On twin density and resistivity of nanometric Cu thin films

Barmak, Katayun,Liu, Xuan,Darbal, Amith,Nuhfer, N. Thomas,Choi, Dooho,Sun, Tik,Warren, Andrew P.,Coffey, Kevin R.,Toney, Michael F. American Institute of Physics 2016 Journal of Applied Physics Vol.120 No.6

Survey of a New Note on Karnaugh Maps

Barmak Honarvar Shakibaei Asli 보안공학연구지원센터 2012 International Journal of Control and Automation Vol.5 No.2

Safflower seed oil, a rich source of linoleic acid, stimulates hypothalamic neurogenesis in vivo

Mehrzad Jafari Barmak,Ebrahim Nouri,Maryam Hashemi Shahraki,Ghasem Ghalamfarsa,Kazem Zibara,Hamdallah Delaviz,Amir Ghanbari 대한해부학회 2023 Anatomy & Cell Biology Vol.56 No.2

Adult neurogenesis has been reported in the hypothalamus, subventricular zone and subgranular zone in thehippocamp. Recent studies indicated that new cells in the hypothalamus are affected by diet. We previously showed beneficial effects of safflower seed oil (SSO), a rich source of linoleic acid (LA; 74%), on proliferation and differentiation of neural stemcells (NSCs) in vitro. In this study, the effect of SSO on hypothalamic neurogenesis was investigated in vivo, in comparison tosynthetic LA. Adult mice were treated with SSO (400 mg/kg) and pure synthetic LA (300 mg/kg), at similar concentrations of LA, for 8 weeks and then hypothalamic NSCs were cultured and subsequently used for Neurosphere-forming assay. In addition, serum levels of brain-derived neurotrophic factor (BNDF) were measured using enzyme-linked immunosorbent assay. Administration of SSO for 8 weeks in adult mice promoted the proliferation of NSCs isolated from SSO-treated mice. Immunofluorescence staining of the hypothalamus showed that the frequency of astrocytes (glial fibrillary acidic protein+cells) are not affected by LA or SSO. However, the frequency of immature (doublecortin+ cells) and mature (neuronal nuclei+cells) neurons significantly increased in LA- and SSO-treated mice, compared to vehicle. Furthermore, both LA and SSO caused a significant increase in the serum levels of BDNF. Importantly, SSO acted more potently than LA in all experiments. The presence of other fatty acids in SSO, such as oleic acid and palmitic acid, suggests that they could be responsible for SSO positive effect on hypothalamic proliferation and neurogenesis, compared to synthetic LA at similar concentrations.

On the Potential of Tungsten as Next-generation Semiconductor Interconnects

최두호,Katayun Barmak 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.5

The continuous scaling of copper (Cu) interconnects produced two majorshortcomings – a severe resistivity size effect and material reliability issues. Tungsten (W), with the expected reduction in resistivity size effect due to itsshorter electron mean free path and improved reliability due to its highactivation energy for diffusion, is a worthwhile candidate to replace Cu. Inthis article, the potential of W for future interconnects is critically discussedby reviewing the current status of W technology, including various Wprocessing methods and the resulting phases, resistivity and microstructure. The compatibility of W with the back-end-of-line processes in CMOSdevices is also discussed. The resistivity of W and Cu wires at similar nanoscaleis compared based on the Fuchs-Sondheimer surface scattering modeland Mayadas-Shatzkes grain boundary scattering model using the reportedscattering parameters (p = 0.11 and R = 0.42 for W, and p = 0.52 andR = 0.43 for Cu), which shows that the resistivity of W wires is predicted toexhibit lower resistivity than that of Cu wires at line-widths below ~15 nm. Finally, anisotropy in the resistivity size effect in W wires is discussed, witha suggested method to reduce wire resistivity.

