This work investigates a new interrogation method of a fiber Bragg grating (FBG) sensor based on longer and shorter wavelengths to distinguish between transversal forces and temperature variations. Calibration experiments were carried out to examine the sensor's repeatability in response to the transversal forces and temperature changes. An automated calibration system was developed for the sensor's characterization, calibration, and repeatability testing. Experimental results showed that the FBG sensor can provide sensor repeatability of 13.21 pm and 17.015 pm for longer and shorter wavelengths, respectively. The obtained calibration coefficients expressed in the linear model using the matrix enabled the sensor to provide accurate predictions for both measurements. Analysis of the calibration and experiment results implied improvements for future work. Overall, the new interrogation method demonstrated the potential to employ the FBG sensing technique where discrimination between two/three measurands is needed.
In the present study, the construction of arrays on silicon for naked-eye detection of DNA dengue was demonstrated. The array was created by exposing a polyethylene glycol (PEG) silane monolayer to 254 nm ultraviolet (UV) light through a photomask. Formation of the PEG silane monolayer and photomodifed surface properties was thoroughly characterized by using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The results of XPS confirmed that irradiation of ultraviolet (UV) light generates an aldehyde functional group that offers conjugation sites of amino DNA probe for detection of a specific dengue virus target DNA. Employing a gold enhancement process after inducing the electrostatic interaction between positively charged gold nanoparticles and the negatively charged target DNA hybridized to the DNA capture probe allowed to visualize the array with naked eye. The developed arrays demonstrated excellent performance in diagnosis of dengue with a detection limit as low as 10 pM. The selectivity of DNA arrays was also examined using a single base mismatch and noncomplementary target DNA.
This work describes a hydrogel fluorescence microsensor for prolonged stable temperature measurements. Temperature measurement using microsensors has the potential to provide information about cells, tissues, and the culture environment, with optical measurement using a fluorescent dye being a promising microsensing approach. However, it is challenging to achieve stable measurements over prolonged periods with conventional measurement methods based on the fluorescence intensity of fluorescent dye because the excited fluorescent dye molecules are bleached by the exposure to light. The decrease in fluorescence intensity induced by photobleaching causes measurement errors. In this work, a photobleaching compensation method based on the diffusion of fluorescent dye inside a hydrogel microsensor is proposed. The factors that influence compensation in the hydrogel microsensor system are the interval time between measurements, material, concentration of photo initiator, and the composition of the fluorescence microsensor. These factors were evaluated by comparing a polystyrene fluorescence microsensor and a hydrogel fluorescence microsensor, both with diameters of 20 µm. The hydrogel fluorescence microsensor made from 9% poly (ethylene glycol) diacrylate (PEGDA) 575 and 2% photo initiator showed excellent fluorescence intensity stability after exposure (standard deviation of difference from initial fluorescence after 100 measurement repetitions: within 1%). The effect of microsensor size on the stability of the fluorescence intensity was also evaluated. The hydrogel fluorescence microsensors, with sizes greater than the measurement area determined by the axial resolution of the confocal microscope, showed a small decrease in fluorescence intensity, within 3%, after 900 measurement repetitions. The temperature of deionized water in a microchamber was measured for 5400 s using both a thermopile and the hydrogel fluorescence microsensor. The results showed that the maximum error and standard deviation of error between these two sensors were 0.5 °C and 0.3 °C, respectively, confirming the effectiveness of the proposed method.
Peptide cross-linked poly(ethylene glycol) hydrogel has been widely used for drug delivery and tissue engineering. However, the use of this material as a biosensor for the detection of collagenase has not been explored. Proteases play a key role in the pathology of diseases such as rheumatoid arthritis and osteoarthritis. The detection of this class of enzyme using the degradable hydrogel film format is promising as a point-of-care device for disease monitoring. In this study, a protease biosensor was developed based on the degradation of a peptide cross-linked poly(ethylene glycol) hydrogel film and demonstrated for the detection of collagenase. The hydrogel was deposited on gold-coated quartz crystals, and their degradation in the presence of collagenase was monitored using a quartz crystal microbalance (QCM). The biosensor was shown to respond to concentrations between 2 and 2000 nM in less than 10 min with a lower detection limit of 2 nM.
