bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants of Earnings and Selection into Labor Market by Controlling Selection Bias in Bangladesh
Authors: Akanda Md Abdus Salam , Khanam Maksuda , Shafiullah Abu Zar Md
Published: February 2015

This paper uses the data of Household Income and Expenditure Survey (HIES) 2005 to estimate the determinants of earnings and selection into labor market in Bangladesh. We deal with the selection bias in earnings by using a maximum likelihood system of equations, and a multinomial selection approach is used modeling for selection into the labor market. By instrumenting years of schooling in both the multinomial selection approach and the earnings equations, we deal with reverse causality between educational attainment and earnings. We find that the estimated parameters of the earnings equation under multinomial selection approach differs from ordinary least square (OLS) estimates and a binomial selection procedure. The estimated parameters that vary the most with those related variables have the strongest impact on multinomial selection into the different labor-market statuses. We also find that workers with higher educational attainment are more likely to search out a salaried employees job, which non-salaried work is as another to inactivity. DOI: http://dx.doi.org/10.3329/dujs.v62i1.21953 Dhaka Univ. J. Sci. 62(1): 11-16, 2014 (January)
Dolphin Whistle Track Estimation Using Sequential Monte Carlo Probability Hypothesis Density Filter
Authors: Ahmed Imtiaz
Published: February 2015

This article focuses on possible automation of dolphin whistle track estimation process within the context of Multiple Target Tracking (MTT). It provides automatic whistle track estimation from raw hydrophone measurements using the Sequential Monte Carlo Probability Hypothesis Density (SMC-PHD) filter. Hydrophone measurements for three different types of species namely bottlenose dolphin (Tursiops truncates), common dolphin (Delphinus delphis) and striped dolphin (Stenella coeruleoalba) have been used to benchmark the tracking performance of the SMC-PHD filter against three major challenges- the presence of multiple whistles, spontaneous death/birth of whistles and multiple whistles crossing each other. Quantitative analysis of the whistle track estimation accuracy is not possible since there is no ground truth type track for the dolphin whistles. Hence visual inspection of estimated tracks has been used corroborate the satisfactory tracking performance in the presence of all three challenges. DOI: http://dx.doi.org/10.3329/dujs.v62i1.21954 Dhaka Univ. J. Sci. 62(1): 17-20, 2014 (January)
Effect Measures in Meta-Analysis
Authors: Hossain Md Belal
Published: February 2015

When conducting a meta-analysis of randomised controlled trials outcomes, appropriate choice of the effect measure is important. This article demonstrates on various types of effect measures in meta-analysis, for example, binary, continuous and ordinal outcomes. A general fixed effects model and a random effects model are employed for combining these outcomes in meta-analysis. Six trials totaling 1876 patients from a meta-analysis of randomised controlled trials evaluating the efficacy and drawbacks of limited (D1) versus extended lymphadenectomy (D2) for proven gastric adenocarcinoma are analysed for binary and continuous outcomes. An individual patient data consisting of five randomised trials of anti-cholinesterase drug tacrine in patients with Alzheimer's disease is also discussed for ordinal outcomes. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21969 Dhaka Univ. J. Sci. 62(2): 75-80, 2014 (July)
Investigating Causal Relations of Economic Variables: Capital, GDP, Labour and Population in Sweden 1870-2000
Authors: Amin Mohammad Mastak Al , Sajib Anamul Haque , Alamgir Mohammad
Published: February 2015

The main objective of this paper was to study the causal relationships of the economic variables GDP, labour, capital and population in Sweden during the time period 1870 to 2000. In this paper the theory of unit root tests, vector auto regressive (VAR) model and Granger-Causality test were ased to find the causality of the variables. Augmented Dickey Fuller test was also used as unit root test. By applying all these tests and methods, the causal relationship among the economic variables has been established. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21970 Dhaka Univ. J. Sci. 62(2): 81-86, 2014 (July)
A Study on 1-D Simplex Search Algorithm with its Numerical Experiments Through Computer Algebra
Authors: Das HK , Saha Tapash , Hasan M Babul
Published: February 2015

Computer techniques have been developed to solve 1-D NLP problems. The 1-D simplex search algorithm was studied and a code corresponding to the modified phase-0 has been developed. The 1-D two phase methods and modified Phase-0 method have been compared with those reported by others. The efficiency of computer techniques and algorithms have been demonstrated with a number of numerical examples. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21972 Dhaka Univ. J. Sci. 62(2): 95-102, 2014 (July)
Numerical Solutions of General Fourth Order Two Point Boundary Value Problems by Galerkin Method with Legendre Polynomials
Authors: Hossain Md Bellal , Islam Md Shafiqul
Published: February 2015

In this paper, Galerkin weighted residual method is presented to find the numerical solutions of the general fourth order linear and nonlinear differential equations with essential boundary conditions. For this, the given differential equations and the boundary conditions over arbitrary finite domain [a, b] are converted into its equivalent form over the interval [0, 1]. Here the Legendre polynomials, over the interval [0, 1], are chosen as trial functions satisfying the corresponding homogeneous form of the Dirichlet boundary conditions. Details matrix formulations are derived for solving linear and nonlinear boundary value problems (BVPs). Numerical examples for both linear and nonlinear BVPs are considered to verify the proposed formulation and the results obtained are compared. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21973 Dhaka Univ. J. Sci. 62(2): 103-108, 2014 (July)
Comparison of Shear Stresses of Different Fluid Flows Arising in the Boundary Layer Theory
Authors: Molla Mohammad Riazuddin
Published: February 2015

