Shear flow behaviour and emulsion-stabilizing effect of natural polysaccharide-protein gum in aqueous system and oil/water (O/W) emulsion.

PubMed

Amid, Bahareh Tabatabaee; Mirhosseini, Hamed

2013-03-01

The main objective of the current work was to characterize the shear rheological flow behaviour and emulsifying properties of the natural biopolymer from durian seed. The present study revealed that the extraction condition significantly affected the physical and functional characteristics of the natural biopolymer from durian seed. The dynamic oscillatory test indicated that the biopolymer from durian seed showed more gel (or solid) like behaviour than the viscous (or liquid) like behaviour (G'>G″) at a relatively high concentration (20%) in the fixed frequency (0.1 Hz). This might be explained by the fact that the gum coils disentangle at low frequencies during the long period of oscillation, thus resulting in more gel like behaviour than the viscous like behaviour. The average droplet size of oil in water (O/W) emulsions stabilized by durian seed gum significantly varied from 0.42 to 7.48 μm. The results indicated that O/W emulsions showed significant different stability after 4 months storage. This might be interpreted by the considerable effect of the extraction condition on the chemical and molecular structure of the biopolymer, thus affecting its emulsifying capacity. The biopolymer extracted by using low water to seed (W/S) ratio at the low temperature under the alkaline condition showed a relatively high emulsifying activity in O/W emulsion. Copyright © 2012 Elsevier B.V. All rights reserved.

An investigation of recent storm histories using Ground Penetrating Radar at Bay-Bay Spit, Bicol, Central Philippines

NASA Astrophysics Data System (ADS)

Switzer, Adam D.; Pile, Jeremy; Soria, Janneli Lea A.; Siringan, Fernando; Daag, Arturo; Brill, Dominik

2016-04-01

The Philippine archipelago lies in the path of seasonal tropical cyclones, and much of the coast is prone to periodic inundation and overwash during storm surges. On example is typhoon Durian a category 3 storm that made landfall on the 30th November 2006, in Bicol province, on the east central Philippine coast. Satellite imagery from May 2007 reveal that Durian breached a sandy spit that runs southeast from the mouth of the Quinale River at Bay-Bay village towards Tabaco City. The imagery also showed that, although the breach site showed signs of partial recovery, geomorphological evidence of the inundation event associated with typhoon Durian still remains. In 2012 we mapped the geomorphological features of Durian. In June 2013 we returned to conduct Ground Penetrating Radar (GPR) surveys on the Bay-Bay spit to investigate potential subsurface evidence of previous storm events. The GPR surveys comprised five, 1.5 km, longshore profiles and 12 cross-shore profiles, of 50 m - 200 m in length. The GPR system used for this study was a Sensors and Software Noggin with 100 Mhz antennas. Near surface velocities were determine using Hyperbolae matching in order to estimate depth. Topographic and positional data were collected using a dGPS system. After minimal processing depth of penetration during the survey varied from 2 - 8 m. The cross-shore GPR profiles reveal at least two erosional events prior to 2006 typhoon Durian, with approximately 10 m of recovery and progradation between each erosion surface. The GPR profiles that captured the erosional features were revisited in September 2013 for trial pitting, stratigraphic description, and sediment sampling. Sediment cores were taken horizontally from the trench walls and vertically from the trench bases to date sediments using Optically Stimulated Luminescence (OSL), which eventually could constrain the timing of the erosional surfaces.

Induction of simultaneous and sequential malolactic fermentation in durian wine.

PubMed

Taniasuri, Fransisca; Lee, Pin-Rou; Liu, Shao-Quan

2016-08-02

This study represented for the first time the impact of malolactic fermentation (MLF) induced by Oenococcus oeni and its inoculation strategies (simultaneous vs. sequential) on the fermentation performance as well as aroma compound profile of durian wine. There was no negative impact of simultaneous inoculation of O. oeni and Saccharomyces cerevisiae on the growth and fermentation kinetics of S. cerevisiae as compared to sequential fermentation. Simultaneous MLF did not lead to an excessive increase in volatile acidity as compared to sequential MLF. The kinetic changes of organic acids (i.e. malic, lactic, succinic, acetic and α-ketoglutaric acids) varied with simultaneous and sequential MLF relative to yeast alone. MLF, regardless of inoculation mode, resulted in higher production of fermentation-derived volatiles as compared to control (alcoholic fermentation only), including esters, volatile fatty acids, and terpenes, except for higher alcohols. Most indigenous volatile sulphur compounds in durian were decreased to trace levels with little differences among the control, simultaneous and sequential MLF. Among the different wines, the wine with simultaneous MLF had higher concentrations of terpenes and acetate esters while sequential MLF had increased concentrations of medium- and long-chain ethyl esters. Relative to alcoholic fermentation only, both simultaneous and sequential MLF reduced acetaldehyde substantially with sequential MLF being more effective. These findings illustrate that MLF is an effective and novel way of modulating the volatile and aroma compound profile of durian wine. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical consequences of three commercial strains of Oenococcus oeni co-inoculated with Torulaspora delbrueckii in durian wine fermentation.

PubMed

Lu, Yuyun; Chua, Jian-Yong; Huang, Dejian; Lee, Pin-Rou; Liu, Shao-Quan

2017-01-15

This work evaluated for the first time the chemical consequences of three commercial strains of Oenococcus oeni co-inoculated with Torulaspora delbrueckii in durian wine fermentation. Compared with the control (yeast only, 5.70% v/v ethanol produced), samples co-inoculated with T. delbrueckii and O. oeni PN4 improved ethanol production (6.06% v/v), which was significantly higher than samples co-inoculated with Viniflora (4.78% v/v) or Enoferm Beta (5.01% v/v). Wines co-fermented with the respective latter two oenococci contained excessive levels of ethyl acetate (>80mg/L) that were likely to affect negatively wine aroma. In addition, they led to significantly higher acetic and lactic acid production relative to PN4. O. oeni PN4 seemed to be the most suitable strain to co-inoculate with T. delbrueckii for simultaneous alcoholic and malolactic fermentation in durian wine by contributing moderately increased concentrations of higher alcohols, acetate esters and ethyl esters that would have positive sensory impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical composition and molecular structure of polysaccharide-protein biopolymer from Durio zibethinus seed: extraction and purification process

