bluuebunny/crossref_metadata_2025 huggingface dataset:
The shock formation and optimal regularities of the resulting shock curves for 1D scalar conservation laws*
Authors: Huicheng Yin , Lu Zhu
Published: January 2022

The study on the shock formation and the regularities of the resulting shock surfaces for hyperbolic conservation laws is a basic problem in the nonlinear partial differential equations. In this paper, we are concerned with the shock formation and the optimal regularities of the resulting shock curves for the 1D conservation law ∂
t

u + ∂
x

f(u) = 0 with the smooth initial data u(0, x) = u
0(x). If

u

0

(

x

)

∈

C

1

(

R

)

and

f

(

u

)

∈

C

2

(

R

)

, it is well-known that the solution u will blow up on the time

T

*

=
−

1

min

g

′

(

x

)

when min g′(x) < 0 holds for g(x) = f′(u
0(x)). Let x
0 be a local minimum point of g′(x) such that g′(x
0) = min g′(x) < 0 and g″(x
0) = 0, g
(3)(x
0) > 0 (which is called the generic nondegenerate condition), then by theorem 2 of Lebaud (1994 J. Math. Pures Appl.
9 523–565), a weak entropy solution u together with the shock curve x = φ(t) ∈ C
2[T*, T* + ɛ) starting from the blowup point (T*, x* = x
0 + g(x
0)T*) can be locally constructed. When the generic nondegenerate condition is violated, namely, when x
0 is a local minimum point of g′(x) such that

g

″

(

x

0

)

=

g

(

3

)

(

x

0

)

=
…
=

g

(

2

k

0

)

(

x

0

)

=
0

but

g

(

2

k

0

+
1

)

(

x

0

)

>
0

for some

k

0

∈
N

with k
0 ⩾ 2; or g
(k)(x
0) = 0 for any

k
∈
N

and k ⩾ 2, we will study the shock formation and the optimal regularity of the shock curve x = φ(t), meanwhile, some precise descriptions on the behaviors of u near the blowup point (T*, x*) are given. Our main aims are to show that: around the blowup point, the shock really appears whether the initial data are degenerate with finite orders or with infinite orders; the optimal regularities of the shock solution and the resulting shock curve have the explicit relations with the degenerate degrees of the initial data.
Printed in-plane electrolyte-gated transistor based on zinc oxide
Authors: Morais Rogério , Vieira Douglas Henrique , Klem Maykel dos Santos , Gaspar Cristina , Pereira Luís , Martins Rodrigo , Alves Neri
Published: January 2022

Printed electronics is a reputable research area that aims at simple alternatives of manufacturing low-cost, eco-friendly, and biodegradable electronic devices. Among these devices, electrolyte-gated transistors (EGTs) stand out due to their simple manufacturing process and architecture. Here we report the study of printed EGTs with in-plane gate transistor (IPGT) architecture based on zinc oxide nanoparticles. The drain, source, and gate electrodes with two different W/L channel ratios were fabricated using a screen-printed carbon-based ink. We also produced a conventional top-gate transistor as a standard device, using the same structure of the IPGT described above with the addition of an indium tin oxide strip positioned over the electrolyte as the top-gate electrode. The IPGT with W/L = 5 presented a high mobility of 7.95 ± 0.55 cm2 V−1 s−1, while the W/L = 2.5 device exhibited a mobility of 3.03 ± 0.52 cm2 V−1 s−1. We found that the measured field-effect mobility of the device can be affected by the high contact resistance from the carbon electrodes. This effect could be observed when the device’s geometric parameters were changed. Furthermore, we also found that the IPGT with W/L = 5 exhibited higher values for mobility and transconductance than the top-gate transistor, showing that the IPGTs architecture is a good approach for cheap and printed transistors with performance comparable to standard top-gate EGTs.
Hydroxylation-induced defect states and formation of a bidentate acetate adstructure of TiO2 catalysts with acetic acid variation for catalytic application
Authors: Rahman Kazi Hasibur , Kar Asit Kumar
Published: January 2022

TiO2 is considered a promising candidate for catalysis applications. The addition of acetic acid and its variation creates a strong bond with oxide surfaces, which generates various oxidizing agents. X-ray diffraction analysis of the prepared TiO2 nanoparticles reveals their semicrystalline nature. The results show that holes are captured by the surface and subsurface, producing

≡

T

i

IV

−

O

H

.

,

≡

T

i

IV

−

O

.
−

−

T

i

IV

≡

and the reducing agent

=

T

i

III

−

, which act as active oxidizers during photocatalysis, thus confirming the occurrence of an OH radical via an advanced oxidation process. Increasing the acetic acid amount leads to disordered structural defects below the conduction band (CB). X-ray photoelectron spectroscopy analysis shows the induction of hydroxylation of surface defects, such as Ti–OH. The results indicate that an oxygen vacancy is favourable due to a large number of surface defects. Detailed discussion of the energy band structure with the concept of a valence band (VB) and a CB maximum is implemented. The electron-withdrawing carboxylic group can affect oxygen vacancies and acetate ligands on the photocatalyst surface. The formation of a bidentate acetate adstructure with a lower acetic acid concentration leads to an explanation for higher visible-light-driven methylene blue degradation. The mechanism for the formation of an additional Ti–O–Ti bond by a condensation process is also illustrated elaborately. Theoretical calculations of the potentials of the VB and CB show the effects of active sites on degradation and can be associated with redox reactions for water splitting abilities. A possible model of sensitized photocatalysis for hydrogen production with hydrogen and oxygen evolution sites is also proposed in this article. Thus, TiO2 nanoparticles with acetic acid variation are promising sources for photocatalytic/catalytic applications.
In-plane selective excitation of arbitrary vibration modes using thickness-shear (d
15) piezoelectric transducers
Authors: Qiu Hao , Li Faxin
Published: January 2022

