241 research outputs found

    STUDYING THE EFFECT OF CATIONIC STARCH- ANIONIC NANOSILICA SYSTEM ON RETENTION AND DRAINAGE

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    Nanoparticles are widely used in the papermaking industry as retention/ drainage aids, usually in conjunction with a high mass cationic polyelectrolyte such as cationic starch. However, little convincing knowledge of their role and mechanism in the wet-end system is yet found. This work focused on the role of nanosilica on papermaking wet end system in response to some processing parameters (drainage, retention, and electrostatic force of the whole system). The observations indicated that the nanosilica performance is defined by interactions of nanosilica with the complex aqueous environment of wet end system. The interaction mechanism seems to rely on introduction of nanoparticles into a cationic starch-fines-fibers network, converting the fiber mat on the forming wire into a porous structure that is responsive to retention and drainage

    The evolution of food security: where are we now, where should we go next?

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    Food security is one of the most challenging topics globally; however, the concept of food security has taken on additional dimensions that are general and are less detailed. This study aims to identify the intellectual structure of food security research and the changes in this structure. This paper analyzed 3169 documents from the Web of Science database through a bibliometric review. A review of the published documents shows an increasing trend over the past 46 years. In accordance with co-occurrence analysis, 125 keywords were grouped into five clusters: food security and sustainable development; food security and socioeconomic factors; food security policy and governance; coping strategies for poverty, inequality, and hunger; and modern food security management. This study identifies four streams within food security research: sustainability and environmental, socioeconomic, cultural, and political factors. The paper concludes that even though food security might investigate many significant areas, other new dimensions should still be considered. Further gaps in the literature emerge that present avenues for future research directions. Reviewing indicators and techniques of food security assessment and identifying high-risk groups should be a priority

    The first case series of malaria overlapped with COVID-19 in Iran

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    Introduction: Although indigenous malaria cases have dramatically declined over the past decades, the COVID pandemic has continued to affect the programs designed to combat malaria, particularly in those countries where hydroxychloroquine and chloroquine have been used as medications for treating COVID. Two immigrants entered Iran illegally from neighboring countries (i.e., Afghanistan and Pakistan). This study mainly aimed to assess the effects of coronavirus disease (COVID-19) on these cases from all aspects (i.e., case-finding, diagnosis, and treatment). Case Presentation: Both cases presented with common symptoms such as fever and shaking chills. In addition, they had no sign of COVID-19, and their oxygen level and CT images were normal in some cases, but they were mistakenly treated as COVID-19 patients long after the onset of malaria symptoms. One of the suspected coronavirus cases was given chloroquine on a voluntary basis for one day, which may have been responsible for the possible relapse in vivax or resistance of plasmodium vivax to chloroquine and the recurrence of parasitemia in falciparum. Conclusions: The active case detection of malaria was affected by the COVID-19 pandemic. Case finding was dramatically decreased with the onset of coronavirus, thereby causing a spurt in malaria incidence. Moreover, the malaria treatment strategy was negatively affected by the misdiagnosis of COVID-19

    Early maladaptive schemas and suicidal risk in inpatients with bipolar disorder

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    The present study aimed to assess the associations of early maladaptive schemas (EMSs) and clinical factors (hypomanic/manic and depressive symptoms) with suicidal risk (current suicidal ideation and lifetime suicide attempts) in inpatients with bipolar disorder (BD). One hundred inpatients with BD completed the Young Schema Questionnaire-Short Form (YSQ-SF), the Bipolar Depression Rating Scale (BDRS), the Young Mania Rating Scale (YMRS), and the Beck Scale for Suicide Ideation (BSSI). 59 of patients had lifetime suicide attempts and 59 showed high suicidal risk (BSSI>/=6). BD patients with lifetime suicide attempts had higher scores on the entitlement and social isolation schemas, depression, and hypomanic/manic symptoms than those without such attempts. Patients with high suicidal risk had higher levels of depressive and hypomanic/manic symptoms as well as some EMSs than those without high suicidal risk. Logistic regression analyses revealed that hypomanic/manic symptoms as well as the entitlement and defectiveness schemas were significantly associated with current suicidal ideation. Also, the entitlement and social isolation schemas were associated with lifetime suicide attempts. These results suggest that the entitlement, social isolation, and defectiveness schemas may relate to suicidal risk in patients with BD

