A New Approximation of Fermi-Dirac Integrals of Order 1/2 by Prony’s Method and Its Applications in Semiconductor Devices

Electronic devices are vital for our modern life. Semiconductor devices are at the core of them. Semiconductor devices are governed by the transport and behavior of electrons and holes which in turn are controlled by Fermi-Level or the Quasi-Fermi Level. The most frequently used approximation for the population of electrons and holes based on the Boltzmann approximation of Fermi-Dirac distribution. However when the Fermi-level is closer to the majority carrier band edge, by less than 3kT, it causes significant errors in the number of the carriers. This in turn causes errors in currents and other quantities of interest. In heavily doped semiconductors, it is desirable to use Fermi-Dirac Integral itself. However this is a tabulated function and therefore approximations are developed. Most of the approximation are mathematically cumbersome and complicated and they are not easily differentiable and integrable. Although several approximations have been developed, some with very high precision, these are not simple nor are they sufficiently useful in semiconductor device applications. In this thesis after exploring and critiquing these approximations, a new set of approximations is developed for the Fermi-Dirac integrals of the order 1/2. This analytical expression can be differentiated and integrated, still maintaining high accuracy. These new approximation is in the form of an exponential series with few terms using Prony’s method. Application of this approximation for semiconductor device calculations are discussed. Substantial errors in carrier densities and Einstein relation are shown when compared with Boltzmann approximation. The efficacy of the approximation in the calculation of Junctionless transistor quantities is demonstrated as an example

A new approximation of Fermi-Dirac integrals of order 1/2 for degenerate semiconductor devices

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.spmi.2018.03.072 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/There had been tremendous growth in the field of Integrated circuits (ICs) in the past fifty years. Scaling laws mandated both lateral and vertical dimensions to be reduced and a steady increase in doping densities. Most of the modern semiconductor devices have invariably heavily doped regions where Fermi-Dirac Integrals are required. Several attempts have been devoted to developing analytical approximations for Fermi-Dirac Integrals since numerical computations of Fermi-Dirac Integrals are difficult to use in semiconductor devices, although there are several highly accurate tabulated functions available. Most of these analytical expressions are not sufficiently suitable to be employed in semiconductor device applications due to their poor accuracy, the requirement of complicated calculations, and difficulties in differentiating and integrating. A new approximation has been developed for the Fermi-Dirac integrals of the order 1/2 by using Prony's method and discussed in this paper. The approximation is accurate enough (Mean Absolute Error (MAE) = 0.38%) and easy enough to be used in semiconductor device equations. The new approximation of Fermi-Dirac Integrals is applied to a more generalized Einstein Relation which is an important relation in semiconductor devices

Dermatological Lesions of Cholesterol Embolization Syndrome and Kaposi Sarcoma Mimic Primary Systemic Vasculitis: Case Report Study

Primary systemic vasculitis can present with a wide spectrum of manifestations ranging from systemic non-specific features such as fever, malaise, arthralgia, and myalgia to specific organ damage. We describe two cases of cholesterol embolization syndrome and Kaposi sarcoma mimicking primary systemic vasculitis, both of which were characterized by features such as livedo reticularis, blue toe syndrome, a brown, purpuric skin rash, and positive p-ANCA associated with Kaposi sarcoma. Establishing the right diagnosis was challenging, and thus we aim in this study to highlight the possible ways to distinguish them from primary systemic vasculitis. Keywords: Dermatological lesions, Cholesterol embolization syndrome, Kaposi sarcoma, vasculitis mimic

Antenatal Magnesium Sulfate for Preterm Neuroprotection: A Single-Center Experience from Kuwait Tertiary NICU

Objectives: The study aimed to evaluate the impact of antenatal exposure of magnesium sulfate (MgSO4) on short- and long-term outcomes in preterm neonates born less than 32 weeks gestation. Methods: Single-center retrospective cohort study of 229 neonates born between 24 and 32 weeks gestation was conducted from January 2018 through December 2018 in a level III neonatal care unit in Kuwait. Antenatal MgSO4 exposure was collected from the medical records, and the indication was for neuroprotection effect. Brain MRI was done on 212 neonates (median gestational age 36 weeks), and brain injury was assessed using the Miller’s score. Neurodevelopmental outcome was assessed by Bayley-III scales of infant development at 36 months corrected age (N = 146). The association of exposure to MgSO4 with brain injury and neurodevelopmental outcomes was examined using multivariable regression analysis adjusting for gestational age at MRI and variables with p value <0.05 on univariate analysis. Results: Among the 229 neonates, 47 received antenatal MgSO4. There were no differences between the groups in gestational age and birth weight. MgSO4 exposure was not associated with an increased risk of necrotizing enterocolitis, chronic lung disease, retinopathy of prematurity, and mortality. The incidence of cerebellar hemorrhage was significantly less in the MgSO4 group (0% vs. 16%, p value = 0.002). Neonates who received MgSO4 had lower risks of grade 3–4 intraventricular hemorrhage (IVH) adjusted OR 0.248 (95% CI: 0.092, 0.66), p = 0.006; moderate-severe white matter injury (WMI) adjusted odd ratio 0.208 (95% CI: 0.044, 0.96), p = 0.046; and grade 3–4 IVH and/or moderate-severe WMI adjusted OR 0.23 (95% CI: 0.06, 0.84), p = 0.027. Neurodevelopmental assessment at 36 months corrected age showed better motor (adjusted beta coefficient 1.08 [95% CI: 0.099, 2.06]; p = 0.031) and cognitive composite scores (adjusted beta coefficient 1.29 [95% CI: 0.36, 2.22]; p = 0.007) in the MgSO4 group. Conclusion: Antenatal exposure to MgSO4 in preterm neonates less than 32 weeks was independently associated with lower risks of brain injury and better motor and cognitive outcomes

The nutritional status of mycetoma affected patients seen at the Mycetoma Research Center, Sudan.