Experimental modal analysis is of great importance for the dynamic characterization of structures. Existing methods typically employ out-of-plane forces for excitation and measure the acceleration or strain for modal analysis. However, these methods encountered difficulties in some cases. In this work, we proposed an in-plane excitation method based on thickness-shear (d
15) piezoelectric transducers. Through the combination of distributed d
15 PZT strips, arbitrary vibration modes can be selectively excited in a wide frequency range. Both simulations and experiments were conducted and the results validated the proposed method. Specifically, bending, torsional, and longitudinal vibration modes of a rectangular bar were selectively excited. Torsional modes of a shaft were excited without the aid of brackets and bending modes of a circular plate were excited with actuators placed at nodal lines. Furthermore, the electromechanical impedance of the PZT-structure system was measured from which the natural frequency and quality factor were directly extracted. Due to its simplicity and flexibility, the proposed vibration excitation method is expected to be widely used in near future.
Composite pulses for high fidelity population transfer in three-level systems
Authors: Shi Zhi-Cheng , Zhang Cheng , Ran Du , Xia Yan , Ianconescu Reuven , Friedman Aharon , Yi X X , Zheng Shi-Biao
Published: January 2022

In this work, we propose a composite pulses (CPs) scheme by modulating phases to achieve high fidelity population transfer in three-level systems. To circumvent the obstacle that not enough variables are exploited to eliminate the systematic errors in the transition probability, we put forward a cost function to find the optimal value. The cost function is independently constructed either in ensuring an accurate population of the target state, or in suppressing the population of the leakage state, or both of them. The results demonstrate that population transfer is implemented with high fidelity even when existing the deviations in the coupling coefficients. Furthermore, our CPs scheme can be extensible to arbitrarily long pulse sequences. As an example, we employ the CPs sequence for achieving the three-atom singlet state in an atom-cavity system with ultrahigh fidelity. The final singlet state shows robustness against deviations and is not seriously affected by waveform distortions. Also, the singlet state maintains a high fidelity under the decoherence environment.
Scattering fingerprints of two-state dynamics
Authors: Dieball Cai , Krapf Diego , Weiss Matthias , Godec Aljaž
Published: January 2022

Particle transport in complex environments such as the interior of living cells is often (transiently) non-Fickian or anomalous, that is, it deviates from the laws of Brownian motion. Such anomalies may be the result of small-scale spatio-temporal heterogeneities in, or viscoelastic properties of, the medium, molecular crowding, etc. Often the observed dynamics displays multi-state characteristics, i.e. distinct modes of transport dynamically interconverting between each other in a stochastic manner. Reliably distinguishing between single- and multi-state dynamics is challenging and requires a combination of distinct approaches. To complement the existing methods relying on the analysis of the particle’s mean squared displacement, position- or displacement-autocorrelation function, and propagators, we here focus on ‘scattering fingerprints’ of multi-state dynamics. We develop a theoretical framework for two-state scattering signatures—the intermediate scattering function and dynamic structure factor—and apply it to the analysis of simple model systems as well as particle-tracking experiments in living cells. We consider inert tracer-particle motion as well as systems with an internal structure and dynamics. Our results may generally be relevant for the interpretation of state-of-the-art differential dynamic microscopy experiments on complex particulate systems, as well as inelastic or quasielastic neutron (incl. spin-echo) and x-ray scattering probing structural and dynamical properties of macromolecules, when the underlying dynamics displays two-state transport.
Natural convection and thermal radiation analysis inside the square cavity filled with non-Newtonian fluid via heatlines and entropy generation
Authors: Iftikhar Babar , Siddiqui Muhammad Arshad , Javed Tariq
Published: January 2022

In the present analysis, natural convection heat transfer coupled with thermal radiation of bi-viscosity fluid contained inside the cavity has been studied through heatlines and entropy generation. Heat is provided to the cavity through heated source with length

L
/
2
,

which is placed at the middle of bottom wall. Side walls of the enclosure at low temperature i.e.

T

c

ad rest of the walls are kept an adiabatic. The idea of Bejan heatlines and average Bejan number have been used to visualized the convective heat folw and dominant irreversibility due to fluid flow or heat transfer, respectively. Finite element method with penalty technique has been applied to obtain the solution of governing equations. Results are obtained through numerically and displayed in terms of streamlines, heat flux lines , isotherms, velocity, temperature, entropy, Nusselt number and average Bejan number against the extensive range of bi-viscosity

β
=
0.002
−
1

and thermal radiation

N

R

=
0
−
5
,

at fixed Rayleigh

R
a
=

10

5

and Prandtl number

P
r
=
10
.

