On the Order of Growth of Solutions to Complex Non-homogeneous Linear Differential Equations

Habib, Habib,Belaidi, Benharrat Department of Mathematics 2016 Kyungpook mathematical journal Vol.56 No.3

In this paper, we study the order of growth of solutions to the non-homogeneous linear differential equation $$f^{(k)}+A_{k-1}e^{az}f^{(k-1)}+{\cdots}+A_1e^{az}f^{\prime}+A_0e^{az}f=F_1e^{az}+F_2e^{bz}$$, where $A_j(z)$ (${\not\equiv}0$) ($j=0,1,{\cdots},k-1$), $F_j(z)$ (${\not\equiv}0$) (j = 1, 2) are entire functions and a, b are complex numbers such that $ab(a-b){\neq}0$.

Ground-State Conditions Promote Robust Prdm14 Reactivation and Maintain an Active Dlk1-Dio3 Region during Reprogramming

Habib, Omer,Habib, Gizem,Moon, Sung-Hwan,Hong, Ki-Sung,Do, Jeong Tae,Choi, Youngsok,Chang, Sung Woon,Chung, Hyung-Min Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.1

Induced pluripotent stem cells (iPSCs) are capable of unlimited self-renewal and can give rise to all three germ layers, thereby providing a new platform with which to study mammalian development and epigenetic reprogramming. However, iPSC generation may result in subtle epigenetic variations, such as the aberrant methylation of the Dlk1-Dio3 locus, among the clones, and this heterogeneity constitutes a major drawback to harnessing the full potential of iPSCs. Vitamin C has recently emerged as a safeguard to ensure the normal imprinting of the Dlk1-Dio3 locus during reprogramming. Here, we show that vitamin C exerts its effect in a manner that is independent of the reprogramming kinetics. Moreover, we demonstrate that reprogramming cells under 2i conditions leads to the early upregulation of Prdm14, which in turn results in a highly homogeneous population of authentic pluripotent colonies and prevents the abnormal silencing of the Dlk1-Dio3 locus.

An improved method for the derivation of high quality iPSCs in the absence of c-Myc

Habib, O.,Habib, G.,Choi, H.W.,Hong, K.S.,Tae Do, J.,Moon, S.H.,Chung, H.M. Academic Press 2013 Experimental cell research Vol.319 No.20

Induced pluripotent stem cells (iPSCs) hold tremendous potential for the development of new regenerative medicine therapies and the study of molecular mechanisms of pluripotency and development. However, reactivation of c-Myc, which results in tumor formation in chimeric mice, is a major roadblock in the translation of iPSCs into therapies. Although ectopic expression of c-Myc is not absolutely required for somatic reprogramming, in the absence of c-Myc, the overall efficiency of reprogramming is drastically reduced and the reprogramming time is increased. Subtle, abnormal epigenetic modifications in iPSCs derived in the absence of c-Myc have also been documented. Therefore, we developed a reprogramming method without c-Myc to generate high-quality iPSCs, a prerequisite to harnessing the full potential of iPSCs. In this study, we determined that serum replacement (SR)-based culture conditions dramatically increased the transcription factor-mediated reprogramming of mouse embryonic fibroblast cells (MEFs). The process was shortened to approximately 8 days when Oct4/Sox2/Klf4 (3F)-transduced MEFs were first cultured for 3 days under low serum conditions (LS protocol). The 3F-derived iPSCs that were generated by this method resembled mouse ES cells (mESCs) in morphology, gene expression, and in vitro differentiation. Finally, we observed that 3F-derived iPSC colonies were able to reach definite pluripotency in terms of molecular signatures when the catalytic function of c-Myc was tolerated. The 3F induction of pluripotency described here should facilitate the use of iPSCs and may also facilitate the mechanistic dissection of somatic reprogramming.

