Popular Modification Research Articles

Organic Trimer Molecule Electrode as a High-Performance Next-Generation Supercapacitor Material

As greenhouse gas emissions such as CO2 continue to increase on a global scale, countries around the world are making changes to reduce their net emissions. One of the primary actions being taken is attempting to decarbonize the transportation sector by moving away from fossil fuel-powered vehicles and adopting electric vehicles (EVs). Supercapacitors are electrical energy storage devices similar in concept to batteries, however they achieve a higher power output, faster charge and discharge rates, and greater longevity. These properties make them excellent devices to work in tandem with batteries that advance their collective performance capabilities in EVs. Supercapacitors using inorganic materials such as transition metal oxides have been explored extensively and although there have been advancements in the field, they continue to struggle with limitations such as mechanical degradation during cycling, low conductivity which slows the charging-discharging processes, and the utilization of environmentally toxic metals. On the other hand, quinones are a class of organic materials considered as the most promising candidates for organic electrodes due to their ≥ 2 reversible redox-active carbonyl groups, inexpensiveness, ease of structural modifications, and environmental sustainability. However, like many organic materials, they suffer from low electrical conductivity and dissolution in electrolyte. To minimize dissolution while retaining and improving its advantages, polymerizing quinones has become a popular modification alternative, especially via polyimide and polythioether bonds. However, because polymer chains are so large and inherently have low electronic conductivity, polymerizing quinones inhibits charge transfer throughout a matrix with a carbon substrate (i.e., rGO, CNT, carbon black) due to interference with the conductive network.In this research, a smaller molecule was made from covalently bonding two different quinones via imide bonds to make an organic trimer. This helped reduce dissolution in electrolyte compared to its monomeric components via increasing the molecular weight while also improving the energy storage capabilities as a supercapacitor electrode. This is attributed to this molecule retaining the original redox active sites of its monomers and its conjugated network which allows it to achieve a 6-electron transfer mechanism per molecule. Its smaller size compared to a polymer is also hypothesized to reduce the degree of conductivity interruptions it causes when part of a carbon substrate network. While polymer chains can agglomerate easily, decreasing its available specific surface area, this trimer may be more available to participate in Faradaic processes. This research hereby reports an electrode material with very high capacitance (318 Fg-1 at 5 mVs-1) and good cycling stability utilizing a low-cost carbon black substrate for supercapacitor applications to improve the performance of next-generation EVs.

Modification Method of High-Efficiency Organic Bentonite for Drilling Fluids: A Review

The requirements for drilling bentonites are tightening due to ever-increasing demands for petroleum resources, coupled with cost and reaction technology constraints. In addition to raising the risk of drilling, bentonite’s poor performance also raises the possibility of safety incidents and significant financial losses. Organically modified bentonites effectively reduce the consumption of drilling fluids, conserve resources, and lessen environmental effects. This paper aims to provide an overview of the several organic modification methods of bentonite for drilling fluids. It also evaluates the characteristics and application impacts of bentonite. We primarily describe the three popular modification methods represented by intercalation, coupling, and grafting. Also, this review provides the effect of molecular simulation on the investigation of structure in microconfined conditions. Through microlearning, organically modified bentonite with exceptional performance is to be further developed.

Comparison of Modification Methods of Photocatalyst G-C3N4 in Hydrogen Production Performance

Non-metallic polymer semiconductor graphite phase carbon nitride (g-C3N4) is a low-cost, environmentally friendly raw material with suitable bandgap width and stable chemical properties. However, there are still problems such as lower surface area, higher recombination rate of photo-excited charge carriers, and lower utilization rate of visible light. This paper introduces the structure, physicochemical properties, preparation methods, and modification ideas of graphite phase carbon nitride, focusing on several popular modification achievements in recent years, as well as a horizontal comparison of their respective production methods, mechanisms, and hydrogen production efficiency. Finally, the challenges and prospects in the modification of carbon nitride are discussed.

Role of interfacial rheology on fingering instabilities in lifting Hele-Shaw flows.