It is observed that there exist a direct relation between bi-viscosity parameter and convection heat transfer due to buoyancy-driven flow. Moreover, the dominant entropy generation has been reported through heat transfer in the lower region of the cavity with and without thermal radiation.
Influence of Cr-doping on structural, magnetic and dielectric properties of M-type hexaferrites synthesized using microwave digestion technique
Authors: Abdel Hakeem A M , Ibrahim E M M , Ali H M , Abd El-Raheem M M , Hamazaoui Adel , Ahmed Mahrous R
Published: January 2022

M-type hexaferrite SrCrxFe12-xO19 compounds doped with Cr (x = 0, 1, 2, 3 and 4 at.%) were prepared by microwave digestion system. X-ray diffraction was used to study the structure and crystallization of the samples. The samples are found to have a hexagonal phase, SrFe12O19, as a main phase at 2θ ≈ 33.144° and 35.618° for x = 0 and 1 respectively, and 32.451° and 34.295° for x ≥ 2. The Rietveld refined parameters such as the lattice parameters (a = b, c), direct and indirect cell volume, crystallite size and microstrain were investigated. TEM and SEM results showed that the samples have hexagonal shape and grain size range from 126 nm to 379 nm. Magnetization, M, as a function of the applied magnetic field, H, was obtained from the hysteresis loop. The coercive field, H

C
, saturation, M

s
and remnant, M

r
, magnetization and squareness ration, M

r
/M

s
, were extracted from the hysteresis loop results. These results revealed that H

C
is inversely proportional with the grains size of the samples but directly proportional with Cr-doping values candidating these compounds to be used in computer hard disk memories applications. M values are inversely proportional with Cr-doping values. The variation of conductivity, σ, impedance, Z, dielectric constant, ε, dielectric loss factor, tan δ and dissipation factor as functions of both AC frequency, F(Hz) and Cr-doping, x, were investigated. The maximum value of the dissipation factor was at x = 2 which equals 8.05 × 109 m F−1 when F = 2 × 105 Hz. The impedance of the samples behaved as a capacitor reactance that makes our compounds candidate for many crucial dielectric applications.
Band gap characteristics of friction stir additive manufactured phononic crystals
Authors: Tan Zhijun , Zhang Zhao
Published: January 2022

Additive Manufacturing (AM) is widely used to fabricate phononic crystals (PnCs) in recent years. Friction Stir Additive Manufacturing (FSAM) is a new-type solid state fabrication technology which is fusion free with low distortions. FSAM was selected to fabricate the designed PnCs. The manufactured specimen was distorted due to the temperature rise in the manufacturing process and the band gaps (BGs) were changed with the distortions. Results indicate that the band gap of the PnCs moves to be in higher frequency domain due to the residual distortions of the manufactured PnCs. The residual distortion of FSAM PnCs is 2.77 times smaller in comparison with the Tungsten Inert Gas (TIG) welding. So, the differences of the band gap between the designed PnCs and the FSAM specimen are only in the range of 0.15%–0.55% due to the lower temperature rise in FSAM. The further analysis shows that the change of the BGs is caused by the growth of the inertia moment for the FSAM PnCs. With the increase of the rotating speed in FSAM, the residual distortion of the FSAM PnCs is increased due to the increase of the welding temperature. This can lead to the increase of the inertia moment, which is the key reason for the increase of the BG characteristics of the FSAM PnCs.
Q-BOR–FDTD method for solving Schrödinger equation for rotationally symmetric nanostructures with hydrogenic impurity
Authors: Firoozi Arezoo , Mohammadi Ahmad , Khordad Reza , Jalali Tahmineh
Published: January 2022

An efficient method inspired by the traditional body of revolution finite-difference time-domain (BOR-FDTD) method is developed to solve the Schrödinger equation for rotationally symmetric problems. As test cases, spherical, cylindrical, cone-like quantum dots, harmonic oscillator, and spherical quantum dot with hydrogenic impurity are investigated to check the efficiency of the proposed method which we coin as Quantum BOR-FDTD (Q-BOR-FDTD) method. The obtained results are analysed and compared to the 3D FDTD method, and the analytical solutions. Q-BOR-FDTD method proves to be very accurate and time and memory efficient by reducing a three-dimensional problem to a two-dimensional one, therefore one can employ very fine meshes to get very precise results. Moreover, it can be exploited to solve problems including hydrogenic impurities which is not an easy task in the traditional FDTD calculation due to singularity problem. To demonstrate its accuracy, we consider spherical and cone-like core-shell QD with hydrogenic impurity. Comparison with analytical solutions confirms that Q-BOR–FDTD method is very efficient and accurate for solving Schrödinger equation for problems with hydrogenic impurity
Assessing relationship of degradation of coastal zones and phytoplankton species structure of Lake Uvildy and Lake Turgoyak (South Ural, Russia)
Authors: Kostryukova A , Mashkova I , Belov S , Shchelkanova E , Trofimenko V , Kargina V
Published: January 2022

