The Functional Roles of Rho-Kinase and Matrix Metalloproteinases in Regulating Corneal Stromal Cell Mechanics in 3-D Collagen Matrices

The file named "ZHOU-DISSERTATION-2013.pdf" is the primary dissertation file. Eleven (11) supplemental movie files are also available.The main focus of my research has been on understanding the biomechanical and biochemical mechanisms of cell-extracellular matrix (ECM) interactions during corneal wound healing, which may allow the development of new therapeutic strategies to promote corneal regeneration. Previous studies have established that the Rho GTPases play a central role in regulating the cytoskeletal changes associated with cell mechanical activity. A novel force monitoring system was successfully developed to investigate the role of Rho in corneal cell force generation in 3-D collagen matrices. Maximum tractional force generated by 9 million corneal fibroblasts in serum culture was around 265 Dynes. Inhibition of Rho kinase by Y-27632 induced a 69% force reduction. These results demonstrated that Rho/Rho kinase play a key role in mediating contractile force generation of corneal stromal fibroblasts in serum culture. I also investigated the functions of Rho GTPase signaling in corneal stromal fibroblast migration and cell-ECM interactions using a 3-D nested matrix construct. The experimental results showed that both the amount and the speed of corneal fibroblast migration and local collagen matrix reorganization were significantly inhibited by Y-27632. Following the inhibition, cells extended thinner dendritic processes into the outer matrix, and generated tractional forces at their leading edge. However, cells were unable to generate contractile forces needed to retract their tail and pull the cell body forward through the collagen matrix. I also studied the role of Matrix metalloproteinases (MMPs) in corneal cell mechanics, since these have been recognized as an influential component in extracellular matrix turnover and corneal repair. I first assessed the expression and collagenolytic activities of MMPs by primary corneal keratocyte in response to different signaling factors. I then studied the functions of MMPs in regulating keratocyte migration, cell-induced matrix contraction, and cell protrusive activity in 3-D collagen matrices. This study suggested that, in serum free PDGF culture, although collagenolysis was limited to a pericellular scale, primary corneal keratocytes utilized MMPs to facilitate cell migration, ECM contraction, cell spreading in 3-D collagen matrices. Thus MMPs may play a key role in facilitating cell-collagen matrix interactions by corneal keratocytes, without producing widespread disruption of corneal ECM structure

Existence of weak solutions to stochastic heat equations driven by truncated α\alpha-stable white noises with non-Lipschitz coefficients

We consider a class of stochastic heat equations driven by truncated $\alpha$-stable white noises for $1<\alpha<2$ with noise coefficients that are continuous but not necessarily Lipschitz and satisfy globally linear growth conditions. We prove the existence of weak solution, taking values in two different spaces, to such an equation using a weak convergence argument on solutions to the approximating stochastic heat equations. For $1<\alpha<2$ the weak solution is a measure-valued c\`{a}dl\`{a}g process. However, for $1<\alpha<5/3$ the weak solution is a c\`{a}dl\`{a}g process taking function values, and in this case we further show that for $0<p<5/3$ the uniform $p$-th moment for $L^p$-norm of the weak solution is finite, and that the weak solution is uniformly stochastic continuous in $L^p$ sense and satisfies a flow property

Comparison principle for stochastic heat equations driven by α\alpha-stable white noises

For a class of non-linear stochastic heat equations driven by $\alpha$-stable white noises for $\alpha\in(1,2)$ with Lipschitz coefficients, we first show the existence and pathwise uniqueness of $L^p$-valued c\`{a}dl\`{a}g solutions to such a equation for $p\in(\alpha,2]$ by considering a sequence of approximating stochastic heat equations driven by truncated $\alpha$-stable white noises obtained by removing the big jumps from the original $\alpha$-stable white noises. If the $\alpha$-stable white noise is spectrally one-sided, under additional monotonicity assumption on noise coefficients, we prove a comparison theorem on the $L^2$-valued c\`{a}dl\`{a}g solutions of such a equation. As a consequence, the non-negativity of the $L^2$-valued c\`{a}dl\`{a}g solution is established for the above stochastic heat equation with non-negative initial function