The existence of positive solution for the singular second-order nonlinear boundary value problem arising in the boundary layer theory for the strong suction is studied. Then we compared the shear stress of the strong suction with the shear stress of the Homann flow. Also we compared the shear stress of the strong suction with the shear stress of the convergent flow. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21975 Dhaka Univ. J. Sci. 62(2): 115-118, 2014 (July)
Application of Fuzzy Optimization Problem in Fuzzy Environment
Authors: Shirin Shapla , Kamrunnahar -
Published: February 2015

In this paper application of optimization problem has been introduced which belong to fuzzy environment. An attempt has been taken to find out a suitable option in order to obtain the optimum solutions of optimization problems in fuzzy environment. Optimum solutions of the proposed optimization problem computed by using three methods, such as Bellman-Zadehs method, Zimmermans Method, and Fuzzy Version of Simplex method, are compared to each other. In support of that the three algorithms of the above three methods have been reviewed. However, the main objective of this paper is to focus on the appropriate method and how to achieve good enough or optimum solution of linear programming using triangular fuzzy numbers with equal widths because of complex and undefined situations in our daily life. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21976 Dhaka Univ. J. Sci. 62(2): 119-125, 2014 (July)
The Effect of Thermal Conductance of Evaporator on Performance of a Two Stage Adsorption Chiller (Reheat) with Different Mass Allocation
Authors: Sultana T , Khan MZI
Published: February 2015

Now a days, adsorption heat pumps receive considerable attention as they are energy savers and environmentally benign. Silica gel/water based adsorption cycles have a distinct advantage in their ability to be driven by heat of near-ambient temperature so that waste heat below 100 °C can be recovered. One interesting feature of refrigeration cycles driven by waste heat is that they do not use primary energy as driving source. In the present paper, an analytic investigation of a two-stage adsorption refrigeration chiller using re-heat with different mass allocation was performed to determine the influence of the thermal conductance of evaporator as well as the heat source temperature on the chiller performance. Result shows that cycle performance is strongly influenced by large thermal conductance values of the evaporator. Besides it is observed that the chilled water outlet has lower value for comparatively higher value of heat source temperature. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21978 Dhaka Univ. J. Sci. 62(2): 133-139, 2014 (July)
Electrochemical Evidences for the Enhancement of Heterogeneous Electron Transfer Rates of Riboflavin in the Presence of Copper
Authors: Jabbar Md Abdul , Salahuddin Shaila , Mannan Rowshan Jahan , Mahmood Abu Jafar
Published: February 2015

Evidences for the enhancement of the heterogeneous electron transfer rates of riboflavin in the presence of copper in aqueous medium with a glassy carbon electrode were investigated by cyclic voltammetry, chronocoulometry and differential anodic stripping pulse voltammetry. It was found that copper exhibits a multi-nuclear complex with riboflavin in aqueous KCl solution. The overall stability constant of the complex was calculated (log? = 11.17), which is in a good agreement for the formation of a stable copper-riboflavin complex. DOI: http://dx.doi.org/10.3329/dujs.v62i2.21980 Dhaka Univ. J. Sci. 62(2): 147-152, 2014 (July)
Admission Serum Uric Acid Levels and In-Hospital Outcomes in Patients with Acute Coronary Syndrome
Authors: Abdullah Abu Sadique , Begum Noortaj , Khan Md Aminul Haque , Hossain Mofazzal , Kabir Shah Mohd Eftar Jahan , Alam Mohammad Sarwar , Chowdhury Abdul Wadud , Khan HI Lutfur Rahman
Published: February 2015

Background: Uric acid is an independent risk factor for cardiovascular disease. Hospital admission for ischemic heart disease (IHD) is increasing rapidly in our country. Although studies were conducted abroad regarding association of serum uric acid with in-hospital outcomes in patients with acute coronary syndrome (ACS), no data is yet available to show the association in our country. Objective: The objective of this study was to assess the association of serum uric acid level on admission with in-hospital outcomes of the patients with ACS. Materials and Methods: This cross sectional comparative study was done in the Department of Cardiology, Dhaka Medical College Hospital (DMCH) from January to December 2012. After proper ethical consideration total 93 ACS patients were enrolled in the study by nonrandom sampling. Serum uric acid of all subjects was measured within 24 hours of admission. Then in-hospital outcomes were observed in all subjects. Results: The frequency of hyperuricemia among ACS patients was 24.7% (22.54% in male and 31.82% in female). Hyperuricemic patients significantly developed heart failure (30.4% vs 11.4%, p=0.032) and conduction defect (13.0% vs 1.4%, p=0.017) than normouricemic subjects. The mean ejection fraction was significantly lower in hyperuricemic patients than patients with normal uric acid level (50.87 ± 10.27% vs 55.94 ± 6.66%). The mean ± SD duration of hospital stay of hyperuricemic group was significantly longer in patients with ACS (8.26 ± 1.18 vs 7.51±1.18 days, p=0.010). Conclusion: The measurement of serum uric acid level, an easily available and inexpensive biochemical tool, might turn out as a valuable risk marker for prediction of in-hospital outcomes in patients with ACS. DOI: http://dx.doi.org/10.3329/jemc.v5i1.21492 J Enam Med Col 2015; 5(1): 15-22
Lipid Profile and Atherogenic Index of Plasma (AIP) in Vegetarians
Authors: Sultana AN Wahida , Begum Noortaj , Abdullah Abu Sadique , Khan Md Aminul Haque , Rahman Md Rezwanur , Kamal Abu Hena Mostafa , Mollah Forhadul Hoque
Published: February 2015