PubMed Central

2012-01-01

Background The biological functions of natural biopolymers from plant sources depend on their chemical composition and molecular structure. In addition, the extraction and further processing conditions significantly influence the chemical and molecular structure of the plant biopolymer. The main objective of the present study was to characterize the chemical and molecular structure of a natural biopolymer from Durio zibethinus seed. A size-exclusion chromatography coupled to multi angle laser light-scattering (SEC-MALS) was applied to analyze the molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (Mw/Mn). Results The most abundant monosaccharide in the carbohydrate composition of durian seed gum were galactose (48.6-59.9%), glucose (37.1-45.1%), arabinose (0.58-3.41%), and xylose (0.3-3.21%). The predominant fatty acid of the lipid fraction from the durian seed gum were palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:2). The most abundant amino acids of durian seed gum were: leucine (30.9-37.3%), lysine (6.04-8.36%), aspartic acid (6.10-7.19%), glycine (6.07-7.42%), alanine (5.24-6.14%), glutamic acid (5.57-7.09%), valine (4.5-5.50%), proline (3.87-4.81%), serine (4.39-5.18%), threonine (3.44-6.50%), isoleucine (3.30-4.07%), and phenylalanine (3.11-9.04%). Conclusion The presence of essential amino acids in the chemical structure of durian seed gum reinforces its nutritional value. PMID:23062269

Effect of different drying techniques on flowability characteristics and chemical properties of natural carbohydrate-protein Gum from durian fruit seed

PubMed Central

2013-01-01

Background A natural carbohydrate biopolymer was extracted from the agricultural biomass waste (durian seed). Subsequently, the crude biopolymer was purified by using the saturated barium hydroxide to minimize the impurities. Finally, the effect of different drying techniques on the flow characteristics and functional properties of the purified biopolymer was investigated. The present study elucidated the main functional characteristics such as flow characteristics, water- and oil-holding capacity, solubility, and foaming capacity. Results In most cases except for oven drying, the bulk density decreased, thus increasing the porosity. This might be attributed to the increase in the inter-particle voids of smaller sized particles with larger contact surface areas per unit volume. The current study revealed that oven-dried gum and freeze-dried gum had the highest and lowest compressibility index, thus indicating the weakest and strongest flowability among all samples. In the present work, the freeze-dried gum showed the lowest angle of repose, bulk, tapped and true density. This indicates the highest porosity degree of freeze dried gum among dried seed gums. It also exhibited the highest solubility, and foaming capacity thus providing the most desirable functional properties and flow characteristics among all drying techniques. Conclusion The present study revealed that freeze drying among all drying techniques provided the most desirable functional properties and flow characteristics for durian seed gum. PMID:23289739

Combined effects of fermentation temperature and pH on kinetic changes of chemical constituents of durian wine fermented with Saccharomyces cerevisiae.

PubMed

Lu, Yuyun; Voon, Marilyn Kai Wen; Huang, Dejian; Lee, Pin-Rou; Liu, Shao-Quan

2017-04-01

This study investigated the effects of temperature (20 and 30 °C) and pH (pH 3.1, 3.9) on kinetic changes of chemical constituents of the durian wine fermented with Saccharomyces cerevisiae. Temperature significantly affected growth of S. cerevisiae EC-1118 regardless of pH with a higher temperature leading to a faster cell death. The pH had a more significant effect on ethanol production than temperature with higher production at 20 °C (5.95%, v/v) and 30 °C (5.56%, v/v) at pH 3.9, relative to that at pH 3.1 (5.25 and 5.01%, v/v). However, relatively higher levels of isobutyl alcohol and isoamyl alcohol up to 64.52 ± 6.39 and 56.27 ± 3.00 mg/L, respectively, were produced at pH 3.1 than at pH 3.9 regardless of temperature. In contrast, production of esters was more affected by temperature than pH, where levels of ethyl esters (ethyl esters of octanoate, nonanoate, and decanoate) and acetate esters (ethyl acetate and isoamyl acetate) were significantly higher up to 2.13 ± 0.23 and 4.61 ± 0.22 mg/L, respectively, at 20 °C than at 30 °C. On the other hand, higher temperature improved the reduction of volatile sulfur compounds. This study illustrated that temperature control would be a more effective tool than pH in modulating the resulting aroma compound profile of durian wine.

Response Surface Methodology for the Optimization of Preparation of Biocomposites Based on Poly(lactic acid) and Durian Peel Cellulose

PubMed Central

Penjumras, Patpen; Abdul Rahman, Russly; Talib, Rosnita A.; Abdan, Khalina

2015-01-01

Response surface methodology was used to optimize preparation of biocomposites based on poly(lactic acid) and durian peel cellulose. The effects of cellulose loading, mixing temperature, and mixing time on tensile strength and impact strength were investigated. A central composite design was employed to determine the optimum preparation condition of the biocomposites to obtain the highest tensile strength and impact strength. A second-order polynomial model was developed for predicting the tensile strength and impact strength based on the composite design. It was found that composites were best fit by a quadratic regression model with high coefficient of determination (R 2) value. The selected optimum condition was 35 wt.% cellulose loading at 165°C and 15 min of mixing, leading to a desirability of 94.6%. Under the optimum condition, the tensile strength and impact strength of the biocomposites were 46.207 MPa and 2.931 kJ/m2, respectively. PMID:26167523

The synthesis of carbon electrode supercapacitor from durian shell based on variations in the activation time

NASA Astrophysics Data System (ADS)

Taer, E.; Dewi, P.; Sugianto, Syech, R.; Taslim, R.; Salomo, Susanti, Y.; Purnama, A.; Apriwandi, Agustino, Setiadi, R. N.

2018-02-01

The synthesis of carbon electrode from durian shell based on variations in the activation time has been carried out. Synthesis of carbon electrode was started by a carbonization process at a temperature of 600°C in nitrogen gas and then followed by physical activation process using water vapor at a temperature of 900°C by varying time of 1, 2 and 3 h. All of the variations of the samples were chemically activated using an activator of ZnCl2 with a concentration of 0.4 M. The physical properties such as density, surface morphology, degree of crystallinity and elemental content were analyzed. Moreover, the electrochemical properties such as specific capacitance of supercapacitor cells were studied using Cyclic Voltammetry methods. The density, stack height and carbon content were increased as activation time increases, while the specific capacitance of the supercapacitor cell decreases against the increase of activation time. Specific capacitances for 1, 2 and 3 h activation time are 88.39 F/g, 80.08 F/g and 74.61 F/g, respectively. Based on the surface morphology study it was shown that the increased in activation time causes narrowing of the pores between particles.