Posthypoxic behavioral impairment and mortality of Drosophila melanogaster are associated with high temperatures, enhanced predeath activity and oxidative stress

Habib Pardes,Jung Jennifer,Wilms Gina Maria,Kokott-Vuong Alma,Habib Shahin,Schulz Jörg B.,Voigt Aaron 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Hypoxia is an underlying pathophysiological condition of a variety of devastating diseases, including acute ischemic stroke (AIS). We are faced with limited therapeutic options for AIS patients, and even after successful restoration of cerebral blood flow, the poststroke mortality is still high. More basic research is needed to explain mortality after reperfusion and to develop adjunct neuroprotective therapies. Drosophila melanogaster (D.m.) is a suitable model to analyze hypoxia; however, little is known about the impacts of hypoxia and especially of the subsequent reperfusion injury on the behavior and survival of D.m . To address this knowledge gap, we subjected two wild-type D.m . strains (Canton-S and Oregon-R) to severe hypoxia (<0.3% O 2 ) under standardized environmental conditions in a well-constructed hypoxia chamber. During posthypoxic reperfusion (21% O 2 ), we assessed fly activity (evoked and spontaneous) and analyzed molecular characteristics (oxidative stress marker abundance, reactive oxygen species (ROS) production, and metabolic activity) at various timepoints during reperfusion. First, we established standard conditions to induce hypoxia in D.m . to guarantee stable and reproducible experiments. Exposure to severe hypoxia under defined conditions impaired the climbing ability and reduced the overall activity of both D.m . strains. Furthermore, a majority of the flies died during the early reperfusion phase (up to 24 h). Interestingly, the flies that died early exhibited elevated activity before death compared to that of the flies that survived the entire reperfusion period. Additionally, we detected increases in ROS and stress marker (Catalase, Superoxide Dismutase and Heat Shock Protein 70) levels as well as reductions in metabolic activity in the reperfusion phase. Finally, we found that changes in environmental conditions impacted the mortality rate. In particular, decreasing the temperature during hypoxia or the reperfusion phase displayed a protective effect. In conclusion, our data suggest that reperfusion-dependent death might be associated with elevated temperatures, predeath activity, and oxidative stress.

Ground-State Conditions Promote Robust Prdm14 Reactivation and Maintain an Active Dlk1-Dio3 Region during Reprogramming

habib omer,Gizem Habib,문성환,홍기성,도정태,Youngsok Choi,장성운,정형민 한국분자세포생물학회 2014 Molecules and cells Vol.37 No.1

Induced pluripotent stem cells (iPSCs) are capable of unlimited self-renewal and can give rise to all three germ layers, thereby providing a new platform with which to study mammalian development and epigenetic reprogramming. However, iPSC generation may result in subtle epigenetic variations, such as the aberrant methylation of the Dlk1-Dio3 locus, among the clones, and this heterogeneity constitutes a major drawback to harnessing the full potential of iPSCs. Vitamin C has recently emerged as a safeguard to ensure the normal imprinting of the Dlk1-Dio3 locus during reprogramming. Here, we show that vitamin C exerts its effect in a manner that is independent of the reprogramming kinetics. Moreover, we demonstrate that reprogramming cells under 2i conditions leads to the early upregulation of Prdm14, which in turn results in a highly homogeneous population of authentic pluripotent colonies and prevents the abnormal silencing of the Dlk1-Dio3 locus.

Effect of uncertainty parameters on graphene sheets Young’s modulus prediction

Habib Sahlaoui,Mohamed Guedri,Habib Sidhom 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.9

Software based on molecular structural mechanics approach (MSMA) and using finite element method (FEM) has been developed to predict the Young’s modulus of graphene sheets. Obtained results have been compared to results available in the literature and good agreement has been shown when the same values of uncertainty parameters are used. A sensibility of the models to their uncertainty parameters has been investigated using a stochastic finite element method (SFEM). The different values of the used uncertainty parameters,such as molecular mechanics force field constants r k and kθ , thickness (t) of a graphene sheet and length ( B L ) of a carboncarbon bonds, have been collected from the literature. Strong sensibilities of 91% to the thickness and of 21% to the stretching force ( r k )have been shown. The results justify the great difference between Young’s modulus predicted values of the graphene sheets and their large disagreement with experimental results.