Background: Diet deficient in fresh fruits and vegetables are associated with an increased risk of coronary diseases. Low levels of vitamin C, vitamin E and other antioxidants may enhance the production of oxidized LDL and are important independent risk factors for coronary disease. Objective: To make a comparative evaluation of lipid profile and atherogenic index of plasma (AIP) between vegetarians and nonvegetarians. Materials and Methods: This case-control study was carried out in the Department of Biochemistry of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka between July 2011 to June 2012. Vegetarian and nonvegetarian subjects of male sex were the study population. Vegetarians were considered as cases while nonvegetarians as controls. After proper ethical consideration a total of 30 vegetarians and 40 nonvegetarians were consecutively included in the study based on predefined inclusion and exclusion criteria. Laboratory investigations were done in the Department of Biochemistry, BSMMU, Dhaka. Results: The vegetarians had significantly lower total cholesterol and LDLcholesterol than the nonvegetarians (p=0.000 and p=0.000 respectively). Serum HDL cholesterol was also lower among the vegetarians (p=0.002) and triglycerides were almost identical in both the groups (p=0.272). Conclusion: The study reveals lower level of total cholesterol, LDLcholesterol and HDL-cholesterol in vegetarians. No difference regarding triglycerides and AIP was found between the groups. So, the findings of this study do not indicate any superiority of vegetarian diet in control and prevention of cardiac diseases. DOI: http://dx.doi.org/10.3329/jemc.v5i1.21494 J Enam Med Col 2015; 5(1): 30-33
Acute Renal Failure as Part of Multi-Organ Failure: How Long We Should Wait before We Intervene? A Dissection of Studies
Authors: Mohammad Najib
Published: February 2015

Mortality rate in multisystem organ failure (MOF) is very high. Acute renal failure is an important part of MOF. In this special feature article I have aimed to streamline the achievements of different studies on continuous renal replacement therapy (CRRT) for a fruitful outcome. For this I have gone for retrospective evaluation of the studies reached through PubMed, internet alert system of different journals, proceedings of conferences on CRRT and personal communication with the experts in this field. I have evaluated the outcome of studies to explore the causes of failure to achieve a positive result and to identify the positive gains of studies. Finally, I have compiled the positive gains to outline a new strategy for future study and greater achievement. The findings of evaluation led to the conclusion that while planning for initiation of CRRT, multiple strategies should be targeted. The strategy should involve early initiation of CRRT guided by new markers of acute kidney injury (AKI), continuous venovenous hemofiltration (CVVH) modality, optimum intensity (intensity should be adequate enough to improve hemodynamics within a targeted period), selection of an effective filter membrane. Elderly patients should be studied in a different group. Cardiac patients with AKI should not be studied in the same group along with the patients with sepsis DOI: http://dx.doi.org/10.3329/jemc.v5i1.21496 J Enam Med Col 2015; 5(1): 39-43
Ebola Virus ? A Global Threat
Authors: Ahmed Mejbah Uddin , Roy Sushmita
Published: February 2015

Ebola virus is a filamentous, enveloped, non-segmented, single-stranded, negative-sense RNA virus. It belongs to the Filoviridae and was first recognized near the Ebola River valley in Zaire in 1976. Since then most of the outbreaks have occurred to both human and nonhuman primates in sub-Saharan Africa. Ebola virus causes highly fatal hemorrhagic fever in human and nonhuman primates. In addition to hemorrhagic fever, it could be used as a bioterrorism agent. Although its natural reservoir is yet to be proven, current data suggest that fruit bats are the possibility. Infection has also been documented through the handling of infected chimpanzees, gorillas, monkeys, forest antelope and porcupines. Human infection is caused through close contact with the blood, secretion, organ or other body fluids of infected animal. Human-to-human transmission is also possible. Ebola virus infections are characterized by immune suppression and a systemic inflammatory response that causes impairment of the vascular, coagulation, and immune systems, leading to multiorgan failure and shock. The virus constitutes an important public health threat in Africa and also worldwide as no effective treatment or vaccine is available till now DOI: http://dx.doi.org/10.3329/jemc.v5i1.21497 J Enam Med Col 2015; 5(1): 44-51
A Case Report on Spontaneous Coronary Artery Dissection
Authors: Khan Tunaggina Afrin , Chowdhury Abdul Wadud , Abdullah Abu Sadique
Published: February 2015

Spontaneous coronary artery dissection is an extremely rare cause of acute coronary syndrome. Although it predominantly affects young women in the peripartum period, it can also occur in men. The left coronary artery is most frequently involved. The usual presentation is ST segment elevation myocardial infarction. Although several treatment modalities have been proposed, the optimal treatment options still remain to be established. This current case report focuses on a 40- year-old male presented with acute coronary syndrome and subsequently was found to have coronary artery dissection. DOI: http://dx.doi.org/10.3329/jemc.v5i1.21498 J Enam Med Col 2015; 5(1): 52-57
College News Vol.5(1)
Authors: Khan Md Aminul Haque , Parvin Rukhsana
Published: February 2015