The lifting Hele-Shaw cell setup is a popular modification of the classic, fixed-gap, radial viscous fingering problem. In the lifting cell configuration, the upper cell plate is lifted such that a more viscous inner fluid is invaded by an inward-moving outer fluid. As the fluid-fluid interface contracts, one observes the rising of distinctive patterns in which penetrating fingers having rounded tips compete among themselves, reaching different lengths. Despite the scholarly and practical relevance of this confined lifting flow problem, the impact of interfacial rheology effects on its pattern-forming dynamics has been overlooked. Authors of recent studies on the traditional injection-induced radial Hele-Shaw flow and its centrifugally driven variant have shown that, if the fluid-fluid interface is structured (i.e., laden with surfactants, particles, proteins, or other surface-active entities), surface rheological stresses start to act, influencing the development of the viscous fingering patterns. In this paper, we investigate how interfacial rheology affects the stability as well as the shape of the emerging fingered structures in lifting Hele-Shaw flows, at linear and early nonlinear dynamic stages. We tackle the problem by utilizing the Boussinesq-Scriven model to describe the interface and by employing a perturbative mode-coupling scheme. Our linear stability results show that interfacial rheology effects destabilize the interface. Furthermore, our second-order findings indicate that interfacial rheology significantly alters intrinsically nonlinear morphological features of the shrinking interface, inducing the formation of narrow sharp-tip penetrating fingers and favoring enhanced competition among them.

Lagging heat models in thermodynamics and bioheat transfer: a critical review

The accuracy of the classical heat conduction model, known as Fourier's law, is highly questioned, dealing with the micro and nanosystems and biological tissues. In other words, the results obtained from the classical equations deviate from the available experimental data. It means that the continuum heat diffusion equation is insufficient and inappropriate for modeling heat transport in these cases. There are several techniques for modeling non-Fourier heat conduction. In the present paper, we place our focus on the dual-phase-lag (DPL) approach. The DPL model, as a popular modification of Fourier's law, has already been utilized in numerous situations, such as simulating ultrafast laser heating and heat conduction in carbon nanotubes. There has been a sharp increase in research on non-Fourier heat conduction in recent years. Several studies have been performed in the fields of thermoelasticity, thermodynamics, transistor modeling, and bioheat transport. This review presents the most recent non-Fourier bioheat conduction works and the related thermodynamics background. The various mathematical tools, modeling different thermal therapies, and relevant criticisms and disputes are discussed. Finally, the novel and other possible studies are also presented to provide a better overview, and the roadmap to the future research and challenges ahead is drawn up.

Breakdown of light transport models in photonic scattering slabs with strong absorption and anisotropy

The radiative transfer equation (RTE) models the transport of light inside photonic scattering samples such as paint, foam and tissue. Analytic approximations to solve the RTE fail for samples with strong absorption and dominant anisotropic scattering and predict unphysical negative energy densities and the diffuse flux in the wrong direction. Here we fully characterize the unphysical regions of three popular approximations to the RTE for a slab, namely the $P_1$ approximation (or diffusion approximation), the $P_3$ approximation, and a popular modification to $P_3$ that corrects the forward scattering in the approximation. We find that the delta function correction to $P_3$ eliminates the unphysical range in the forward scattering. In addition, we compare the predictions of these analytical methods to exact Monte Carlo simulations for the physical and unphysical regions. We present maps of relative errors for the albedo and the anisotropy of the scatterers for a realistic index contrast typical of a polymer slab in air and optical thickness. The relative error maps provide a guideline for the accuracy of the analytical methods to interpret experiments on light transport in photonic scattering slabs. Our results show that the $P_1$ approximation is significantly inaccurate to extract transport parameters unless the sample scatters purely isotropic and elastic. The $P_3$ approximation exceeds $P_1$ in terms of accuracy in its physical range for moderate absorption, and the $P_3$ with the delta function correction is the most accurate approximation considered here for the forward direction.

