Bottle Neck Research Articles

Genetic features of the island populations of sockeye salmon Oncorhynchus nerka (Walbaum, 1792) in Russian part of the species range

Sockeye salmon genetic diversity in the Kuril Islands (Iturup, Urup, Paramushir, Shumshu) and the Commander Islands (Bering Island) was examined on 7 microsatellite loci. Average estimates of the heterozygocity observed on different loci vary from 0.300 to 0.858. General estimate of genetic differentiation θst is 15%, with a 95% confidence bootstrap interval [10.40–21.18%]. The results obtained in the program BOTTLENECK 1.2.02 made it possible to identify the passage of the “bottle neck” by all island populations. Unique properties and significant differences from each other are shown for allfivчe populations examined. The level of sockeye salmon intrapopulation diversity found in the Kuril and Commander Islands is significantly lower compared to that in the continental water bodies, what is generally typical for marginal populations of the species range.

Trailing-edge far-field noise and noise source characterization in high inflow turbulence conditions.

Airframe noise currently is a bottle neck in various applications, e.g., wind energy, maritime applications, and aircraft. Airframe noise is significantly increased by the presence of inflow turbulence. High inflow turbulence influences the boundary layer and wall-pressure fluctuations close to the trailing edge of airfoils. In this research, measurements of boundary layer and wall-pressure fluctuations near the trailing edge of an airfoil are conducted to investigate how the inflow turbulence affects the trailing-edge noise generation mechanism. Far-field noise measurements of additional three airfoils are shown to understand the role of the airfoil geometry in the dominant noise source for the cases of inflow turbulence and to generalize the observed increase in trailing-edge noise. Inflow turbulence leads to an increase in both the wall-pressure spectrum and spanwise correlation length. Trailing-edge noise increases due to the inflow turbulence in the entire frequency range at least 2 dB up to more than 15 dB for all the cases. The contribution of leading- and trailing-edge noise to the total noise varies with the airfoil geometry and inflow velocity, with the trailing-edge noise dominating in a larger frequency range for the thickest airfoil and for lower velocities.

An improved workflow for the development of MS-compatible liquid chromatography assay purity and purification methods by using automated LC Screening instrumentation and in silico modeling.

The development of liquid chromatography UV and mass spectrometry (LC-UV-MS) assays in pharmaceutical analysis is pivotal to improve quality control by providing critical information about drug purity, stability, and presence and identity of byproducts and impurities. Analytical method development of these assays is time-consuming, which often causes it to become a bottle neck in drug development and poses a challenge for process chemists to quickly improve the chemistry. In this study, a systematic and efficient workflow was designed to develop purity assay and purification methods for a wide range of compounds including peptides, proteins, and small molecules with MS-compatible mobile phases (MP) by using automated LC screening instrumentation and in silico modeling tools. Initial LC MPs and chromatography column screening experiments enabled quick identification of conditions which provided the best resolution in the vicinity of the target compounds, which is further optimized using computer-assisted modeling (LC Simulator from ACD/Labs). The experimental retention times were in good agreement with the predicted retention times from LC Simulator (ΔtR < 7%). This workflow presents a practical workflow to significantly expedite the time needed to develop optimized LC-UV-MS methods, allowing for a facile, automatic method optimization and reducing the amount of manual work involved in developing new methods during drug development.

Effect of Adhesion Layer at the Pt/TiO2 Interface on the Degradation Pathways of TiO2-Protected III-V Water-Splitting Photocathodes