Abstract not available DOI: http://dx.doi.org/10.3329/jemc.v5i1.21965 J Enam Med Col 2015; 5(1): 62-63
Reviewers in this Issue Vol.5(1)
Authors: Editor The
Published: February 2015

Abstract not available DOI: http://dx.doi.org/10.3329/jemc.v5i1.21966 J Enam Med Col 2015; 5(1): 64
Microbial Community Shifts during Biogas Production from Biowaste and/or Propionate
Authors: Li Chaoran , Moertelmaier Christoph , Winter Josef , Gallert Claudia
Published: February 2015

Propionate is the most delicate intermediate during anaerobic digestion as its degradation is thermodynamically unfavorable. To determine its maximum possible degradation rates during anaerobic digestion, a reactor was fed Monday to Friday with an organic loading rate (OLR) of 12/14 kg CODbiowaste·m−3·d−1 plus propionate up to a final OLR of 18 kg COD·m−3·d−1. No feed was supplied on weekends as it was the case in full-scale. To maintain permanently high propionate oxidizing activity (POA), a basic OLR of 3 kg CODpropionate·m−3·d−1 all week + 11 kg CODbiowaste·m−3·d−1 from Monday to Friday was supplied. Finally a reactor was operated with an OLR of 12 kg CODbiowaste·m−3·d−1 from Monday to Friday and 5 kg CODpropionate·m−3·d−1 from Friday night to Monday morning to maintain a constant gas production for permanent operation of a gas engine. The propionate degradation rates (PDRs) were determined for biowaste + propionate feeding. Decreasing PDRs during starvation were analyzed. The POA was higher after propionate supply than after biowaste feeding and decreased faster during starvation of a propionate-fed rather than a biowaste-fed inoculum. Shifts of the propionate-oxidizing and methanogenic community were determined.
Determination of Trichloroethylene in Water by Liquid–Liquid Microextraction Assisted Solid Phase Microextraction
Authors: Zhang Mengliang , Harrington Peter
Published: February 2015

A method for the determination of trichloroethylene (TCE) in water using portable gas chromatography/mass spectrometry (GC/MS) was developed. A novel sample preparation method, liquid–liquid microextraction assisted solid phase microextraction (LLME–SPME), is introduced. In this method, 20 µL of hexane was added to 10 mL of TCE contaminated aqueous samples to assist headspace SPME. The extraction efficiency of SPME was significantly improved with the addition of minute amounts of organic solvents (i.e., 20 µL hexane). The absolute recoveries of TCE at different concentrations were increased from 11%–17% for the samples extracted by SPME to 29%–41% for the samples extracted by LLME–SPME. The method was demonstrated to be linear from 10 to 1000 ng mL−1 for TCE in water. The improvements on extraction efficiencies were also observed for toluene and 1, 2, 4-trichlorobenzene in water by using LLME–SPME method. The LLME–SPME method was optimized by using response surface modeling (RSM).
Thermodynamic Analysis about Nucleation and Growth of Cubic Boron Nitride Crystals in the hBN-Li3N System under High Pressure and High Temperature
Authors: Guo Xiao-Fei , Xu Bin , Zhang Wen , Lv Mei-Zhe , Yang Hong-Mei , Fan Xiao-Hong
Published: February 2015

The nucleation of cubic boron nitride (cBN) single crystals synthesized with lithium nitride (Li3N) as a catalyst under high pressure and high temperature (HPHT) was analyzed. Many nanometer-sized cubic boron nitride nuclei formed in the near surface layer, as detected by high resolution transmission electron microscopy. Based on the experiment results, the transformation kinetics is described by a nucleation and growth process in the thermodynamic stability region of cBN. A theoretical description is developed based on the heterogeneous nucleation and layer growth mechanism, and the relevant parameters are estimated and discussed. The critical crystal radius, r*, increases with the temperature under constant pressure; the change with temperature more pronounced at lower pressure (such as 4.5 GPa). The crystal growth velocity increased with the temperature, and it is parabolic with temperature under certain pressure. These results are consistent with experimental data.
Quantropy
Authors: Baez John , Pollard Blake
Published: February 2015

There is a well-known analogy between statistical and quantum mechanics. In statistical mechanics, Boltzmann realized that the probability for a system in thermal equilibrium to occupy a given state is proportional to \(\exp(-E/kT)\), where \(E\) is the energy of that state. In quantum mechanics, Feynman realized that the amplitude for a system to undergo a given history is proportional to \(\exp(-S/i\hbar)\), where \(S\) is the action of that history. In statistical mechanics, we can recover Boltzmann's formula by maximizing entropy subject to a constraint on the expected energy. This raises the question: what is the quantum mechanical analogue of entropy? We give a formula for this quantity, which we call ``quantropy''. We recover Feynman's formula from assuming that histories have complex amplitudes, that these amplitudes sum to one and that the amplitudes give a stationary point of quantropy subject to a constraint on the expected action. Alternatively, we can assume the amplitudes sum to one and that they give a stationary point of a quantity that we call ``free action'', which is analogous to free energy in statistical mechanics. We compute the quantropy, expected action and free action for a free particle and draw some conclusions from the results.
Modeling Crown Biomass for Four Pine Species in China
Authors: Zou Wen-Tao , Zeng Wei-Sheng , Zhang Lian-Jin , Zeng Ming
Published: February 2015