Effect of Polymer and Warm mix Modification on Asphalt Mixture Properties

Among various kinds of asphalt binder modification methods, polymer modification and warm mix modification are two of the most popular ones. While polymer modification improves the lower and higher temperature performances of the asphalt mixture, warm mix modification reduces the mixing and compaction temperatures. So, the present study examines the effect of warm mix and polymer modification on the Marshall properties and moisture susceptibility of the asphalt mixes. In order to take advantage of both these popular modification methods, warm mix polymer modified bitumen (WMPMB) was prepared by mixing polymer and warm mix modifier in the conventional binder. The effect of the combined modification (warm mix and polymer) was studied with the help of experiments on the asphalt binders and mixtures. Based on the results it is concluded that using both the modifiers together we can avail the benefits of both the modification methods.

A facile, inexpensive and green electrochemical sensor for sensitive detection of imidacloprid residue in rice using activated electrodes.

The development of sensitive, facile, cost-effective and eco-friendly sensors is essential for monitoring imidacloprid (IDP) residue on a large scale. Compared with popular modification of electrodes with advanced materials, electrochemical activation is promising at this point. In this paper, we found that strongly basic electrolytes (e.g. KOH and K3PO4) and applying cyclic potential during the activating process are beneficial to greatly amplify the electro-reduction response of IDP by nearly 16 times. Combining the characterization of activated electrodes with electrochemical behavior analysis of IDP, it is speculated that specific oxygen-contained functional groups were formed to bond with IDP molecules, leading to fast electron transfer kinetics. Then a sensitive IDP sensor has been developed with a low limit of detection (LOD) of 0.03 μM in the range of 0.1-100 μM. The methodological evaluation including reproducibility, stability and recovery has been also carefully studied, verifying the potential of proposed activated electrodes for application in rice samples.

Electrochemical evidence of the modification of carbon materials with anthraquinone moiety by a Diels Alder process

Interfaces play a key role in electrochemical energy storage. They are directly responsible for performances (and thus indirectly costs), safety and lifetime of the batteries and electrochemical capacitors. A way to improve devices is to control these interfaces and one attractive approach to achieve this goal is to modify electrodes by grafting molecules bearing desired moieties (hydrophilic/hydrophobic, redox…). Diazonium (electro)chemistry is the most popular modification technique in the field of energy storage but it has some limitations. Two major drawbacks are the lack of control on the grafted layer (structure and morphology) and the chemical nature of the diazonium itlself that could, in some cases, makes it difficult to manipulate. Thus, our objective is to propose an alternative option to modify electrodes and, particularly this work aims to validate the use of the Diels Alder reaction to modify carbon materials with redox molecules for electrochemical storage purposes. A new molecule (propargyl anthraquinone) was synthesized to make this Diels Alder reaction possible. The modification was evidenced by electrochemical characterizations, comparing carbon electrodes modified with the synthesized propargyl anthraquinone and other commercial anthraquinone derivatives. The modified carbons were stable in both acidic and buffered neutral conditions and rate capability similar to unmodified carbon. Very interestingly, the electrochemical behavior of our electrodes is comparable to those fabricated by the state-of-the-art diazonium chemistry. In this study, we investigated and validated the possibility to use the Diels Alder reaction to modify carbon for electrochemical storage application. This is a critical input because it allows to expand modification methods suitable to tune interfaces for electrochemical storage applications.

Gene signature and prognostic merit of M6a regulators in colorectal cancer

Although new diagnostic techniques and treatments are increasingly updated for CRC, the clinical outcomes of CRC patients are still not encouraging with a low survival rate. N6-methyladenosine (m6A) as a popular modification on mRNA is associated with multiple types of cancers. Our purpose is to identify gene signature and prognostic ability of m6A modulators in CRC. For the first time, we identified genetic changes of m6A modulators and built prognostic gene signature in CRC, which may provide effective targets for the diagnosis and management of CRC.