    Absence seizures in C3H/HeJ and knockout mice caused by mutation of the AMPA receptor subunit Gria4

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    Absence epilepsy, characterized by spike–wave discharges (SWD) in the electroencephalogram, arises from aberrations within the circuitry of the cerebral cortex and thalamus that regulates awareness. The inbred mouse strain C3H/HeJ is prone to absence seizures, with a major susceptibility locus, spkw1, accounting for most of the phenotype. Here we find that spkw1 is associated with a hypomorphic retroviral-like insertion mutation in the Gria4 gene, encoding one of the four amino-3-hydroxy-5-methyl-4isoxazolepropionic acid (AMPA) receptor subunits in the brain. Consistent with this, Gria4 knockout mice also have frequent SWD and do not complement spkw1. In contrast, null mutants for the related gene Gria3 do not have SWD, and Gria3 loss actually lowers SWD of spkw1 homozygotes. Gria3 and Gria4 encode the predominant AMPA receptor subunits in the reticular thalamus, which is thought to play a central role in seizure genesis by inhibiting thalamic relay cells and promoting rebound burst firing responses. In Gria4 mutants, synaptic excitation of inhibitory reticular thalamic neurons is enhanced, with increased duration of synaptic responses—consistent with what might be expected from reduction of the kinetically faster subunit of AMPA receptors encoded by Gria4. These results demonstrate for the first time an essential role for Gria4 in the brain, and suggest that abnormal AMPA receptor-dependent synaptic activity can be involved in the network hypersynchrony that underlies absence seizures

    The non-octarepeat copper binding site of the prion protein is a key regulator of prion conversion

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    The conversion of the prion protein (PrP(C)) into prions plays a key role in transmissible spongiform encephalopathies. Despite the importance for pathogenesis, the mechanism of prion formation has escaped detailed characterization due to the insoluble nature of prions. PrP(C) interacts with copper through octarepeat and non-octarepeat binding sites. Copper coordination to the non-octarepeat region has garnered interest due to the possibility that this interaction may impact prion conversion. We used X-ray absorption spectroscopy to study copper coordination at pH 5.5 and 7.0 in human PrP(C) constructs, either wild-type (WT) or carrying pathological mutations. We show that mutations and pH cause modifications of copper coordination in the non-octarepeat region. In the WT at pH 5.5, copper is anchored to His96 and His111, while at pH 7 it is coordinated by His111. Pathological point mutations alter the copper coordination at acidic conditions where the metal is anchored to His111. By using in vitro approaches, cell-based and computational techniques, we propose a model whereby PrP(C) coordinating copper with one His in the non-octarepeat region converts to prions at acidic condition. Thus, the non-octarepeat region may act as the long-sought-after prion switch, critical for disease onset and propagation

    The diagnostic suitability of a xerostomia questionnaire and the association between xerostomia, hyposalivation and medication use in a group of nursing home residents

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    The study objective was to explore the diagnostic suitability of the Xerostomia Inventory and the association between xerostomia, hyposalivation and medication use in a group of nursing home residents. A cross-sectional study was carried out in 50 physically impaired nursing home residents (20 men) with a mean age of 78.1 years (range, 53–98) in The Netherlands. The Xerostomia Inventory-Dutch version was completed for all residents and the data were subjected to exploratory factor analysis to determine the diagnostic suitability. Residents’ data on xerostomia, whole saliva secretion rates and hyposalivation-related medications used were collected and statistically analyzed. The diagnostic suitability of the Xerostomia Inventory-Dutch version appeared restricted. The prevalence of xerostomia was 52%, without gender and age difference. The prevalence of hyposalivation was 24% for resting, 60% for chewing-stimulated and 18% for acid-stimulated whole saliva. All whole saliva secretion rates were significantly lower in women than in men and in older than in younger residents. Forty-four percent of all medications used were hyposalivation-related and women used significantly more medications than men. Xerostomia was significantly negatively correlated with the resting whole saliva secretion rate. The number of hyposalivation-related medications used was not significantly correlated with the various whole saliva secretion rates. In nursing home residents, xerostomia, hyposalivation and using hyposalivation-related medications seem common and partially associated features
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