To analyze the main variables affecting crown biomass, we measured crown biomass and a number of variables describing tree size, such as stem diameter at breast height (D), tree height (H), crown width (Cw) and crown length (Cl), from 754 sample trees of four pine species in China, specifically, Pinus massoniana, P. yunnanensis, P. tabulaeformis and P. elliottii. In addition, we developed individual tree crown biomass equations and compatible branch and needle biomass equations based on one-, two- and multi-variable models using nonlinear mixed-effects modeling and error-in-variable simultaneous equations. The results showed that: (i) crown biomass was strongly correlated to D and H, and the new combined variables (D4/H) and (D2/H) were suitable for modeling two- and multi-variable crown biomass equations, respectively; (ii) the four species were ranked as P. yunnanensis, P. massoniana, P. elliottii and P. tabulaeformis from small to large based on estimates from crown biomass equations, and the crown biomass estimate of P. tabulaeformis was about 60% greater than that of P. yunnanensis; (iii) the ratio of branch to crown biomass increased with increasing D, and the four species were ranked as P. elliottii, P. tabulaeformis, P. massoniana and P. yunnanensis from small to large by the proportion of the branch to crown biomass; (iv) the mean prediction errors (MPE’s) of the crown biomass equations for the four species were less than 10%, which could meet precision needs for biomass estimation.
Gender Differences in the VDR-FokI Polymorphism and Conventional Non-Genetic Risk Factors in Association with Lumbar Spine Pathologies in an Italian Case-Control Study
Authors: Colombini Alessandra , Brayda-Bruno Marco , Ferino Lucia , Lombardi Giovanni , Maione Vincenzo , Banfi Giuseppe , Cauci Sabina
Published: February 2015

Recently, the FokI polymorphism (rs2228570) in the vitamin D receptor gene (VDR) and conventional risk factors were associated with spine disorders in the Italian population, but without gender analysis. Two-hundred and sixty-seven patients (149 males, 118 females) with lumbar spine disorders were assessed by magnetic resonance imaging (MRI) and 254 (127 males, 127 females) asymptomatic controls were enrolled. The exposure to putative risk factors was evaluated and FokI polymorphism was detected by PCR-restriction fragment length polymorphism (PCR-RFLP). An association between lumbar spine pathologies and higher than average age; overweight; family history; lower leisure physical activity; smoking habit; higher number of hours/day exposure to vibration and more sedentary or intense physical job demand was observed in male patients. In contrast, in females, only higher age, overweight, family history and lower leisure physical activity were risk factors. FF genotype was a 2-fold risk factor to develop discopathies and/or osteochondrosis concomitant with disc herniation for both gender patients, while heterozygous Ff was protective for females only. In males only ff genotype was protective for discopathies and/or osteochondrosis and F allele was a 2-fold risk factor for hernia; discopathies; discopathies and/or osteochondrosis. Sex-related differences in voluntary behaviors, exposure to environmental risks and genetic background could be crucial for a gender-differentiated management of patients with spine disorders.
Protocells: At the Interface of Life and Non-Life
Authors: Ma Wentao , Feng Yu
Published: February 2015

The cellular form, manifesting as a membrane-bounded system (comprising various functional molecules), is essential to life. The ultimate reason for this is that, typically, one functional molecule can only adopt one “correct” structure to perform one special function (e.g., an enzyme), and thus molecular cooperation is inevitable. While this is particularly true for advanced life with complex functions, it should have already been true for life at its outset with only limited functions, which entailed some sort of primitive cellular form—“protocells”. At the very beginning, the protocells may have even been unable to intervene in the growth of their own membrane, which can be called “pseudo-protocells”. Then, the ability to synthesize membrane components (amphiphiles) may have emerged under selective pressure, leading to “true-protocells”. The emergence of a “chromosome” (with genes linked together)—thus avoiding “gene-loss” during the protocell division, was another key event in the evolution of protocells. Such “unitary-protocells”, containing a central genetic molecule, may have appeared as a milestone—in principle, since then life could evolve endlessly, “gaining” more and more functions by introducing new genes. To synthesize in laboratory these different types of protocells, which stand at the interface between life and non-life, would greatly enhance our understanding on the essence of life.
Does DNA Exert an Active Role in Generating Cell-Sized Spheres in an Aqueous Solution with a Crowding Binary Polymer?
Authors: Tsumoto Kanta , Arai Masafumi , Nakatani Naoki , Watanabe Shun , Yoshikawa Kenichi
Published: February 2015

We report the spontaneous generation of a cell-like morphology in an environment crowded with the polymers dextran and polyethylene glycol (PEG) in the presence of DNA. DNA molecules were selectively located in the interior of dextran-rich micro-droplets, when the composition of an aqueous two-phase system (ATPS) was near the critical condition of phase-segregation. The resulting micro-droplets could be controlled by the use of optical tweezers. As an example of laser manipulation, the dynamic fusion of two droplets is reported, which resembles the process of cell division in time-reverse. A hypothetical scenario for the emergence of a primitive cell with DNA is briefly discussed.
Gold Nanoparticles Surface Plasmon Resonance Enhanced Signal for the Detection of Small Molecules on Split-Aptamer Microarrays (Small Molecules Detection from Split-Aptamers)
Authors: Melaine Feriel , Roupioz Yoann , Buhot Arnaud
Published: February 2015

