Role of Myosin II and Arp 2/3 in the motility and force generation of Neuronal Growth Cones

Differentiating neurons have to find chemical cues to form the correct synaptic connections with the other neurons so that they can create a functional neuronal network. During their development differentiating neurons project neurites, at the distal part of which there is a growth cone (GCs). The growth cone has highly motile structures, referred as lamellipodia and filopodia. Lamellipodia and filopodia sense the environment and process the mechanical and chemical stimulus and also exert forces. During my work for the completion of my PhD thesis, I used Optical Tweezers, video imaging and immunocytochemistry to quantify the motility and the force exerted by lamellipodia and filopodia from Dorsal Ganglion (DRG) neurons. I have also precisely quantified the role of some proteins and signaling pathways which regulate the motility of the DRG GCs. The first part of my results entitled, \u201cThe role of myosin-II in force generation of DRG filopodia and lamellipodia\u201d, characterizes the role of Myosin II in growth cone dynamics. Myosin II has been shown to control the retrograde flow of actin polymers, to be involved in the orchestration of actin and microtubules (MTs) dynamics and to possess contractile activity. GCs advance due to combined effects of the adhesion of lamellipodia and filopodia on the substrate and the contractile activity of Myosin II. Therefore, I probed the functional role of Myosin II on GCs dynamics by using its specific inhibitor, Blebbistatin. I show that the force exerted by lamellipodia decreased but surprisingly the force exerted by filopodia increased upon treatment with Blebbistatin. Moreover I show that the well organized and distributed structures of lamellipodia and filopodia of the GCs depend on the activity of Myosin II and confirmed the coupling between actin and microtubule dynamics. The next chapter, \u201cThe role of Rac1 in force generation of DRG neurons\u201d, describes the function of Rac1 and its downstream effector Arp2/3 in lamellipodia and filopodia formation and dynamics. It is well known that Rac1 Rho-GTPase acts as a switch between GTP bound active state and GDP bound inactive state. I observed that GCs retract following partial inhibition of Arp2/3 but recover their usual motility within 5-10 minutes. I found that this recovery is caused by the activation of Rac1. This indicates that Rac1 acts as switch and activates upon Arp2/3 inhibition, possibly through integrin pathways. I also confirmed that the activity of Arp2/3 not only regulates the formation of lamellipodia but also controls the dynamics and formation of filopodia

Studi kritis pemikiran Siti Musdah Mulia dan Khoiruddin Nasution tentang urgensi pencatatan nikah masuk dalam rukun nikah

Fokus penelitian ini, yaitu: (1) Pemikiran dan metode istinbāṭ Siti Musdah Mulia tentang urgensi pencatatan nikah masuk dalam rukun nikah, (2) Pemikiran dan metode istinbāṭ Khoiruddin Nasution tentang urgensi pencatatan nikah masuk dalam rukun nikah, (3) Relevansi pemikiran Siti Musdah Mulia dan Khoiruddin Nasution tentang urgensi pencatatan nikah masuk dalam rukun nikah pada konteks sekarang. Jenis penelitian adalah penelitian kepustakaan (library research). Teknik pengumpulan data menggunakan metode dokumentasi dan wawancara. Pendekatan yang digunakan pendekatan fikih, pendekatan filsafat hukum Islam (uṣūl al-fiqh) dan pendekatan komparatif (comparative approach). Penyajian data menggunakan metode deskriptif dan deduktif. Analisis data menggunakan metode deskriptif-analitik dan content analysis. Hasil penelitian ini, yakni: (1) Pemikiran Siti Musdah Mulia tentang urgensi pencatatan nikah masuk dalam rukun nikah adalah karena banyak dampak mudarat yang ditimbulkan akibat pernikahan siri/bawah tangan. Metode istinbāṭ yang digunakan Siti Musdah Mulia dalam menetapkan pencatatan nikah sebagai rukun nikah adalah surah al-Baqarah ayat 282 dengan metode qiyas aulawi, dilalah al-maqāṣid sejumlah hadis tentang pengumuman nikah dan metode maṣlaḥah mursalah, (2) Pemikiran Khoiruddin Nasution tentang urgensi pencatatan nikah masuk dalam rukun nikah adalah karena adanya perubahan konteks pengakuan dan penjaminan hak yang pada masa Rasul SAW cukup dengan walimah, pengumuman dan saksi, sedangkan pengakuan dan penjaminan hak konteks sekarang adalah dengan pencatatan nikah. Khoiruddin Nasution menggunakan metode kombinasi tematik-holistik dalam menetapkan pencatatan nikah sebagai rukun nikah, (3) Melihat kondisi masyarakat, hukum, norma-norma dan sosial-kultural yang berkembang pada masyarakat Indonesia saat ini, pemikiran Siti Musdah Mulia dan Khoiruddin Nasution tentang pencatatan nikah sebagai rukun nikah yang ditinjau secara filosofis, yuridis dan sosiologis dapat dikatakan tidak relevan. Sebab, keberlakuan pencatatan nikah baik secara filosofis, yuridis dan sosiologis hanyalah sebagai alat bukti autentik dan agar pernikahan tertib, sehingga bukanlah penentu keabsahan dalam pernikahan

