Enhanced Foam Stability Using Nanoparticle in High Salinity High Temperature Condition for Eor Application

The capability of commercial nanoparticles to perform as foam stabilizer were investigated at reservoir temperature of 96°C. Al2O3, Fe3O4, Co3O4, CuO, MgO, NiO, ZrO2, ZnO and SiO2 nanoparticles that were characterized using XRD, FTIR, FESEM-EDX, TEM and PSA, were blended in the in-house formulated surfactant named IVF respectively at a particular ratio. The test was performed with and without the presence of reservoir crude oil. Results showed that formulation with nanoparticles enhanced foam stability by having longer foam half-life than the IVF surfactant alone, especially in the absence of oil. Only SiO2 nanoparticles were observed to have improved the foam stability in both test conditions. The unique properties of SiO2 as a semi-metal oxide material may have contributed to the insensitivity of SiO2 nanoparticle towards crude oil which is known as a foam destabilizer. The physical barrier that was formed by SiO2 nanoparticles at the foam lamella were probably unaffected by the presence of crude oil, thus allowing the foams to maintain its stability. In thermal stability tests, we observed the instability of all nanoparticles in the IVF formulation at 96°C. Nanoparticles were observed to have separated and settled within 24 hours. Therefore, surface modification of nanoparticle was done to establish steric stabilization by grafting macro-molecule of polymer onto the surface of SiO2. This in-house developed polymer grafted silica nanoparticles are named ZPG nanoparticles. The ZPG nanoparticles passed the thermal stability test at 96°C for a duration of 3 months. In the foam wetness analysis, ZPG nanoparticles were observed to have produced more wet foams than IVF formulation alone, indicating that ZPG is suitable to be used as foam stabilizer for EOR process as it showed catalytic behaviour and thermally well-stable at reservoir temperature.

Ultrafast Vibrational Spectroscopy of the Eumelanin pigment

<p>Solar ultraviolet (UV) radiation is a highly toxic carcinogen prevalent in our environment. Eumelanin pigment is a photo-stable biopolymer naturally produced in the skin's pigmentary system, providing the skin a unique photo-protection mechanism against exposure to UV radiation. The large macro-molecule rapidly dissipates 99 % of incident UV photons as thermal energy on ultra-fast femtosecond (fs) - picosecond (ps) time scales, before damage can occur to the underlying cells. The fundamental nature of eumelanin's structure and its vibrational energy dissipation mechanism is not yet fully understood, with complexities in the molecule's highly disordered chemical structure, and the ultrafast time-scale on which the energy dissipation occurs, rendering its characterisation elusive. </p><p><br></p> <p>Indeed, the absorption spectrum of eumelanin gives little away, rising monotonically in wavelength towards the UV - quite unusual in organic polymers. It is proposed that due to the highly disordered structure of the molecule, multiple chromophores of overlapping energies may be selectively excited with differing irradiation wavelengths. This theory is further supported by eumelanin’s transient absorption signatures and its wavelength dependant photo-luminescence spectra, however the fundamental non-radiative relaxation pathways are not yet understood. </p> <p><br></p><p>To bridge this knowledge gap, we present here the application of femtosecond stimulated Raman spectroscopy (FSRS) to eumelanin pigment. FSRS reveals ultra-fast vibrational dynamics on fs – ps time scales, allowing excited state vibrational pathways to be mapped, providing essential structural information of this intriguing molecule. </p> <p><br></p><p>Following the introduction of eumelanin’s known photo-physical and structural properties as presented in chapter 1, an introduction to FSRS is presented in chapter 2. The build method and optical construction of the FSRS experiment are presented in chapter 4 including a novel bandwidth compression method used to generate a narrow-band Raman pump using frequency-domain nonlinear optics, presented in chapter 3. Here, using a 1.5 kHz, 800 nm Ti:Sapphire pulsed laser at a power of 3 W, conversion efficiencies of up to 30 % are achieved, generating intense second harmonic Raman pump pulses centred at 400 nm with <20 cm-1 bandwidths. Additionally, the well-known spatial filtering technique is used to generate tuneable, narrow-band pulses centered at the fundamental 800 nm laser pulse. </p> <p><br></p><p>The application of FSRS to the study of eumelanin’s indole subunits, 5-6-dihydroxyindole (DHI) and its carboxylated form, 5-6-dihydroxyindole-2-carboxylic acid (DHICA) (and their oligomers) are presented in chapter 5. These studies provide direct evidence for excited state proton transfer (ESPT) in DHICA, and a reference for the interpretation of the complex eumelanin macro-molecule, as well as its dynamic vibrational signatures, which are discussed in chapter 6. Here, vibrational dynamics are resolved on From these FSRS studies, ESPT – proposed as a relaxation pathway in eumelanin’s subunit DHICA – is demonstrated. Direct vibrational relaxation measurement mapped using density functional theory (DFT) provides strong evidence of excited state de-activation of DHICA via this mechanism. Further, eumelanin’s vibrational mode deactivation pathways are presented, providing evidence of specific mode excitations of the macro-molecule upon photo-excitation in both the UV (267 nm) and visible (400 nm) regions. </p><p><br></p><p>Resolving eumelanin’s excited state vibrational modes and kinetics using FSRS provides dynamic structural information of eumelanin's thermal energy transfer system, including that of its indole subunits. Determining FSRS signatures as a function of excitation wavelength in both the visible and UV regions, reveals insights into this highly efficient UV absorbing material. </p>

