Engineering and Technology

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2D-Discrete Fourier Transform: Generalization of the MIA-QSAR strategy in molecular modeling
(Chemometrics and Intelligent Laboratory Systems, 2015) Barigye, Stephen J.; Freitas, Matheus P.
Adequate alignment of chemical structure images with respect to the basic scaffold in a series of chemical compounds constitutes an indispensable requirement for constructing multivariate images (MVIs) and subsequent molecular modeling using the Multivariate Image Analysis applied to Quantitative Structure–Activity Relationship (MIA-QSAR) approach. However, up to the moment, this alignment procedure has been manually performed, based on subjective ocular precision. The 2D-Discrete Fourier Transform (2D-DFT) is introduced as a strategy for creating a common base to construct MVIs for chemical structures using their magnitude spectra. The utility of magnitude spectra in QSAR studies has been evaluated through models for the antimalarial, anticancer and trichomonicidal activity of a series of 2, 5-diaminobenzophenone, 4-phenylpyrrolocarbazole and benzimidazole derivatives, respectively, yielding satisfactory results comparable to superior to those reported in the literature. It is anticipated that this strategy should enable the application of the MIA-QSAR approach to structurally diverse datasets other than a series of congeneric datasets.
3D Nerve Cell Cultures and Complex Physiological Relevance
(Drug Discovery Today, 2018) Cheng, Xin; Ndyabawe, Kenneth; Asthana, Amish; Kisaalita, William S.
The field of tissue engineering has not yet provided knowledge on which a consensus for the complex physiological relevance (CPR) of neuronal cultures could be established. The CPR of 3D neuronal cultures can have a profound impact on the drug discovery process through the validation of in vitro models for the study of neuropsychiatric and degenerative diseases, as well as screening for neurotoxicity during drug development. Herein, we assemble evidence in support of the potential of [Ca 2+] i oscillation frequency as a CPR outcome that can demonstrate the in vivo-like behavior of 3D cultures and differentiate them from 2D monolayers. We demonstrate that [Ca 2+] i oscillation frequencies in 2D cultures are significantly higher than those found in 3D cultures, and provide a possible molecular explanation.
3D structure design and simulation for efficient particles capture: The influence of nanofiber diameter and distribution
(Materials Today Communications, 2020) Wu, Jiajun; Akampumuza, Obed; Liu, Penghong; Qin, Xiaohong
Software simulation is a convenient and efficient way to design and check different air filter structures with high efficiency and low pressure drop. In this work, nanofiber filters of different diameters ranging from 100 to 900 nm were designed to check their influence on filtration efficiency, pressure drop and quality factor (QF). Slip-flow effect of air molecules was considered on the surface of single fiber. Then, filters with different diameter distributions were constructed to study the filtration efficiency discrepancy when the filter thickness and porosity were kept equal. With a rotation of the filters composed of nanofibers of 500 nm in diameter in the computational domain, the filtration efficiency and QF increased steadily. The simulation results were partially verified by electrospun cellulose acetate nanofiber filter, and meanwhile provide with new insights into the filter structure design of high filtration efficiency with low pressure drop.