Photoelectrochemical (PEC) water splitting has been identified as a promising route towards the production of green hydrogen as a solar fuel to meet the global energy demands [1]. Highly efficient photoelectrodes made of III-V compounds are promising candidates to reach the goal of >15% solar-to-hydrogen efficiency [2]. However, the main bottle neck of these materials is their poor stability in direct contact with acidic electrolytes, which is needed to ensure efficient mass transport and an efficient hydrogen evolution reaction (HER). Atomic layer deposited (ALD) titanium dioxide (TiO2) is commonly utilized as a protective layer to shield the absorber from the electrolyte [3]. To reduce HER overpotentials, the TiO2 film needs to be modified with a catalyst layer. In a demonstration of a TiO2 protected III-V PEC device, Cheng et al. proposed that the detachment of the catalyst layer induced the degradation of the protective TiO2 film in a pH 0 electrolyte which eventually led to the corrosion of the photoabsorber [4].In this work, GaInP/GaAs/Ge photocathodes for water reduction were protected with ALD TiO2 layers deposited from tetrakis(dimethylamido)titanium (TDMAT) and water precursors with varying thicknesses. A 2 nm catalytic Pt layer was deposited via electron beam evaporation (EBE) to reduce the overpotential of the HER. The conformal coverage of the absorber with TiO2 was confirmed with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). None of the TiO2 films were able to stabilize the illuminated III-V electrodes for 60 min at 0 V versus the counter electrode (CE) in a pH 0 electrolyte (1 M H2SO4). Characterization of the electrochemical potential at the electrode’s front side revealed an unstable regime for the TiO2 protection layer. ICP-MS of the electrolytes, SEM/EDX and electrochemical analyses revealed the detachment of the catalytic Pt layer that led to the dissolution of the TiO2 and the III-V degradation (Figure 1A). The adhesion of Pt on TiO2 was improved by depositing a 2 nm Ti layer via EBE at the Pt/TiO2 interface (Figure 1B). The adhesion layer acts as a wetting layer for Pt, reducing the nucleation energy barrier and increasing the number of nucleation sites compared to Pt/TiO2. The enhanced wetting is due to the formation of Ti−Pt chemical bonds [5] and the overpotential @ 10 mA/cm2 to perform HER was 60 mV, similar to that of a pristine EBE Pt layer. The Ti layer greatly improves the stability of TiO2/III-V photoelectrodes, confirming the results of Cheng et al. and illustrating the importance of a stable catalyst layer.Figure 1. A) SEM micrograph of degradation of Ge/GaAs/GaInP/TiO2/Pt photocathode after 60 min. of photocurrent measurements at 0 V vs. CE in 1 M H2SO4. B) Accelerated stability test in dark for 2 nm Pt/15 nm TiO2 on FTO with (red curve) and without (black curve) a 2 nm Ti adhesion layer in between the Pt and TiO2 layers.

Novel tactile bottle neck adaptor facilitates eye drop adherence in visually impaired patients

PurposeTo test the use of Ring-IT, a novel 3D tactile bottle neck adaptor in topical eye drop adherence in visually impaired patients.MethodsBottle neck ring adaptors with either one, two or...

Comparative Study of Plastomes in Solanum tuberosum with Different Cytoplasm Types

The potato is one of the most important food crops in the world. Improving the efficiency of potato breeding is of great importance for solving the global food problem. Today, researchers distinguish between six potato cytoplasm types: A, M, P, T, W, D. In the current study, the complete chloroplast genomes of Solanum tuberosum accessions with five out of the six major cytoplasmic genome types were sequenced (T-, W-, D-, A-, and P-genomes). A comparative analysis of the plastomes in potato accessions with different cytoplasm types was carried out for the first time. The time of origin of the different cytoplasm types was estimated. The presence of two main groups of chloroplast genomes among cultivated potato was confirmed. Based on the phylogenetic analysis of the complete plastome sequences, five main evolutionary branches of chloroplast genomes can be distinguished within the Petota section. Samples with A- and P- cytoplasm formed isolated and distant groups within a large and polymorphic group of samples with M-type cytoplasm, suggesting that A and P genomes arose independently. The findings suggest that the diversity of the T-genome in S. tuberosum Group Tuberosum could be initially low due to a bottle neck already existing at the origin of the Chilean clade. Differences in the rbcL gene sequence may be one of the factors causing differences in economically important traits in species with A and T-type cytoplasm. The data obtained will contribute to the development of methods for molecular marking of cytoplasm types and increase knowledge about the evolution and diversity of potato.