Pores Structure Change Induced by Heat Treatment in Cold-Sprayed Ti6Al4V Coating

In this study, the evolution of pores structure in cold-sprayed Ti6Al4V coating (TC4) was analyzed before and after 600-1100 °C heat treatment. It was found that almost no change happened to pores under the heat treatment temperature below 600 °C. When the heat treatment temperature was increased to 700 °C, the coating recrystallized, and pores turned to spheroid and healed because of the “bridging” effect. Some of the pores coarsened after 800 °C and 900 °C heat treatment. This kind of phenomenon grew severer when the heat treatment temperature increased to 1000 °C and 1100 °C. On the whole, with the increment of temperature, for the coating prepared at relatively low temperature, apparent porosity measured by image analysis method tended to go down first and then up, but it decreased all the time for the coating prepared at relatively high temperature. The reason for this phenomenon was contributed to the bonding state of particles in the coating. Only when there were fewer weakly bonded interfaces, the detachment between the particle interfaces which may be caused by release of residual stress did not occur, and there was no pores expansion and internal connectivity, so the porosity continuously decreased

Dehydroepiandrosterone sulfate mediates activation of transcription factors CREB and ATF-1 via a Gα11-coupled receptor in the spermatogenic cell line GC-2

AbstractDehydroepiandrosterone sulfate (DHEAS) is a circulating steroid produced in the adrenal cortex, brain, and gonads. Whereas a series of investigations attest to neuroprotective effects of the steroid in the brain, surprisingly little is known about the physiological effects of DHEAS on cells of the reproductive system. Here we demonstrate that DHEAS acting on the spermatogenic cell line GC-2 induces a time- and concentration-dependent phosphorylation of c-Src and Erk1/2 and activates the transcription factors activating transforming factor-1 (ATF-1) and cyclic AMP-responsive element binding protein (CREB). These actions are consistent with the non-classical signaling pathway of testosterone and suggest that DHEAS is a pro-androgen that is converted into testosterone in order to exert its biological activity. The fact, however, that steroid sulfatase mRNA was not detected in the GC-2 cells and the clear demonstration of DHEAS-induced activation of Erk1/2, ATF-1 and CREB after silencing the androgen receptor by small interfering RNA (siRNA) clearly contradict this assumption and make it appear unlikely that DHEAS has to be converted in the cytosol into a different steroid in order to activate the kinases and transcription factors mentioned. Instead, it is likely that the DHEAS-induced signaling is mediated through the interaction of the steroid with a membrane-bound G-protein-coupled receptor, since silencing of Guanine nucleotide-binding protein subunit alpha-11 (Gnα11) leads to the abolition of the DHEAS-induced stimulation of Erk1/2, ATF-1, and CREB. The investigation presented here shows a hormone-like activity of DHEAS on a spermatogenic cell line. Since DHEAS is produced in male and female reproductive organs, these findings could help to define new roles for DHEAS in the physiology of reproduction

THE APPLICATION OF SPEED READING AT INTERMEDIATE LEVEL (A Case Study of Qualitative Research in One of Senior High School at Majalengka)