50 Gb/s DMT and 120 Mb/s LTE signal transmission over 5 km of optical fiber using a silicon photonics transceiver
(In Integrated Photonics Research, Silicon and Nanophotonics, 2018) Rahim, Abdul; Abbasi, Amin; Shahin, Mahmoud; Sequeira André, Nuno; Richter, André; Kerrebrouck, Joris Van; Van Gasse, Kasper; Katumba, Andrew; Moeneclaey, Bart; Yin, Xin; Morthier, Geert; Baets, Roel; Roelkens, Gunther
Next-generation passive optical networks will require the use of low-cost, high-performance transceivers to cope with the increasing bandwidth demands for emerging applications such as fixed-mobile convergence for 5G. Silicon photonics is widely acknowledged as a technology that can provide manufacturing of low-cost photonic integrated circuits by using existing CMOS fabrication infrastructure. Intensity modulation/direct detection solutions can reach 100 Gb/s per wavelength, but require high-speed electronics and photonics, which adversely affects the cost. An alternative approach is to use advanced multi-carrier modulation schemes, such as Discrete Multi-Tone (DMT), a real-valued Orthogonal Frequency Division Multiplexing (OFDM) scheme. This technique uses Digital Signal Processing (DSP) to relax electrical and optical bandwidth requirements on the transmitter and receiver side. It promises high spectral efficiency and granularity, higher tolerance to fiber impairments and channel adaptation through flexible multi-level / multi-carrier coding [1]. DMT transmission at 100 Gb/s and even 4x100 Gb/s using modest bandwidth (~ 20 GHz) electronic and optical components has already been demonstrated [2-4]. Despite requiring computationally more expensive DSP compared to single carrier baseband schemes (e.g., OOK, PAM), DMT’s added advantage is that it allows transmission of a mobile data signal within its bandwidth using the same optical transceiver [5]. In this work we demonstrate the combined transmission of a Long Term Evolution (LTE) 4G mobile communication signal (at 3.48 GHz carrier frequency) and a 50 Gb/s DMT signal using a directly modulated InP-on-Silicon Distributed Feedback (DFB) laser. Direct modulation is poised to provide low power consumption and a reduced number of optical components in the transceiver. On the receiver side, a silicon-waveguide-coupled germanium photodiode (GeSi-PD) with a co-designed trans-impedance amplifier (TIA) is used and its performance is compared with a commercial III-V photodiode and TIA.
A Fiber-optic System for Measuring Single Excitation-Dual Emission Fluorescence Ratios in Real Time
(Biotechnology progress, 1992) McCarthy, John F.; Magin, Richard L.; Kisaalita, William S.; Slininger, Patricia J.
The development and subsequent evaluation of a fiber‐optic system for measuring single excitation—dual emission fluorescence ratios in real time is described. The design of the flashlamp excitation source, optics, electronics, and computer software is discussed. The dual emission pH sensitive fluorophore 1, 4‐dihydroxyphthalonitrile (1, 4‐DHPN) was used to test the performance of this system. The flexible design of this modular system permits the use of other single excitation—dual emission fluorophores by simply changing the appropriate optical filters. Upon a single 340–380‐nm excitation, pH‐sensitive emissions were monitored at 488 nm and 434 nm. The ratio of these emissions (488/434) was then computed in real time, for a 2 mM solution of 1, 4‐DHPN, while the pH was titrated over the range 5–9. The nonlinear, system‐dependent, calibration curve of pH versus the ratio of emission wavelengths was empirical fit by a fourth‐order polynomial (r2 = 0.995). Reliable pH measurements in the range 6–8 were obtained using concentrations of 1, 4‐DHPN as low as 50 μM. The standard deviation of pH measurements using a 1 mM solution of 1, 4‐DHPN, near neutral pH, was found to be approximately 0.1 pH unit
A Hardy Cross Approach for Hydraulic Modelling of Water Pipe Networks
(East African Nature and Science Organization, 2022-02-03) Obura, Denis; Kimera, David; Khaldi, Abdelkrim
Whenever there are substantial variations in the quantity of demands within a metropolitan water network, it is necessary to assess the pipe network to aid the water utilities in decision making. Variability in demand exists every time new industries or residences are connected to the network. In cases where no analyses are done prior to making new connections, unnecessarily huge funds are incurred and use of unreasonably bigger pipes is inevitable, some of which may stay redundant. The present study aims at developing a user-friendly numerical hydraulics model for analysing compound pipe networks. The model was developed using the V-Model approach, written in visual basic language to resolve the elementary pipe system equations using the improved Hardy Cross method. This program examines steady-state flows, head losses, flow velocities, and pressures for single, two, three, and four loop water distribution networks. The four-loop example represents the entire network of the case study area in consideration. The comparative study conducted on results from the program and EPANET indicated consistency in the results as coefficient of determinant, R^2, for all the computed variables was approximately unity (1). The Root Mean Square Error (RMSE) and Mean Bias Error (MBE) were found to be reasonably so small. Therefore, it can be concluded from the statistical analysis that the model is reliable for the analysis of a water network consisting of 1, 2, 3, and 4 closed loops.
