Energy-independent System Research Articles

Implications of strategic photovoltaic deployment on regional electricity self-sufficiency by 2050: A case study in Iraq

The study explored the impact of strategic photovoltaic (PV) deployment on regional electricity self-sufficiency in Iraq, offering key insights into the advantages and challenges of transitioning towards an energy-independent system by 2050. Findings indicate a noteworthy contribution of rising PV supply towards improved self-sufficiency, with a PV supply of 83.1 TWh catering to a total demand of 66.2 TWh in 2022, achieving a 76% self-sufficiency level. This suggests PV generation covers 76% of the districts electricity needs, thus bolstering energy security by reducing external energy source reliance. Furthermore, the study emphasizes the significance of expanded rooftop PV capacity to augment self-sufficiency and decrease dependency on conventional energy. Predictions suggest a potential rise in rooftop utilization for PV installations from 66% in 2022 to 88% by 2050, accentuating the need for policy initiatives to endorse and incentivize rooftop PV system adoption. The paper offers several recommendations, including the creation of supportive regulatory frameworks for PV integration, the introduction of financial incentives, capacity building initiatives, public awareness campaigns, grid modernization efforts, and regional energy planning which incorporates PV deployment considerations and sets self-sufficiency targets..

Diagnostic roles of MUC1 and GLUT1 in differentiating thymic carcinoma from type B3 thymoma

MUC1 is a transmembrane mucin that has been related to tumor progression and outcome in various malignancies. GLUT1 is a member of the mammalian facilitative glucose transporter (GLUT) family of passive carriers that functions as an energy-independent system for transporting glucose. Both of them are useful markers for the diagnosis, progression, and prognosis of various tumors, especially those that are cancerous. However, the clinical significance of MUC1 and GLUT1 in thymic epithelial tumors remains uncertain due to a lack of quality specimen and studies at sufficient scale, both owing, in part, to the rarity of the tumors. The aim of this article is to study the expression patterns of MUC1 and GLUT1 in thymic carcinoma and type B3 thymoma, and to evaluate their diagnostic value for these two types of tumors via immunohistochemistry. Forty-three patients were included in the study, including twenty-two with thymic carcinoma and twenty-one with type B3 thymoma. Tumor tissue sections were immunohistochemically stained for MUC1 and GLUT1; meanwhile, some tumors were also stained with CKpan, TDT, CD5, and CD117. MUC1 was expressed in a total of 17 cases, with a positive rate of 77.27% (17/22) in thymic carcinoma and 9.52% (2/21) in type B3 thymoma, revealing a significant difference (p<0.0001). A significant difference (p<0.0001) was also shown for GLUT1, where the positive rates for thymic carcinoma and type B3 thymoma were 100% (22/22) and 42.86% (9/21), respectively. The expression of MUC1 was significantly correlated with GLUT1 (p<0.0001). Furthermore, GLUT1 staining sensitivity and specificity for thymic carcinoma were 100% (22/22) and 70.97% (22/31), respectively, while MUC1 staining sensitivity and specificity were 77.27% (17/22) and 89.47% (17/19), respectively.In conclusion, our study shows that MUC1 and GLUT1 staining may play a useful role in differentiating thymic carcinoma from type B3 thymoma, with high sensitivity and specificity.

Respiration of Escherichia coli Can Be Fully Uncoupled via the Nonelectrogenic Terminal Cytochrome bd -II Oxidase

The respiratory chain of Escherichia coli is usually considered a device to conserve energy via the generation of a proton motive force, which subsequently may drive ATP synthesis by the ATP synthetase. It is known that in this system a fixed amount of ATP per oxygen molecule reduced (P/O ratio) is not synthesized due to alternative NADH dehydrogenases and terminal oxidases with different proton pumping stoichiometries. Here we show that P/O ratios can vary much more than previously thought. First, we show that in wild-type E. coli cytochrome bo, cytochrome bd-I, and cytochrome bd-II are the major terminal oxidases; deletion of all of the genes encoding these enzymes results in a fermentative phenotype in the presence of oxygen. Second, we provide evidence that the electron flux through cytochrome bd-II oxidase is significant but does not contribute to the generation of a proton motive force. The kinetics support the view that this system is as an energy-independent system gives the cell metabolic flexibility by uncoupling catabolism from ATP synthesis under non-steady-state conditions. The nonelectrogenic nature of cytochrome bd-II oxidase implies that the respiratory chain can function in a fully uncoupled mode such that ATP synthesis occurs solely by substrate level phosphorylation. As a consequence, the yield with a carbon and energy source can vary five- to sevenfold depending on the electron flux distribution in the respiratory chain. A full understanding and control of this distribution open new avenues for optimization of biotechnological processes.

Iron in Neisseria meningitidis: minimum requirements, effects of limitation, and characteristics of uptake.

A simple defined medium (neisseria defined medium) was devised that does not require iron extraction to produce iron-limited growth of Neisseria meningitidis (SDIC). Comparison of this medium to Mueller-Hinton broth and agar showed nearly identical growth rates and yields. The defined medium was used in batch cultures to determine the disappearance of iron from the medium and its uptake by cells. To avoid a number of problems inherent in batch culture, continuous culture, in which iron and dissolved oxygen were varied independently, was used. Most of the cellular iron was found to be nonheme and associated with the particulate fraction in sonically disrupted cells. Nonheme and catalase-heme iron were reduced by iron starvation far more than cytochromes b and c and N,N,N',N'-tetramethylphenylenediamine-oxidase. The respiration rate and efficiency also decreased under iron limitation, whereas generation times increased. The iron-starved meningococcus took up iron by an energy-independent system operating in the first minute after an iron pulse and a slower energy-dependent system inhibited by respiratory poisons and an uncoupler. The energy-dependent system showed saturation kinetics and was stimulated nearly fourfold by iron privation. In addition, to determine the availability to the meningococcus of the iron in selected compounds, a sensitive assay was devised in which an iron-limited continuous culture was pulsed with the iron-containing compound.

Positive solutions and subcriticality of energy dependent transport systems in slab geometry

The energy dependent transport system in an anisotropic medium in slab geometry subjecting to internal source and incoming fluxes is investigated. The investigation is based on a corresponding integral equation of the boundary value problem from which a recursion formula for the determination of the solution is obtained. It is shown by using the notion of an upper solution that the convergence or divergence of the sequence of iterations depends solely on the existence or nonexistence of an upper solution. Through the construction of a suitable upper solution one can obtain an explicit estimate for the value of c, which represents the average number of secondary neutrons per collision, in terms of the (optical) slab length 2a so that the system is either critical or subcritical. It is shown in particular that if c&amp;lt;[1−E2(a)]−1, where E2(a) is the exponential integral of order two, then the integral equation has exactly one nonnegative solution for any nonnegative source and incoming fluxes. This result insures the subcriticality of the system as well as a constructive recursion formula for the determination of the solution. Estimates for a more general system and the energy independent system are also obtained.