In-vitro screening of Malaysian honey from different floral sources for antibacterial activity on human pathogenic bacteria.

PubMed

Ng, Wen-Jie; Ken, Khai-Wei; Kumar, Roshani-Vijaya; Gunasagaran, Hemamalani; Chandramogan, Vanaysha; Lee, Ying-Yee

2014-01-01

Different researches on therapeutic effects of honey have been conducted in different regions; however the study on the potential antibacterial activity of Malaysian honey is still limited. In this study, antibacterial activities of different monofloral honey samples were tested against several common human pathogenic bacteria. The well-diffusion method, minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) techniques were employed to investigate the putative antibacterial activity of Malaysian monofloral honey from Koompassia excelsa (Becc.) Taub (Tualang), Melaleuca cajuputi Powell (Gelam) and Durio zibethinus Murr. (Durian). Honey samples were tested against Staphylococcus aureus ATCC6518 and ATCC25923, Staphylococcus epidermidis ATCC12228, Enterococcus faecium LMG16192, Enterococcus faecalis LMG16216 and ATCC29212, Escherichia coli ATCC25922, Salmonella enterica serovar Typhimurium ATCC14028 and Klebsiella pneumoniae ATCC13883. Marked variations were observed in the antibacterial activity of these honey samples. Durian honey failed to produce substantial antibacterial activity, whereas Tualang and Gelam honey showed a spectrum of antibacterial activity with their growth inhibitory effects against all of the tested bacterial species including vancomycin-resistant enterococci (VRE). Present findings suggested Gelam honey possesses highest antibacterial effect among the tested Malaysian honey samples.

The Growing Role of Trade as A Development Assistance Mechanism.

DTIC Science & Technology

1981-08-11

emphasizing that these elements should accompany foreign 1/Approved crops include cashew nuts , cocoa, coconut, coffee, durian, mangosteen, manila hemp, palm...products; essen- tial oils; spices; forest products (e.g., rattan and resins); tobacco; tea; nuts . --Industrial products: plywood and processed wood...Gabon and Ivory Coast (timber), Ethiopia (coffee), Benin (cotton), Tanzania (sisal), Niger and Senegal (ground nuts ), Mauritania (iron ore). SYSTEM FOR

The effect of dilute acid pre-treatment process in bioethanol production from durian (Durio zibethinus) seeds waste

NASA Astrophysics Data System (ADS)

Ghazali, K. A.; Salleh, S. F.; Riayatsyah, T. M. I.; Aditiya, H. B.; Mahlia, T. M. I.

2016-03-01

Lignocellulosic biomass is one of the promising feedstocks for bioethanol production. The process starts from pre-treatment, hydrolysis, fermentation, distillation and finally obtaining the final product, ethanol. The efficiency of enzymatic hydrolysis of cellulosic biomass depends heavily on the effectiveness of the pre-treatment step which main function is to break the lignin structure of the biomass. This work aims to investigate the effects of dilute acid pre-treatment on the enzymatic hydrolysis of durian seeds waste to glucose and the subsequent bioethanol fermentation process. The yield of glucose from dilute acid pre-treated sample using 0.6% H2SO4 and 5% substrate concentration shows significant value of 23.4951 g/L. Combination of dilute acid pre-treatment and enzymatic hydrolysis using 150U of enzyme able to yield 50.0944 g/L of glucose content higher compared to normal pre-treated sample of 8.1093 g/L. Dilute acid pre-treatment sample also shows stable and efficient yeast activity during fermentation process with lowest glucose content at 2.9636 g/L compared to 14.7583g/L for normal pre-treated sample. Based on the result, it can be concluded that dilute acid pre-treatment increase the yield of ethanol from bioethanol production process.

Effect of coupling agent on durian skin fibre nanocomposite reinforced polypropylene

NASA Astrophysics Data System (ADS)

Siti Nur E'zzati, M. A.; Anuar, H.; Siti Munirah Salimah, A. R.

2018-01-01

This paper reports on the development of a composite-based natural fiber to reduce the reliance on petroleum-based product in order to amplify environmental awareness. The production of Durian Skin Nanofiber (DSNF) was conducted using biological fermentation method via rhizopus oryzae in order to obtain the nano dimension of the particle size. Polypropylene (PP) and DSNF were produced using Haake internal mixer via melt blending technique. The significant effect of maleic anhydride grafted polypropylene (MAPP) on the properties of PP/DSNF nanocomposite was investigated to study its mechanical properties which are tensile strength and thermal stability using thermogravimetric (TGA) and differential scanning analysis (DSC). The tensile property of PP nanocomposites increased from 33 MPa to 38 MPa with the presence of MAPP. The addition of MAPP also increased the thermal stability of PP/DSNF nanocomposite where the char residue increased by 52%. Besides that, the thermal degradation of PP/DSNF and PP/DSNF-MAPP were higher than PP where they exerted higher amount of weight loss at an elevated temperature. The percentage of crystallinity, %Xc, of PP nanocomposites improved with the addition of MAPP by 35% based on the differential scanning calorimetry (DSC) result. The SEM analysis showed that the PP/DSNF-MAPP exerts ductile fracture while PP/DSNF exerts brittle fracture.

Minimization of Food Cost on 2000-Calorie Diabetic Diet

NASA Astrophysics Data System (ADS)

Urrutia, J. D.; Mercado, J.; Tampis, R. L.

2017-03-01

This study focuses on minimization of food cost that satisfies the daily nutrients required based on 2000-calorie diet for a diabetic person. This paper attempts to provide a food combination that satisfies the daily nutrient requirements of a diabetic person and its lowest possible dietary food cost. A linear programming diet model is used to determine the cheapest combination of food items that satisfy the recommended daily nutritional requirements of the diabetic persons. According to the findings, a 50 year old and above diabetic male need to spend a minimum of 72.22 pesos for foods that satisfy the daily nutrients they need. In order to attain the minimum spending, the foods must consist of 60.49 grams of anchovy, 91.24 grams of carrot, 121.92 grams of durian, 121.41 grams of chicken egg, 70.82 grams of pork (lean), and 369.70 grams of rice (well-milled). For a 50 year old and above diabetic female, the minimum spending is 64.65 pesos per day and the food must consist of 75.87 grams of anchovy, 43.38 grams of carrot, 160.46 grams of durian, 69.66 grams of chicken egg, 23.16 grams of pork (lean) and 416.19 grams of rice (well-milled).