The detection of small molecules by biosensors remains a challenge for diagnostics in many areas like pharmacology, environment or homeland security. The main difficulty comes from both the low molecular weight and low concentrations of most targets, which generally requires an indirect detection with an amplification or a sandwich procedure. In this study, we combine both strategies as the amplification of Surface Plasmon Resonance imaging (SPRi) signal is obtained by the use of gold nanoparticles and the sequence engineering of split-aptamers, short oligonucleotides strands with strong affinity towards small targets, allows for a sandwich structure. Combining those two strategies, we obtained state-of-the-art results in the limit of detection (LOD = 50 nM) with the model target adenosine. Furthermore, the SPRi detection led on aptamer microarrays paves the way for potential multi-target detections thanks to the multi-probe imaging approach.
Novel Zinc-Catalytic Systems for Ring-Opening Polymerization of ε-Caprolactone
Authors: Żółtowska Karolina , Sobczak Marcin , Olędzka Ewa
Published: February 2015

Polycaprolactone (PCL) is a biodegradable synthetic polymer that is currently widely used in many pharmaceutical and medical applications. In this paper we describe the coordination ring-opening polymerization of ε-caprolactone in the presence of two newly synthesized catalytic systems: diethylzinc/gallic acid and diethylzinc/propyl gallate. The chemical structures of the obtained PCLs were characterized by 1H- or 13C-NMR, FTIR spectroscopy and MALDI TOF mass spectrometry. The average molecular weight of the resulting polyesters was analysed by gel permeation chromatography and a viscosity method. The effects of temperature, reaction time and type of catalytic system on the polymerization process were examined. Linear PCLs with defined average molecular weight were successfully obtained. Importantly, in some cases the presence of macrocyclic products was not observed during the polymerization process. This study provides an effective method for the synthesis of biodegradable polyesters for medical and pharmaceutical applications due to the fact that gallic acid/propyl gallate are commonly used in the pharmaceutical industry.
Correction: Calderon, C.P. Data-Driven Techniques for Detecting Dynamical State Changes in Noisily Measured 3D Single-Molecule Trajectories. Molecules 19, 18381-18398
Authors: Calderon Christopher
Published: February 2015

The author wishes to make the following corrections to paper [1] (doi:10.3390/molecules191118381, website: http://www.mdpi.com/1420-3049/19/11/18381):
The Games Radicals Play: Special Issue on Free Radicals and Radical Ions
Authors: Walton John , Williams Ffrancon
Published: February 2015

Chemistry and Physics have aptly been described as “most excellent children of Intellect and Art” [1]. Both these “children” engage with many playthings, and molecules rank as one of their first favorites, especially radicals, which are amongst the most lively and exciting. Checking out radicals dancing to the music of entropy round their potential energy ballrooms is surely both entertaining and enlightening. Radicals’ old favorite convolutions are noteworthy, but the new styles, modes and arrangements appearing on the scene are even more interesting. Some of these are ephemeral and enjoy only a brief appearance, others are retro-types reappearing in new guises, still others are genuinely new and “go viral” in the scientific world. This Special Issue of Molecules contains the observations and reflections of a select group of chemists and physicists fascinated by this spectacle. It contains an eclectic mix reflecting on new modes and advances as well as on permutations and combinations that revive mature themes. [...]
Development of a Halogen Free Flame Retardant Masterbatch for Polypropylene Fibers
Authors: Rault François , Giraud Stéphane , Salaün Fabien , Almeras Xavier
Published: February 2015

The efficiency of new phosphinates, in combination with melamine cyanurate, was studied using different polypropylene textile structures. The influence of different ratios up to a total amount of 6 wt% in the polypropylene fiber was investigated using the limiting oxygen index (LOI) and cone calorimeter method for research purposes, while the performances were correlated to the standards FMVSS 302 (Federal Motor Vehicle Safety Standards) and DIN 4102-l (Deutsches Institut für Normung) used more specifically for automotive and building sector.
Poriferan Chitin as a Versatile Template for Extreme Biomimetics
Authors: Wysokowski Marcin , Petrenko Iaroslav , Stelling Allison , Stawski Dawid , Jesionowski Teofil , Ehrlich Hermann
Published: February 2015

In this mini-review, we shall first cover a short history of the discovery of chitin isolated from sponges; as well as its evolutionarily ancient roots. Next, we will delve into the unique structural, mechanical, and thermal properties of this naturally occurring polymer to illuminate how its physicochemical properties may find uses in diverse areas of the material sciences. We show how the unique properties and morphology of sponge chitin renders it quite useful for the new route of “Extreme Biomimetics”; where high temperatures and pressures allow a range of interesting bioinorganic composite materials to be made. These new biomaterials have electrical, chemical, and material properties that have applications in water filtration, medicine, catalysis, and biosensing.
P(MMA-EMA) Random Copolymer Electrolytes Incorporating Sodium Iodide for Potential Application in a Dye-Sensitized Solar Cell
Authors: Dzulkurnain Nurul , Ahmad Azizan , Mohamed Nor
Published: February 2015