Evaluation of the Effect of Pentoxifylline on Cisplatin-Induced Testicular Toxicity in Rats

Fallahzadeh, Ali Reza,Rezaei, Zohreh,Rahimi, Hamid Reza,Barmak, Mehrazd Jafari,Sadeghi, Hossein,Mehrabi, Sadrollah,Rabani, Seyed Mohammadreza,Kashani, Iraj Ragerdi,Barati, Vahid,Mahmoudi, Reza Korean Society of ToxicologyKorea Environmental Mu 2017 Toxicological Research Vol.33 No.3

Chemotherapy is associated with male infertility. Cisplatin (cis-diamminedichloro-platinum (II) (CDDP) as a chemotherapy medication used to treat a number of cancers has been reported to most likely induce testicular toxicity. Administration of antioxidants, such as pentoxifylline (PTX) may reduce some Adverse Drug Reactions (ADRs) of CDDP. Therefore, this study investigated the potentially protective effects of PTX on CDDP-induced testicular toxicity in adult male rats. For this purpose, 42 male rats were randomly divided into 7 groups. The rats were orally pretreated with PTX at the 3 doses of 75, 150, and 300 mg/kg once a day for 14 successive days. On the $14^{th}$ day of the study, they were intraperitoneally (IP) administered with a single dose of CDDP (7 mg/kg). Finally, the sperm/testis parameters, serum levels of reproductive hormones, including testosterone, Luteinizing Hormone (LH), and Follicle Stimulating Hormone (FSH) as the pivotal endocrine factors controlling testicular functions, and histopathological changes of testis tissue were examined. Pretreatment with the two doses of 75 and 150 mg/kg PTX indicated significant increases in the sperm count and motility induced by CDDP administration. The right and significantly left testis weights were decreased following the treatment with 300 mg/kg of PTX plus CDDP. However, 75 mg/kg of PTX plus CDDP showed the best near-to-normal histopathological features. The results demonstrated that PTX alone enhanced some parameters, such as the sperm count, while reducing other parameters, including sperm fast motility and germ layer thickness. Furthermore, despite testosterone or LH levels, the mean serum FSH level was significantly augmented by the doses of 75 and 150 mg/kg. It was concluded that PTX administration cannot reduce CDDP-induced testicular toxicity even at high doses (e.g., 300 mg/kg), while it seemed to partially intensify CDDP toxicity effects at a dose of 75 mg/kg. Thus, further research is required in this regard.

Evaluation of the Effect of Pentoxifylline on Cisplatin-Induced Testicular Toxicity in Rats

Ali Reza Fallahzadeh,Zohreh Rezaei,Hamid Reza Rahimi,Mehrazd Jafari Barmak,Hossein Sadeghi,Sadrollah Mehrabi,Seyed Mohammadreza Rabani,Iraj Ragerdi Kashani,Vahid Barati,Reza Mahmoudi 한국독성학회 2017 Toxicological Research Vol.33 No.3

Chemotherapy is associated with male infertility. Cisplatin (cis-diamminedichloro-platinum (II) (CDDP) as a chemotherapy medication used to treat a number of cancers has been reported to most likely induce testicular toxicity. Administration of antioxidants, such as pentoxifylline (PTX) may reduce some Adverse Drug Reactions (ADRs) of CDDP. Therefore, this study investigated the potentially protective effects of PTX on CDDP-induced testicular toxicity in adult male rats. For this purpose, 42 male rats were randomly divided into 7 groups. The rats were orally pretreated with PTX at the 3 doses of 75, 150, and 300 mg/kg once a day for 14 successive days. On the 14<SUP>th</SUP> day of the study, they were intraperitoneally (IP) administered with a single dose of CDDP (7 mg/kg). Finally, the sperm/testis parameters, serum levels of reproductive hormones, including testosterone, Luteinizing Hormone (LH), and Follicle Stimulating Hormone (FSH) as the pivotal endocrine factors controlling testicular functions, and histopathological changes of testis tissue were examined. Pretreatment with the two doses of 75 and 150 mg/kg PTX indicated significant increases in the sperm count and motility induced by CDDP administration. The right and significantly left testis weights were decreased following the treatment with 300 mg/kg of PTX plus CDDP. However, 75 mg/kg of PTX plus CDDP showed the best near-to-normal histopathological features. The results demonstrated that PTX alone enhanced some parameters, such as the sperm count, while reducing other parameters, including sperm fast motility and germ layer thickness. Furthermore, despite testosterone or LH levels, the mean serum FSH level was significantly augmented by the doses of 75 and 150 mg/kg. It was concluded that PTX administration cannot reduce CDDP-induced testicular toxicity even at high doses (e.g., 300 mg/kg), while it seemed to partially intensify CDDP toxicity effects at a dose of 75 mg/kg. Thus, further research is required in this regard.