A Descriptive Study of Military Police Officer Graduates of the Master of Arts Program of Sam Houston State University

DTIC Science & Technology

1991-12-07

are male and the positions in military corrections are male dominated. The racial make-up was overwhelmingly white with only 5.4% of the respondents...sample was middle age with 53.6.% thirty to thirty-three years of age. B. The graduates were all male and the racial make-up was overwhelmingly while...Attempt at Decriminalization of Deviant Behavior. Unpublished master’s thesis, Sam Houston State University, Huntsville, Texas. Durian, Ronald S. (1971

Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

NASA Astrophysics Data System (ADS)

M Ali, M. K.; Ruslan, M. H.; Muthuvalu, M. S.; Wong, J.; Sulaiman, J.; Yasir, S. Md.

2014-06-01

The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m2 and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea of this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R2), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.

Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

DOE Office of Scientific and Technical Information (OSTI.GOV)

M Ali, M. K., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Ruslan, M. H., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Muthuvalu, M. S., E-mail: sudaram-@yahoo.com, E-mail: jumat@ums.edu.my

2014-06-19

The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m{sup 2} and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea ofmore » this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R{sup 2}), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.« less

Floricoccus tropicus gen. nov., sp. nov. and Floricoccus penangensis sp. nov. isolated from fresh flowers of durian tree and hibiscus.

PubMed

Chuah, Li-Oon; Yap, Kien-Pong; Shamila-Syuhada, Ahamed Kamal; Thong, Kwai Lin; Ahmad, Rosma; Liong, Min Tze; Rusul, Gulam

2017-12-01

Three strains of Gram-staining-positive, coccus-shaped, lactic acid bacteria, designated as HibF3 T , HibF2 and HibF5 were isolated from fresh flowers of hibiscus, and a fourth, DF1 T , was isolated from fresh flowers of durian tree, in Penang, Malaysia. Taxonomic characterisation was performed by polyphasic analysis. Sequence similarities of the 16S rRNA gene and the housekeeping rpoA and pheS genes of these strains with their closely-related lactococcal and streptococcal relatives were 92-94, 78 and 81 %, respectively. The results of phylogenetic analysis indicated that strains DF1 T , HibF2, HibF5 and HibF3 T were clustered together but were clearly separated from species of the genera Streptococcus and Lactococcus, indicating that they represent members of a novel genus of the family Streptococcaceae. Calculation of average nucleotide identity (ANI) values between the genomes of DF1 T and HibF3 T yielded values of 92.50-92.93 %. ANI values below the cut-off value and distinctive chemotaxonomic characteristics supported the hypothesis that these strains represented two novel species. Major cellular fatty acids in DF1 T , HibF2 and HibF5 were C18 : 1ω7c and C16 : 0, while C12 : 0 and C14 : 0 were also dominant, in addition to C18 : 1ω7c and C16 : 0, in HibF3 T . A novel genus is proposed with the name Floricoccus gen. nov. which consists of two species, Floricoccus tropicus sp. nov as the type species, and Floricoccus penangensis sp. nov. The respective type strains are DF1 T (=LMG 29833 T =JCM 31733 T ) and HibF3 T (=LMG 29831 T =DSM 31735 T ).

Distinctive exotic flavor and aroma compounds of some exotic tropical fruits and berries: a review.

PubMed

Lasekan, Ola; Abbas, Kassim A

2012-01-01

The characteristic flavor of exotic tropical fruits is one of their most attractive attributes to consumers. In this article, the enormous diversity of exotic fruit flavors is reviewed. Classifying some of the exotic fruits into two classes on the basis of whether esters or terpenes predominate in the aroma was also attempted. Indeed, as far as exotic tropical fruits are concerned, the majority of fruits have terpenes predominating in their aroma profile. Some of the fruits in this group are the Amazonian fruits such as pitanga, umbu-caja, camu-camu, garcinia, and bacuri. The ester group is made up of rambutan, durians, star fruit, snake fruit, acerola, tamarind, sapodilla, genipap, soursop, cashew, melon, jackfruit, and cupuacu respectively. Also, the role of sulphur-volatiles in some of the exotic fruits is detailed.

Isolation of lactic acid bacteria from Malaysian foods and assessment of the isolates for industrial potential.

PubMed

Mohd Adnan, Ahmad Faris; Tan, Irene K P

2007-05-01

Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk.

Avalanches and diffusion in bubble rafts

NASA Astrophysics Data System (ADS)

Maloney, C. E.

2015-07-01

Energy dissipation distributions and particle displacement statistics are studied in the mean-field version of Durian's bubble model. A two-dimensional (2D) bi-disperse mixture is simulated at various strain rates, \\dotγ , and packing ratios, ϕ, above the rigidity onset at φ=φc . Well above φc , and at sufficiently low \\dotγ , the system responds in a highly bursty way, reminiscent of other dynamically critical systems with a power-law distribution of energy dissipation. As one increases \\dotγ at fixed ϕ or tunes φ→ φc at fixed \\dotγ , the bursty behavior vanishes. Displacement distributions are non-Fickian at short times but cross to a Fickian regime at a universal strain, Δγ* , independent of \\dotγ and ϕ. Despite the profound differences in short-time dynamics, at intermediate Δγ the systems exhibit qualitatively similar spatial patterns of deformation with lines of slip extending across large fractions of the simulation cell. These deformation patterns explain the observed diffusion constants and the universal crossover time to Fickian behavior.

The angular distribution of diffusely backscattered light

NASA Astrophysics Data System (ADS)

Vera, M. U.; Durian, D. J.

1997-03-01

The diffusion approximation predicts the angular distribution of light diffusely transmitted through an opaque slab to depend only on boundary reflectivity, independent of scattering anisotropy, and this has been verified by experiment(M.U. Vera and D.J. Durian, Phys. Rev. E 53) 3215 (1996). Here, by contrast, we demonstrate that the angular distribution of diffusely backscattered light depends on scattering anisotropy as well as boundary reflectivity. To model this observation scattering anisotropy is added to the diffusion approximation by a discontinuity in the photon concentration at the source point that is proportional to the average cosine of the scattering angle. We compare the resulting predictions with random walk simulations and with measurements of diffusely backscattered intensity versus angle for glass frits and aqueous suspensions of polystyrene spheres held in air or immersed in a water bath. Increasing anisotropy and boundary reflectivity each tend to flatten the predicted distributions, and for different combinations of anisotropy and reflectivity the agreement between data and predictions ranges from qualitatively to quantitatively good.