Fibrosarcoma is a rare type of cancer that affects cells known as fibroblasts that are malignant, locally recurring, and spreading tumor in fibrous tissue. In this work, an iron plate immersed in an aqueous solution of double added deionized water, supplemented with potassium permanganate solution (KMnO4) was carried out by the pulsed laser ablation in liquid method (PLAIL). Superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized using different laser wavelengths (1064, 532, and 266 nm) at a fluence of 28 J/cm2 with 100 shots of the iron plate to control the concentration, shape and size of the prepared high-stability SPIONs. The drug nanocarrier was synthesized by coating SPION with paclitaxel (PTX)-loaded chitosan (Cs) and polyethylene glycol (PEG). This nanosystem was functionalized by receptors that target folate (FA). The physiochemical characteristics of SPION@Cs-PTX-PEG-FA nanoparticles were evaluated and confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods. Cell internalization, cytotoxicity assay (MTT), apoptosis induction, and gene expression of SPION@Cs-PTX-PEG-FA were estimated in fibrosarcoma cell lines, respectively. In vivo studies used BALB/c tumor-bearing mice. The results showed that SPION@Cs-PTX-PEG-FA exhibited suitable physical stability, spherical shape, desirable size, and charge. SPION@Cs-PTX-PEG-FA inhibited proliferation and induced apoptosis of cancer cells (P
The use of nanocarriers composed of polyethylene glycol- and polyvinyl alcohol-coated vesicles encapsulating active molecules in place of conventional chemotherapy drugs can reduce many of the chemotherapy-associated challenges because of the increased drug concentration at the diseased area in the body. The present study investigated the structure and magnetic properties of iron oxide nanoparticles in the presence of polyvinyl alcohol and polyethylene glycol as the basic surface coating agents. We used superparamagnetic iron oxide nanoparticles (FNPs) as the core and studied their effectiveness when two polymers, namely polyvinyl alcohol (PVA) and polyethylene glycol (PEG), were used as the coating agents together with magnesium-aluminum-layered double hydroxide (MLDH) as the nanocarrier. In addition, the anticancer drug sorafenib (SO), was loaded on MLDH and coated onto the surface of the nanoparticles, to best exploit this nano-drug delivery system for biomedical applications. Samples were prepared by the co-precipitation method, and the resulting formation of the nanoparticles was confirmed by X-ray, FTIR, TEM, SEM, DLS, HPLC, UV-Vis, TGA and VSM. The X-ray diffraction results indicated that all the as-synthesized samples contained highly crystalline and pure Fe3O4. Transmission electron microscopy analysis showed that the shape of FPEGSO-MLDH nanoparticles was generally spherical, with a mean diameter of 17 nm, compared to 19 nm for FPVASO-MLDH. Fourier transform infrared spectroscopy confirmed the presence of nanocarriers with polymer-coating on the surface of iron oxide nanoparticles and the existence of loaded active drug consisting of sorafenib. Thermogravimetric analyses demonstrated the thermal stability of the nanoparticles, which displayed enhanced anticancer effect after coating. Vibrating sample magnetometer (VSM) curves of both produced samples showed superparamagnetic behavior with the high saturation magnetization of 57 emu/g for FPEGSO-MLDH and 49 emu/g for FPVASO-MLDH. The scanning electron microscopy (SEM) images showed a narrow size distribution of both final samples. The SO drug loading and the release behavior from FPEGSO-MLDH and FPVASO-MLDH were assessed by ultraviolet-visible spectroscopy. This evaluation showed around 85% drug release within 72 h, while 74% of sorafenib was released in phosphate buffer solution at pH 4.8. The release profiles of sorafenib from the two designed samples were found to be sustained according to pseudo-second-order kinetics. The cytotoxicity studies confirmed the anti-cancer activity of the coated nanoparticles loaded with SO against liver cancer cells, HepG2. Conversely, the drug delivery system was less toxic than the pure drug towards fibroblast-type 3T3 cells.
