IPA Recipients for February 2017

Katrina Lois M. Taaca and Magdaleno R. Vasquez Jr.
Department of Mining Metallurgical and Materials Engineering
College of Engineering
UP Diliman

Fabrication of Ag-Exchanged Zeolite/Chitosan Composites and Effects of Plasma Treatment. Microporous and Mesoporous Materials, 241: 383–391, 15 March 2017. 

Catchy title of research: Biocompatible and biodegradable composites for biomedical applications

Plan view images of the AgZ-Ch composites observed from the optical microscope (magnication: 200x and scale: 0.2 mm): (a) 0% AgZ-Ch, (b) 0.5% AgZ-Ch, (c) 1.0% AgZ-Ch, (d) 1.5% AgZ-Ch and (e) 2.0% AgZ-Ch.

Wetting envelope of pristine and plasma-treated AgZ-Ch composites. Shown alsoare the dispersive and polar components of the surface tension of water and blood.

Zeolites are minerals that can occur naturally. In the Philippines, these minerals are mined. Zeolites find a lot of applications in different fields such as catalysis, adsorption, and ion exchangers. One property of zeolite is that it can be used to host different atoms such as silver. Since silver has antibacterial property, putting silver in the zeolite can make zeolite an antibacterial agent. On the other hand, chitosan is an abundant natural fiber that can be derived from shrimps and crabs. It is biocompatible and biodegradable and can be used as support matrix for composite materials. Together, silver-zeolite dispersed in chitosan matrix creates a material that is biocompatible with antibacterial property. This combination finds promising applications in the biomedical field. In order to enhance its properties for a target application, plasma-based processes can be used to tune surfaces properties ranging such as wettability and biocompatibility.

Link to the article: http://www.sciencedirect.com/science/article/pii/S1387181117300021
Impact Factor: (2015/2016) 3.349

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Larry N. Digal and Shemaiah Gail P. Placencia
School of Management
UP Mindanao

Factors Affecting the Adoption of Sustainable Tuna Fishing Practices: The Case of Municipal Fishers in Maasim, Sarangani Province, Region 12, Philippines. Marine Policy, 77: 30–36, March 2017.

Mature yellowfin tuna unloaded in General Santos Fish Port Complex.

Major buyers bidding for high quality tuna in the General Santos Fish Port Complex.

Tuna species, being one of the most marketable aquatic resources, have been facing severe threats towards over exploitation and depletion. Continuous increase in demand for tuna products has driven a hike in fishing pressure which led to the exhaustion of tuna stocks in the sea. With this, several measures have been made in order to uphold the sustainability of the methods employed in the extraction of tuna. Thus, this study attempts to identify the factors affecting the municipal fishers’ adoption and non-adoption of sustainable tuna fishing practices in Region 12, Philippines, the most significant tuna producing region in the country. Employing logic regression, the fishers’ household size, education, experience in fishing, the type of buyer, and effort days per fishing trip appeared to significantly affect the fishers’ adoption decision. Interestingly, both private and government initiated incentives did not appear to affect their adoption decision, although the breadth of the recipients was not vast. Moreover, the estimated rate of adoption among municipal fishers was still seen to be low, despite the fishers’ acknowledgement of the industry’s potential collapse.

Link to the article: http://www.sciencedirect.com/science/article/pii/S0308597X16306431
Impact Factor: (2015/2016) 2.453

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Michael C. Velarde
Institute of Biology
College of Science
UP Diliman

Positive and Negative Effects of Cellular Senescence During Female Reproductive Aging and Pregnancy. Journal of Endocrinology, 230: R52-R76, August 2016.

Catchy title of research: Female reproductive aging: the good and the bad

Figure 3
Cellular senescence maintains proper homeostasis during pregnancy by ensuring normal placental, fetal and fetal membrane development. Cellular senescence contributes to the complex interplay of chemical signals during pregnancy. In the placenta, cellular senescence ensures normal placental development, but may also be associated with intrauterine growth restriction and stillbirth. In the embryo, cellular senescence facilitates elimination of tissue structures by macrophages and maintains a proper number of cells between different populations. In the fetal membrane, senescent cells initiate parturition.

Figure 4
Pleiotropic contributions of senescent cells during aging. Beneficial effects of cellular senescence manifest early in life to facilitate proper fetal development and timely parturition. However, detrimental effects of cellular senescence later in life appear to accelerate the decline in ovarian and uterine function.