Failure of semiclassical models to describe resistivity of nanometric, polycrystalline tungsten films

Choi, Dooho,Liu, Xuan,Schelling, Patrick K.,Coffey, Kevin R.,Barmak, Katayun American Institute of Physics 2014 Journal of Applied Physics Vol.115 No.10

<P>The impact of electron scattering at surfaces and grain boundaries in nanometric polycrystalline tungsten (W) films was studied. A series of polycrystalline W films ranging in thickness from 10 to 310 nm and lateral grain size from 74 to 133 nm were prepared on thermally oxidized Si. The Fuchs-Sondheimer surface-scattering model and Mayadas-Shatzkes grain-boundary scattering model were employed for quantitative analyses. Predictions from the theoretical models were found to deviate systematically from the experimental data. Possible reasons for the failure of the theoretical models to describe the experimental data are explored. Finally, a discussion of the crucial features lacking from existing models is presented, along with possible avenues for improving the models to result in better agreement with experimental data. (C) 2014 AIP Publishing LLC.</P>

Via Method for Lithography Free Contact and Preservation of 2D Materials

Telford, Evan J.,Benyamini, Avishai,Rhodes, Daniel,Wang, Da,Jung, Younghun,Zangiabadi, Amirali,Watanabe, Kenji,Taniguchi, Takashi,Jia, Shuang,Barmak, Katayun,Pasupathy, Abhay N.,Dean, Cory R.,Hone, Ja American Chemical Society 2018 NANO LETTERS Vol.18 No.2

<P>Atomically thin 2D materials span the common components of electronic circuits as metals, semiconductors, and insulators, and can manifest correlated phases such as superconductivity, charge density waves, and magnetism. An ongoing challenge in the field is to incorporate these 2D materials into multilayer heterostructures with robust electrical contacts while preventing disorder and degradation. In particular, preserving and studying air-sensitive 2D materials has presented a significant challenge since they readily oxidize under atmospheric conditions. We report a new technique for contacting 2D materials, in which metal <I>via contacts</I> are integrated into flakes of insulating hexagonal boron nitride, and then placed onto the desired conducting 2D layer, avoiding direct lithographic patterning onto the 2D conductor. The metal contacts are planar with the bottom surface of the boron nitride and form robust contacts to multiple 2D materials. These structures protect air-sensitive 2D materials for months with no degradation in performance. This via contact technique will provide the capability to produce “atomic printed circuit boards” that can form the basis of more complex multilayer heterostructures.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2018/nalefd.2018.18.issue-2/acs.nanolett.7b05161/production/images/medium/nl-2017-05161z_0005.gif'></P>

Interfacial orientation and misorientation relationships in nanolamellar Cu/Nb composites using transmission-electron-microscope-based orientation and phase mapping

Liu, X.,Nuhfer, N.T.,Rollett, A.D.,Sinha, S.,Lee, S.B.,Carpenter, J.S.,LeDonne, J.E.,Darbal, A.,Barmak, K. Elsevier Science 2014 Acta materialia Vol.64 No.-

A transmission-electron-microscope-based orientation mapping technique that makes use of beam precession to achieve near-kinematical conditions was used to map the phase and crystal orientations in nanolamellar Cu/Nb composites with average layer thicknesses of 86, 30 and 18nm. Maps of high quality and reliability were obtained by comparing the recorded diffraction patterns with pre-calculated templates. Particular care was taken in optimizing the dewarping parameters and in calibrating the frames of reference. Layers with thicknesses as low as 4nm were successfully mapped. Heterophase interface plane and character distributions (HIPD and HICD, respectively) of Cu and Nb phases from the samples were determined from the orientation maps. In addition, local orientation relation stereograms of the Cu/Nb interfaces were calculated, and these revealed the detailed layer-to-layer texture information. The results are in agreement with previously reported neutron-diffraction-based and precession-electron-diffraction-based measurements on an accumulated roll bonding (ARB)-fabricated Cu/Nb sample with an average layer thickness of 30nm as well as scanning-electron-microscope-based electron backscattered diffraction HIPD/HICD plots of ARB-fabricated Cu/Nb samples with layer thicknesses between 200 and 600nm.