The current paper aims at analyzing the species structure of the phytoplankton community of two reservoirs on the territory of South Ural. The given water bodies are of different trophicity, namely, oligotrophic Lake Turgoyak and oligomesotrophic Lake Uvildy. Both lakes, being natural monuments, are subject to intensive recreational use. A large flow of tourists is a serious problem for the ecological state of the water bodies coastal areas. Also, tourist activities can affect the state of aquatic biocenoses. In this work, the degree of recreational degression of the selected study sites was assessed. The analysis was carried out according to the state of landscapes, vegetation and trampledness of the surveyed area. Based upon the research the current paper reveals spatial patterns in the distribution of recreational load on the coastal geosystems and the level of anthropogenic transformation of the territory. Mainly due to the high density of recreational centres and camping areas, the coastal area is characterized by a high degree of regression. Some signs allow forecasting changes in the species composition of phytoplankton communities and the trophic status of the lakes depending on the degradation of the coastal zones. Diatoms (Bacillariophyta) have been dominant in plankton phytocoenosis of Turgoyak and Uvildy. At the same time, in the oligomesotrophic lake (Uvildy), the number of diatom species is significantly reduced in areas with a higher degree of regression. Thus, diatoms are sensitive indicators of anthropogenic impact on aquatic ecosystems. Green and blue-green algae biodiversity has grown in the water body. However, no relationship was found between their species diversity and the level regression. But the following tendency is observed for the oligotrophic Lake Turgoyak. The species diversity of green algae grows with an increase in the degression degree. To forecast the further state of the studied water bodies, the revealed patterns in the change of the phytoplankton species structure depending on the degradation level of the coastal territories can be used as eutrophication signs.
Monitoring the evolution of drought conditions over Africa
Authors: Ebobenow J , Arreyndip N A
Published: January 2022

Droughts have been found to have serious repercussions on humans, animals, and plants’ lives and they are likely to intensify under increasing global mean temperature. Monitoring drought conditions help in designing appropriate adaptations and mitigation strategies. This paper monitors the evolution of drought conditions in Africa over the past 30 years and the potential repercussions posed by this disaster event. We analyze and compare trends in surface temperatures, precipitation, soil moisture, Outgoing Longwave Radiation (OLR), and Palmer Drought Severity Index (PDSI). We use the NCEP/NCAR Reanalysis, the University of Delaware, the Climate Prediction Center (CPC), and the DAI PDSI gridded data for the period 1984-2014. Results from the NCEP/NCAR, University of Delaware, CPC, and the DAI PDSI gridded data show an increasingly warmer, drier, and less cloudy Sub-Saharan climate but with an intensification of the West African monsoon rainfall. Moreover, more than 80% of the continent shows strong evidence of droughts with an average increase in drought severity index. These conditions will likely have a negative effect on the agricultural sector which accounts for more than 70% of the Gross Domestic Product (GDP) of this region thereby posing a serious threat to regional food security. We recommend the research into and the development of new crop varieties that can tolerate higher temperatures and need less water. Additionally, our findings can also be used in Sub-Saharan Africa’s water management systems.
GMS-MODFLOW application in the investigation of groundwater potential in Concepcion, Tarlac, Philippines
Authors: Quitaneg L C
Published: January 2022

This study used GMS-Modflow to investigate the ten-year groundwater potential in Concepcion, Tarlac. This region in Central Luzon, Philippines, with limited surface water, depends on groundwater as its primary freshwater source. The water demand projection estimated an increase of 38.5% from 2020 to 2030; hence, higher groundwater abstraction is perceived in the next ten years. To deviate from the risk associated with reliance on groundwater, this study, through GMS-MODFLOW, developed a groundwater model to mimic the aquifer’s current condition and investigated its behavior in response to future spatial and temporal variables. The simulation results generally showed a sustainable groundwater supply in Concepcion, Tarlac, for the next ten years, with no significant decline in hydraulic heads.
Design of a column test bench for the evaluation of alternative absorbent materials in wastewater treatment
Authors: Mayacela M , Maldonado L , Morales F , Peñafiel R
Published: January 2022

One of the most used processes for wastewater treatment is filtration, still having unknowns related to the new possible absorbent materials which can provide better pollutant removal. This project proposes a column test bench capable of working with different materials, particle diameters (> 0.35mm) and densities and densities with three columns of 1.5 m length and 4 inches of diameter.. To perform this project, the type of reactive material for the filter medium was identified, considering the nominal and critical size of the fine sand (0.35m), as a basis for determining the design of the length, diameter of the and thickness column. The design conditions were taken so that the hydraulic system can function as a slow and rapid filter. The most critical operating conditions were selected, Qmax: 16.72 lpm and Filtration Rate: 19.80 m / h. Under these operating conditions, a hydraulic head loss of 2.77 m was obtained within the sand column. The result of this research is the design of a column test system that can work under different hydraulics conditions and absorbent materials with sizes greater than 0.35 mm, intended for the investigation of wastewater treatment from car washers and the removal of heavy metals. The final cost of building the column test is about 25% of the commercial price system.
Evapotranspiration estimation of Urmia Lake Basin using GCOM-C thermal imagery
Authors: Tasumi M , Moriyama M
Published: January 2022