Ultrafast Vibrational Spectroscopy of the Eumelanin pigment

<p>Solar ultraviolet (UV) radiation is a highly toxic carcinogen prevalent in our environment. Eumelanin pigment is a photo-stable biopolymer naturally produced in the skin's pigmentary system, providing the skin a unique photo-protection mechanism against exposure to UV radiation. The large macro-molecule rapidly dissipates 99 % of incident UV photons as thermal energy on ultra-fast femtosecond (fs) - picosecond (ps) time scales, before damage can occur to the underlying cells. The fundamental nature of eumelanin's structure and its vibrational energy dissipation mechanism is not yet fully understood, with complexities in the molecule's highly disordered chemical structure, and the ultrafast time-scale on which the energy dissipation occurs, rendering its characterisation elusive. </p><p><br></p> <p>Indeed, the absorption spectrum of eumelanin gives little away, rising monotonically in wavelength towards the UV - quite unusual in organic polymers. It is proposed that due to the highly disordered structure of the molecule, multiple chromophores of overlapping energies may be selectively excited with differing irradiation wavelengths. This theory is further supported by eumelanin’s transient absorption signatures and its wavelength dependant photo-luminescence spectra, however the fundamental non-radiative relaxation pathways are not yet understood. </p> <p><br></p><p>To bridge this knowledge gap, we present here the application of femtosecond stimulated Raman spectroscopy (FSRS) to eumelanin pigment. FSRS reveals ultra-fast vibrational dynamics on fs – ps time scales, allowing excited state vibrational pathways to be mapped, providing essential structural information of this intriguing molecule. </p> <p><br></p><p>Following the introduction of eumelanin’s known photo-physical and structural properties as presented in chapter 1, an introduction to FSRS is presented in chapter 2. The build method and optical construction of the FSRS experiment are presented in chapter 4 including a novel bandwidth compression method used to generate a narrow-band Raman pump using frequency-domain nonlinear optics, presented in chapter 3. Here, using a 1.5 kHz, 800 nm Ti:Sapphire pulsed laser at a power of 3 W, conversion efficiencies of up to 30 % are achieved, generating intense second harmonic Raman pump pulses centred at 400 nm with <20 cm-1 bandwidths. Additionally, the well-known spatial filtering technique is used to generate tuneable, narrow-band pulses centered at the fundamental 800 nm laser pulse. </p> <p><br></p><p>The application of FSRS to the study of eumelanin’s indole subunits, 5-6-dihydroxyindole (DHI) and its carboxylated form, 5-6-dihydroxyindole-2-carboxylic acid (DHICA) (and their oligomers) are presented in chapter 5. These studies provide direct evidence for excited state proton transfer (ESPT) in DHICA, and a reference for the interpretation of the complex eumelanin macro-molecule, as well as its dynamic vibrational signatures, which are discussed in chapter 6. Here, vibrational dynamics are resolved on From these FSRS studies, ESPT – proposed as a relaxation pathway in eumelanin’s subunit DHICA – is demonstrated. Direct vibrational relaxation measurement mapped using density functional theory (DFT) provides strong evidence of excited state de-activation of DHICA via this mechanism. Further, eumelanin’s vibrational mode deactivation pathways are presented, providing evidence of specific mode excitations of the macro-molecule upon photo-excitation in both the UV (267 nm) and visible (400 nm) regions. </p><p><br></p><p>Resolving eumelanin’s excited state vibrational modes and kinetics using FSRS provides dynamic structural information of eumelanin's thermal energy transfer system, including that of its indole subunits. Determining FSRS signatures as a function of excitation wavelength in both the visible and UV regions, reveals insights into this highly efficient UV absorbing material. </p>

Effects of iron injection timing on suckling and subsequent nursery and growing-finishing performance and hematological criteria