Polymer electrolytes based on 90 wt% of methyl methacrylate and 10 wt% of ethyl methacrylate (90MMA-co-10EMA) incorporating different weight ratios of sodium iodide were prepared using the solution casting method. The complexation between salt and copolymer host has been investigated using Fourier transform infrared spectroscopy. The ionic conductivity and thermal stability of the electrolytes were measured using impedance spectroscopy and differential scanning calorimetry, respectively. Scanning electron microscopy was used to study the morphology of the polymer electrolytes. The ionic conductivity and glass transition temperature increased up to 20 wt% of sodium iodide (5.19 × 10−6 S·cm−1) and decreased with the further addition of salt concentration, because of the crosslinked effect. The morphology behavior of the highest conducting sample also showed smaller pores compared to the other concentration. The total ionic transference number proved that this system was mainly due to ions, and the electrochemical stability window was up to 2.5 V, which is suitable for a dye-sensitized solar cell application. This sample was then tested in a dye-sensitized solar cell and exhibited an efficiency of 0.62%.
Moving Target Detection Based on the Spreading Characteristics of SAR Interferograms in the Magnitude-Phase Plane
Authors: Gao Gui , Shi Gongtao , Yang Lei , Zhou Shilin
Published: February 2015

We propose a constant false alarm rate (CFAR) algorithm for moving target detection in synthetic aperture radar (SAR) images based on the spreading characteristics of interferograms on the magnitude-phase (M-P) plane. This method is based on the observation that, in practice, both moving and stationary targets along with clutter are located at different regions in the M-P plane, and hence reasonable partitions of the M-P plane can help in detecting moving targets. To ensure efficient CFAR detection and to resolve the effect of factors that influence detection results, the proposed algorithm is divided into three distinct stages: coarse detection, fine detection, and post-processing. First, to accurately describe the statistical behavior of clutter, a global censoring strategy, called coarse detection, is introduced to adaptively eliminate the influences of the moving and stationary target points from the given data. Then, to acquire fine detection results, a novel CFAR detector is developed on the basis of the fits of a known theoretical M-P joint probability density function (PDF) against the two-dimensional (2-D) histogram of the censored clutter. The joint PDF’s projected contour line that satisfies the desirable probability of false alarm (PFA) corresponds to the required threshold of detection in the M-P plane. Finally, two filters, the magnitude and phase filters, are applied to reduce the false alarms generated from the previous procedures. The effectiveness of the proposed algorithm is validated through experimental results obtained from a two-channel SAR complex image.
Forest Canopy LAI and Vertical FAVD Profile Inversion from Airborne Full-Waveform LiDAR Data Based on a Radiative Transfer Model
Authors: Ma Han , Song Jinling , Wang Jindi
Published: February 2015

Forest canopy leaf area index (LAI) is a critical variable for the modeling of climates and ecosystems over both regional and global scales. This paper proposes a physically based method to retrieve LAI and foliage area volume density (FAVD) profile directly from full-waveform Light Detection And Ranging (LiDAR) data using a radiative transfer (RT) model. First, a physical interaction model between LiDAR and a forest scene was built on the basis of radiative transfer theories. Next, FAVD profile of each laser shot of full-waveform LiDAR was inverted using the physical model. In addition, the missing LiDAR data, caused by high-density forest and LiDAR system limitations, were filled in based on the inverted FAVD and the ancillary CHM data. Finally, LAI of the study area was retrieved from the inverted FAVD at a 10-m resolution. CHM derived LAI based on the Beer-Lambert law was compared with the LAI derived from full-waveform data. Also, we compared the results with the field measured LAI. The values of correlation coefficient r and RMSE of the estimated LAI were 0.73 and 0.67, respectively. The results indicate that full-waveform LiDAR data is a reliable data source and represent a useful tool for retrieving forest LAI.
Shiftable Leading Point Method for High Accuracy Registration of Airborne and Terrestrial LiDAR Data
Authors: Cheng Liang , Tong Lihua , Wu Yang , Chen Yanming , Li Manchun
Published: February 2015

A new automated approach to the high-accuracy registration of airborne and terrestrial LiDAR data is proposed, which has three primary steps. Firstly, airborne and terrestrial LiDAR data are used to extract building corners, known as airborne corners and terrestrial corners, respectively. Secondly, an initial matching relationship between the terrestrial corners and airborne corners is automatically derived using a matching technique based on maximum matching corner pairs with minimum errors (MTMM). Finally, a set of leading points are generated from matched airborne corners, and a shiftable leading point method is proposed. The key feature of this approach is the implementation of the concept of shiftable leading points in the final step. Since the geometric accuracy of terrestrial LiDAR data is much better than that of airborne LiDAR data, leading points corresponding to anomalous airborne corners could be modified for the improvement of the geometric accuracy of registration. The experiment demonstrates that the proposed approach can advance the geometric accuracy of two-platform LiDAR data registration effectively.
Nano-Magnetic Immunosensor Based on Staphylococcus Protein A and the Amplification Effect of HRP-Conjugated Phage Antibody
Authors: Mu Xihui , Tong Zhaoyang , Huang Qibin , Liu Bing , Liu Zhiwei , Hao Lanqun , Zhang Jinping , Gao Chuan , Wang Fenwei
Published: February 2015