Basin-scale monthly and annual evapotranspiration (ET) is estimated for Urmia Lake Basin by applying the Global Change Observation Mission for Climate (GCOM-C) global ETindex estimation algorithm to thermal imagery observed by the GCOM-C satellite. In total, 297 satellite images acquired during 2018-2019 were used in this study. ET estimation accuracy was examined for an area dominated by apple fields using traditional surface irrigation. The estimated ET was 15% lower than the standard crop ET, which was computed using a procedure suggested by the Food and Agriculture Organization of the United Nations on a monthly timescale, and was 8% lower on an annual timescale. Comparison of estimated ET with a satellite-based ET map derived by using the Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC) model showed a similar difference. The 8%–15% differences among the different sources of ET were small, given that a similar or wider range of uncertainty is frequently available even in ground-based ET measurements. Comparison between the estimated ET and the MODIS ET Product (MOD16) revealed a greater difference in the evaluated area of the apple fields. Given the climatic ET demands and the irrigation practices of the area, ET estimation accuracy is more likely to be higher using the dataset derived from this study than using MOD16. The GCOM-C satellite started routine surface observations in January 2018. Its contribution to agricultural water management, such as by estimating ET as presented in this study, will increase as the amount of historical data stored continues to accumulate.
Degradation of aqueous organic dye pollutants by heterogeneous photo-assisted Fenton-like process using natural mineral activator: Parameter optimization and degradation kinetics
Authors: Karim M A H , Aziz K H H , Omer K M , Salih Y M , Mustafa F , Rahman K O , Mohammad Y
Published: January 2022

Degradation of organic pollutants by heterogeneous Fenton-based advanced oxidation processes has been proved to be an efficient method. The use of naturally occurring catalysts as H2O2 activators is of particular interest in environmental remediation. This work applied a low-cost and eco-friendly natural mineral under UV-light irradiation to degrade organic dye in water. To study the performance of the natural mineral in photo-Fenton oxidation, methylene blue (MB) was employed as a model dye pollutant. The morphology and chemical composition of the natural mineral were characterized using various techniques. The effects of different experimental conditions such as the initial pH of the solution, the amount of catalyst, and initial dye concentrations on the degradation efficiency were investigated. The degradation of methylene blue reached 91.3% at optimum reaction conditions; 0.1g catalyst and 100 mg L‒1 H2O2 concentrations for 10 mg L‒1 initial dye concentration after 180 min of treatment. The pseudo-first-order kinetic model exhibited a better correlation coefficient (R2 > 0.98) in explaining the degradation kinetics of MB. The applied natural mineral showed good catalytic activity and will open a door towards large-scale wastewater purification from dyes. Furthermore, the plausible mechanism of the heterogeneous photo-Fenton oxidation is discussed.
Meander floodplain management and stabilization of riverbank in urban region
Authors: Murniningsih S
Published: January 2022

The normalization of the Meander River in the past caused environmental problems, changed the river’s ecology, and required heavy maintenance such as stabilizing riverbanks with revetments, sheet piles and other constructions. Pesanggrahan River, located at Southern Region of Jakarta, Indonesia which has a meander channel at the border between the middle reach and downstream reach. The river was normalized at the end of the year 2012 with several modifications such as resection, realignment and cutting-off meandering bends. Analysis the effect of normalization consisting of meander cut-off and riverbank stabilization presented in this paper in term of the behaviour of sediment transport along the channel that has been normalized. HEC-RAS program is used to track the Pesanggrahan river flow from upstream to downstream before and after normalization. The Ackers-White equation used to calculate the amount of sediment for each section based on the change of the river section due to sediment motion after normalizing of the channel river. From the results of the study, it is proposed that a river naturalization or low impact development (LID) approach, such as floodplain management especially at the meander bend with riparian ecosystems that maintain stabilization at the riverbank also maintain habitat heterogeneity, is an important factor for the long-term survival of several rare and endangered species.
Groundwater geochemistry and hydrogeochemical processes assessment in Bantul, Yogyakarta, Indonesia
Authors: Ratri D , Putra D P E , Wilopo W
Published: January 2022

In Bantul, Southern Yogyakarta, groundwater is the main source of domestic water needs. Therefore, knowing the hydrogeochemistry of groundwater is crucial in order to manage a sustainable groundwater resource. To characterize the compelling geochemical processes that control the groundwater chemistry, further hydrogeochemical examinations were directed in the area. Thirty groundwater samples were collected from shallow dug wells during the early dry season (April 2021). Sampling procedures and chemical analysis were carried out as per standard methods with secondary data obtained in 2006. The geochemical evaluations were depicted using several graphical plots dependent on the ionic constituents, hydrochemical facies, and controlling factors of groundwater quality. Two major hydrochemical facies were identified: alkaline-earth water with higher alkali; bicarbonate predominated (62%) and alkaline-earth water; bicarbonate predominated (32%). Weathering of silicate minerals occurs in 70% of recent samples and predominantly regulates major ion chemistry such as calcium, magnesium, sodium, and potassium. Chloro-alkaline indices 1,2 values signify that there are two potential rock-water interaction processes in the study region, namely the ion exchange and reverse ion exchange. Concentrations of nitrate, sulfate, and chloride indicate that the water chemistry has not been heavily contaminated by the land use in the area and is still mainly controlled by geogenic processes rather than anthropogenic activities.
Effect of channel slope and roughness on hydraulic jump in open channel flow
Authors: Laishram K , Kumar P A , Devi T T
Published: January 2022

