Theory on the Dynamics of Oscillatory Loops in the Transcription Factor Networks

We develop a detailed theoretical framework for various types of transcription factor gene oscillators. We further demonstrate that one can build genetic-oscillators which are tunable and robust against perturbations in the critical control parameters by coupling two or more independent Goodwin-Griffith oscillators through either -OR- or -AND- type logic. Most of the coupled oscillators constructed in the literature so far seem to be of -OR- type. When there are transient perturbations in one of the -OR- type coupled-oscillators, then the overall period of the system remains constant (period-buffering) whereas in case of -AND- type coupling the overall period of the system moves towards the perturbed oscillator. Though there is a period-buffering, the amplitudes of oscillators coupled through -OR- type logic are more sensitive to perturbations in the parameters associated with the promoter state dynamics than -AND- type. Further analysis shows that the period of -AND- type coupled dual-feedback oscillators can be tuned without conceding on the amplitudes. Using these results we derive the basic design principles governing the robust and tunable synthetic gene oscillators without compromising on their amplitudes.Comment: 37 pages, 13 figures, 2 table

Theory on the mechanism of DNA renaturation: Stochastic nucleation and zipping

Renaturation of complementary single strands of DNA is one of the important processes that requires better understanding in the view of molecular biology and biological physics. Here we develop a stochastic dynamical model on the DNA renaturation. According to our model there are at least three steps in the renaturation process viz. incorrect-contact formation, correct-contact formation and nucleation, and zipping. Most of the earlier two-state models combined nucleation with incorrect-contact formation step. In our model we suggest that it is considerably meaningful when we combine the nucleation with the zipping since nucleation is the initial step of zipping and the nucleated and zipping molecules are indistinguishable. Incorrect-contact formation step is a pure three-dimensional diffusion controlled collision process. Whereas nucleation involves several rounds of one-dimensional slithering dynamics of one single strand of DNA on the other complementary strand in the process of searching for the correct-contact and then initiate nucleation. Upon nucleation, the stochastic zipping follows to generate a fully renatured double stranded DNA. It seems that the square-root dependency of the overall renaturation rate constant on the length of reacting single strands originates mainly from the geometric constraints in the diffusion controlled incorrect-contact formation step. Further the inverse scaling of the renaturation rate on the viscosity of the reaction medium also originates from the incorrect-contact formation step. On the other hand the inverse scaling of the renaturation rate with the sequence complexity originates from the stochastic zipping which involves several rounds of crossing over the free-energy barrier at microscopic levels.Comment: 17 pages, 2 figure

Potensi keterlibatan pelajar kejuruteraan elektrik semester akhir KUiTTHO dalam bidang keusahawanan

Kajian ini adalah bertujuan untuk mengenal pasti potensi keterlibatan pelajarpelajar kejuruteraan elektrik semester akhir KUiTTHO dalam bidang keusahawanan. Di samping itu, kajian ini juga cuba mengenal pasti perbezaan penglibatan di dalam bidang keusahawanan dari segi jantina. Pengumpulan data adalah melalui soal selidik. Sebanyak 86 soal selidik telah di analisis berdasarkan kaedah kualitatif iaitu taburan frekuensi, peratusan dan skor min dan secara kuantitatif ujian -t dengan menggunakan perisian Statistical Package for Social Science(SPSS ver 10.0). Hasil kajian menunjukkan bahawa majoriti daripada responden mempunyai sikap yang positif terhadap bidang keusahawanan. Walau bagaimanapun secara keseluruhan tahap potensi keterlibatan dalam bidang keusahawanan adalah di paras sederhana. Ini mungkin disebabkan pelajar-pelajar kejuruteraan lebih cenderung untuk menceburi bidang keijaya lain yang menawarkan pendapatan yang tetap dan berhasrat menjadi seorang profesional seperti jurutera. Hasil kajian juga menunjukkan bahawa tiada terdapat perbezaan signifikan dari segi jantina, potensi keterlibatan dalam bidang keusahawanan. Adalah dicadangkan agar pihak KUiTTHO dapat mengenal pasti calon-calon atau bakal-bakal usahawan semasa mereka masih menuntut untuk membolehkan penyaluran bantuan dilakukan dengan secepat mungkin sebelum semangat mereka lentur. Satu kajian dicadangkan untuk melihat potensi keterlibatan semua pelajar kejuruteraan IPTA dan IPTS di seluruh Malaysia dan melihat siapakah di kalangan mereka bcnar-benar mempunyai potensi menceburi bidang keusahawanan

Effect of heavy metals on the level of vitamin E, total lipid and glycogen reserves in the liver of common carp (Cyprinus carpio L.)