In this research, super-paramagnetic Fe3O4 nanoparticles (magnetic particles) were coated with Staphylococcus protein A (SPA) and coupled with polyclonal antibody (pcAb) to construct magnetic capturing probes, and HRP-conjugated phage antibody was then used as specific detecting probe to design a labeled immunosensor for trace detection of Staphylococcus aureus enterotoxin B (SEB). The linear detection range of the sensor was 0.008~125 µg/L, the regression equation was Y = 0.487X + 1.2 (R = 0.996, N = 15, p < 0.0001), the limit of detection (LOD) was 0.008 µg/L, and the limit of quantification (LOQ) was 0.008 µg/L. HRP-conjugated phage antibody, SPA and magnetic particles can enhance the sensitivity 4-fold, 3-fold and 2.6-fold higher, respectively. Compared with conventional double-antibody sandwich ELISA, the detection sensitivity of the sensor was 31-fold higher resulting from the integrated amplifying effect. The immunosensor integrates the unique advantages of SPA-oriented antibody as magnetic capturing probe, HRP-conjugated phage antibody as detecting probe, magnetic separation immunoassay technique, and several other advanced techniques, so it achieves high sensitivity, specificity and interference-resistance. It is proven to be well suited for analysis of trace SEB in various environmental samples with high recovery rate and reproducibility.
Modeling and Analysis of Reservation Frame Slotted-ALOHA in Wireless Machine-to-Machine Area Networks for Data Collection
Authors: Vázquez-Gallego Francisco , Alonso Luis , Alonso-Zarate Jesus
Published: February 2015

Reservation frame slotted-ALOHA (RFSA) was proposed in the past to manage the access to the wireless channel when devices generate long messages fragmented into small packets. In this paper, we consider an M2M area network composed of end-devices that periodically respond to the requests from a gateway with the transmission of fragmented messages. The idle network is suddenly set into saturation, having all end-devices attempting to get access to the channel simultaneously. This has been referred to as delta traffic. While previous works analyze the throughput of RFSA in steady-state conditions, assuming that traffic is generated following random distributions, the performance of RFSA under delta traffic has never received attention. In this paper, we propose a theoretical model to calculate the average delay and energy consumption required to resolve the contention under delta traffic using RFSA.We have carried out computer-based simulations to validate the accuracy of the theoretical model and to compare the performance for RFSA and FSA. Results show that there is an optimal frame length that minimizes delay and energy consumption and which depends on the number of end-devices. In addition, it is shown that RFSA reduces the energy consumed per end-device by more than 50% with respect to FSA under delta traffic.
Short-Term Forecasting of Water Yield from Forested Catchments after Bushfire: A Case Study from Southeast Australia
Authors: Gharun Mana , Azmi Mohammad , Adams Mark
Published: February 2015

Forested catchments in southeast Australia play an important role in supplying water to major cities. Over the past decades, vegetation cover in this area has been affected by major bushfires that in return influence water yield. This study tests methods for forecasting water yield after bushfire, in a forested catchment in southeast Australia. Precipitation and remotely sensed Normalized Difference Vegetation Index (NDVI) were selected as the main predictor variables. Cross-correlation results show that water yield with time lag equal to 1 can be used as an additional predictor variable. Input variables and water yield observations were set based on 16-day time series, from 20 January 2003 to 20 January 2012. Four data-driven models namely Non-Linear Multivariate Regression (NLMR), K-Nearest Neighbor (KNN), non-linear Autoregressive with External Input based Artificial Neural Networks (NARX-ANN), and Symbolic Regression (SR) were employed for this study. Results showed that NARX-ANN outperforms other models across all goodness-of-fit criteria. The Nash-Sutcliffe efficiency (NSE) of 0.90 and correlation coefficient of 0.96 at the training-validation stage, as well as NSE of 0.89 and correlation coefficient of 0.95 at the testing stage, are indicative of potentials of this model for capturing ecological dynamics in predicting catchment hydrology, at an operational level.
Quantifying the Fecal Coliform Loads in Urban Watersheds by Hydrologic/Hydraulic Modeling: Case Study of the Beauport River Watershed in Quebec
Authors: Thériault Amélie , Duchesne Sophie
Published: February 2015

A three-step method for the identification of the main sources of fecal coliforms (FC) in urban waters and for the analysis of remedial actions is proposed. The method is based on (1) The statistical analysis of the relationship between rainfall and FC concentrations in urban rivers; (2) The simulation of hydrology and hydraulics; and (3) Scenario analysis. The proposed method was applied to the Beauport River watershed, in Canada, covering an area of 28.7 km2. FC loads and concentrations in the river, during and following rainfall events, were computed using the Storm Water Management Model (SWMM) hydrological/hydraulic simulation model combined with event mean concentrations. It was found that combined sewer overflows (CSOs) are the main FC sources, and that FC from stormwater runoff could still impair recreational activities in the Beauport River even if retention tanks were built to contain CSOs. Thus, intervention measures should be applied in order to reduce the concentration of FC in stormwater outfalls. The proposed method could be applied to water quality components other than FC, provided that they are present in stormwater runoff and/or CSOs, and that the time of concentration of the watershed is significantly lower than their persistence in urban waters.