Muhammad Salim Pajri. 14111330143. THE APPLICATION OF SPEED READING AT INTERMEDIATE LEVEL (A Case Study of Qualitative Research in One of Senior High School at Majalengka) Reading is the important things in education, because people can get knowledge and information from reading. Without reading people cannot absorb many sciences. Here, the researcher use speed reading technique as the tool of analyzing to know the learning and teaching process at intermediate level. Moreover, the aims of this research are (1). To know the teaching and learning process of speed reading. (2). To know students’ attitude towards teaching and learning speed reading. (3). To know overcome of the difficulties of speed reading. Theoretically, is regarding to the reading area, especially in the reading comprehension by using speed reading technique. Practically, the researcher will analyze of speed reading in one of Senior High School at Majalengka which has benefit for teacher to know students’ ability in school. The research finding and discussion told about the teaching and learning process of speed reading at intermediate level. There are three activities of speed reading techniques. (1) Preparation Activity: teacher begins with greetings, deliver material and prepare students by warming up to focuss in learning process. (2) Core Activity: teacher teaches all the materials of speed reading. (3) Follow-up Activity: teacher gives exercise as the activity to know students score of speed reading test. The result of the analysis shows there are 5 students’ attitude towards teaching and learning speed reading. then, the finding shows that (1). Students’ feeling towards teaching and learning using speed reading in general: students like speed reading then also comfortable. (2). Students’ feeling towards the process of teaching and learning speed reading: they get comprehension of this technique. (3). Students’ difficulties in learning using speed reading: there are unfamiliar word on athe text. (4). Students’ feeling towards their comprehension in learning using speed reading: they get purpose in speed reading learning. (5). Students’ motivation in learning using speed reading: they can read books in fast time. It was found the overcome of difficulties of speed reading technique they are the process of the teaching speed reading and response the students’ response towards it, difficulties, disadvantages and teaching using speed reading technique and the result, usefulness, critics, and suggestions of teaching using speed reading technique. From the research that has been done, it can be concluded that there is way to apply speed reading by using steps of speed reading. From this technique will increase students’ ability in reading process. It can help students to read fast and efficient time. Keywords: Reading Comprehension, Speed Reading, Intermediate Leve

UPAYA MENINGKATKAN MOTIVASI BELAJAR SISWA MELALUI MEDIA GAME EDUCATION DALAM PEMBELAJARAN IPS DI MTs HASBUR RACHMAN ALIF DESA LENGKONG WETAN KABUPATEN MAJALENGKA

ASEP SAMSUL MA'ARIF : Berdasarkan Observasiawal di kelas VII MTs Hasbur Rachman Alif terlihat proses pembelajaran IPS masih menggunakan media spidol dan papan tulis. Sehingga banyak siswa yang kurang memperhatikan guru pada saat proses pembelajaran., Hal ini berakibat pada kejenuhan dan kebosanan yang berdampak pada hasil belajar siswa yang kurang dari KKM yang diterapkan di MTs Hasbur Rachman Alif yakni 70. Tujuan penelitian ini untuk mengetahui bagaimana penerapan pembelajaran dengan menggunakan media Game Education pada mata pelajaran IPS Terpadu, aktivitas siswa dan kinerja guru dengan pembelajaran dengan menggunakan media Game Education, dan mengetahui motivasi belajar siswa sebelum dan setelah diterapkannya pembelajaran dengan menggunakan media Game education pada mata pelajaran IPS Terpadu di MTs Hasbur Rachman Alif. Pembelajaran dengan menggunakan media Game Education menekankan motivasi siswa untuk berpikir kritis dan menuangkan. Hal ini memudahkan siswa untuk mengakses materi IPS yang banyak dimanapun, serta mempemudah daya ingat siswa tentang apayatgtelah didapatkan selama proses pembelajaran. Penelitian ini menggunakan Penelitian Tindakan Kelas (pTK) yang dilaksanakan selama tiga siklus. Teknik Pengumpulan data menggunakan observasi, tes, dan dokumentasi. Subjek penelitian ini adalah siswa kelas VII MTs Hasbur Rachman Alif sebanyak 31 siswa yang terdiri dari 18 siswa laki-laki dan 13 siswa perempuan. Pembelajaran dengan menggunakan media Game Education dapat meningkatkan motivasi belajar siswa hal ini terlihat dari hasil tes yang telah dilakukan selama tiga siklus, dimana pada pratindakan (pretes) nilai sebesar 65,25 dan ketuntasan belajar 25 yo, siklus I nilai rata-rata sebesar 76,75 dan ketuntasan_ belajar siswa sebesar 65,5%o siklus II nilai rata-rata siswa 85,75 dan nilai ketuntasan belajar sebesar 90% siklus III dengan nilai rata-rata 92,25 dan ketuntasan belajar mengalami peningkatanya itu 97,5yo. Dengan demikian dapat disimpulkan bahwa pembelajaran dengan menggunakan media Game Education merupakan salah satu upaya untuk meningkatkan hasil belajar siswa pada mata pelajaran IPS Terpadu di MTs Hasbur Rachman Alif. Kata Kunci: Game Education, MotivasiBelajar, PTK