A Mathematical Model on Linkage Leakage in Sewage Pipes Laid in a Porous Ground Using Computation Fluid Dynamics.
(East African Nature and Science Organization, 2021-11-25) Ebelait, Joseph; Semwogerere, Twaibu; Nagulama, Moses; Keikara, Asaph Muhumuza
This study describes the linkage leakage in sewage pipes through a porous media using computational fluid dynamics with the presence of one leak through fluid simulations using the Ansys fluent 17.2 commercial software based on standard k-ε model under steady-state condition. The pipe section is three-dimensional with a pipe length of 40 mm, a pipe diameter of 20 mm, and leak orifice diameter of 2 mm with a porous media of length 25 mm and width 30 mm. The interest of this study was to reduce the rate of sewage leakage in pipes laid underground by use computational fluid dynamics. The simulation results obtained shows that when the flow is subjected to an outlet pressure between 100000 Pa to 275000 Pa the sewage leaks at pressures of 99499 Pa to 278799.8 Pa indicating that increase of outlet pressures increases the pressure at the leak point and also an increase in the inlet velocity resulted into an increase of velocity at the leak point and no significant change in sewage flow rate with increased inlet velocities. Therefore, monitoring of the pressure and velocity fields along the pipeline is an extremely important tool to identify leaks since these fields are affected by perturbations both before the leak point and after the leak point.
A microwell pattern for C17.2 cell aggregate formation with concave cylindrical surface induced cell peeling
(Biomaterials, 2014) Zhang, Li-Guang; Zhong, Dong-Huo; Zhang, Yiguo; Li, Chen-Zhong; Kisaalita, William S.; Wu, Ze-Zhi
We have developed a polydimethylsiloxane (PDMS) pattern with arrays of microwells for the formation of multicellular aggregates by C17.2 neural stem cells. Upon interfacing with the patterns, the neural stem cells would firstly attach to the microwell sidewalls, forming cellular strips on day 1 after plating. For channel connected microwells, cellular strips on the concave semi-cylindrical sidewall surfaces continued among wells and through channels, followed by strip peeling due to prestress arising from actin filaments and assembly of suspending cellular aggregates within the microwells in the following 1–2 days. Our results also suggested that a small microwell diameter of 80 and 100 μm and a narrow channel width of 20 μm would facilitate the aggregate formation among the structural dimensions tested. Finite element method (FEM) simulation revealed that cellular strips on the semi-cylindrical sidewall surfaces peeled under significantly smaller prestresses (critical peeling prestress, CPP), than cells on flat substrates. However, the CPP by itself failed to fully account for the difference in aggregate inducing capability among the patterns addressed, suggesting cell growth behaviors might play a role. This study thus justified the current patterning method as a unique and practical approach for establishing 3D neural stem cell-based assay platform
A Process Model to Enhance the Accuracy of Digital Forensic Investigations: A case of National Identification and Registration Authority (NIRA-Uganda)
(East African Nature and Science Organization, 2022-12-19) Makheti, Alex; Ocen, Gilbert Gilibrays; Lusiba, Badru; Twaibu, Semwogerere; Alunyu, Andrew Eguar; Matovu, Davis; Odongtoo, Godfrey
The field of digital forensics has become commonplace due to the increasing prevalence of technology since the late 20th century and the inevitable relevance of this technology in the conducting of criminal activity. In traditional forensics, the evidence is generally something tangible that could identify the criminal, such as hair, blood or fingerprints. In contrast, digital forensics deals with files and data in digital form extracted from digital devices like computers, and phones, among other digital devices, meaning is derived from the fact that a computer or computerized device is the subject or object of crime. In this paper, we explore the challenges faced by the National Identification and Registration Authority (NIRA) digital forensic investigation and develop a process model that enhances the accuracy of digital forensic investigation. We adopted a mixed method approach of research involving qualitative, quantitative and experimental design. The study makes significant findings in areas of enhancement accuracy of digital forensic investigation by enumerating the processes that must be followed. As a recommendation for future work, for purposes of generalisation of the study findings, a wider study involving other security agencies such as the police should be conducted.