The journey of Indonesian nurse migration: a scoping review

The migration of nurses from Indonesia to other foreign countries is an inevitable part of the global mobility of the nurse profession. This phenomenon requires investigation to understand the current trajectories of Indonesian nurses in the global market. This scoping review aimed to investigate the Indonesian nurses' mobility to the international healthcare market. A scoping review of primary research addressing Indonesian nurses migration journey overseas. A range of databases were searched, including Scopus, Web of Science Clarivate Analytics, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and PubMed. A systematic process was performed guided by the work of Arksey and O'Malley. Four databases were searched, and 68 articles were retrieved. After screening articles and abstracts, 19 full texts were assessed for eligibility, and finally, 17 studies were further analyzed and synthesized. Eleven qualitative studies, five quantitative study and one literature review study met inclusion criteria, emphasizing the three phases of migration: pre-migration, migration and post-migration. The destination countries of Indonesian nurses including Japan, Kuwait, Saudi Arabia and Taiwan. At the pre-migration stage there are several aspects that must be considered, there were: language, understanding of the job position, reason to work and comprehensive understanding of the destination countries. Migration stage include issues language, deskilling, mental health, unclear career path, cultural adaptation, lack of religious services and homesickness. At the post-migration stage includes deskilling, brain waste and re-integration with brain circulation platform. The comprehensive approach of Indonesian nurses migration from pre-migration, migration and post-migration has shown us the trajectory of Indonesian nurses in international migration. Understanding the bottle neck of each stage with improve policy support is needed to create safe and sound migration channel for Indonesian nurses. This review highlighted to the need for future research in key areas such as the impact of nurse migration on Indonesia's health systems.

The molecular level degradation state of drift plastics in the Sea of Japan coastline

Polyethylene (PE) and polyethylene terephthalate (PET) are among the most abundant plastics polluting the oceans. However, their environmental fate depends on how they have been weathered. Due to its unique geography, the Sea of Japan is a pollution hotspot where plastics accumulate. In this study, the structures of plastics, having drifted into the Sea of Japan coastline environment, were analyzed with a particular focus on examining polymer crystallization and carbonyl formation; two factors which influence microplastic formation and the adsorption of contaminants onto plastic surfaces. PE in the coastal environment did not show evidence of crystallization, although carbonyl formation did increase. By contrast, PET bottles were shown to not be uniform in structure, with unaged bottles being less crystalline in the neck component compared to the body. Because of this difference, in environmental PET bottles, it was the bottle neck that showed increases in crystallization and carbonyl group formation.

Bubbles as high-frequency rheometers for soft matter characterization

Precise knowledge of bubble dynamics in tissue is essential for optimizing both ultrasound imaging and ultrasound therapy. Great efforts have therefore been made, over the past decade, to model the behavior of (micro)bubbles in viscoelastic materials. This has led to a series of models based on modified Rayleigh–Plesset equations. Last to date, we propose a novel generalized model build on finite strain theory and relaxation functions. At this stage however, the bottle neck remains our limited knowledge of tissue viscoelasticity at high strain rates, which is a necessary input to any theoretical model. Indeed, traditional rheometers cannot reach frequencies above 1kHz, which is 3 orders of magnitude below the desired MHz frequencies. We will show how ultrasound-driven bubbles can be used as microscale rheometers. More specifically, we use the volumetric oscillations of (monodisperse) phospholipid-coated microbubbles embedded in hydrogels to measure the storage and loss moduli in the MHz frequency range. In addition, we can bridge the gap between kHz and MHz using the surface modes of cylindrical microbubbles trapped in micropits. These oscillations can be both modelled and simulated, and provide access to the effective surface tension and viscosity in the range of 50 to 500 kHz.

Bioconversion of Black Soldier Fly (BSF) from Organic Waste Composting into Biodiesel Assisted by Whole Cell Microbial Lipase Biocatalyst through Direct Transesterification Process

Black Soldier Fly or Hermetia Illucens (BSF) is known for its potential as a biological agent that helps in the process of natural conversion of organic waste. Resulting compost and a large number of BSF colonies, potentially to be use as a non-food raw material in bioenergy production. The Method is BSF conversion experiment by direct transesterification reaction using Lab-scale bioreactor in 100ml three bottle neck flasks, the solution mixture consists of BSF powder, immobilized whole cell biocatalyst, and solvent. The Result is although in appearance the structure of the test mixture solution did not show an oily character, but based on the viscosity and density test, the test solution had density value 0.81 g/cm3 and viscosity value 1,024 mm2 /s which are above the value of the viscosity and density of methanol but still below the value of the viscosity and density of both SNI and EN14214 biodiesel standard, this could be due to insufficient separation or reaction, imperfect condition, and impurities that are still present in biodiesel products. It can be concluded that a transesterification reaction has occurred in this trial, however further analysis and more experiments are required to definitely conclude the changes in biodiesel production.

