse-Dzyaloshinsky-Moriya(DM) effect and d-p hybridization mechanism. We have also demonstrated that the spin-orbit interaction in Fe ions, coupling spin and orbital orders, plays a crucial role to the ferroelectricity in both of which break the crystal symmetry, by observing incommensurate 2q orbital modulation in the ferroelectric phase of CuFe1-xGaO2 by soft X-ray resonant diffraction.[2] When nonmagnetic Cu ions on A-site are substituted by Ag or Na ions, the magnetic orderings are completely modified from CuFeO2. In AgFeO2, cycloid type magnetic structure with m1' point group is stabilized, which is concomitant with ferroelectric polarization, as the lowest temperature phase in zero-field.[3] Also in alpha-NaFeO2, the other type of cycloidal ordering (m1') appears mainly in magnetic field. In these systems, taking account of extended inverse DM effect, ferroelectric polarization direction is along general direction in the ac plane and does not follow the well-known inverse DM formula. In this presentation, I will discuss the relationship between the magnetic ordering and ferroelectricity in these delafossite family compounds.

Perceptual Priming Versus Explicit Memory: Dissociable Neural Correlates at Encoding

We addressed the hypothesis that perceptual priming and explicit memory have distinct neural correlates at encoding. Event-related potentials (ERPs) were recorded while participants studied visually presented words at deep versus shallow levels of processing (LOPs). The ERPs were sorted by whether or not participants later used studied words as completions to three-letter word stems in an intentional memory test, and by whether or not they indicated that these completions were remembered from the study list. Study trials from which words were later used and not remembered (primed trials) and study trials from which words were later used and remembered (remembered trials) were compared to study trials from which words were later not used (forgotten trials), in order to measure the ERP difference associated with later memory (DM effect). Primed trials involved an early (200–450 msec) centroparietal negative-going DM effect. Remembered trials involved a late (900–1200 msec) right frontal, positive-going DM effect regardless of LOP, as well as an earlier (600–800 msec) central, positive-going DM effect during shallow study processing only. All three DM effects differed topographically, and, in terms of their onset or duration, from the extended (600–1200 msec) fronto-central, positive-going shift for deep compared with shallow study processing. The results provide the first clear evidence that perceptual priming and explicit memory have distinct neural correlates at encoding, consistent with Tulving and Schacter's (1990) distinction between brain systems concerned with perceptual representation versus semantic and episodic memory. They also shed additional light on encoding processes associated with later explicit memory, by suggesting that brain processes influenced by LOP set the stage for other, at least partially separable, brain processes that are more directly related to encoding success.

When encodong yields remembering: insights from event-related neuroimaging

To understand human memory, it is important to determine why some experiences are remembered whereas others are forgotten. Until recently, insights into the neural bases of human memory encoding, the processes by which information is transformed into an enduring memory trace, have primarily been derived from neuropsychological studies of humans with select brain lesions. The advent of functional neuroimaging methods, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), has provided a new opportunity to gain additional understanding of how the brain supports memory formation. Importantly, the recent development of event–related fMRI methods now allows for examination of trial–by–trial differences in neural activity during encoding and of the consequences of these differences for later remembering. In this review, we consider the contributions of PET and fMRI studies to the understanding of memory encoding, placing a particular emphasis on recent event–related fMRI studies of the Dm effect: that is, differences in neural activity during encoding that are related to differences in subsequent memory. We then turn our attention to the rich literature on the Dm effect that has emerged from studies using event–related potentials (ERPs). It is hoped that the integration of findings from ERP studies, which offer higher temporal resolution, with those from event–related fMRI studies, which offer higher spatial resolution, will shed new light on when and why encoding yields subsequent remembering.