A single magnetic field exposure system for sequential investigation of real time and downstream cellular responses
(Bioelectromagnetics, 2004) Rao, Raj R.; Kisaalita, William S.
To be able to correlate real time membrane potential or ion flux changes with further downstream gene transcription responses due to extremely low frequency (ELF) electromagnetic field (EMF) exposure, we devised an experimental system consisting of a pair of symmetric circular coils. This system can be used on an inverted microscope stage (real time signaling) as well as inside controlled environment incubators (gene transcription end points). The system includes a unique, custom made switch box for blinding the experimental staff and a power amplifier. We report herein the design and characterization of the system with respect to parameters considered important in in vitro ELF–EMF exposure studies, including linear magnetic field distribution, compensation for microscope objective lens interference, heating effects of the coils, and harmonic content of the signals. Bioelectromagnetics 25:27–32, 2004. © 2003 Wiley-Liss, Inc.
Accuracy of using leaf blade length and leaf blade width measurements to calculate the leaf area of Solanum aethiopicum Shum group
(Heliyon, 2018) Nakanwagi, Mildred Julian; Sseremba, Godfrey; Nahamya, Pamela Kabod; Masanza, Michael; Balyejusa Kizito, Elizabeth
Leaf area is an important parameter when determining growth response under normal as well as stressed environments. No attempt had been made to come up with an affordable but accurate alternative of measuring leaf size in research neglected leafy vegetable crops. Other techniques such as use of leaf area meters are either destructive, expensive or both. A study was conducted to determine leaf area in like-shaped leaves of research neglected crop plants, taking case of S. aethiopicum Shum group (SAS) germplasm. Data was collected on 552 individual plants (including pure lines and hybrids) at eight weeks after planting where a third fully open leaf from top of each plant was considered. Leaf blade length (LBL) and leaf blade width (LBW) were linearly measured while leaf area (LA) was measured using a leaf area meter. This was followed by correlation and regression analysis of LA with LBL, LBW, and LBL þ LBW. Correlation coefficients at p < 0.001 ranged between 0.84 and 0.92, 0.79 and 0.88, 0.86 and 0.95 for total germplasm, pure lines and hybrids, respectively. The coefficient of determination (R2) ranged between 0.72 and 0.92. The best prediction for LA was obtained with hybrid plants (LA ¼ -165.82 þ 5.38LBL þ 16.17LBW) at R2 of 92%. The implication is that we can accurately and affordably predict LA from duo measurements of LBL and LBW in SAS as well as in other crops having similar leaf shapes.
Achieving Highly Selective Electrocatalytic CO2 Reduction by Tuning CuO-Sb2O3 Nanocomposites
(ACS Sustainable Chemistry & Engineering, 2020) Li, Yangmei; Chu, Senlin; Shen, Huidong; Xia, Qineng; Robertson, Alex W.; Masa, Justus; Siddiqui, Umer; Sun, Zhenyu
The development of highly active and selective electrocatalysts with low cost and earth abundance for electrochemical CO2 reduction (ECR) remains an important area of interest. Here, we report the modification of CuO with other metal (Bi, Sb, Cd, and Zr) oxides to form bimetallic oxide nanocomposite catalysts exhibiting efficient ECR. In particular, CuO-Sb2O3 nanoparticles anchored on carbon black (CB) facilitated ECR selectively to CO at low overpotentials, providing a CO faradaic efficiency (FE) of up to 90.0% at −0.8 V versus reversible hydrogen electrode, in contrast to individual CuO/CB and Sb2O3/CB, which gave rise to CO FEs of less than 31.0%, outperforming many previously reported catalysts. A strong interaction between CuO and Sb2O3 is found, which likely contributes to the enhanced ECR activity.