On Training Targets and Activation Functions for Deep Representation Learning in Text-Dependent Speaker Verification

Deep representation learning has gained significant momentum in advancing text-dependent speaker verification (TD-SV) systems. When designing deep neural networks (DNN) for extracting bottleneck (BN) features, the key considerations include training targets, activation functions, and loss functions. In this paper, we systematically study the impact of these choices on the performance of TD-SV. For training targets, we consider speaker identity, time-contrastive learning (TCL), and auto-regressive prediction coding, with the first being supervised and the last two being self-supervised. Furthermore, we study a range of loss functions when speaker identity is used as the training target. With regard to activation functions, we study the widely used sigmoid function, rectified linear unit (ReLU), and Gaussian error linear unit (GELU). We experimentally show that GELU is able to reduce the error rates of TD-SV significantly compared to sigmoid, irrespective of the training target. Among the three training targets, TCL performs the best. Among the various loss functions, cross-entropy, joint-softmax, and focal loss functions outperform the others. Finally, the score-level fusion of different systems is also able to reduce the error rates. To evaluate the representation learning methods, experiments are conducted on the RedDots 2016 challenge database consisting of short utterances for TD-SV systems based on classic Gaussian mixture model-universal background model (GMM-UBM) and i-vector methods.

A modified Levenberg–Marquardt scheme for solving a class of parameter identification problems

Parameter identification problems in PDEs are special class of nonlinear inverse problems which has many applications in science and technology. One such application is the Electrical Impedance Tomography (EIT) problem. Although many methods are available in literature to tackle nonlinear problems, the computation of Fréchet derivative is often a bottle neck for deriving the solution. Moreover, many assumptions are required to establish the convergence of such methods. In this paper, we propose a modified form of Levenberg–Marquardt scheme which does not require the knowledge of exact Fréchet derivative, instead, uses an approximate form of it and at the same time, no additional assumptions are required to establish the convergence of the scheme. We illustrate the theoretical result through numerical examples. In order to ensure that the proposed scheme can be applied to practical problems, we have applied the scheme to EIT problem and the reconstruction process clearly demonstrates that the method can be successfully applied to practical problems.

On the drag reduction and heeling stability of a heeled planing air cavity hull

The air cavity planing hull enables the feasibility of running at a low drag-to-lift ratio at high speeds by reducing the wetted area. During the voyage, the ventilation rate and heel are essential parameters for the performance of the air cavity ship (ACS). In this study, three-dimensional Reynolds-averaged Navier-Stokes equations coupled with the volume of fluid method (RANS-VOF) are applied to examine the characteristics of the ACS across a wide range of ventilation rates (Cq = 0–1.120) and heel angles (β = 0–5 deg). The drag reduction and cavity morphology of the ACS are well predicted by the numerical method. The difference between the predicted total resistance and the experiment is less than 5%. The air cavity gradually develops from the meniscus growth cavity (MGC) (Cq ≤ 0.168) to the bottle neck stable cavity (BNSC) (Cq ≥ 0.336) with increasing Cq. Once a stable cavity form (i.e., BNSC) is established, the excessive ventilation would expand the tail air leakage opening in width and thickness. Under the effect of the heel, air coverage and drag reduction are diminished with a critical heel angle (β) of around 2 deg. When β ≥ 2 deg, the cavity shape gradually degenerates to the one-side branch cavity (OSBC). The air coverage also has a negative effect on the heeling stability, which means that the smaller heeling moment may cause a greater heel angle. More importantly, the restoring moment reduction monotonically decreases from 54.3% to 7.1% with the increment of heel angle, which deteriorates the heeling stability of the ACS.