Evaluation of agrowastes as immobilizers for probiotics in soy milk.

PubMed

Teh, Sue-Siang; Ahmad, Rosma; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

2009-11-11

The objective of this study was to evaluate agricultural wastes as immobilizers for probiotics in liquid foods, such as soy milk. Probiotic strains were initially evaluated for acid and bile tolerance and the ability to produce alpha-galactosidase. Rinds of durian, mangosteen, and jackfruit were dried, ground, and sterilized prior to immobilization of selected strains ( Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and Lactobacillus bulgaricus FTCC 0411). Immobilized cells were inoculated into soy milk, and growth properties were evaluated over 168 h at 37 degrees C. Soy milk containing free cells without agrowastes was used as the control. Immobilized probiotics showed increased growth, greater reduction of stachyose, sucrose, and glucose, higher production of lactic and acetic acids, and lower pH in soy milk compared to the control. The results illustrated that agrowastes could be used for the immobilization of probiotics with enhanced growth, utilization of substrates, and production of organic acids.

Determination of acrylamide in Thai-conventional snacks from Nong Mon market, Chonburi using GC-MS technique.

PubMed

Komthong, P; Suriyaphan, O; Charoenpanich, J

2012-01-01

Acrylamide in Thai-conventional snacks was analysed by GC/MS with a linear response ranged of 5-50 µg and r² > 0.99. The limit of detection (s/n = 3) and limit of quantification (s/n = 10) were 4 and 15 µg kg⁻¹, respectively, and RSD < 2%. Acrylamide in 19 food samples ranged from <15 µg kg⁻¹ to 1.26 mg kg⁻¹ with highest concentrations in Kanom Jak. Moderate levels (150-500 µg kg⁻¹) were detected mostly in deep-fried products, especially sweet potato and taro crisps, Kanom Kai Hong, banana fritters, durian chips and spring rolls. Thai-conventional snacks possessed low concentrations (<150 µg kg⁻¹) including Khao Larm, Pa Tong Koo, sweet banana crisps and deep-fried Chinese wonton. Acrylamide was lowest (<15 µg kg⁻¹) in fish strips, rice crackers, Hoi Jor and fried fish balls. Dietary habits by 400 tourists indicate a daily intake of acrylamide <150 ng, well below a toxic dose.

Second generation bioethanol potential from selected Malaysia's biodiversity biomasses: A review.

PubMed

Aditiya, H B; Chong, W T; Mahlia, T M I; Sebayang, A H; Berawi, M A; Nur, Hadi

2016-01-01

Rising global temperature, worsening air quality and drastic declining of fossil fuel reserve are the inevitable phenomena from the disorganized energy management. Bioethanol is believed to clear out the effects as being an energy-derivable product sourced from renewable organic sources. Second generation bioethanol interests many researches from its unique source of inedible biomass, and this paper presents the potential of several selected biomasses from Malaysia case. As one of countries with rich biodiversity, Malaysia holds enormous potential in second generation bioethanol production from its various agricultural and forestry biomasses, which are the source of lignocellulosic and starch compounds. This paper reviews potentials of biomasses and potential ethanol yield from oil palm, paddy (rice), pineapple, banana and durian, as the common agricultural waste in the country but uncommon to be served as bioethanol feedstock, by calculating the theoretical conversion of cellulose, hemicellulose and starch components of the biomasses into bioethanol. Moreover, the potential of the biomasses as feedstock are discussed based on several reported works. Copyright © 2015 Elsevier Ltd. All rights reserved.

A critical review on the spray drying of fruit extract: effect of additives on physicochemical properties.

PubMed

Krishnaiah, Duduku; Nithyanandam, Rajesh; Sarbatly, Rosalam

2014-01-01

Spray drying accomplishes drying while particles are suspended in the air and is one method in the family of suspended particle processing systems, along with fluid-bed drying, flash drying, spray granulation, spray agglomeration, spray reaction, spray cooling, and spray absorption. This drying process is unique because it involves both particle formation and drying. The present paper reviews spray drying of fruit extracts, such as acai, acerola pomace, gac, mango, orange, cactus pear, opuntia stricta fruit, watermelon, and durian, and the effects of additives on physicochemical properties such as antioxidant activity, total carotenoid content, lycopene and β-carotene content, hygroscopy, moisture content, volatile retention, stickiness, color, solubility, glass transition temperature, bulk density, rehydration, caking, appearance under electron microscopy, and X-ray powder diffraction. The literature clearly demonstrates that the effect of additives and encapsulation play a vital role in determining the physicochemical properties of fruit extract powder. The technical difficulties in spray drying of fruit extracts can be overcome by modifying the spray dryer design. It also reveals that spray drying is a novel technology for converting fruit extract into powder form.

Current trends of tropical fruit waste utilization.

PubMed

Cheok, Choon Yoong; Mohd Adzahan, Noranizan; Abdul Rahman, Russly; Zainal Abedin, Nur Hanani; Hussain, Norhayati; Sulaiman, Rabiha; Chong, Gun Hean

2018-02-11

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.

Nanocellulose-Zeolite Composite Films for Odor Elimination.

PubMed

Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

2015-07-08

Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

Malaria in tree crop plantations in south-eastern and western provinces of Thailand.

PubMed

Singhasivanon, P; Thimasarn, K; Yimsamran, S; Linthicum, K; Nualchawee, K; Dawreang, D; Kongrod, S; Premmanisakul, N; Maneeboonyang, W; Salazar, N

1999-09-01

During the past three decades almost half of the existing natural tropical forests in Thailand were destroyed and replaced by cash crops, rubber, coffee, fruit orchards (durian, rambutan, mangosteen) and other commercial plantations. In order to determine the proportion of malaria cases contracted from such commercial plantations, an epidemiological study was conducted between June 1996 to May 1997 in two districts, one in Pong Nam Ron, located in a south-eastern province near the Cambodian border and another in Sai Yok, in a western province along the Myanmar border. Data were collected by passive case detection from patients attending the existing malaria clinics and active case detection by monthly malariometric survey in selected villages. All malaria cases were thoroughly investigated and classified according to exposure to different ecotypes prior to onset of malaria symptoms in the preceding two weeks. Malaria cases acquired from commercial plantations accounted for 35.2% and 11.2% in Pong Nam Ron and in Sai Yok districts respectively. In such plantations, most of the malaria cases were contracted from fruit orchards and to a lesser extent from rubber and teak plantations. From this study it is evident that commercial plantations provide a significant site of malaria transmission in addition to the forest and foothills areas in Southeast Asia where efficient vectors such as An. dirus and An. minimus are prevalent and have adapted to such changed ecosystems.