In this study, the rice husk flour-plastic waste composites (RPC) was produced from polypropylene (PP) and high density polyethylene (HDPE) wastes with 30 and 50% rice husk flour (RHF) contents. RPC was made by melt compounding and compression moulding processes. The electrical resistivity, thermal stability and tensile strength of RPC were determined. The RPC was tested in electrical resistivity and tensile strength according to the ASTM D-257 and ASTM D-638 respectively, while thermal stability was tested using thermogravimetric analysis (TGA) method. From the results, high content of RHF reduces all properties, except for tensile modulus of elasticity (TMOE) in tensile strength test. The ability of moisture absorption and the presence of hemicelluloses, cellulose and silica in RHF reduce the electrical resistivity and thermal stability behaviour of RPC from 50% RHF. The good binding elements and filler agglomeration in RPC from 50% RHF improve only TMOE. Insufficient stress transfer and rigid interphase occurred between RHF and plastics during tensile maximum load and elongation at break (Eb) in tensile strength test. In general, RPC from HDPE indicates better thermal stability, tensile modulus of rupture and Eb (in tensile strength test) compared to PP, based on the good behaviour of thermal conductivity, low water absorption, high molecular weight and good elongation properties of HDPE. However, RPC from PP shows good electrical resistance due to the low thermal expansion coefficient of PP.
The electrical resistivity and flexural strength of plastic composites reinforced with pineapple leaf particles (PCPLP) is presented. PCPLP were produced using different plastic materials; Polyethylene (PE) and Polypropylene (PP), and different plastic pineapple leaf particle ratios; 50:50 and 70:30. The PCPLP were tested and evaluated with respect to electrical resistivity and flexural strength according to ASTM D257 and D790, respectively. The results indicate that PCPLP made from PP exhibits better electrical resistance than PE, which may be attributed to the better frequency insulation behaviour ofPP. PCPLP using the higher ratio of 70:30 also exhibited better electrical resistance than the lower 50:50 ratio. Cellulose materials inherently influence the electrical resistance of plastic composites, due to their natural propensity to absorb moisture. The PCPLP produced using a ratio of 50:50 for both PP and PE composites exhibited better MOE results than the 70:30 composites, however the converse is true with respect to the MOR. MOE of PCPLP was increased with increasing pineapple leaf particles content due to the greater matrix stiffness of this natural particle with respect to plastic matrix. However, high percentage offiller particles in the matrix (70:30 ratio) has reduced the toughness in the composite structure due to the lost ofphysical contact between high accumulated particles.
Recently, research and development in the field of drug delivery systems (DDS) facilitating site-specific therapy has reached significant progression. DDS based on polymer micelles, coated micro- and nanoparticles, and various prodrug systems including water-soluble polymer have been prepared and extensively studied as novel drugs designed for cancer chemotherapy and brain delivery. Since polymers are going to be used in human, this study has the interest of testing two types of polymer, polyimides (PI) and polyphenylenevinylene (PPV) on neuronal cells. The objective of this study was to determine the possible neurotoxicity and potential neuroprotective effects of PI and PPV towards SH-SY5Y neuronal cells challenged by hydrogen peroxide (1120) as an oxidant. Cells were pretreated with either PI or PPV for 1 hour followed by incubation for 24 hour with 100 ,uM of 11201. MTS • assay was used to assess cell viability. Results show that PI and PPV are not harmful within the concentration up to 10 pM and 100 pM, respectively. However, PI and PPV do not protect neuronal cells against toxicity induced by H2O, or further up the cell death.
Diabetic wounds are difficult to treat due to multiple causes, including reduced blood flow and bacterial infections. Reduced blood flow is associated with overexpression of prostaglandin transporter (PGT) gene, induced by hyperglycaemia which causing poor vascularization and healing of the wound. Recently, gold nanoparticles (AuNPs) have been biosynthesized using cold and hot sclerotium of Lignosus rhinocerotis extracts (CLRE and HLRE, respectively) and capped with chitosan (CS) to produce biocompatible antibacterial nanocomposites. The AuNPs have shown to produce biostatic effects against selected gram positive and negative bacteria. Therefore, in this study, a dual therapy for diabetic wound consisting Dicer subtract small interfering RNA (DsiRNA) and AuNPs was developed to improve vascularization by inhibiting PGT gene expression and preventing bacterial infection, respectively. The nanocomposites were incorporated into thermoresponsive gel, made of pluronic and polyethylene glycol. The particle size of AuNPs synthesized using CLRE (AuNPs-CLRE) and HLRE (AuNPs-HLRE) was 202 ± 49 and 190 ± 31 nm, respectively with positive surface charge (+30 to + 45 mV). The thermoresponsive gels containing DsiRNA-AuNPs gelled at 32 ± 1 °C and released the active agents in sufficient amount with good texture and rheological profiles for topical application. DsiRNA-AuNPs and those incorporated into thermoresponsive pluronic gels demonstrated high cell viability, proliferation and cell migration rate via in vitro cultured cells of human dermal fibroblasts, indicating their non-cytotoxicity and wound healing properties. Taken together, the thermoresponsive gels are expected to be useful as a potential dressing that promotes healing of diabetic wounds.