Impact of Foreign Direct Investment on Financial Institution Performance in Nigeria: A Study of Jos Metroplolitan City of Plateau State

Financial institutions are confronted thru gradually keen opposition and increasing effect of supervisory necessities, financial plus high-tech innovations, influential grief and new dares which have melodramatic effects on their concerts. The ambition of this paper is to examine impact of foreign direct investment on financial institution performance in Nigeria. The study was grounded on three theories (revenue maximization principle, pecking order theory and Internationalization Model) in relation FDI performance. This study employs a survey design because which aimed at establishing effects of the variables of independence on dependent variable, population of this study was based on 10 selected financial institution operating in Jos Metropolitan city of Plateau Nigeria as at 1^st January, 2022. Each bank is represented by its Chief finance officer (CFO). Primary data and secondary data was obtained thru yearly financial statement of selected financial institution through the respective Chief finance officers also, books, journals and publications, while primary data was obtained via questionnaire. Descriptive statistics and content analysis were used to analyze the data collected. The results reveled that that FDI variables indicates a strong impact on financial institution performance among Nigeria financial institutions, it recommends that solid framework ought to be set up in order to curtails bottle neck and other issues in relation to FDI among Financial institution performance. The study concludes FDI with financial institutions transaction be able to be intermediated thru its dimensions (Foreign exchange, Capital adequacy, Equity capital and Reinvested foreign earning).

Exhausted T cells hijacking the cancer-immunity cycle: Assets and liabilities.

T cell exhaustion is an alternative differentiation path of T cells, sometimes described as a dysfunction. During the last decade, insights of T cell exhaustion acting as a bottle neck in the field of cancer immunotherapy have undoubtedly provoked attention. One of the main drivers of T cell exhaustion is prolonged antigen presentation, a prerequisite in the cancer-immunity cycle. The umbrella term "T cell exhaustion" comprises various stages of T cell functionalities, describing the dynamic, one-way exhaustion process. Together these qualities of T cells at the exhaustion continuum can enable tumor clearance, but if the exhaustion acquired timeframe is exceeded, tumor cells have increased possibilities of escaping immune system surveillance. This could be considered a tipping point where exhausted T cells switch from an asset to a liability. In this review, the contrary role of exhausted T cells is discussed.

SECHO: A deep reinforcement learning-based scheme for secure handover in mobile edge computing

The experience of users in Mobile Edge Computing (MEC) highly depends on data offloading whose major bottle neck is the design of handover scheme. Existing research advocates that offloading security and quality of service (QoS) should be both considered for an optimal handover. However, recent studies concentrate on improving QoS while neglect security. Due to the complexity of MEC scenarios, generating an optimal handover scheme improving both QoS and security remains a challenge. To solve this problem, we propose SECHO, a secure handover scheme for blockchain-based single-user mobile edge computing system. Then, we design a security policy selection algorithm of offloading tasks to guarantees security performance and controls overhead. Finally, we customize the neural network for a deep reinforcement learning algorithm to realize optimal handover, where a security policy selection method is engaged to collaboratively enhance offloading QoS while decreasing underlying risks. Simulation results show that SECHO leads a 29.6%–302% advantage in overall performance than existing approaches. It proves that our proposal is effective to achieve secure handover while not degrading offloading QoS.

3-sulfonyloxyaryl(mesityl)iodonium triflates as 1,2-benzdiyne precursors with activation via ortho-deprotonative elimination strategy

Benzyne has long captivated the attention of chemists and has gained numerous synthetic achievements. Among typical benzyne generation methods, removal of two vicinal substituents from 1,2-difunctionalized benzenes, i.e., Kobayashi’s protocol, are prevailing, while ortho-deprotonative elimination from mono-substituted benzene lags far behind. Despite the advantages of atom economy and ready achievability of precursors, a bottle neck for ortho-deprotonative elimination strategy resides in the weak acidity of the ortho-hydrogen, which normally demands strong bases as the activating reagents. Here, an efficient aryne generation protocol is developed, where ortho-deprotonative elimination on 3-sulfonyloxyaryl(mesityl)iodonium triflates occurs under mild conditions and the generated 3-sulfonyloxyarynes can serve as efficient 1,2-benzdiyne synthons. This array of 1,2-benzdiyne precursors can be conveniently prepared with high functional group tolerance, and densely substituted scaffolds can be accessed as well. Carbonate and fluoride salts are found to serve as efficient activating reagents, which are the weakest bases used in ortho-deprotonative elimination strategies. Particularly, this scaffold has predictable chemoselective generation of the designated aryne intermediates. The success of this ortho-deprotonative elimination protocol sets up a unique platform with a broad spectrum of synthetic applications.

