Tiny Difference Research Articles

Analyzing the image quality using a quantitative index for the robotic ultrasound probe maneuver system

This paper presents a quantitative index introduced, ‘clarity,’ which can address both the ultrasound probe's brightness and full contact states to indicate ultrasound image quality for the robotic ultrasound system. Furthermore, it evaluates its performance through an experiment, a comparative analysis, and a questionnaire. The index is calculated based on pixel statistics within the predefined region of interest. Experimental validation is conducted by implementing a robotic ultrasound system and performing experiments using two phantoms. Notably, the Results demonstrate the distinction of the visible difference in ultrasound images but also show that it is hard to classify the tiny difference. Additionally, a questionnaire was carried out to ask about the recognition of good image quality. The opinions are the same trends and patterns. The 53.4 clarity value was determined from the answers as the boundary between good and bad-quality images. The experiment results, and questionnaire findings suggest that the proposed clarity index could be a reliable tool for evaluating ultrasound image quality in robotic systems, offering insights for improving diagnostic accuracy and efficiency. This research provides a clear framework for assessing ultrasound image quality in robotic applications, paving the way for advancements in the efficacy and precision of ultrasound imaging techniques.

In-situ aberration correction for Laguerre-Gaussian optical tweezers via optimization of orbit shape

We introduce a concept of aberration correction under microscopy that is based on observation of circular Brownian motion of an object driven by orbital angular momentum of a Laguerre-Gaussian (LG) beam. Following the concept, we establish an aberration-correction scheme by using a holographic optical tweezers setup equipped with a spatial light modulator that produces the LG beam as well as corrects the light wavefront. The light wavefront is modified adaptively to improve circular symmetry and uniformity of the orbit of a colloidal dielectric sphere revolving in mid-water under the irradiation of the LG beam. We reveal that the proposed scheme is sensitive to tiny phase difference of less than the accuracy of a highest-grade optical flat, 0.05λ, and is applicable to aberrations of up to the first 21 terms of the Zernike series expansion. The scheme not only improves the quality of optical tweezers but also enables to distinguish individual objective lenses assigned a common product code from difference in aberration-correction patterns. The present contribution therefore provides a useful tool for microscopy and laser fabrication in addition to the immediate application to optical trapping.

Simultaneous SERS Sensing of Cysteine and Homocysteine in Blood Based on the CBT-Cys Click Reaction: Toward Precisive Diagnosis of Schizophrenia.

At present, there is a lack of sufficiently specific laboratory diagnostic indicators for schizophrenia. Serum homocysteine (Hcy) levels have been found to be related to schizophrenia. Cysteine (Cys) is a demethylation product in the metabolism of Hcy, and they always coexist with highly similar structures in vivo. There are few reports on the use of Cys as a diagnostic biomarker for schizophrenia in collaboration with Hcy, mainly because the rapid, economical, accurate, and high-throughput simultaneous detection of Cys and Hcy in serum is highly challenging. Herein, a click reaction-based surface-enhanced Raman spectroscopy (SERS) sensor was developed for simultaneous and selective detection of Cys and Hcy. Through the efficient and specific CBT-Cys click reaction between the probe containing cyan benzothiazole and Cys/Hcy, the tiny methylene difference between the molecular structures of Cys and Hcy was converted into the difference between the ring skeletons of the corresponding products that could be identified by plasmonic silver nanoparticle enhanced molecular fingerprint spectroscopy to realize discriminative detection. Furthermore, the SERS sensor was successfully applied to the detection in related patient serum samples, and it was found that the combined analysis of Cys and Hcy can improve the diagnostic accuracy of schizophrenia compared to a single indicator.

Constraints on pseudo-Dirac neutrinos using high-energy neutrinos from NGC 1068

Neutrinos can be pseudo-Dirac in Nature - they can be Majorana fermions while behaving effectively as Dirac fermions. Such scenarios predict active-sterile neutrino oscillations driven by a tiny mass-squared difference (δm2), which is an outcome of soft lepton number violation. Oscillations due to tiny δm2 can only take place over astrophysical baselines and hence are not accessible in terrestrial neutrino oscillation experiments. This implies that high-energy neutrinos coming from large distances can be naturally used to test this scenario. We use the recent observation of high-energy neutrinos from the active galactic nuclei NGC 1068 by the IceCube collaboration to rule out δm2 in the region [1.4×10−18,10−17]eV2 at more than 90% confidence level - one of the strongest limits to date on the values of δm2. We also discuss possible uncertainties which can reduce the sensitivity of these results.

A Relationship between the Molecular Parity-Violation Energy and the Electronic Chirality Measure.

