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Abstrak :
ABSTRAK
In this paper we present a numerical procedure for calculation of electrical conductivity in a periodic lattice of one dimensional zero range potentials with a case of dominant impurity scattering. The conductivity was previously obtained in an integral form via an approximate solution of the kinetic Kolmogorov equation. The proposed approach is based on the quadrature formula for certain type of integrals. The results are compared with the low temperature limit approximation.

Abstrak :
ABSTRAK
Latar Belakang: Tujuan dari penelitian ini adalah untuk mengetahui pengaruh stres oksidatif pada ketahanan hidup spermatozoa manusia melalui peningkatan ekspresi caspase 3 dan aktivasi Akt. Informasi ini berhubungan dengan infertilitas laki-laki yang menurunkan viabilitas dan parameter kinetik spermatozoa. Metode: Spermatozoa manusia diperoleh dari donor normozoospermia. Spermatozoa dimurnikan menggunakan larutan percoll. Spermatozoa dari seminal plasma dilarutkan dalam media Bigger, Whitter, dan Whittingham (BWW). Kemudian, spermatozoa diinkubasi dengan hidrogen peroksida (H2O2) 50 M, 100 M, 150 M, 200 M dan 250 M selama 2 jam. Stres oksidatif diuji dengan uji malondialdehid (MDA). Viabilitas diperiksa dengan larutan eosin Y. Parameter motilitas diukur dengan Computer Assisted Sperm Analyzer (CASA). Deteksi protein western blot akan dilakukan dengan antibodi anti-caspase-3 untuk mengenali caspase-3 dan antibodi phosphodetect yang mengenali fosforilasi Akt. Hasil: Setelah inkubasi H2O2 selama 2 jam, terdapat efek H2O2 terhadap penurunan viabilitas dan motilitas (VAP, VSL, VCL) secara signifikan. Selain itu, viabilitas dan motilitas memiliki hubungan positif dengan proses apoptosis dan ketahanan hidup spermatozoa dengan menggunakan caspase 3 (meningkat) dan fosforilasi Akt (menurun) secara signifikan. Kesimpulan: Stres oksidatif dapat menurunkan viabilitas dan kinetik spermatozoa melalui peningkatan ekspresi caspase-3 dan penurunan aktivitas Akt

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ABSTRACT
Background: The purposes of this study was to evaluate the effect of oxidative stress on survival of human spermatozoa through releasing apoptotic process, This information has correlated with idiopathic infertility that decrease viability and motility parameters spermatozoa. Methods: Human spermatozoa were obtained from normozoospermic volunteer donors. Spermatozoa was purified using discontinuous Percoll. Spermatozoa from the plasma seminal dissolved in Bigger, Written, and Whittingham (BWW) medium. Then, spermatozoa were incubated with 50 M, 100 M, 150 M, 200 M dan 250 M hydrogen peroxide (H2O2) for 2-h. Oxidative stress were assed by malondialdehyde (MDA) assay. Viability was examined by eosin Y solution. Kinectic parameters were assessed by Computer Assisted Sperm Analyzer (CASA). Detection of perotein in the western blot was examined with anti-caspase-3 antibodies to recognize caspase-3 activity and phsophodetect antibody that recognizes the phosphorylation of Akt. Results: After 2-h incubation H2O2, there was dose dependent effect of H2O2 on viability and motility parameters significantly decrease. Therefore, viability and kinetic were positive relationship on apoptotic and survival effect by using caspase-3 activation (increase) and akt (decrease) significantly. Conclusions: Oxidative stress can decreases viability and kinetic spermatozoa through increase caspse 3 and decrease Akt activation

Abstrak :
Penelitian ini difokuskan pada aspek ¬aspek kinetika dekomposisi metana dalam reaktor DBD koaksial yang terbuat dari kuarsa dan elektroda stainless steel. Reaksi berlangsung pada tekanan atmosfer dan laju alir umpan 250 cc/menit. Konversi metana semakin stabil pada volume reaktor yang besar dan tegangan yang rendah. Dekomposisi optimal diperoleh pada reaktor 55,4 cc dengan tegangan 9,5 kV. Berdasarkan penelitian ini diperoleh bahwa laju reaksi dipengaruhi oleh tegangan reaktor, 9,5 kV memberikan laju reaksi yang paling besar. Laju reaksi dekomposisi dan formasi metana masing¬masing dipengaruhi waktu tinggal. Laju reaksi tersebut tidak dapat dimodelkan dengan pendekatan reaksi elementer. ......This experiment is focused in kinetic aspects of methane decomposition through coaxial DBD reactor made from quartz dielectric and stainless steel electrodes. Reaction occurs at atmospheric pressure and 250 cc/min feed flow rate. Methane conversion is more stable in the larger reactor volume and lower voltage. Optimal decomposition is obtained in 55,4 cc reactor and 9,5 kV voltage. The data showed that reaction reaction rate is affected by reactor voltage, 9,5 kV results the fastest reaction rate. Both decomposition and formation rate of methane are affected by residence time. Those reaction rates model can?t be developed well with elementary reaction approach.