Large‐Domain Multisite Precipitation Generation: Operational Blueprint and Demonstration for 1,000 Sites

AbstractStochastic simulations of spatiotemporal patterns of hydroclimatic processes, such as precipitation, are needed to build alternative but equally plausible inputs for water‐related design and management, and to estimate uncertainty and assess risks. However, while existing stochastic simulation methods are mature enough to deal with relatively small domains and coarse spatiotemporal scales, additional work is required to develop simulation tools for large‐domain analyses, which are more and more common in an increasingly interconnected world. This study proposes a methodological advancement in the CoSMoS framework, which is a flexible simulation framework preserving arbitrary marginal distributions and correlations, to dramatically decrease the computational burden and make the algorithm fast enough to perform large‐domain simulations in short time. The proposed approach focuses on correlated processes with mixed (zero‐inflated) Uniform marginal distributions. These correlated processes act as intermediates between the target process to simulate (precipitation) and parent Gaussian processes that are the core of the simulation algorithm. Working in the mixed‐Uniform space enables a substantial simplification of the so‐called correlation transformation functions, which represent a computational bottle neck in the original CoSMoS formulation. As a proof of concept, we simulate 40 years of daily precipitation records from 1,000 gauging stations in the Mississippi River basin. Moreover, we extend CoSMoS incorporating parent non‐Gaussian processes with different degrees of tail dependence and suggest potential improvements including the separate simulation of occurrence and intensity processes, and the use of advection, anisotropy, and nonstationary spatiotemporal correlation functions.

Molecular Characteristics of Water-Insoluble Tin-Porphyrins for Designing the One-Photon-Induced Two-Electron Oxidation of Water in Artificial Photosynthesis

Faced with the new stage of water oxidation by molecular catalysts (MCs) in artificial photosynthesis to overcome the bottle neck issue, the "Photon-flux density problem of sunlight," a two-electron oxidation process forming H2O2 in place of the conventional four-electron oxidation evolving O2 has attracted much attention. The molecular characteristics of tin(IV)-tetrapyridylporphyrin (SnTPyP), as one of the most promising MCs for the two-electron water oxidation, has been studied in detail. The protolytic equilibria among nine species of SnTPyP, with eight pKa values on the axial ligands' water molecules and peripheral pyridyl nitrogen atoms in both the ground and excited states, have been clarified through the measurements of UV-vis, fluorescence, 1H NMR, and dynamic fluorescence decay behaviour. The oxidation potentials in the Pourbaix diagram and spin densities by DFT calculation of the one-electron oxidized form of each nine species have predicted that the fully deprotonated species ([SnTPyP(O-)2]2-) and the singly deprotonated one ([SnTPyP(OH)(O-)]-) serve as the most favourable MCs for visible light-induced two-electron water oxidation when they are adsorbed on TiO2 for H2 formation or SnO2 for Z-scheme CO2 reduction in the molecular catalyst sensitized system of artificial photosynthesis.

Rural Households’ Livelihood Diversification Activities: A Case Study from Borena District, North Central Ethiopia

In Ethiopia, farm households are not adequately engage and pursue diverse livelihood activities to cope with various challenges due to livelihood asset crisis and persistent cultural bottle neck. Thus, the main purpose of this study was to identify the rural households’ livelihood diversification activities in Borena district, north central Ethiopia. The study follows a pragmatism paradigm with a cross sectional study design. The required data were drawn both from primary and secondary sources. The study used multistage sampling procedure, involving a combination of purposive and random sampling techniques to select 358 sample household heads. Household sample surveys, key informant interviews and focus group discussions were the principal means used to acquire primary data. In analyzing and interpreting the primary data, quantitative research techniques was employed. Percentages, mean and standard deviation were employed to analyze the quantitative data while thematic narration techniques were used to analyses the qualitative data. The result indicate that slightly more than one-third (33.8%), one-fourth (26.5%) and nearly half (49.7%) of the respondents were engaged exclusively in on-farm, off-farm and non-farm activities, respectively. Thus, policy makers need to intervene in the highest possible means of livelihood diversification while designing and reforming strategies related to diversification of livelihoods.