830 research outputs found

    Optimization of up-flow anaerobic sludge blanket reactor for treatment of composite fermentation and distillation wastewater

    Get PDF
    Optimization of up-flow anaerobic sludge blanket (UASB) reactor operation for treatment of a composite fermentation and distillation wastewater was achieved using a locally available thickened municipal sludge instead of imported commercial anaerobic granulated sludge. Over the first 12 days, a fed batch start-up operation was maintained and anaerobic stable sludge granules with 11.2% of extra cellular polymers (ECP) were successfully developed and further used for long-term continuous operation. Two types of granules were developed within the reactor but with very different characteristics. Granules grown in the bottom part of UASB reactor were more compact and tense than those that occurred in the upper part. The latter were fragile, irregular in shape and with much lower methanogenic activities. Bottom granules were dominated by both Methanosarcina spp. and Methanosaeta spp. whereas upper granules harbored only Methanosarcina spp. During continuous anaerobic treatment of composite fermentation and distillation wastewater with organic load of 24 g.l-1 of chemical oxygen demand (COD), a removal efficiency of up to 84% was achieved. Moreover, biogas was produced with a production rate of o.52 m3/Kg COD removed.Keywords: Composite wastewater, up-flow anaerobic sludge blanket (UASB), anaerobic biological treatment, biogas, granulated anaerobic sludge, industrial wastewater.African Journal of Biotechnology, Vol. 13(10), pp. 1136-1142, 5 March, 201

    Soft Tissue Attenuation Patterns Associated with Upright Acquisition SPECT Myocardial Perfusion Imaging: A Descriptive Study

    Get PDF
    Abstract: Purpose: Soft-tissue attenuation patterns in SPECT-myocardial perfusion imaging (MPI) of supine acquisition systems are well recognized. Their prevalence and interaction with body-habitus and gender are ill-defined, which we sought to describe in this study. Methods: In a cross-sectional study, we described the prevalence of soft-tissue attenuation patterns in normal SPECT-MPI studies acquired with a supine patient-position SPECT system. Results: In 263 normal, clinically-indicated, supine-acquisition SPECT-MPIs the attenuation patterns observed were: anterior (35.4%), inferior (41.8%) and lateral (13.3%). Anterior attenuation was more prevalent among women (50.7 % vs. 15.7%, P<0.001) and was associated with chest circumference among men. Conversely, inferior attenuation was more prevalent among men (78.3 % vs. 13.5%, P<0.001) and was not affected by body-habitus. Lateral attenuation was more common among women (19.6 % vs. 5.2%, p=0.001) and was associated with obesity (p=0.015). Conclusions: Soft-tissue attenuation artifacts are common in supine-acquisition SPECT-MPI. The recognition of their prevalence and association with body-habitus and gender is critical for the accurate interpretation of SPECT-MPI

    Epidemiology of Coxiella burnetii infection in Africa: a OneHealth systematic review

    Get PDF
    Background: Q fever is a common cause of febrile illness and community-acquired pneumonia in resource-limited settings. Coxiella burnetii, the causative pathogen, is transmitted among varied host species, but the epidemiology of the organism in Africa is poorly understood. We conducted a systematic review of C. burnetii epidemiology in Africa from a “One Health” perspective to synthesize the published data and identify knowledge gaps.<p></p> Methods/Principal Findings: We searched nine databases to identify articles relevant to four key aspects of C. burnetii epidemiology in human and animal populations in Africa: infection prevalence; disease incidence; transmission risk factors; and infection control efforts. We identified 929 unique articles, 100 of which remained after full-text review. Of these, 41 articles describing 51 studies qualified for data extraction. Animal seroprevalence studies revealed infection by C. burnetii (≤13%) among cattle except for studies in Western and Middle Africa (18–55%). Small ruminant seroprevalence ranged from 11–33%. Human seroprevalence was <8% with the exception of studies among children and in Egypt (10–32%). Close contact with camels and rural residence were associated with increased seropositivity among humans. C. burnetii infection has been associated with livestock abortion. In human cohort studies, Q fever accounted for 2–9% of febrile illness hospitalizations and 1–3% of infective endocarditis cases. We found no studies of disease incidence estimates or disease control efforts.<p></p> Conclusions/Significance: C. burnetii infection is detected in humans and in a wide range of animal species across Africa, but seroprevalence varies widely by species and location. Risk factors underlying this variability are poorly understood as is the role of C. burnetii in livestock abortion. Q fever consistently accounts for a notable proportion of undifferentiated human febrile illness and infective endocarditis in cohort studies, but incidence estimates are lacking. C. burnetii presents a real yet underappreciated threat to human and animal health throughout Africa.<p></p&gt

    The porin and the permeating antibiotic: A selective diffusion barrier in gram-negative bacteria

    Get PDF
    Gram-negative bacteria are responsible for a large proportion of antibiotic resistant bacterial diseases. These bacteria have a complex cell envelope that comprises an outer membrane and an inner membrane that delimit the periplasm. The outer membrane contains various protein channels, called porins, which are involved in the influx of various compounds, including several classes of antibiotics. Bacterial adaptation to reduce influx through porins is an increasing problem worldwide that contributes, together with efflux systems, to the emergence and dissemination of antibiotic resistance. An exciting challenge is to decipher the genetic and molecular basis of membrane impermeability as a bacterial resistance mechanism. This Review outlines the bacterial response towards antibiotic stress on altered membrane permeability and discusses recent advances in molecular approaches that are improving our knowledge of the physico-chemical parameters that govern the translocation of antibiotics through porin channel

    Urticaria and angioedema

    Get PDF
    Urticaria (hives) is a common disorder that often presents with angioedema (swelling that occurs beneath the skin). It is generally classified as acute, chronic or physical. Second-generation, non-sedating H1-receptor antihistamines represent the mainstay of therapy for both acute and chronic urticaria. Angioedema can occur in the absence of urticaria, with angiotensin-converting enzyme (ACE) inhibitor-induced angioedema and idiopathic angioedema being the more common causes. Rarer causes are hereditary angioedema (HAE) or acquired angioedema (AAE). Although the angioedema associated with these disorders is often self-limited, laryngeal involvement can lead to fatal asphyxiation in some cases. The management of HAE and AAE involves both prophylactic strategies to prevent attacks of angioedema (i.e., trigger avoidance, attenuated androgens, tranexamic acid, and plasma-derived C1 inhibitor replacement therapy) as well as pharmacological interventions for the treatment of acute attacks (i.e., C1 inhibitor replacement therapy, ecallantide and icatibant). In this article, the authors review the causes, diagnosis and management of urticaria (with or without angioedema) as well as the work-up and management of isolated angioedema, which vary considerably from that of angioedema that occurs in the presence of urticaria

    Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

    Get PDF
    The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

    Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

    Get PDF
    Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
    corecore