Acid-Responsive Decomposable Nanomedicine Based on Zeolitic Imidazolate Frameworks for Near-Infrared Fluorescence Imaging/Chemotherapy Combined Tumor Theranostics
(Pharmaceutics, 2024) Guo, Heze; Mukwaya, Vincent; Wu, Daikun; Xiong, Shuhan; Dou, Hongjing
Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) are gaining traction in tumor theranostics for their effectiveness in encapsulating both imaging agents and therapeutic drugs. While typically, similar hydrophilic molecules are encapsulated in either pure aqueous or organic environments, few studies have explored co-encapsulation of chemotherapeutic drugs and imaging agents with varying hydrophilicity and, consequently, constructed multifunctional ZIF-8 composite NPs for acid-responsive, near-infrared fluorescence imaging/chemotherapy combined tumor theranostics. Here, we present a one-pot method for the synthesis of uniform Cy5.5&DOX@ZIF-8 nanoparticles in mixed solvents, efficiently achieving simultaneous encapsulation of hydrophilic doxorubicin (DOX) and hydrophobic Cyanine-5.5 (Cy5.5). Surface decoration with dextran (Dex) enhanced colloidal stability and biocompatibility. The method significantly facilitated co-loading of Cy5.5 dyes and DOX drugs, endowing the composite NPs with notable fluorescent imaging capabilities and pH-responsive chemotherapy capacities. In vivo near-infrared fluorescence (NIRF) imaging in A549 tumor-bearing mice demonstrated significant accumulation of Cy5.5 at tumor sites due to enhanced permeability and retention (EPR) effects, with fluorescence intensities approximately 48-fold higher than free Cy5.5. Enhanced therapeutic efficiency was observed in composite NPs compared to free DOX, validating tumor-targeted capability. These findings suggest ZIF-8-based nanomedicines as promising platforms for multifunctional tumor theranostics
Activation and Stabilization of Nitrogen-Doped Carbon Nanotubes as Electrocatalysts in the Oxygen Reduction Reaction at Strongly Alkaline Conditions
(The Journal of Physical Chemistry C, 2013) Zhao, Anqi; Masa, Justus; Schuhmann, Wolfgang; Xia, Wei
Nitrogen-doped carbon nanotubes (NCNTs) are highly active electrocatalysts in the oxygen reduction reaction (ORR) at alkaline conditions. However, the initial activation and stabilization of NCNTs have rarely been investigated at industrially relevant conditions. Three types of NCNTs were synthesized by catalytic growth (NCNT-growth) or posttreatment of oxygen-functionalized CNTs with NH3 (NCNT-NH3) or aniline (NCNT-aniline). The obtained NCNTs were treated in 10 M KOH at 80 °C for 5 h, and the formation of oxygen groups by alkaline treatment and their interaction with existing nitrogen groups was analyzed. X-ray photoelectron spectroscopy showed that the concentrations of pyridinic and quaternary nitrogen increased in NCNT-growth due to the KOH treatment accompanied by the decrease of pyrrolic nitrogen, whereas the nitrogen groups changed differently in NCNT-NH3 and NCNT-aniline. NCNT-NH3 showed the highest ORR activity before alkaline treatment. After the treatment, the activity of NCNT-growth was higher, whereas those of NCNT-NH3 and NCNT-aniline were lower. These results were found to be correlated with changes in the nitrogen groups caused by alkaline treatment. Furthermore, NCNTs showed different C═O/C–O ratios after alkaline treatment as compared to a strong increase of C–O in CNTs, indicating that the presence of nitrogen in NCNTs influences the formation of oxygen groups on carbon and surface oxidation.