A suitable and cost-effective microfabrication technique for processing aluminum micropart is required, as the choice
of aluminum microparts for aerospace, electronics and automobile components is preferred over other metals due to its
excellent properties. Meanwhile, powder injection molding (PIM) is identified as an economical manufacturing technique
for processing ceramic and micro-metal powders into microparts and or components. Therefore, this study investigates
formulation and processing of aluminum PIM feedstock using a custom-made machine. The investigation is focused on
the effect of mixing process parameters (powder loading, rotor speed and mixing temperature) and the suitability of
the backbone polymer. The formulated PIM feedstock constituents are paraffin wax (PW), stearic acid (SA), high-density
polyethylene (HDPE)/ medium-density polyethylene (MDPE) alternatively and aluminum micro-metal powder. Taguchi
method is used for the design of experiments (DOEs) and analysis. In addition, response surface methodology (RSM) is
employed to develop empirical viscosity models. The optimum powder-binder mixing ratio of 58:42 vol. % with rotor
speed of 43 rpm were determined for preparing aluminum PIM feedstock using mini-lab mixer developed. The empirical
model developed for aluminum PIM feedstock viscosity shows a good fit with R2
values of 0.84 using HDPE and 0.96 for
MDPE binder system. This investigation demonstrates preparation and suitability of aluminum PIM feedstock using waxbased
binder system.
Protein degradation can occur through Ubiquitin 26S-Proteosome System (UPS). The degradation can be mediated by
the SCF E3 ubiquitin ligase complex consisting of Skp1, Cullin, and F-box protein as the main components. The F-box
protein at the C-terminal domain functions to recognize the targeted protein to be ubiquitinated and degraded via UPS.
A stress-responsive F-box gene, PmF-box1 from Persicaria minor was categorized in the F-box containing kelch repeat
(FBK) family; a family that specific to plant kingdom. To identify the targeted protein of PmF-box1, yeast-two hybrid system
(Y2H) was used. In the Y2H screening process, mating efficiency is very important to fish out the interacting proteins.
Therefore, one modification was conducted to increase the mating efficiency. In this screening, PmF-box1 was used as a
bait to screen for the Y2H library which was constructed using RNA from plant samples treated with abscisic acid (ABA)
and polyethylene glycol (PEG)-8000 and control sample. Autoactivation and toxicity tests of bait were performed before
the Y2H screening. Tests on PmF-box1 showed that it is not toxic to the yeast and cannot autoactivate the yeast reporter
genes. Mating efficiency was improved from 2.07% to 9.15% after addition of PEG-4000 in the mating culture compared
to the original protocol, which it also increased the colony number in the screening step afterward. Additionally, bands
of gene with different sizes were observed on electrophoresis gel after colony PCR analysis from the improved technique.
Those genes may code for potential interacting proteins that needs further identification and confirmation.
This paper reports on the preparation of magnetic lumen loaded handsheets from bleached and unbleached mixed tropical hardwood kraft pulps. The lumen coating technique is a physical approach whereby fillers were deposited inside the fibre lumen. In order to produce magnetically responsive fibres, magnetic fillers were loaded into the fibre lumen. The magnetic filler chosen was magnetite which is usually used to make mylar as found in a diskette. Low and high molecular weights of polyacrylamide (PAM) were used as retention aids. The effect of different molecular weight of PAM on filler content in the bleached and unbleached handsheets were studied. The results showed that the amount of fillers deposited in the pulp fibres increased with increasing molecular weight of PAM using both pulps. However the bleached pulps gave better lumen loading than the unbleached when using high molecular weight of PAM.