When the weak forces producing parity-violating effects are taken into account, there is a tiny energy difference between the total electronic energies of two enantiomers (ΔEPV), which might be the key to understanding the evolution of the biological homochirality. We focus on the electronic chirality measure (ECM), a powerful descriptor based on the electronic charge density, for quantifying the chirality degree of a molecule, in a representative set of chiral molecules, together with their EPV energies. Our results show a novel, strong, and positive correlation between ΔEPV and ECM, supporting a subtle interplay between the weak forces acting within the nuclei of a given molecule and its chirality. These findings suggest that experimental investigations for molecular parity violation detection should consider molecules with ECM values as large as possible and may support that a chiral signature is imprinted on life by fundamental physics via the parity-violating weak interactions.

Continuous flowing technology for efficient and stable scale‐up production of Pt nanoparticles catalysts in PEMFC

A stable scale-up production strategy is necessary to propel high-performance Pt nanoparticles (NPs) catalysts from academic research to industrial applications. Conventional batch-type reactors scale up the production of Pt NPs catalysts by expanding the volume of the reaction vessel, which induces insufficient reaction control due to the limited heat transfer capacity. It can lead to severe agglomeration of Pt NPs and prevent the original high catalytic activity. Here, the continuous flow technology with efficient heat transfer was demonstrated to possess excellent properties of efficient and stable reaction control, which can effectively avoid agglomeration and stably produce Pt NPs catalysts with Pt NPs of uniform size and homogeneous dispersion on carbon supports at various production scales. The results show that the continuous flow technology enables the reaction slurry to reach the equilibrium temperature with a tiny difference (<1 °C) from the preset temperature within 1 min, reducing the reaction time from 4 h in the batch-type reactor to 10 min. The Pt NPs catalyst synthesized by it achieved a performance of 1.32 W cm−2 at 0.6 V, 1.4 times that of the batch-type reactor. It is an ideal solution to promote the rapid industrial application of high-performance Pt NPs catalysts that conduct laboratory synthesis studies of small amounts by the efficient and convenient continuous flow reactor and then use the same continuous flow reactor to perform efficient and stable scale-up production.

Using video-based examiner score comparison and adjustment (VESCA) to compare the influence of examiners at different sites in a distributed objective structured clinical exam (OSCE)

PurposeEnsuring equivalence of examiners’ judgements within distributed objective structured clinical exams (OSCEs) is key to both fairness and validity but is hampered by lack of cross-over in the performances which different groups of examiners observe. This study develops a novel method called Video-based Examiner Score Comparison and Adjustment (VESCA) using it to compare examiners scoring from different OSCE sites for the first time.Materials/ methodsWithin a summative 16 station OSCE, volunteer students were videoed on each station and all examiners invited to score station-specific comparator videos in addition to usual student scoring. Linkage provided through the video-scores enabled use of Many Facet Rasch Modelling (MFRM) to compare 1/ examiner-cohort and 2/ site effects on students’ scores.ResultsExaminer-cohorts varied by 6.9% in the overall score allocated to students of the same ability. Whilst only a tiny difference was apparent between sites, examiner-cohort variability was greater in one site than the other. Adjusting student scores produced a median change in rank position of 6 places (0.48 deciles), however 26.9% of students changed their rank position by at least 1 decile. By contrast, only 1 student’s pass/fail classification was altered by score adjustment.ConclusionsWhilst comparatively limited examiner participation rates may limit interpretation of score adjustment in this instance, this study demonstrates the feasibility of using VESCA for quality assurance purposes in large scale distributed OSCEs.

Manipulation of Hierarchical Chiral Self-assembly and Anion Recognition by Supramolecular Systems of β-Glucopyranoside, Pillar[5]arenes, and Polyoxometalates.

Hierarchical chiral structures have broad applications in optical devices, asymmetric catalysis, and biological systems. The delicate balance of various interactions are key to the self-assembly of chiral structures. Herein, a ternary co-assembly consisting of cationic pillar[5]arenes (P5As), anionic β-glucopyranoside (βGlcD/βGlcL), and Anderson-type polyoxometalates (POMs) were constructed. Through adjusting the stoichiometry of βGlcD, the assemblies were effectively controlled to form hierarchical nano-leaf assemblies with twisted nanoribbons in a homochiral direction. The co-assemblies exhibit strong Cotton effects, and successfully induced the chirality of Anderson-type POMs. More interestingly, by changing the central metal in Anderson-type POMs (XMo6 O24 3- (X=Cr, Al, and Ga)), even though the three clusters have the same numbers of charge and size, the hierarchical chirality of the related assemblies varied in the morphology of the assemblies and the Cotton effect in the CD spectra. Results in theoretical calculations and ITC titration indicates that the tiny difference in long-range electrostatic interaction would result in the anion recognition of POMs, modulated by βGlcD through host-guest inclusion and hydrogen bonding in the assembly process.