Effect of interstitial fluid on the fraction of flow microstates that precede clogging in granular hoppers

NASA Astrophysics Data System (ADS)

Koivisto, Juha; Durian, Douglas J.

2017-03-01

We report on the nature of flow events for the gravity-driven discharge of glass beads through a hole that is small enough that the hopper is susceptible to clogging. In particular, we measure the average and standard deviation of the distribution of discharged masses as a function of both hole and grain sizes. We do so in air, which is usual, but also with the system entirely submerged under water. This damps the grain dynamics and could be expected to dramatically affect the distribution of the flow events, which are described in prior work as avalanche-like. Though the flow is slower and the events last longer, we find that the average discharge mass is only slightly reduced for submerged grains. Furthermore, we find that the shape of the distribution remains exponential, implying that clogging is still a Poisson process even for immersed grains. Per Thomas and Durian [Phys. Rev. Lett. 114, 178001 (2015), 10.1103/PhysRevLett.114.178001], this allows for an interpretation of the average discharge mass in terms of the fraction of flow microstates that precede, i.e., that effectively cause, a stable clog to form. Since this fraction is barely altered by water, we conclude that the crucial microscopic variables are the grain positions; grain momenta play only a secondary role in destabilizing weak incipient arches. These insights should aid ongoing efforts to understand the susceptibility of granular hoppers to clogging.

Time-resolved dual transcriptomics reveal early induced Nicotiana benthamiana root genes and conserved infection-promoting Phytophthora palmivora effectors.

PubMed

Evangelisti, Edouard; Gogleva, Anna; Hainaux, Thomas; Doumane, Mehdi; Tulin, Frej; Quan, Clément; Yunusov, Temur; Floch, Kévin; Schornack, Sebastian

2017-05-11

Plant-pathogenic oomycetes are responsible for economically important losses in crops worldwide. Phytophthora palmivora, a tropical relative of the potato late blight pathogen, causes rotting diseases in many tropical crops including papaya, cocoa, oil palm, black pepper, rubber, coconut, durian, mango, cassava and citrus. Transcriptomics have helped to identify repertoires of host-translocated microbial effector proteins which counteract defenses and reprogram the host in support of infection. As such, these studies have helped in understanding how pathogens cause diseases. Despite the importance of P. palmivora diseases, genetic resources to allow for disease resistance breeding and identification of microbial effectors are scarce. We employed the model plant Nicotiana benthamiana to study the P. palmivora root infections at the cellular and molecular levels. Time-resolved dual transcriptomics revealed different pathogen and host transcriptome dynamics. De novo assembly of P. palmivora transcriptome and semi-automated prediction and annotation of the secretome enabled robust identification of conserved infection-promoting effectors. We show that one of them, REX3, suppresses plant secretion processes. In a survey for early transcriptionally activated plant genes we identified a N. benthamiana gene specifically induced at infected root tips that encodes a peptide with danger-associated molecular features. These results constitute a major advance in our understanding of P. palmivora diseases and establish extensive resources for P. palmivora pathogenomics, effector-aided resistance breeding and the generation of induced resistance to Phytophthora root infections. Furthermore, our approach to find infection-relevant secreted genes is transferable to other pathogen-host interactions and not restricted to plants.

The floating houses of Sintang City: space, resources and political nexus

NASA Astrophysics Data System (ADS)

Lubis, M. S.; Harjoko, T. Y.; Susanto, D.

2018-03-01

Sintang is a city in the interior of West Kalimantan, located at the confluence of two large rivers, Kapuas River and Melawi River. Growing from the river’s edge, the present Sintang still maintains its riverine culture in the form of floating houses (‘rumah lanting’), as its legacy of the past, when rivers played important role as main transportation routes for political and economic activities. This paper explores several concepts related to power, space, and resources, to examine the complexity of life of lanting dwellers, conducted at two locations of lanting houses that spread around Sintang urban area: Pasar Sungai Durian and Pasar Inpres. The results show that there are two main factors affecting the life as well as the spatiality of lanting dwellers: First, the relationship with river’s ecology and river’s behavior, and second, the linkages with the activities on the mainland, where both of them are strongly influenced by political and economic considerations. The impact of changes in the river’s ecology and behavior on the lanting dwellers has shown how government policies affected the rivers and thus, the lanting communities. The key contribution of this study is a clear depiction of the political and power relations in the context of spatiality and resources on the riverine culture, especially the lanting communities along Kapuas and Melawi River in Sintang City, which tends to reveal the marginalization of the lanting community among the other urban community. So far, there has been no serious and detailed studies about the politics of space in relation to nature and resources and local livelihoods in the area. This paper wishes to explore the challenges to strive for a livable and just place for river community in the future.

The abundance and importance value of tree in “Sendang Kalimah Toyyibah” surrounding and its implication to the spring

NASA Astrophysics Data System (ADS)

Wiryani, Erry; Murningsih; Jumari

2018-05-01

One important factor affecting sustainability of spring is composition of vegetation around it. “Sendang Kalimah Toyyibah” is one of many springs in Semarang with intensive utilization. Vulnerability of spring can be monitored by dominant vegetation species indicated by vegetation importance value indices, especially for tree. This research aimed to study the variation of tree species around “Sendang Kalimah Toyyibah”, to analyze the importance value index of tree species and to analyze the implication of tree species which had dominant importance value index on “Sendang Kalimah Toyyibah” spring. Data collection was conducted via line transect with the length of 200 m on 4 directions which were defined based on the stream direction and the spring as the central point. Each transect has 4 observation plots occupying 20 x 20 m2. Data collection was including tree species, abundance, presence frequency and basal area of tree. Data analysis was conducted for vegetation importance value index. The result showed that around “Sendang Kalimah Toyyibah” there were 28 tree species inwhich the abundance was dominated by Mahogany (33 individuals stands), Albizia (31 stands), Coffee (20 stands), Coconut (18 stands), Mangosteen (16 stands) and Banana (16 stands). Vegetation importance value index around “Sendang Kalimah Toyyibah” was dominated by the above 7 treeswith important values (IV) respectively species including Mahogany (28,97%), Albizia (26,70%), Mangosteen (23,47%), Java Black Bamboo (22,18%), Coffee (19,23%), Coconut (17,98%) and Durian (16,41%). Cumulatively, these 7 treesspecieses dominated the importance value of tree around “Sendang Kalimah Toyyibah” which was 154,95%. These dominant species had represented the ecosystem function in infiltration, filtration and absorption of water which were required for spring ecosystem sustainability.