Cellular aging, also called cellular senescence, is thought to accelerate aging and promote age-related diseases. However, recent data suggests that cellular senescence is also important in proper fetal development. This paper discusses the different roles of senescence on female reproductive aging and pregnancy.  Cellular senescence is associated with less viable egg cells, impaired sex hormone production, poor embryo development, and increased risk of preterm birth. In contrast, cell senescence is important in organ development, as it shapes a variety of organs including the reproductive tract, kidneys, and limbs. It may also promote signals to initiate normal childbirth. Recognition of the pleiotropic effects of cellular senescence will enable us to view this process in a different perspective, providing us with a better insight into female reproductive aging and fetal development.

Link to the article: http://joe.endocrinology-journals.org/content/230/2/R59.full
Impact Factor: (2015/2016)4.498

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Richard Espiritu
Department of Mining, Metallurgical and Materials Engineering
College of Engineering
UP Diliman

Degradation of Radiation Grafted Hydroxide Anion Exchange Membrane Immersed in Neutral pH: Removal of Vinylbenzyl Trimethylammonium Hydroxide Due to Oxidation. Journal of Materials Chemistry A, 5 (3): 1248-1267, 21 January 2017.

Catchy title of research: Elucidation of the degradation of radiation grafted anion exchange membrane due to oxidation

SEM micrograph of the (a) surface at 100x and the (b) cross-section at 200x of the aged membrane.

The chemical stability of anion exchange membranes, particularly at high operating temperatures, poses a critical challenge that limits the wide scale use of alkaline fuel cells. Thus, a more fundamental understanding of the chemical stability of anion exchange membranes is required to adequately design robust solid-state anion exchange membrane fuel cell and electrolysers. This study is the first to report the degradation of the OH- exchanged membrane stored in deionised water, which is the usual medium present in electrolyser and fuel cell operations. The results obtained suggest that the degradation of the membrane is not only due to the removal of the functional head group, but also attributed to the loss of the benzyl group. Such findings will have a significant impact on the way we design and fabricate anion exchange membranes in order to obtain excellent thermal and chemical stability properties.

Link to the article: http://pubs.rsc.org/en/Content/ArticleLanding/2017/TA/C6TA08232G#!divAbstract
Impact Factor: (2015/2016) 8.262

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Marc D. Rosales
Electrical and Electronics Engineering Institute
College of Engineering
UP Diliman

An 850 nm SiGe/Si HPT with a 4.12 GHz Maximum Optical Transition Frequency and 0.805A/W Responsivity. International Journal of Microwave and Wireless Technologies, 9 (1): 17-24, 1 February 2017.

Catchy title of research: Silicon Germanium Phototransistors for 850nm Operation

Simplified schematic cross-section of an extended Emitter Base Collector HPT.

a) Top view of the fiber probe spot illuminating the phototransistor, with RF probes at the extremities of GSG access lines; b) Side view through the tilted mirror of the fiber probe illuminating the phototransistor.

A Silicon Germanium based heterorjunction bipolar phototransistor (HPT) is fabricated using a commercial SiGe bipolar integrated circuit process technology. It as has an optical window with size of 10×10 μm2 and anproximately similar sized intrinsic transistor. The process technology allows for the fabrication of transistors with transistion frequency of 80GHz.  In this research the optomicrowave dynamic performance is studied and analyzed versus different bias conditions.  This allows us to determine an optimum biasing poiint that will maximize the optical transition frequency (fTopt ) and the opto-microwave responsivity of the HPT.  This is the frequency at which no opto-microwave gain is expected and the phototransistor operates as a photodiode.  The phototransistor is also characterized by means of opto-microwave scanning near-field optical microscopy (OM-SNOM) at the optimum bias conditions. This allows us to localize the region of the phototransistor with the highest frequency response. The  OM-SMOM measurement results allows us to extract the optical coupling of the optical probe to the phototransistor is around 32%. This value is used to determine  the absolute responsivity of the phototransisor. Furthermore, the effect of the substrated is also studied as it observed to limits the extraction of the intrinsic phototransistor performance.  We have extracted a maximum optical transition frequency of 4.12 GHz and an absolute low frequency opto-microwave respsonsivity of 0.805A/W  when illuminated with an 850nm vertical cavity surface illuminating  laser.This shows that phototransistor can be implemented without any process modification in a commercial SiGe bipolar IC processing technology. This opens up possible implementation of a single chip opto-microwave receiver IC.

Link to the article: https://doi.org/10.1017/S1759078715001531
Impact Factor: (2015/2016) 0.472