The aim of this study is to examine some changes in the biochemical profile of the liver tissue of common carp (Cyprinus carpio L.) exposed to a sublethal concentration of heavy metal mixture (cadmium, chromium, nickel and lead). The biochemical profile, specifically glycogen, total lipid and vitamin E content in the liver tissue was examined and compared to that of the control group. The exposed group showed a marked decline in glycogen and vitamin E reserves. Conversely an increase in total lipid in comparison to control was observed. The result reflects the sensitivity of these biochemical parameters to the effects of sublethal levels of combined heavy metals for this the widely consumed freshwater fish

Przestrzenna zmienność morfologii plaży pod kątem grzbietów i strumieni spowodowana powstaniem kopalni złóż okruchowych wzdłuż Vembar – Wybrzeże Kallar w Indiach

This article does not contain abstracts in English.Celem tej pracy jest omówienie przestrzennych i krótkotrwałych zmian w morfologii plaży pod kątem grzbietów i strumieni na podstawie profili plaży w Vembar, na wybrzeżu Kallar, Tamil Nadu, Indie. Plaże składają się głównie z średniego do grubego piasku i ciężkich minerałów. Dla plaż charakterystyczne są grzbiety, strumienie i zagłębienia. Grzbiety i strumienie są niewielkie ze względu na prace kopalniane prowadzone w okolicy. Ustalono, że przestrzenne i tymczasowe zmiany w systemie grzbietów i strumieni są kontrolowane przez pianę morską/łamiące się fale. Zmiany objętości sedymentu wynikają z nieregulowanej aktywności kopalni. Erozja ma wpływ na profil wszystkich plaż, zwłaszcza strumieni. Strefy przyrostu znajdują się wyżej, to znaczy na najwyższych grzbietach i wałach plażowych. Krótkotrwałe zmiany wielkości plaży wyjaśniają zniekształcenie grzbietów i strumieni. Ma to związek z pobliską kopalnią. Zaobserwowano wzorzec wiatru wyżej plaży, gdzie warunki pozwalają na transport sedymentu piasku i jego ruch na grzbietach i strumieniach

Analysis and implementation of FMECA methodology – vacuum machine

The production of injection moulding components for the automotive market, meeting the highly demanding requirements of the industry, requires a continuous capacity of investment in the maintenance of the machine park. Although many companies perform this maintenance in a corrective lens, others already use the more sophisticated tools that have to avoid possible problems during the manufacturing process, ensuring levels of production and quality required by the automotive industry. This report presents the contributions obtained during an internship in a company of production of injected casting components for the automotive market and whose objective was to apply the methodology of analysis of the mode of failure, effects and criticality (FMECA – Failure mode effects and criticality analysis) to one of the company's most critical machines, the vacuum pressure die-casting machine Work begins with the understanding, in terms of operation and purpose, of the machine under analysis. Subsequently, and given its vital character for the high performance of the vacuum die-casting machine, an analysis is made of the type of failures that may occur in the vacuum equipment of the machine The FMECA methodology is applied to the vacuum equipment in order to identify its potential failure modes and to evaluate the effects that these failures may have on the foundry machine. The contributions resulting from the application of the FMECA methodology gave rise to a specific control plan for the detected problems and to a schedule and mandatory equipment maintenance.A produção de componentes de fundição injetada para o mercado automóvel, cumprindo com os requisitos altamente exigentes da indústria, requer uma capacidade contínua de investimento na manutenção do parque de máquinas. Embora sejam muitas as empresas que executam esta manutenção numa ótica corretiva, outras já recorrem a ferramentas mais sofisticadas que têm com objetivo evitar possíveis problemas durante o processo de fabrico, assegurando níveis de produção e qualidade exigidos pela indústria automóvel. Neste relatório apresentam-se as contribuições obtidas durante a realização de um estágio numa empresa de produção de componentes de fundição injetada para o mercado automóvel e que tinha como objetivo aplicar a metodologia de análise do modo de falhas, efeitos e criticidade (FMECA) a uma das máquinas mais críticas da empresa, a máquina de fundição sob pressão de vácuo. Iniciam-se os trabalhos com a compreensão, em termos de funcionamento e propósitos, da máquina em análise. Seguidamente, e dado seu caráter vital para o alto desempenho da máquina de fundição sob pressão de vácuo, faz-se uma análise do tipo de falhas que podem ocorrer nos equipamentos para vácuo da máquina. É aplicada a metodologia FMECA ao equipamento de vácuo por forma a identificar os seus potenciais modos de falha e avaliar os efeitos que estas falhas possam acarretar sobre a máquina de fundição. As contribuições resultantes da aplicação da metodologia FMECA deram origem a um plano de controle específico para os problemas detectados e a um calendário e manutenção obrigatória dos equipamentos

HPV and Cervical Cancer Control Programs: Effective Translation of Knowledge into Practice

Cervical cancer is a major cancer affecting 5.3 million women annually, worldwide, and is responsible for about 2.7 million deaths per year. More than 85% of the incident cases occur in developing countries. Cervical cancer is a totally preventable cancer, if diagnosed in the precancer stages and treated effectively. HPV vaccination has been introduced in many countries. Effective screening and treatment programs are available in many health settings. Posttreatment histopathological follow-up is done for 3–5 years. Cure from precancer condition and prevention of invasive cervical cancer are thus attained. But the main hurdle in achieving the above ambitious goal is the lacunae and deficiencies in conversion of knowledge into practice by the women who are otherwise well informed about the prevention of cervical cancer, as result of massive inputs in the field of health education. Thus, the screening participation and compliance to precancer treatment remain low. This barrier in translational knowledge should be overcome efficiently. The author, from his vast experience in planning and implementing one of the largest cervical cancer screening programs in India, has conceptualized “the STAR model P6 principles of Raj” for successful conversion of “knowledge into practice.