Pesticide Exposure and Cholinesterase Levels in Migrant Farm Workers in Thailand.

PubMed

Thetkathuek, Anamai; Yenjai, Pornthip; Jaidee, Wanlop; Jaidee, Patchana; Sriprapat, Poonsak

2017-01-01

In this study, we examined the effects of pesticides in migrant farm workers from Cambodia after workplace exposure on fruit plantations in eastern Thailand. We studied 891 migrant farm workers employed on pineapple, durian, and rambutan plantations in Thailand. Data were collected via a detailed questionnaire survey and measurements of serum cholinesterase level (SChE). The majority of subjects was male (57.7%), with an average age of 30.3 years. Most subjects (76.8%) were moderately aware of good industrial hygiene practices. SChE level was divided into four groups based on the results. Only 4.4% had normal levels of cholinesterase activity, 20.5% had slightly reduced levels, 58.5% had markedly reduced levels and were "at risk," and 16.6% who had highest levels of cholinesterase inhibition were deemed to be in an "unsafe" range. SChE was classified into two groups, SChE value of 87.5 was "normal" and <87.5 units/mL "abnormal." For the multiple logistic regression analysis of the abnormal SChE levels, the variables entered in the model included gender, period of insecticide use, the total area of plantation, frequency of spraying, period of daily insecticide spraying, and insecticide spraying method. The results indicated that the aOR (adjust odds ratio) for male migrant farm workers (95% confidence interval [CI]) was 1.58 (1.14, 2.17). The OR for farm migrant workers who worked on larger plantations of more than 39.5 acres (95% CI) was 2.69 (1.51, 4.82). Finally, the OR for the migrant farm workers who used a backpack sprayer (95% CI) was 2.07 (1.28, 3.34). These results suggest that health screening should be provided to migrant farm workers, especially those who spray pesticides on plantations of >39 acres, use a backpack sprayer, or have a low level of compliance with accepted industrial hygiene practices. These three classes of workers are at increased risk of chemical exposures and developing acute or chronic illness from pesticide exposures.

Vesta and low gravity impact mixing

NASA Astrophysics Data System (ADS)

Hoffmann, Martin; Nathues, Andreas; Vincent, Jean-Baptiste; Sierks, Holger

2013-04-01

Re-impacting material in the velocity range of a few meters per second to a couple of hundred meters per second encounters the surface of Vesta. Studying Vesta's ejecta blankets, this specific constraint has to be taken into account. As on other planetary bodies, young craters are characterized by ray patterns. Combining this information with the evidence of Vesta's unique compaction patterns, the kinematics of the deposition process and its consequences for the spectral properties can be studied. We attempt to tackle the following questions: From which depth of a primary crater and to which extent does ejected material contribute to the mixing of surface material? What are the consequences for the local morphology and a global layer of regolith? Experiments of slow impacts into granular material resulted in the following significant effects: 1) Different depth to diameter ratios, and different profiles of the impact crater have been found, indicating transition from three dimensional interaction to surface effects. 2) The inner surfaces as well as their ejecta blanket showed quite different mixtures of material from different depths of the target area. These are interpreted as the result of pattern formation, slope and boundary effects. 3) At sufficiently low velocity and suitable projectile density the transition from inelastic to elastic interaction has been observed. 4) Between the elastic response of very slow impacts and a violent irregular agitation of the material by faster impacts, a regime of de-voiding and hence of compaction has been observed. 5) The action of force chains (Daniels et al. 2004, Rivas et al. 2011) became apparent inside the granular material, which efficiently trap energy (Daraio et al. 2006) and lead to the ray system. These results confirm and expand previous experimental, simulated and theoretically investigated evidence on the behavior of mobilized granular material. As already demonstrated by Cook and Mortensen (1967), low velocity impacts into granular material lead to anything but a simple crater morphology. Unusual scaling laws (Uehara et al. 2003) and much more diverse phase patterns than in ordinary solid media have to be taken into account, if a consistent interpretation of the formation of a crater in very deep regolith is attempted (e.g. Opsomer et al. 2011). Additional effects are due to the low gravity environment on a small planetary body like Vesta (Tancredi et al. 2012). On Vesta many apparent counterparts to the results of the experiments can be found, as demonstrated by some examples. On a global scale, the multitude of small, unresolved primary and secondary impacts into the granular regolith contributes to the observed maturity on Vesta even after short time scales. References Cook, M. A., Mortensen, K. S. 1967. Impact cratering in granular materials. J. Appl. Phys. 38, 5125-5128. Daniels, K. E., Coppock, J. E., Behringer, R. P. 2004. Dynamics of meteor impacts. Chaos 14, 84. Daraio, C., Nesterenko, V. F., Herbold, E. B., Jin S. 2006. Energy trapping and shock desintegration in a composite granular medium. Phys. Rev. Lett. 96, 058002, 1-4. Opsomer, E., Ludewig, F., Vandewalle, N. 2011. Phase transitions in vibrated granular systems in microgravity. Phys. Rev. E84, 051306, 1-5. Rivas, N., Ponce, S., Gellet, B., Risso, D., Soto, R., Cordero, P. 2011. Sudden chain energy transfer events in vibrated granular media. Phys. Rev. Lett. 106, 088001, 1-4. Tancredi, G., Maciel, A., Heredia, L., Richeri, P., Nesmachnow, S. 2012. Granular physics in low-gravity environments using discrete element method. Monthly Not. Royal Astron. Soc. 420, 3368-3380. Uehara, J. S., Ambroso, M. A., Ojha, R. J., Durian, D. J. 2003. Low-speed impact craters in loose granular media. Phys. Rev. Lett. 90, 194301, 1-4.

EDITORIAL: Focus on Micro- and Nanofluidics FOCUS ON MICRO- AND NANOFLUIDICS

NASA Astrophysics Data System (ADS)

Ajdari, Armand; Stone, Howard A.