URGENSI PENCATATAN NIKAH SEBAGAI RUKUN NIKAH (STUDI KRITIS PEMIKIRAN SITI MUSDAH MULIA DAN KHOIRUDDIN NASUTION)

Fokus dari penelitian ini adalah tentang pemikiran Siti Musdah Mulia dan Khoiruddin Nasutionserta metode istinbā tentang urgensi pendaftaran pernikahan sebagai pilar pernikahan. Penelitianini merupakan penelitian kepustakaan. Teknik pengumpulan data menggunakan metodedokumentasi dan wawancara. Penelitian ini menggunakan pendekatan yurisprudensi, pendekatanfilsafat hukum Islam (uṣūlal-fiqh), dan pendekatan komparatif. Presentasi data menggunakanmetode deskriptif dan deduktif. Menganalisis data menggunakan metode analisis deskriptifanalitikdan konten. Hasil dari penelitian ini, adalah: (1) Pemikiran Siti Musdah Mulia tentangpentingnya pendaftaran pernikahan sebagai pilar pernikahan adalah karena ada banyak dampaknegatif yang disebabkan oleh perkawinan yang tidak terdaftar atau pernikahan informal. MetodeIstinbāṭ yang digunakan oleh Siti Musdah Mulia untuk menentukan pendaftaran nikah sebagaipilar pernikahan adalah surah al-Baqarah ayat 282 dengan metode qiyas aulawi, dilalah al-maqāṣid beberapa hadis tentang pengumuman perkawinan dan metode ma mlaḥah mursalah, (2)pemikiran Khoiruddin Nasution tentang urgensi pencatatan perkawinan sebagai pilar pernikahan adalah karena perubahan pengakuan dan jaminan konteks hak pada zaman Nabi SAW sudahcukup dengan walimah, pengumuman dan saksi, sementara sekarang pengakuan dan jaminanyang benar adalah pendaftaran nikah. Khoiruddin Nasution menggunakan metode kombinasitematik-holistik untuk menentukan pendaftaran pernikahan sebagai pilar pernikahan. (3)Mempertimbangkan kondisi masyarakat, hukum, norma dan sosial budaya yang berkembangpada masyarakat Indonesia saat ini maka Siti Musdah Mulia dan Khoiruddin Nasution tentangpendaftaran pernikahan sebagai pilar perkawinan yang ditinjau secara filosofis, yuridis dansosiologis , bisa dikatakan sudah tidak relevan lagi. Karena, keabsahan pendaftaran pernikahanbaik secara filosofis, yuridis dan sosiologis hanya sebagai bukti otentik dan ketertibanpernikahan orde nikah yang tertib, sehingga bukan penentu legitimasi dalam perkawinan

The effect of nitrogen on seed and oil yield of seven sesame (Sesamum indicumL.) genotypes in Isfahan

Nitrogen is a major part of plant nutrition in agricultural ecosystems. It greatly affects the yield of crops, specially ''oilseed crops'' such as sesame. In order to study the effect of nitrogen and genotype on the seed and oil yield of sesame; an experiment was laid out in split plots based on randomized complete block design with three replications and 35 plants m-2 at the Lavark Research Farm, Isfahan University of Technology, in 2006. Three nitrogen levels (50, 100 and 150 Kg N ha-1) and seven sesame genotypes (Local Ardestan, Nonbracching Naz, Branching Naz, Yekta, Oltan, Darab 14 and Varamin 2822) were used in main and sub plots, respectively. With an increase in nitrogen application to at least 150 kg N ha-1, despite a decrease in oil content, the seed and oil yield increased (P 0.01) averaged over genotypes. Since Yekta and Oltan outyielded the rest of genotypes, the latter genotypes with application of at least 150 kg N ha-1 could be recommended for sesame production in Isfahan

Improvement of Seed Germination of Date-plum (Diospyros lotus L.) by Physical and Chemical Treatments