Realizing High Voltage Lithium Cobalt Oxide in Lithium-Ion Batteries

The combination of high voltage cathode and metal or graphite anodes provides a feasible way for future high-energy batteries. Among various battery cathodes, lithium cobalt oxide is outstanding for its excellent cycling performance, high specific capacity, and high working voltage and has achieved great success in the field of consumer electronics in the past decades. Recently, demands for smarter, lighter, and longer standby-time electronic devices have pushed lithium cobalt oxide-based batteries to their limits. To obtain high voltage batteries, various methods have been adopted to lift the cutoff voltage of the batteries above 4.45 V (vs Li/Li+). This review summarizes the mechanism of capacity decay of lithium cobalt oxide during cycling. Various modifications to achieve high voltage lithium cobalt oxide, including coating and doping, are also presented. We also extend the discussion of popular modification methods for electrolytes including electrolyte additives, quasi-solid electrolytes, and electr...

HPV6 and HPV11 Genome Methylation in Condyloma AccuminatumMeasured by Bisulfite Sequencing

To the Editor: Condyloma acuminatum (CA, or genital warts) is a highly contagious and common sexually transmitted disease and caused by the infection of some types of human papillomavirus (HPV), especially types 6 and 11.1 Methylation is the most popular modification in human genome and has been observed to be correlated with human diseases.2 Moreover, it was known that methylation of partial region in multiple HPV genomes, including 16, 18, 30, and 45, was correlated with cervical cancer,3,4 another disease in women caused by HPV infection. All these facts made us hypothesize that methylation of HPV genome might also be correlated with CA. However, the HPV methylation status in CA is unknown. In this pilot study, we investigated the HPV genome methylation status in patients with CA by bisulfite sequencing. To this end, multiple genital skin tissues from typical male patients with CA with giant genital warts were collected from surgery and genotyped for HPV infection by Polymerase Chain Reaction (PCR) and xMAP (Luminex, Austin, TX; primer and probe set available on request). All patients were diagnosed based on typical clinical presentations5 and further confirmed by biopsy findings. From these samples, 4 patients with HPV6 infection and 3 with HPV11 were chosen for this study. DNA was isolated by standard phenol–chloroform method and treated with freshly prepared bisulfite using the EZ DNA methylation kit (Zymo Research, Orange, CA) according to the manufacturer's protocol. In bisulfite treatment, unmethylated C was converted into U, which was then converted to T in following PCR, whereas methylated C remained unmodified. Because HPV genome methylation in cervical tissue showed a gene-specific manner,3,4 which meant that the methylation in one segment could represent the situation in whole gene, we designed one PCR assay (see Table S1, Supplemental Digital Content 1, https://links.lww.com/AJDP/A65) for each protein-coding gene and upstream regulatory region by Methprimer6 (http://www.urogene.org/methprimer/index1.html). All segments were amplified by Taq DNA polymerase (Takara, Dalian, China) and directly sequenced in AB 3730 sequencer (Thermo Fisher, Waltham, MA) after purification, which was an accurate approach, and had been widely used in previous studies.7 This study was approved by the Institutional Ethics Committee, and informed consent was obtained from all individuals. In this study, 76 and 54 CpG sites were surveyed for HPV6 and 11 genomes, respectively, which account for ∼35–48% of total CpG sites, and the chromatograms for each CpG sites were inspected visually. None of the CpG sites displayed a clear C peak, which indicated that no methylation was observed in HPV6 and 11 genomes from CA tissues, and was consistent with recent report in HPV11 and 6 from respiratory8 and laryngeal9 papillomas tissues, respectively. Although the normal skin tissue was not available for control (persons with HPV infection but without CA symptom) in this study, we still could deduce that the methylation in normal genital tissue was also absent because of the hypomethylation of HPV genome in cervix without neoplasia3,4 and the lack of genes coding for DNA methyltransferase in HPV genome. Another concern was the relatively small sample size and sample bias (only male patients included) in this study. Because most patients were prone to receive pharmacotherapy instead of surgery, it was difficult to obtain more tissues. Further investigation with larger sample size and female patients might generalize our conclusion. In another side, because DNA methylation level was relatively similar among the different patients with same disease, it could be speculated that other patients with CA might also present hypomethylation in HPV genome. All these facts indicated that the methylation of HPV genome was not changed during the development of CA, which might indicate that the methyltransferase system still worked properly in CA tissues.