2009-07-01

This focus issue of New Journal of Physics concentrates on recent developments in microfluidics, and related small-scale flow themes. This subject touches on many areas with the common element that they are engaged with understanding, measuring or manipulating flows at the scale of a few hundred microns or smaller. Microfluidics is of interest to many scientists and engineers from many disciplines because it is a toolbox from which they can investigate basic questions in their respective fields. In particular, the field has led to new studies of small-scale fluid flows, especially those dominated by surface effects, which is crucial for understanding electrokinetics, chemical reactions and phase changes, and multiphase systems, including those involving dispersed liquid and gas phases, suspended particles, cells, vesicles, capsules, etc. The lower length scale of these kinds of flows concerns nanoscale manipulation of objects such as DNA or nanoparticles, nanofabrication of surfaces, studies of the flow within nanometers of substrates, etc. Microfluidics has also given rise to technologies because it enables design and implementation of new devices for sensing, detection, measurement, materials characterization, combinatorial discovery, cellular-scale manipulation, miniaturization of reactors, etc. The fact that these systems are small, cheap, physically flexible, portable, multifunctional, and, when they are working, produce measurements quickly, offers many new avenues for innovation. In this issue we highlight contributions from around the world that explore research directions inspired by the manifold possibilities of microfluidics. In particular, the papers include reports of single-phase flows that are driven by electrical fields, so-called electrokinetics. Although the field has its origins in the 19th century, if not even earlier, new theoretical ideas are required to understand dynamics close to charged surfaces, and new applications of the basic ideas are being introduced for driving flows and manipulating suspended particles (e.g. DNA). In addition, the subject of mixing and the study of transport processes coupling diffusion and convection is a necessary component of many studies aimed at lab-on-a-chip environments. At the other extreme from mixing there is interest in the precise placement of particles in microfluidic flows. Although the majority of microfluidic studies focus on the consequences of low Reynolds number motions, the flows can frequently have large enough particle-scale Reynolds numbers that inertial effects can appear. Also, chemical gradients, via osmotic effects, can be significant, and, where surface effects are significant, particle deposition can occur. Multiphase flows constitute another major area of microfluidic research. For example, there has been great interest in using drops as individual containers since both the chemical composition inside and outside the drop can be controlled. Also, the interface between the two phases provides both a natural chemical barrier (surfactants are generally added to reduce the probability of coalescence between drops) as well as potentially being the site for reactions or localized organization of particles suspended in solution. Thus, there is interest in both the controlled breakup of liquid threads, the dynamics of such a thread, which can fold or buckle, and application of these processes to fabricating new materials. Not surprisingly the themes mentioned in this short summary are just a small window into the myriad of ideas being investigated in the research world of small-scale flows that is the playground of micro- and nanofluidics. We are grateful to all of the contributors for their efforts and to the referees, whose feedback has added value to every contribution. We hope you, as readers, will find benefit in the many ideas discussed in this Focus on Micro- and Nanofluidics, which represents a sampling of current activity, including experiment, simulation and theory, in this rapidly developing field. Focus on Micro- and Nanofluidics Contents The anti-lotus leaf effect in nanohydrodynamic bump arrays Keith Morton, Ophelia K C Tsui, Chih-Kuan Tung, James C Sturm, Stephen Y Chou and Robert Austin Transport in nanofluidic systems: a review of theory and applications W Sparreboom, A van den Berg and J C T Eijkel The effects of polymer molecular weight on filament thinning and drop breakup in microchannels P E Arratia, L-A Cramer, J P Gollub and D J Durian Mass transfer and interfacial properties in two-phase microchannel flows Jeffrey D Martin and Steven D Hudson Temporal response of an initially deflected PDMS channel Priyadarshi Panda, Kai P Yuet, Dhananjay Dendukuri, T Alan Hatton and Patrick S Doyle Gas-liquid two-phase flow patterns in rectangular polymeric microchannels: effect of surface wetting properties D Huh, C-H Kuo, J B Grotberg and S Takayama Mixing via thermocapillary generation of flow patterns inside a microfluidic drop María Luisa Cordero, Hans Olav Rolfsnes, Daniel R Burnham, Paul A Campbell, David McGloin and Charles N Baroud Pressure-driven DNA transport across an artificial nanotopography J T Del Bonis-O'Donnell, W Reisner and D Stein Eulerian indicators for predicting and optimizing mixing quality Rob Sturman and Stephen Wiggins Asymmetric flows over symmetric surfaces: capacitive coupling in induced-charge electro-osmosis T S Mansuripur, A J Pascall and T M Squires High-viscosity fluid threads in weakly diffusive microfluidic systems T Cubaud and T G Mason Interfacial mass transport in steady three-dimensional flows in microchannels Joseph D Kirtland, Corey R Siegel and Abraham D Stroock Active connectors for microfluidic drops on demand Jean-Christophe Galas, Denis Bartolo and Vincent Studer Electrokinetic control of sample splitting at a channel bifurcation using isotachophoresis Alexandre Persat and Juan G Santiago Differential inertial focusing of particles in curved low-aspect-ratio microchannels Aman Russom, Amit K Gupta, Sunitha Nagrath, Dino Di Carlo, Jon F Edd and Mehmet Toner Capillary instability on a hydrophilic stripe Raymond L Speth and Eric Lauga Universal nanocolloid deposition patterns: can you see the harmonics of a Taylor cone? Xinguang Cheng and Hsueh-Chia Chang Osmotic manipulation of particles for microfluidic applications B Abécassis, C Cottin-Bizonne, C Ybert, A Ajdari and L Bocquet Scaling the drop size in coflow experiments E Castro-Hernández, V Gundabala, A Fernández-Nieves and J M Gordillo Pattern formation during the evaporation of a colloidal nanoliter drop: a numerical and experimental study Rajneesh Bhardwaj, Xiaohua Fang and Daniel Attinger Topology and shape optimization of induced-charge electro-osmotic micropumps M M Gregersen, F Okkels, M Z Bazant and H Bruus Fabrication of multiphasic and regio-specifically functionalized PRINT® particles of controlled size and shape H Zhang, J K Nunes, S E A Gratton, K P Herlihy, P D Pohlhaus and J M DeSimone Using TIRF microscopy to quantify and confirm efficient mass transfer at the substrate surface of the chemistrode Delai Chen, Wenbin Du and Rustem F Ismagilov Nonlinear electrokinetics at large voltages Martin Z Bazant, Mustafa Sabri Kilic, Brian D Storey and Armand Ajdari Interdiffusion of liquids of different viscosities in a microchannel J Dambrine, B Géraud and J-B Salmon Microfluidic fabrication of microparticles with structural complexity using photocurable emulsion droplets Shin-Hyun Kim, Jae Won Shim, Jong-Min Lim, Su Yeon Lee and Seung-Man Yang