An experimental study is conducted on hydraulic jump characteristics for understanding the impact of slope in an open channel flume. Hydraulic jump on different channel characteristics (horizontal smooth & rough and sloping smooth & rough) were analysed. The measured characteristics of hydraulic jump with different channel roughness and different slope were compared. The results showed that the sequent depth ratio (y2/y1
) increases with the increase in Froude number (Fr1
) for smooth horizontal bed and horizontal rough bed. It was also observed that with an increase in Fr1
, a decrease in y2/y1
in smooth sloping bed condition and decreases for rough sloping bed. New empirical relationships were also developed with the experimental data and results were found similar with the observed hydraulic characteristics data.
Evaluation method of allowable concentration of pollutants considering the state of bottom sediments
Authors: Zhou D , Savichev O G
Published: January 2022

Considering the dilution of sewage and the interaction between river water and bottom sediments, a mathematical model for the conversion of pollutants in water bodies has been developed. Taking the small rivers in northern Vietnam (Ban Thi River and Dai River in the Red River Basin) as an example, it shows that more than 60% of the chemical composition of the river waters studied is determined by the interaction of the following factors: Co-precipitation of sediments and trace elements on solid particles, and sediments at the bottom of the river. The impact of water runoff is first manifested in the change of solid runoff, and to a lesser extent in the process of regulating the water, which takes longer to establish equilibrium in the solution. On the basis of the proposed model, a simplified version of the model and a standardized pollutant discharge method have been developed for whether there is an option of river water chemical composition observation data. In this case, the influence of interaction with bottom sediments is indirectly considered through the structure of the model and its parameter values. The simplified model was tested with the Jinjiang River in the Poyang Lake Basin as an example.
3D bioprinted tumor model with extracellular matrix enhanced bioinks for nanoparticle evaluation
Authors: Chen You , Xu Langtao , Li Weilin , Chen Wanqi , He Qiubei , Zhang Xiaoge , Tang Junjie , Wang Yizhen , Liu Bo , Liu Jie
Published: January 2022

The traditional evaluation of nanoparticles (NPs) is mainly based on 2D cell culture and animal models. However, these models are difficult to accurately represent human tumor microenvironment (TME) and fail to systematically study the complex transportation of NPs, thus limiting the translation of nano-drug formulations to clinical studies. This study reports a tumor model fabricated via 3D bioprinting with adipose decellularized extracellular matrix (ECM) enhanced hybrid bioink. Compared with 2D cultured cells, the 3D printed tumor models with multicellular spheroids formation are closer to real tumor in protein, gene expression and tumorigenicity both in vitro and in vivo. Two characteristics of TME, ECM remodeling and epithelial-mesenchymal transition, are tracked simultaneously under 3D conditions. Furthermore, the cellular uptake efficiency of two different NPs is significantly lower in the printed 3D tumor model than the 2D individual cells, and higher drug resistance is observed in 3D group, which suggest the ECM barrier of tumor can significantly affect the permeability of NPs. These results suggest that this 3D printed tumor model is capable of mimicking the multiple TME, potentially providing a more accurate platform for the design and development of NPs before moving into animal and clinical trials.
Multilayer microfluidic platform for the study of luminal, transmural, and interstitial flow
Authors: Lee Gi-hun , Huang Stephanie A , Aw Wen Y , Rathod Mitesh L , Cho Crescentia , Ligler Frances S , Polacheck William J
Published: January 2022

Efficient delivery of oxygen and nutrients to tissues requires an intricate balance of blood, lymphatic, and interstitial fluid pressures (IFPs), and gradients in fluid pressure drive the flow of blood, lymph, and interstitial fluid through tissues. While specific fluid mechanical stimuli, such as wall shear stress, have been shown to modulate cellular signaling pathways along with gene and protein expression patterns, an understanding of the key signals imparted by flowing fluid and how these signals are integrated across multiple cells and cell types in native tissues is incomplete due to limitations with current assays. Here, we introduce a multi-layer microfluidic platform (MμLTI-Flow) that enables the culture of engineered blood and lymphatic microvessels and independent control of blood, lymphatic, and IFPs. Using optical microscopy methods to measure fluid velocity for applied input pressures, we demonstrate varying rates of interstitial fluid flow as a function of blood, lymphatic, and interstitial pressure, consistent with computational fluid dynamics (CFD) models. The resulting microfluidic and computational platforms will provide for analysis of key fluid mechanical parameters and cellular mechanisms that contribute to diseases in which fluid imbalances play a role in progression, including lymphedema and solid cancer.
Surface sum-frequency generation from chiral medium by elliptically polarized light beyond plane-wave approximation and coplanar geometry of incidence
Authors: Grigoriev K S , Makarov V A
Published: January 2022

Aiming to study the nonlinear response of the surface of isotropic chiral medium, we obtained analytical expression relating the transverse amplitudes of the spatial Fourier-spectra of two incident arbitrary polarized fundamental beams and one signal reflected beam at the sum-frequency within the first-order approximation by their divergence angles. The calculations, carried out in paraxial approximation, simultaneously take into account the spatial dispersion of the bulk of the medium, its near-surface heterogeneity and the transverse finiteness of the three interacting light beams with arbitrary amplitude profiles and orientation in space. A special compact form for the final formulas was found, which makes use of effective nonlinear transformation tensors, the components of which are solely determined by the geometry of incidence of the beams and the material constants of the medium. A possibility of ‘switching off’ the certain mechanisms of nonlinear response by choosing the specific polarization states of the incident beams is discussed.
Developing sensor materials for screening intestinal diseases
Authors: Zhao Cheng , Zhang Xiaoxuan , Chen Guopu , Shang Luoran
Published: January 2022