Activation of Oxygen evolving Perovskites for Oxygen Reduction by Functionalization with Fe-Nx/C groups
(Chemical communications, 2014) Rincón, Rosalba A.; Masa, Justus; Mehrpour, Sara; Tietz, Frank; Schuhmann, Wolfgang
The incorporation of Fe–Nx/C moieties into perovskites remarkably activates them for the oxygen reduction reaction (ORR) and also leads to notable improvement of their activity towards the oxygen evolution reaction (OER) thus presenting a new route for realizing high performance, low cost bifunctional catalysts for reversible oxygen electrodes.
Active Pharmaceutical Ingredients Sequestrated fromWater Using Novel Mesoporous Activated Carbon Optimally Prepared from Cassava Peels
(Water, 2022) Kayiwa, Ronald; Kasedde, Hillary; Lubwama, Michael; Kirabira, John Baptist
The increasing occurrence of active pharmaceutical ingredients (APIs) in water systems coupled with their recalcitrance to conventional water treatment methods calls for research into more eco-friendly and cost-effective curbing media. Mesoporous cassava peel activated carbon (CPAC) was prepared under conditions derived from optimizing the surface area and yield with the temperature and holding time as the model inputs using the response surface methodology. The sequestration potential and mechanisms of the resultant activated carbon (AC) for active pharmaceutical ingredients from wastewater were studied using batch experiments. The CPAC adsorption kinetics and isothermal mechanisms for the three pharmaceuticals (carbamazepine (CBZ), clarithromycin (CLN), and trimethoprim (TRM)) were studied in both wastewater and Milli-Q water. The API concentrations were measured using liquid chromatography coupled to a mass spectrometer (LC-MS) system. The maximum removal efficiencies were 86.00, 58.00, and 68.50% for CBZ, CLN, and TRM for wastewater, which were less than those from the Milli-Q water at 94.25, 73.50, and 84.5%, respectively. The sorption process for the CLN was better explained by the Freundlich model, whereas the CBZ and TRM adsorption processes could suitably be explained by both the Langmuir and Freundlich models. At an initial concentration of 20 mgL􀀀1 for all APIs and a CPAC dosage of 2.0 gL􀀀1, the maximum adsorption capacities were 25.907, 84.034, and 1.487 mgg􀀀1 for CBZ, TRM, and CLN, respectively. These results demonstrated the potential of CPAC to remove APIs from water, with its sequestration potential being more exhibited after the removal of the organic matter owing to the lower competition for active sites by the APIs. Additionally, positive adsorbates were better removed than negatively charged adsorbates due to the dominance of anions in the cassava peel lattice.
Activity and Stability of Oxides During Oxygen Evolution Reaction‐‐‐From Mechanistic Controversies Toward Relevant Electrocatalytic Descriptors
(Frontiers in Energy Research, 2021) Zeradjanin, Aleksandar R.; Masa, Justus; Schlögl, Robert
Plotting the roadmap of future “renewable energy highway” requires drastic technological advancement of devices like electrolyzers and fuel cells. Technological breakthrough is practically impossible without advanced fundamental understanding of interfacial energy conversion processes, including electrocatalytic water splitting. Particularly challenging is the oxygen evolution reaction which imposes high demands on the long-term activity of electrocatalysts and electrode support materials. To cross the “Rubicon” and in a deterministic manner claim that we developed principles of rational catalyst design, we need first to comprehend the determinants of electrocatalytic activity as well as character of their time evolution. How reliable are reported activity and stability trends, could we interrelate activity and stability, and how meaningful that relation really is are some of the important questions that have to be tackled in building of a more comprehensive view on critically important anodic oxygen evolution.