Effect of welding conditions on erosive wear of hard-faced Co-based alloy layer

Degradation of materials due to the impact of solid particle is a major material wastage process. Modifying the surface of materials can be considered to be a potential method of improving the resistance to erosion. In the present days, weld hard-facing is a popular surface modification process. Engineering industries are opting for hard-facing because of its low capital cost, low operational cost, and operational simplicity. In the context of erosion-resistant hard materials, a series of Co-based alloys that can be deposited by hard-facing is one of the most suitable materials. The present analysis has been carried out to evaluate the influence of processing conditions of hard-faced Co-based alloyed layer on solid particle erosion response at ambient temperature. These layers were deposited on mild steel substrate by weld hard-facing. The mechanical properties and microstructural features of these coatings were evaluated by means of X-ray diffraction technique, optical microscopy, scanning electron microscopy, and microhardness tester. Erosion rate was measured using an air jet erosion test rig. The eroded surface morphology and the transverse section of eroded surfaces were viewed using scanning electron microscopy. The results showed that hard-facing improves erosion resistance of the substrate. The erosion responses of most of the coatings were ductile. Material loss from hard-faced coating was by formation of lips followed by their fracture which initiated in the interdendritic regions.

Attitude and the normativity of law

Though legal positivism remains popular, HLA Hart’s version has fallen somewhat by the wayside. This is because, according to many, the central task of a theory of law is to explain the so-called ‘normativity of law’. Hart’s theory, it is thought, is not up to the task. Some have suggested modifying the theory accordingly. This paper argues that both Hart’s theory and the normativity of law have been misunderstood. First, a popular modification of Hart’s theory is considered and rejected. It stems from a misunderstanding of Hart and his project. Second, a new understanding of the mysterious but often-mentioned ‘normativity of law’ is presented. Once we have dispelled some misunderstandings of Hart’s view and clarified the sense in which law is supposed to be normative, we see that Hart’s view, unmodified, is well suited to the task of explaining law’s normativity.

Bulk viscous fluid cosmological models in f(R, T) gravity

In the literature, a number of modified theories have been discussed to explain early and late time expansion of the universe. In this context, f(R) gravity (R being the Ricci scalar) is the simplest and most popular modification of general relativity. Other modified theories like f(T) gravity, where T is the torsion has been proposed to overcome many problems in cosmology. Kaluza–Klein cosmological models in f(R, T) theory of gravity are investigated when the source of gravitation is the bulk viscous fluid. In this work, it is considered that the function f(R, T) as f(R,T)=R+2f(T) or f(R,T)=f1(R)+f2(T). Such a choice of the functional f(R, T) leads to an evolving effective cosmological constant Λ, which depends on the stress energy tensor. f1(R) and f2(T) are arbitrary functions of R and T, respectively and f(R, T) = R f(T) may be considered to solve the field equations. We however do not consider the general case, but restrict ourselves to the following form f(R, T) = R + 2f(T), where f(T) is an arbitrary function of the trace of energy-momentum tensor of matter. The term 2f(T) in the gravitational action modified the gravitational interaction between matter and curvature. It is observed that the first case of the model be reduced to effective stiff fluid model of the universe while the second case gives general bulk viscous model of the universe. The exact solutions of the field equations are obtained. Keeping an eye on the accelerating nature of the universe in the present epoch, the dynamics and physical behaviour of the models are discussed.

The signed Kolmogorov-Smirnov test: why it should not be used.

The two-sample Kolmogorov-Smirnov (KS) test is often used to decide whether two random samples have the same statistical distribution. A popular modification of the KS test is to use a signed version of the KS statistic to infer whether the values of one sample are statistically larger than the values of the other. The underlying hypotheses of the KS test are intrinsically incompatible with this approach and the test can produce false positives supported by extremely low p-values. This potentially makes the signed KS test a tool of p-hacking, which should be discouraged by replacing it with standard tests such as the t-test and by providing confidence intervals instead of p-values.