Intestinal diseases that have high mortality and morbidity rates and bring huge encumbrance to the public medical system and economy worldwide, have always been the focus of clinicians and scientific researchers. Early diagnosis and intervention are valuable in the progression of many intestinal diseases. Fortunately, the emergence of sensor materials can effectively assist clinical early diagnosis and health monitoring. By accurately locating the lesion and sensitively analyzing the level of disease markers, these sensor materials can help to precisely diagnose the stage and state of lesions, thereby avoiding delayed treatment. In this review, we provide comprehensive and in-depth knowledge of diagnosing and monitoring intestinal diseases with the assistance of sensor materials, particularly emphasizing their design and application in bioimaging and biodetection. This review is dedicated to conveying practical applications of sensor materials in the intestine, critical analysis of their mechanisms and applications and discussion of their future roles in medicine. We believe that this review will promote multidisciplinary communication between material science, medicine and relevant engineering fields, thus improving the clinical translation of sensor materials.
Resistance exercise as a treatment for sarcopenia: prescription and delivery
Authors: Hurst Christopher , Robinson Sian M , Witham Miles D , Dodds Richard M , Granic Antoneta , Buckland Charlotte , De Biase Sarah , Finnegan Susanne , Rochester Lynn , Skelton Dawn A , Sayer Avan A
Published: January 2022

Sarcopenia is a generalised skeletal muscle disorder characterised by reduced muscle strength and mass and associated with a range of negative health outcomes. Currently, resistance exercise (RE) is recommended as the first-line treatment for counteracting the deleterious consequences of sarcopenia in older adults. However, whilst there is considerable evidence demonstrating that RE is an effective intervention for improving muscle strength and function in healthy older adults, much less is known about its benefits in older people living with sarcopenia. Furthermore, evidence for its optimal prescription and delivery is very limited and any potential benefits of RE are unlikely to be realised in the absence of an appropriate exercise dose. We provide a summary of the underlying principles of effective RE prescription (specificity, overload and progression) and discuss the main variables (training frequency, exercise selection, exercise intensity, exercise volume and rest periods) that can be manipulated when designing RE programmes. Following this, we propose that an RE programme that consists of two exercise sessions per week and involves a combination of upper- and lower-body exercises performed with a relatively high degree of effort for 1–3 sets of 6–12 repetitions is appropriate as a treatment for sarcopenia. The principles of RE prescription outlined here and the proposed RE programme presented in this paper provide a useful resource for clinicians and exercise practitioners treating older adults with sarcopenia and will also be of value to researchers for standardising approaches to RE interventions in future sarcopenia studies.
Potential Effects of the Coronavirus Disease 2019 (COVID-19) Pandemic on Human Immunodeficiency Virus (HIV) Transmission: A Modeling Study in 32 US Cities
Authors: Fojo Anthony , Wallengren Emma , Schnure Melissa , Dowdy David W , Shah Maunank , Kasaie Parastu
Published: January 2022

Background

The degree to which the 2019 novel coronavirus disease (COVID-19) pandemic will affect the US human immunodeficiency virus (HIV) epidemic is unclear.

Methods

We used the Johns Hopkins Epidemiologic and Economic Model to project HIV infections from 2020 to 2025 in 32 US metropolitan statistical areas (MSAs). We sampled a range of effects of the pandemic on sexual transmission (0–50% reduction), viral suppression among people with HIV (0–40% reduction), HIV testing (0–50% reduction), and pre-exposure prophylaxis use (0–30% reduction), and indexed reductions over time to Google Community Mobility Reports.

Results

Simulations projected reported diagnoses would drop in 2020 and rebound in 2021 or 2022, regardless of underlying incidence. If sexual transmission normalized by July 2021 and HIV care normalized by January 2022, we projected 1161 (1%) more infections from 2020 to 2025 across all 32 cities than if COVID-19 had not occurred. Among “optimistic” simulations in which sexual transmission was sharply reduced and viral suppression was maintained we projected 8% lower incidence (95% credible interval: 14% lower to no change). Among “pessimistic” simulations where sexual transmission was largely unchanged but viral suppression fell, we projected 11% higher incidence (1–21% higher). MSA-specific projections are available at www.jheem.org?covid.