Persimmon (Diospyros kaki) is an important subtropical, monoecious, dioeocious and polygamous tree which belongs to Ebenaceae family. Because of low total seed and low viability seed in persimmon, grafting on seedling rootstock is generally used for its propagation. The common rootstock is Diospyros lotus, but its seeds have long dormancy. So, the study was carried out to investigate the effects of stratification (0, 25, 50 and 70 days) at 4-70C, scarification with (97%) sulphuric acid (0, 2.5, 5 and7.5 minute) and GA3 (0, 250, 500 and 750 mgL-1) on seed germination of D. lotus. Results showed that the most germination rate was observed in GA3 at 250 mgL-1. Stratification for 70 days had the most germination percent. The most germination uniformity was observed in GA3 at 500 mgL-1. In scarification plus stratification, the germination percent was lower than control and stratification

The effect of polyamines and SICS on the compatibility, fertility and yield indices of apple cv. Golden Delicious

The most critical problems of temperate fruit trees are poor fruit setand low yield. To solve the problem, some major chemical compounds such as polyamines and SICS (self-incompatibility control substance, Mn+B) can be used. Popular polyamines including Putrescine (0.1 and 0.25 mM), both Spermine and Spermidine (0.05 and 0.25 mM), and SICS (1 and 2 mg L-1) were used alone or with cotton coverage bags to cover branches in order to investigate self-incompatibility in Malus domestica. Results showed that Spermidine (0.25 mM) led to higher yields in comparison with that of the control. SICS (2 mg L-1), also, demonstrated the highest yield compared with that of the control. At June fruit set, treatment with Spermidine (0.25 mM) led to the highest percentage of fruit set and also the highest index of self-incompatibility and percentageof final fruit set among treatments

The effect of polyamines and SICS on the compatibility, fertility and yield indices of apple cv. Golden Delicious

The most critical problems of temperate fruit trees are poor fruit setand low yield. To solve the problem, some major chemical compounds such as polyamines and SICS (self-incompatibility control substance, Mn+B) can be used. Popular polyamines including Putrescine (0.1 and 0.25 mM), both Spermine and Spermidine (0.05 and 0.25 mM), and SICS (1 and 2 mg L-1) were used alone or with cotton coverage bags to cover branches in order to investigate self-incompatibility in Malus domestica. Results showed that Spermidine (0.25 mM) led to higher yields in comparison with that of the control. SICS (2 mg L-1), also, demonstrated the highest yield compared with that of the control. At June fruit set, treatment with Spermidine (0.25 mM) led to the highest percentage of fruit set and also the highest index of self-incompatibility and percentageof final fruit set among treatments

Design and Modeling of a D–Shaped PCF Refractive Index Sensor Based on SPR Effect

Abstract: This study introduces an efficient D-shaped sensor for refractive index (RI) sensing based on the surface plasmon resonance (SPR) phenomenon. The sensor design was examined through numerical simulations utilizing the finite element method (FEM). The calculations revealed that the proposed fiber demonstrates particular suitability for sensing within the wavelength spectrum spanning from 0.5 to 0.7μm. Our results yielded a remarkable wavelength sensitivity and substantial RI resolution of 9500 nm/RIU and 6.5 ×10–6 RIU, respectively which observed as the analyte RI ranged 1.33~1.36. Additionally, a maximum amplitude sensitivity of 215 RIU–1, accompanied by an impressive linearity of 0.99862 was acheived

Mechanistic study to investigate the effects of different gas injection scenarios on the rate of asphaltene deposition: An experimental approach

Asphaltene deposition during enhanced oil recovery (EOR) processes is one of the most problematic challenges in the petroleum industry, potentially resulting in flow blockage. Our understanding of the deposition mechanism with emphasis on the rate of the asphaltene deposition is still in its infancy and must be developed through a range of experiments and modelling studies. This study aims to investigate the rate of asphaltene deposition through a visual study under different gas injection scenarios. To visualise the asphaltene deposition, a high-pressure setup was designed and constructed, which enables us to record high-quality images of the deposition process over time. Present research compares the effects of nitrogen (N2), carbon dioxide (CO2) and methane (CH4) on the rate of asphaltene deposition at different pressures. The experimental results in the absence of gas injection revealed that the rate of asphaltene deposition increases at higher pressures. The results showed that the rate of asphaltene deposition in the case of CO2 injection is 1.2 times faster than CH4 injection at 100 bar pressure. However, N2 injection has less effect on the deposition rate. Finally, it has been concluded that the injection of CO2 leads to more asphaltene deposition in comparison with CH4 and N2. Moreover, the experimental results confirmed that gas injection affects the mechanism of asphaltene flocculation and leads to the formation of bigger flocculated asphaltene particles. The findings of this study can help for a better understanding of the mechanism of the asphaltene deposition during different gas-EOR processes