Finite Element Method and Sharp Features Enhanced Laplacian for Interactive Shape Design of Mechanical Parts

Laplacian based model editing is one of the most popular shape modification methods for product design. However, most existing Laplacian based methods suffer shape structure and saliency feature distortion, which limits its possible application in shape design of mechanical parts. In this paper, to improve the mesh rigidity and to make the shape deforms physically, finite element method is employed to enhance the Laplacian based model editing, and to keep the saliency features, a robust sharp feature detecting method is further proposed for guiding the modification of the mesh Laplacian in shape deformation. We show how to utilize the enhanced Laplacian for interactive shape design of mechanical parts. The empirical results illustrate that the proposed method yield improved performance compared with conventional methods.

Deep sequencing of microRNAs from hickory reveals an extensive degradation and 3′ end modification

The degradation and 3′ end modification of plant microRNAs (miRNAs) may play crucial roles in regulating miRNA function and stability. However, the mechanism as to how the degradation and the modification are processed are still poorly characterized. Here, we report a survey of miRNA degradation and 3′ modification from two hickory floral differentiation stages through deep sequencing. We constructed two small RNA (sRNA) libraries from two hickory floral differentiation stages and obtained a large number of truncated miRNAs and miRNAs with 3′ end modifications. The presence of so many truncated miRNAs suggests a mechanism degrading through both ends simultaneously. Further analysis reveals that the truncation from the 3′ end has higher probability than from the 5′ end. Single- or double-nucleotide additions to the 3′ end have been observed in many families. We found that the addition of adenine base to the 3′ end is the most common event, accounting for more than 50 % of all miRNA 3′ end modification in the two sRNA libraries. Uridine addition is the second popular modification. These observations suggest that the 3′ end modification of miRNAs preferentially selects adenine and uridine in the hickory plant. Furthermore, we observed that expression of either truncated miRNA or isomiR associates with mature miRNAs. Altogether, our study provides more information regarding the degradation and 3′ end modification of miRNAs in plants.

Effects of Anodic Oxidation in Ethylene Glycol Based Electrolyte on the Corrosion Resistance and Biocompatibility of NiTi Shape Memory Alloy

Nickel titanium (NiTi) is the most attractive shape memory alloy in industrial and in medical application but suffer from corrosion attack by body fluids. Nowadays, Electrochemical anodization has become a popular surface modification method for biomaterials. In this study we prepared TiO2 coating with nanoporous surface morphology on NiTi shape memory alloy by using electrochemical anodization in ethylene glycol based electrolyte followed by annealing in 600 °C and explored its appropriateness for biomedical applications. Morphology and crystal structure of the film was characterized by Field emission scanning electron microscopiy (FE-SEM) and X-ray diffraction (XRD) tests. The corrosion resistance of the treated NiTi alloy was investigated by potentiodynamic polarization test and The findings showed that the anodization in ethylene glycol solution extremely increased the corrosion resistance and hence biocompatibility.

Sequential extraction procedures for the determination of phosphorus forms in sediment

This article summarizes the main extraction methods for sedimentary phosphorus (P) determination. With sequential chemical extractions, P is supposed to be selectively removed from different compounds in the sediments. Extraction schemes using strong acids and alkaline solutions have been tested on different sediments and found not to extract well-defined fractions. In addition, several systematic errors in these schemes have been detected. Thus, these schemes have been modified and simplified accordingly. The Standards Measurements and Testing Program of the European Commission (SMT) method is a popular modification of these extraction schemes, as it is simple to handle, allows laboratories to achieve reproducible results and could provide a useful tool for routine use by water managers. The SEDEX (sequential extraction method) method, another popular modification, is widely applied in biogeochemical research as it can separate authigenic carbonate fluorapatite from fluorapatite. Other chemical extractions using chelating compounds have attempted to extract P bound with iron and calcium in sediments without disturbing clay-bound or organic P, the purpose being to determine the algal-available non-apatite, apatite and organic fractions of sediment P. All extraction procedures still yield operationally defined fractions and cannot be used for identification of discrete P compounds. Future modifications of the extraction scheme should aim to achieve better extraction efficiency and selectivity, simple handling techniques and methods that can prevent the extracted P from being re-adsorbed onto Fe(OOH) and CaCO3.