Conclusions

The effects of COVID-19 on HIV transmission remain uncertain and differ between cities. Reported diagnoses of HIV in 2020–2021 are likely to correlate poorly with underlying incidence. Minimizing disruptions to HIV care is critical to mitigating negative effects of the COVID-19 pandemic on HIV transmission.
Abandonment of Human Immunodeficiency Virus Preexposure Prophylaxis Prescriptions at Retail Pharmacies—United States, 2019
Authors: Huang Ya Lin A , Zhu Weiming , Carnes Neal , Hoover Karen W
Published: January 2022

We analyzed a national pharmacy database to estimate the annual number of persons who abandoned preexposure prophylaxis (PrEP) prescriptions and assessed associated factors. About 9% of persons prescribed PrEP abandoned prescriptions in 2019; abandonment was associated with sex, age, insurance type, black race/ethnicity, and drug copayment amount.
Clinical and haemodynamic variables associated with intensive care unit length of stay and early adverse outcomes after the Norwood procedure
Authors: Staehler Helena , Ono Masamichi , Schober Patrick , Kido Takashi , Heinisch Paul Philipp , Strbad Martina , Vodiskar Janez , Cleuziou Julie , Lemmer Julia , Balling Gunter , Hager Alfred , Ewert Peter , Hörer Jürgen
Published: January 2022

OBJECTIVES

This study was performed to determine the clinical and haemodynamic variables associated with early adverse outcomes after the neonatal Norwood procedure.

METHODS

Patients who underwent the neonatal Norwood procedure between 2001 and 2019 were included. The patient diagnosis, morphological characteristics and haemodynamic parameters were analysed to identify factors associated with length of stay (LOS) in the intensive care unit (ICU) and mortality during the stay.

RESULTS

A total of 322 patients were depicted. The median age and weight at the Norwood procedure were 9 days and 3.2 kg, respectively. Certain morphological and preoperative parameters, such as birth weight below 2.5 kg, restrictive atrial septal defect, extracardiac anomalies and the diameter of the ascending aorta, were found to be associated with the LOS in the ICU. Analysis using early postoperative haemodynamic variables revealed that systolic arterial pressure, diastolic arterial pressure, serum lactate levels and reduced ventricular function at 2 days postoperatively were associated with the LOS in the ICU. Birth weight <2.5 kg (P = 0.010), a restrictive atrial septal defect (P = 0.001) and smaller ascending aorta (P = 0.039) were associated with death in the ICU. Reduced ventricular function, lower systolic aortic pressure and higher lactate levels at various time points (P < 0.05) were also associated with ICU deaths. The LOS in the ICU was significantly associated with late mortality (P < 0.001, Hazard Ratio (HR) = 1.015).

CONCLUSIONS

The LOS in the ICU after the Norwood procedure was predicted by early postoperative haemodynamic variables, suggesting that good early postoperative haemodynamics determine early recovery. A prolonged stay in the ICU after the Norwood procedure was associated with late mortality.
The effects of a primary care low-carbohydrate, high-fat dietary educational intervention on laboratory and anthropometric data of patients with chronic disease: a retrospective cohort chart review
Authors: Myshak-Davis Alexandra T , Evans Janet , Howay Heidi , Sakakibara Brodie M
Published: January 2022

Background

Low-carbohydrate and high-fat (LCHF) diets are shown to have health benefits such as weight loss and improved cardiovascular health. Few studies, however, on LCHF diets have been completed in a real-world primary care setting over an extended period of time.

Objectives

To examine the efficacy of a low-carbohydrate, high-fat dietary educational intervention delivered in a family practice setting on weight, body mass index (BMI), blood pressure, glycated haemoglobin (HbA1c), fasting insulin, estimated glomerular filtration rate (eGFR), and albumin to creatinine ratio (ACR). A secondary objective was to determine whether compliance to the program had an effect on outcomes.

Methods

In this retrospective chart review, we collected laboratory and anthropometric data from an electronic medical record system for patients (n = 122) at least 19 years of age, who attended at least 2 LCHF educational sessions between January 2018 and May 2020. Pre-post mean differences of outcome were analysed using paired sample t-tests. Independent sample t-tests examined the effect of compliance on the outcomes.

Results

Statistically significant reductions in weight (3.96 kg [P < 0.001]) and BMI (1.46 kg/m2 [P = 0.001]) were observed. Compared with patients who participated in ≤5 educational visits, patients who participated in >5 visits showed trends towards more clinically significant changes in weight, BMI, systolic blood pressure, diastolic blood pressure, HbA1c, eGFR, and ACR.

Conclusion

Improvements in weight and BMI indicate the utility of providing LCHF health promotion interventions in primary care settings. Greater compliance to LCHF interventions results in greater improvement in laboratory and anthropometric outcomes, including HbA1c.
Evolution of polygenic traits under global vs local adaptation
Authors: Yeaman Sam
Published: January 2022

Observations about the number, frequency, effect size, and genomic distribution of alleles associated with complex traits must be interpreted in light of evolutionary process. These characteristics, which constitute a trait’s genetic architecture, can dramatically affect evolutionary outcomes in applications from agriculture to medicine, and can provide a window into how evolution works. Here, I review theoretical predictions about the evolution of genetic architecture under spatially homogeneous, global adaptation as compared with spatially heterogeneous, local adaptation. Due to the tension between divergent selection and migration, local adaptation can favor “concentrated” genetic architectures that are enriched for alleles of larger effect, clustered in a smaller number of genomic regions, relative to expectations under global adaptation. However, the evolution of such architectures may be limited by many factors, including the genotypic redundancy of the trait, mutation rate, and temporal variability of environment. I review the circumstances in which predictions differ for global vs local adaptation and discuss where progress can be made in testing hypotheses using data from natural populations and lab experiments. As the field of comparative population genomics expands in scope, differences in architecture among traits and species will provide insights into how evolution works, and such differences must be interpreted in light of which kind of selection has been operating.