Serbuk sekam padi (SP) merupakan serabut semula jadi yang boleh bertindak sebagai pengisi penguat dalam adunan getah asli termoplastik (TPNR) NR/HDPE selepas permukaan serbuk dimodifikasikan sewajarnya. Rawatan serbuk SP merangkumi pra-rawatan dengan 5% larutan natrium hidroksida (NaOH), rendaman dalam larutan getah asli cecair (LNR) dan dedahan SP tersalut LNR kepada sinaran electron (EB). Komposit TPNR/SP disediakan secara pengadunan leburan dalam pengadun dalaman pada keadaan yang telah ditentupastikan terlebih dahulu. Morfologi komposit yang dianalisis menggunakan mikroskop elektron imbasan (SEM), menunjukkan taburan zarah pengisi SP termodifikasi adalah homogen dan kewujudan interaksi matriks-zarah. Komposit terisi SP terubahsuai LNR-EB menunjukan perubahan sifat mekanik yang ketara. Nilai maksimum tegasan dan kekuatan impak adalah masing masing 6.7 MPa dan 13.2 kJ/cm2 pada dedahan 20 kGy dos EB, manakala modulus regangan adalah 79 MPa pada dos 30 kGy. Ini menunjukkan terdapat peningkatan interaksi berkesan antara-muka SP dan TPNR bagi SP terwat LNR pada dos 20-30kGy EB. Peningkatan dos EB pada SP tersalut LNR menyebabkan degradasi salutan NR dan meningkatakan interaksi antara zarah SP. Pengaglomerasian zarah SP akan berlaku dan menyebabkan serakan zarah dalam komposit menjadi tidak homogen.
Polymeric materials such as polypropylene (PP), polyethylene (PE) and ethylene propylene diene monomer (EPDM) are widely used as insulators for cable applications. We investigated the effect of alumina trihydrate (ATH) loading on the mechanical properties of PP/EPDM blend. Preliminary study showed that PP/EPDM (60:40) was the optimum composition. ATH filled PP/EPDM composites was prepared by using twin screw extruder. In this study, the tensile properties and hardness of the composites were evaluated. The tensile modulus and hardness increased while elongation at break and tensile strength decreased with increasing ATH content. Scanning electron microscope was used to study the morphology of ATH in PP/EPDM blend.
Surface modification of rice husk (RH) with alkali pre-treatment (NaOH solution 5% w/v) was carried out at the initial state to investigate the effect of surface treatment of fibre on the surface interaction between fibre and rubber. Further modification of RH surfaces after alkali treatment was using Liquid Epoxidized Natural Rubber (LENR) coating at three concentrations, 5%, 10%, and 20% wt LENR solution in toluene. Interfacial morphology and chemical reactions between RH fibre and rubber were analyzed by FTIR and Scanning Electron Microscope (SEM). It was found that 10% wt LENR solution gave the optimum interaction between fibre and rubber. Matrix and composite blends derived from 60% natural rubber (NR), 40% high density polyethylene (HDPE) reinforced with RH fibre were prepared using an internal mixer (Brabender Plasticoder). Result showed that pre-treatment of RH treated with 5% NaOH followed by treatment with 10% LENR solution given the maximum interaction between fibre and matrix that gave rise to better mechanical properties of the composites.
Adunan polietilena berketumpatan rendah (LDPE)/getah asli cecair (LNR) dalam komposisi 100LDPE/0LNR, 70LDPE/30LNR, 60LDPE/40LNR dan 40LDPE/60LNR telah dihasilkan melalui penyebaran emulsi LDPE dan LNR.. LNR diperolehi melalui tindak balas pemekaan fotokimia ke atas getah asli (NR) dan emulsi LNR disediakan dengan menggunakan natrium dodesil sulfat (SDS) sebagai agen pengemulsi dan 1-heksanol sebagai ko-pengemulsi. Emulsi LDPE dihasilkan dengan cara yang sama menggunakan larutan LDPE dalam karbon tetraklorida, SDS dan 1-heksanol. Adunan LDPE/LNR disediakan melalui pencampuran emulsi LNR dan LDPE. Sifat mekanik adunan LDPE/LNR dianalisis melalui ujian regangan, hentaman dan kekerasan. Sifat mekanik optimum diperhatikan bagi adunan dengan komposisi 60LDPE/40LNR yang memberi nilai tegasan dan terikan yang maksimum. Suhu peralihan kaca, Tg, seperti yang diperolehi daripada analisis kalorimetri imbasan pembezaan (DSC) menunjukkan adunan yang dihasilkan adalah homogen. Kajian morfologi yang dilakukan dengan menggunakan mikroskop imbasan elektron (SEM) juga menunjukkan kehomogenan adunan yang dihasilkan.