Two experiments were conducted to evaluate the effects of Fe injection timing after birth on suckling and subsequent nursery and growing-finishing pig performance. The injectable Fe source used in both experiments was GleptoForte (Ceva Animal Health, LLC., Lenexa, KS). GleptoForte contains gleptoferron which is a Fe macro-molecule complex. In Exp. 1, a total of 324 newborn pigs [DNA 241 × 600, initially 1.6 ± 0.04 kg body weight (BW)] within 27 litters were used. Two days after birth, all piglets were weighed, and six barrows and six gilts per litter were allotted to 1 of 6 treatments consisting of no Fe injection or 200 mg of injectable Fe provided in a single injection on d 2, 4, 6, 8, or 10 of age. Pigs were weaned (~21 d of age) and allotted to nursery pens with all pigs in each pen having received the same Fe treatment. In Exp. 2, a total of 1,892 newborn pigs (PIC 359 × C40; initially 1.5 ± 0.02 kg BW) within 172 litters were used. One day after birth, piglets were weighed, and 11 pigs within each litter were allotted to 1 of 6 treatments consisting of no Fe injection or 200 mg of injectable Fe provided on d 1, 3, 5, or 7 of age, or 200 mg on d 1 plus 200 mg on d 12 of age. Pigs were weaned (19 d of age) and placed in a commercial wean-to-finish facility in a total of 15 pens with equal representation of treatments in each pen. In both experiments, not providing an Fe injection after birth decreased (P &lt; 0.05) preweaning average daily gain (ADG), weaning weight, and hemoglobin and hematocrit values compared to all other treatments. In Exp. 1, increasing the age that piglets received an Fe injection until 4 or 6 d after birth provided marginal evidence for an improvement (quadratic; P = 0.070) in preweaning ADG. For the nursery period, increasing the age that piglets received an Fe injection improved (quadratic; P = 0.013) d 80 BW, but there was no evidence of a difference (P &gt; 0.10) in d 173 BW at the end of the grow-finish period. In Exp. 2, increasing the age that piglets received a 200 mg Fe injection showed no evidence of difference (P &gt; 0.10) for subsequent nursery and growing-finishing ADG. In both experiments, hemoglobin and hematocrit values were decreased (linear; P &lt; 0.05) at weaning with increasing age when pigs received an Fe injection. These experiments suggest that providing a 200 mg Fe injection within 7 d after farrowing is sufficient for optimizing preweaning and subsequent growth performance.

Construction and Loss of Bacterial Flagellar Filaments

The bacterial flagellar filament is an extracellular tubular protein structure that acts as a propeller for bacterial swimming motility. It is connected to the membrane-anchored rotary bacterial flagellar motor through a short hook. The bacterial flagellar filament consists of approximately 20,000 flagellins and can be several micrometers long. In this article, we reviewed the experimental works and models of flagellar filament construction and the recent findings of flagellar filament ejection during the cell cycle. The length-dependent decay of flagellar filament growth data supports the injection-diffusion model. The decay of flagellar growth rate is due to reduced transportation of long-distance diffusion and jamming. However, the filament is not a permeant structure. Several bacterial species actively abandon their flagella under starvation. Flagellum is disassembled when the rod is broken, resulting in an ejection of the filament with a partial rod and hook. The inner membrane component is then diffused on the membrane before further breakdown. These new findings open a new field of bacterial macro-molecule assembly, disassembly, and signal transduction.

Ensemble epistasis: thermodynamic origins of non-additivity between mutations

Non-additivity between mutations—epistasis—profoundly shapes evolution. It can be difficult to understand its mechanistic origins. Here we show that “ensemble epistasis” is likely a universal feature of macromolecules. Using a simple analytical model, we found that epistasis arises when two conditions are met: 1) a macro-molecule populates at least three structures and 2) mutations have differential effects on a least two of the inactive structures. To explore the relative magnitude of ensemble epistasis, we performed a virtual deep-mutational scan of the allosteric Ca2+ signaling protein S100A4. We found that 27% of mutation pairs gave ensemble epistasis with a magnitude on the order of thermal fluctuations, 1 kT. We observed many forms of epistasis: magnitude, sign, and reciprocal sign epistasis. Depending on the effector concentration, the same mutation pair could even exhibit different forms of epistasis. The ubiquity of ensembles in biology and its pervasiveness in our dataset suggests that ensemble epistasis may be a universal mechanism of epistasis.Significance statementAddressing the mechanistic origins of evolutionary unpredictability is critical to understanding how mutations combine to determine phenotype. Here we lay the theoretical foundations and investigate the plausibility of a potentially universal mechanism of unpredictability in macromolecules. Macromolecules often adopt a set of interchanging structures, called a thermodynamic ensemble. Mutations can change the relative population of each structure, introducing unpredictability in the mapping between genotype and phenotype. The conditions under which we expect this to arise are common in macromolecules, suggesting that this form of unpredictability may be pervasive in evolution. We conclude that the thermodynamic ensemble bakes unpredictability into biology and that future attempts to address it might incorporate this mechanistic insight.

The Effect of Polyacrilamide Gel Electrophoresis Duration on separation of Cassava SSR PCR Fragments

DNA bands formed from the results of electrophoresis with Polyacrilamide gel are considered as 1 character representing 1 allele. PCR products produce multiple bands (multy bands), which indicates that there are multi alleles in the sample. Electrophoresis is a chemical analysis method based on the movement of charged protein molecules in the electric field. Separation is carried out based on differences in the size of the molecular weight and the electric charge contained by the macro-molecule. In addition, the effect of gel concentratio n, buffer and electrophoresis time also has a role in the results of electrophoresis. This study was conducted to compare the best separation time for acrilamide gel electrophoresis with the results of cassava DNA amplification. The materials used in this study are two cassava varieties, namely: Adira IV 1, Adira IV 2, Adira IV 3, Carvita 25 1, Carvita 25 2, and Carvita 25 3. Using electrophoresis by poly-acrilamide gel with two different time effects: 1 hour 30 minutes and 3 hours. The results of electrophoresis with 3 hours gave better results of DNA visualization compared to 1 hour 30 minutes.