Nutrition plays a critical and crucial role in addressing neglected tropical diseases (NTDs) and their complications, as they often contribute to malnutrition, which can worsen the impact of these conditions. Therefore, it is necessary to investigate the nutritional status of mycetoma patients, which has not been explored previously. This descriptive cross-sectional hospital-based study was conducted at the Mycetoma Research Center (MRC), University of Khartoum, Sudan. The study included 179 confirmed mycetoma patients and an equal number of age- and sex-matched normal controls. The nutritional status of the mycetoma patients was assessed and compared with that of the control group. The majority of the patients were young adults with varying educational levels, predominantly from Central Sudan. The foot was the most commonly affected part; most patients had lesions more than 10 cm in diameter. The Body Mass Index (BMI) was calculated for both study groups, revealing that 43.5% of the patients and 53.6% of controls had a normal BMI. Furthermore, 36% of patients were underweight, contrasting with only 11% in the control group. Correlation analyses indicated no significant associations between BMI and age groups, educational levels, daily meals, food quantity, and appetite in the study population (p > 0.05). Similarly, no significant differences were observed in BMI concerning disease duration and affected sites (p = 0.0577). The Kruskal-Wallis test did not reveal significant differences in BMI means among the groups. The study revealed that most participants consumed three meals daily, and the control group showed a more robust appetite and consumed more food than the patient group (p = 0.005). Nevertheless, there were no significant differences in the consumption of different food types between the patient and control groups and among different BMI categories (p = 0.025 and 0.040, respectively)

Transcriptional analysis of Rhazya stricta in response to jasmonic acid

Background: Jasmonic acid (JA) is a signal transducer molecule that plays an important role in plant development and stress response; it can also efficiently stimulate secondary metabolism in plant cells. Results: RNA-Seq technology was applied to identify differentially expressed genes and study the time course of gene expression in Rhazya stricta in response to JA. Of more than 288 million total reads, approximately 27% were mapped to genes in the reference genome. Genes involved during the secondary metabolite pathways were up- or downregulated when treated with JA in R. stricta. Functional annotation and pathway analysis of all up- and downregulated genes identified many biological processes and molecular functions. Jasmonic acid biosynthetic, cell wall organization, and chlorophyll metabolic processes were upregulated at days 2, 6, and 12, respectively. Similarly, the molecular functions of calcium-transporting ATPase activity, ADP binding, and protein kinase activity were also upregulated at days 2, 6, and 12, respectively. Time-dependent transcriptional gene expression analysis showed that JA can induce signaling in the phenylpropanoid and aromatic acid pathways. These pathways are responsible for the production of secondary metabolites, which are essential for the development and environmental defense mechanism of R. stricta during stress conditions. Conclusions: Our results suggested that genes involved in flavonoid biosynthesis and aromatic acid synthesis pathways were upregulated during JA stress. However, monoterpenoid indole alkaloid (MIA) was unaffected by JA treatment. Hence, we can postulate that JA plays an important role in R. stricta during plant development and environmental stress conditions. How to cite: Hajrah, NH, Rabah SO, Alghamdi MK, et al. Transcriptional analysis of Rhazya stricta in response to jasmonic acid. Electron J Biotechnol 2021;50. https://doi.org/10.1016/j.ejbt.2021.01.00

Effect of nocturnal hypoxemia on glycemic control among diabetic Saudi patients presenting with obstructive sleep apnea

BackgroundObstructive sleep apnea (OSA) is a prevalent disease that is associated with an increased incidence of type II diabetes mellitus (DM) if left untreated. We aimed to determine the association between glycosylated hemoglobin (HbA1c) levels and both nocturnal hypoxemia and apnea-hypopnea index (AHI) among a Saudi patients with OSA.MethodsA cross-sectional study that enrolled 103 adult patients diagnosed with DM and confirmed to have OSA by full night attended polysomnography between 2018 and 2021. Those who presented with acute illness, chronic obstructive pulmonary disease (COPD)/restrictive lung diseases causing sleep-related hypoxemia, or no available HbA1c level within 6 months before polysomnography were excluded from the study. Univariate and multivariate linear regression analyses between HbA1c levels and parameters of interest were tested.ResultsSixty-seven (65%) of the studied population had uncontrolled DM (HbA1c ≥7%). In univariate regression analysis, there was a significant positive association between HbA1c, and sleep time spent with an oxygen saturation below 90% (T90), female gender, and body mass index (BMI) (p<0.05) but not AHI, or associated comorbidities (p>0.05). In the multivariate analysis, HbA1c was positively associated with increasing T90 (p<0.05), and ODI (p<0.05), but not with AHI (p>0.05).ConclusionNocturnal hypoxemia could be an important factor affecting glycemic control in patients with OSA suffering from DM irrespective of the severity of both diseases