Layer potential techniques in spectral analysis. Part I: Complete asymptotic expansions for eigenvalues of the Laplacian in domains with small inclusions

Ammari, Habib,Kang, Hyeonbae,Lim, Mikyoung,Zribi, Habib American Mathematical Society 2010 Transactions of the American Mathematical Society Vol.362 No.6

An Integrated High Linearity CMOS Receiver Frontend for 24-GHz Applications

Habib Rastegar,Jee-Youl Ryu 대한전자공학회 2016 Journal of semiconductor technology and science Vol.16 No.5

Utilizing a standard 130-nm CMOS process, a RF frontend is designed at 24 GHz for automotive collision avoidance radar application. Single IF direct conversion receiver (DCR) architecture is adopted to achieve high integration level and to alleviate the DCR problem. The proposed frontend is composed of a two-stage LNA and downconversion mixers. To save power consumption, and to enhance gain and linearity, stacked NMOS-PMOS gm-boosting technique is employed in the design of LNA as the first stage. The switch transistors in the mixing stage are biased in subthreshold region to achieve low power consumption. The single balanced mixer is designed in PMOS transistors and is also realized based on the well-known folded architecture to increase voltage headroom. This frontend circuit features enhancement in gain, linearity, and power dissipation. The proposed circuit showed a maximum conversion gain of 19.6 dB and noise figure of 3 dB at the operation frequency. It also showed input and output return losses of less than -10 dB within bandwidth. Furthermore, the port-to-port isolation illustrated excellent characteristic between two ports. This frontend showed the third-order input intercept point (IIP3) of 3 dBm for the whole circuit with power dissipation of 6.5 mW from a 1.5 V supply.

Bank Competition, Financial Development and Growth of Financially Dependent Industries: Fresh Evidence from China

Habib Hussain Khan,Abdul Ghafoor,Fiza Qureshi,Ijaz Ur Rehman 연세대학교 동서문제연구원 2018 Global economic review Vol.47 No.2

We empirically examine the role of the banking market structure and financial development for the growth of manufacturing and the financially dependent industries in China over the period of 1999–2014. We use both structural and non-structural approaches to assess the banking market structure and relate them to the growth of the manufacturing industries. The results of the study indicate that bank competition inspires industrial growth, particularly the growth of the financially dependent industries. Our findings further suggest that bank concentration undermines the growth of manufacturing industries in general and growth of the financially dependent industries in particular. These results are consistent across a number of sensitivity checks covering alternative measures of financial dependence, institutional factors such as property rights, quality of accounting standards and bank ownership and endogeneity consideration.

PROBING GALAXY FORMATION MODELS IN COSMOLOGICAL SIMULATIONS WITH OBSERVATIONS OF GALAXY GROUPS

HABIB. G., KHOSROSHAHI,GOZALIASL, GHASSEM,FINOGUENOV, ALEXIS,RAOUF, MOJTABA,MIRAGHEE, HALIME The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

We use multi-wavelength observations of galaxy groups to probe the formation models for galaxy formation in cosmological simulations, statistically. The observations include Chandra and XMM-Newton X-ray observations, optical photometry and radio observations at 1.4 GHz and 610 MHz. Using a large sample of galaxy groups observed by the XMM-Newton X-ray telescope as part of the XMM-Large Scale Survey, we carried out a statistical study of the redshift evolution of the luminosity gap for a well defined mass-selected group sample and show the relative success of some of the semi-analytic models in reproducing the observed properties of galaxy groups up to redshift z ~ 1.2. The observed trend argues in favour of a stronger evolution of the feedback from active galactic nuclei at z < 1 compared to the models. The slope of the relation between the magnitude of the brightest cluster galaxy and the value of the luminosity gap does not evolve with redshift and is well reproduced by the models. We find that the radio power of giant elliptic galaxies residing in galaxy groups with a large luminosity gap are lower compared to giant ellipticals of the same stellar masses but in typical galaxy groups.