In this study, poly(ethylene terephthalate) (PET) wastes bottle was recycled by glycolysis process using ethylene glycol. The unsaturated polyester resin (UPR) was then prepared by reacting the glycolysed product with maleic anhydride. The blend of UPR based on recycled PET wastes with liquid natural rubber (LNR) was carried out by varying the amount of LNR from 0 to 7.5 wt%. Mechanical tests such as tensile and impact were conducted to investigate the effects of LNR on the mechanical properties. Scanning Electron Microscopy (SEM) was used to analyze the morphology of the breaking area resulted from the tensile tests on the UPR and blend samples. From the results, the blend of 2.5 wt% LNR in UPR based recycled PET wastes achieved the highest strength in the mechanical properties and showed a well dispersed of elastomer particles in the sample morphology compared to other blends concentrations. This blend sample was then compared to the optimum blend of LNR with commercial resin through the glass transition temperature value Tg, mechanical strength and morphology properties. The comparison study showed that the Tg for UPR based recycled PET was higher than the value represented from commercial resin due to the degree of crystalinity in the molecular structure of the materials. LNR was found to be an effective impact modifier which gave a greater improvement in UPR from recycled PET wastes structure but not to the commercial one which needs 5% LNR to achieve the optimum properties. Thus, the compatibility between the UP resin based recycled PET and LNR was much better than with the commercial resin.
The effects of HVA-2 on radiation-induced cross-linkings in 60/40 natural rubber/ linear low density polyethylene (NR/LLDPE) blends was studied. NR/LLDPE was irradiated by using a 3.0 MeV electron beam machine with doses ranging from 0 to 250 kGy. Results showed that under the irradiation employed, the blends NR/LLDPE were cross-linked by the electron beam irradiation. The presence of HVA-2 in the blends caused the optimum dose to decrease and the blends to exhibit higher tensile properties. Further, within the dose range studied, the degradation caused by electron beam irradiation was found to be minimal. The optimized processing conditions were 120oC, 50 rpm rotor speed and 13 min processing time. The gel content, tensile strength, elongation at break, hardness and impact test studies were used to follow the irradiation-induced cross-linkings in the blend. For blends of 60/40 NR/LLDPE with 2.0 phr HVA-2, the optimum tensile strength and dose, were 19 MPa and 100 kGy, respectively. Blends of 60/40 NR/LLDPE without HVA-2, the optimum tensile strength and dose were 17.2 MPa and 200 kGy, respectively.
Long term environmental problems of non-biodegradable plastic, the need to conserve finite fossil fuels and the impact of globalization of food supply are some of the driving forces in looking towards biodegradable plastics as an alternative to the existing petrochemical-based polymers for food packaging application. The stability of nutritional composition, lipid oxidation, physical traits of beef patties packed with different types of plastics and the surface morphology of plastics after 3 months of frozen storage (-18 were studied. Beef patties were packed with either non-biodegradable high density polyethylene (PE), hydro-biodegradable low density polyethylene/ thermoplastic sago starch plastic (PEs), hydro-biodegradable polylactic acid plastic (PIA) or oxo-biodegradable plastic (oxo)). There were no differences in most of the nutrients analyzed and lipid oxidation values of beef patties packed with either biodegradable or non-biodegradable plastics after storage. There were significant (p decreased in fat for cooked patties and moisture for both raw and cooked patties. Lipid oxidation indices of beef patties increased after storage but they were not significant (p Beef patties packed with biodegradable packaging materials were able to retain moisture without jeopardizing the diameter reduction during storage. In summary, the application of biodegradable plastics for packing beef patties was considered acceptable and can be suggested as an alternative packaging item to replace conventional polyethylene plastic packaging.