Photon centroids and their subluminal propagation

We examine properties of the energy-density and photon-probability centroids of electromagnetic wavepackets in free space. In the second-order paraxial approximation, both of these centroids propagate with the same subluminal velocity because of the transverse confinement of the wavepacket and its diffraction. The tiny difference between the energy and probability centroid velocities appears only in the fourth order. We consider three types of wavepackets: Gaussian, Bessel, and non-diffracting Bessel. In all these cases, the subluminal propagation is clearly visible in the intensity distributions and can be measured experimentally in both classical-light and single-photon regimes. For Gaussian wavepackets, the half-wavelength delay is accumulated after propagation over about 12 Rayleigh lengths.

A Model for Direct Effect of Graphene on Mechanical Property of Al Matrix Composite

Direct effect of graphene on mechanical property of Al matrix composite has been studied by using molecular dynamic (MD) methods. The models of graphene-reinforced composite are achieved by modeling the sintering system consisting of Al particles and graphene nanosheets (GNSs), while pure Al models are obtained by deleting graphene in the composites. Structural analysis on composites indicate the increment of GNSs can promote the densification of metal matrix, increase the porosity in composite, and restrict the metal grain size. Such analysis is also performed on pure Al models, and the similarity in structure between pure Al and composite models is confirmed by the tiny difference in the nanopores, atomic images, and the number of ordered atoms. Tensile processes on the similar structures with or without graphene reveal that the direct effect of graphene shows an obvious anisotropy, low graphene content may weaken the composite in some directions, while high graphene content can strengthen the composite in more directions. However, the highest content of GNSs just brings a slight increase of 2.7% in tensile strength. The atomic images of crack propagation and the atomic stress confirm that graphene is not efficient in load transfer. Therefore, the direct effect of graphene is believed to play a very small role in strengthening mechanisms.

Engineering the pentapeptide gelation in ethanol by a tiny side-chain difference

Peptide-based gels hold promise for applications in fields ranging from material development to biomedical engineering. However, challenge remains in controlling the assembly of peptides owing to their structure complexity and formation pathways. Here, we report the gelation of four pentapeptides that are slightly different in the side chains of the molecules in ethanol. Results indicated that ECAFF, ECAYF and ECGFF formed ethanol gels, while a transparent solution was obtained by ECGYF. A high storage modulus of ECAFF hydrogel could be up to ∼104 Pa, and such a gel was composed of tightly entangled fiber bundles with more β-sheet secondary structures. We proposed that removing a hydroxyl group from the tyrosine in the pentapeptides enhanced the π-π stacking interactions between the peptides, thus increased the self-assemble tendency into fibrils. In addition, we suggest that a methyl group on the alanine in the peptide sequence play a positively collaborative role in the gelation of peptides compared with glycine. The findings may shed light on devising the peptide gels with desired properties.

Release behavior of fertilizers and heavy metals from iron-loaded sludge biochar in the aqueous environment

In this study, the release behavior of fertilizers (NH4+-N, PO43− and K) and heavy metals (Mn, Zn, Ni, Cu, Pb and Cr) from iron-loaded sludge biochar (ISBC) was investigated to evaluated the feasibility and risks of ISBC as a slow release fertilizer. Their release capacity was significantly enhanced with decreasing initial pH, increasing solid-liquid ratio (RS-L) and rising temperature (p < 0.05). When the initial pH, RS-L and temperature were separately 5 (fertilizers)/1 (heavy metals), 1:5 and 298 K, the final concentrations of NH4+-N, PO43−, K, Mn, Zn and Ni were 6.60, 14.13, 149.4, 53.69, 72.56, and 1.01 mg L−1, while the maximum concentrations of Cu, Pb and Cr were 0.94, 0.77, and 0.22 mg L−1, respectively. Due to the tiny difference between the R2 values, revised pseudo-first-order and pseudo-second-order kinetics models described their release behavior well, suggesting that physical and chemical interactions played an important role. Activation energies greater than 40 kJ mol−1 indicated that the rate-controlling steps of the release of NH4+-N, PO43− and Ni were chemical reactions, while chemical reactions and diffusion together determined the release rates of K, Mn, Zn, Cu, Pb and Cr because their activation energies were in the range of 20–40 kJ mol−1. The increasingly negative ΔG and positive ΔH and ΔS suggested that their release was a spontaneous (except Cr) and endothermic process with an increase of randomness between the solid-liquid interface. The release efficiency of NH4+-N, PO43− and K were in the ranges of 28.21%–53.97%, 2.09%–18.06% and 39.46%–66.14%, respectively. Meanwhile, the pollution index and evaluation index of heavy metals were in the ranges of 33.31–227.4 and 4.64–29.24, respectively. In summary, ISBC could be used as a slow-release fertilizer with low risk when the RS-L was less than 1:40.