Addressing Differential Axial Deformation Effect and Sway in 3D Building Frame Analysis
(East African Nature and Science Organization, 2024-05-01) Tukashaba, Shafan
The Differential Axial Deformation Effect (DADE) is a significant consideration in the 3D analysis of building frames, where elements like columns and walls experience compression forces leading to differential shortening. Traditional design methods often overlook DADE, yet the existing building stock seems serviceable despite this omission. However, modern 3D analysis inherently introduces DADE, prompting designers to seek methods to approximate traditional design forces while utilizing advanced analysis techniques. The aim is to achieve design forces close to those historically used, ensuring structural integrity without disregarding DADE entirely. The methods outlined in this report demonstrate how to reconcile 3D analysis results with traditional design principles while also addressing concerns about sway deflections and the need for a conservative approach. While there's a debate about the economic viability of designing for a wider envelope of design conditions, the report illustrates that the additional reinforcement needed is typically minimal. Notably, the DADE phenomenon is universal across Finite Element Method (FEM) analysis software, and the strategies discussed here can be applied across different platforms. The notion that staged construction analysis effortlessly resolves DADE issues is debunked. Staged construction analysis is complex, doesn't fully eliminate DADE, and can yield unreliable results if not used carefully. In summary, this report offers practical insights into navigating DADE in 3D structural analysis, emphasizing the importance of balancing modern techniques with traditional design considerations
Adhesion And Composite Micro-Hardness Of DLC And Si-DLC Films Deposited On Nitrile Rubber
(Surface and Coatings Technology, 2012) Lubwama, M.; Corcoran, B.; Sayers, K.; Kirabira, J.B.; Sebbit, A.; McDonnell, K.A.; Dowling, D.
Thin films of hydrogenated diamond-like carbon (DLC) and silicon (Si) doped diamond-like carbon (Si-DLC) have been deposited on acrylonitrile butadiene rubber (NBR) using a closed field unbalanced magnetron sputtering ion plating system. A sputter cleaning process was integrated into the deposition process so as to reduce the likelihood of re-contamination between the cleaning and deposition stages. The deposited coatings showed excellent adherence with an adhesion rating of 4 A for films with a Si-C interlayer. The composite micro-hardness was highest for DLC films at 15.5 GPa for indentation load of 147.1 mN using a Vickers microhardness tester. Tribological tests undertaken under normal load of 5 N using a pin-on-disc tribometer for all of the samples of DLC and Si-DLC films, with and without Si-C interlayer, show a friction increase between 0.25 and 0.4 to between 0.45 and 0.6. This friction increase has been related to the micro-hardness of the films.
Administration of BDNF/ginsenosides combination enhanced synaptic development in human neural stem cell
(Journal of neuroscience methods, 2011) Wang, Lina; Kisaalita, William S.
Ginsenosides Rg1 and Rb1, major pharmacologically active ingredients from Ginseng, the root of Panax ginseng C.A. Meyer (Araliaceae), were applied in the differentiation media for human neural stem cells (hNSCs), together with brain-derived neurotrophic factor (BDNF), a commonly used compound for neural stem cell (NSC) differentiation. Cell locomotion and neurite extension were observed by time-lapse microscopy and analyzed by ImageJ software. The expression of synaptic formation was confirmed by immunostaining of synaptophysin (SYN) or/and the co-localization of synapsin I and microtubule associated protein-2 (MAP-2). Effects of cell density on neural differentiation were also examined. Results have shown that administration of BDNF/ginsenosides (Rg1 and Rb1) combination in differentiation medium promoted cell survival, enhanced neurite outgrowth and synaptic marker expression during differentiation. High cell density enhanced synaptic marker expression in BDNF/ginsenosides combination medium. In all, this study established a condition for hNSCs synaptic development in early differentiation, which is a crucial step in applying this cell line in neural network-based assay.

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