"Single Knot-Single Running Suture" Vesicourethral Anastomosis with Posterior Musculofascial Reconstruction during Robot-Assisted Radical Prostatectomy: A Step-by-Step Guide of Surgical Technique.

Background: Our aim is to describe Gallucci's (VV-G) technique for vesicourethral anastomosis and posterior musculofascial reconstruction (PMFR) during robot-assisted radical prostatectomy (RARP) and to assess early urinary continence recovery and perioperative outcomes. VV-G consists of a "single knot-single running suture" vesicourethral anastomosis with PMFR. Methods: Between September 2019 and October 2021, we prospectively compared VV-G vs. conventional Van Velthoven anastomosis (VV-STD) during RARP. We excluded patients with urinary incontinence, pelvic radiotherapy, and urethral and BPH surgery prior to RARP. Social continence (SC) recovery, perioperative complications, and length of hospital stay (LOS) were compared between VV-G vs. VV-STD. SC was defined as 0-1 pad/die. We applied 1:1 propensity score matching (PSM) adjusting for different covariates (age, Charlson Comorbidity Index, BMI, prostate volume, nerve-sparing and lymph node dissection). Results: From 166 patients, 1:1 PSM resulted in two equally sized groups of 40 patients each with no residual differences (all p ≥ 0.2). VV-G yielded higher 3-month SC rates than VV-STD (97.5 vs. 55.0%, p < 0.001). A tiny difference was still recorded at one-year follow-up (97.5 vs. 80.0%, p = 0.029, HR: 2.90, 95% CI: 1.74-4.85, p < 0.001). Conversely, we observed no differences in any perioperative complications (15.0 vs. 22.5%, OR: 0.61, 95% CI 0.19-1.88, p = 0.4) and LOS (3 vs. 4 days, Δ: -0.69 ± 0.61, p = 0.1). Conclusions: VV-G significantly improved early SC recovery without increasing perioperative morbidity. In our opinion, VV-G represents an easy-to-learn and easy-to-teach technique due to its single-suture, single-knot, and symmetrical design.

Parity Violation Energy Difference Calculation of Atropisomers.

Enantiomers have a different energy due to the parity violation effects. Up to now, these effects are difficult to calculate and their final effect on the choice of one enantiomer in the homochirality issue is still a matter of debate. Nevertheless, many scientists support the role of this tiny energy difference in the triggering of homochirality. In this work, we studied the energy difference in atropisomers, a class of stereoisomers in which the chirality is given by the block of rotation around one bond. Atropisomers might have a low energy barrier for the interconversion and this is interesting for the equilibration of the two enantiomers and the choice of the most stable enantiomer. Moreover, structures might be extended like in the case of polymers or crystals having helical framework and thus giving an additive effect on the parity violation energy of the whole structure. The parity violation energy difference here is discussed with the correlation on the general structure of the final molecule giving a qualitative model to predict the sign of local contributions of atoms.

Study on the uneven flow distribution and non-uniform heat transfer in microchannels

The power module is one of the main heating sources with non-uniform heat flux in high-power electrical servo systems used for flight vehicles. Faults in the power module are usually caused by a high or a non-uniform temperature. Given the environment of heat dissipation during flight, a regenerative cooling method is typically used, and the cooling system is designed as a microchannel heat sink with supercritical fuel. This is an effective means of solving thermal problems in the flight vehicles. However, because of the high heating power and non-uniform heat distribution of the power module, it is necessary to optimize its heat sink to restrict the high temperature rise and suppress the non-uniform distribution of temperature. In light of these considerations, a 3D numerical model of the microchannel heat sink of a power module with non-uniform heat flux was established in this study to examine the heat transfer and the thermal performance of the cooling channels. Based on the validation of the mesh and numerical method, the simulations of the flow distributions of the channels were performed to assess the thermal performance of the heat sink. It included investigating the effects of the inlet location of the manifold and its injection angle on the flow distribution in the channels, and the influences of the flow distribution and the operational parameters on the thermal performance of the heat sink. The results revealed that the Z30 configuration provided the best location and injection angle of the inlet to match the non-uniform heat flux of the power module. In this case, the values of Stanton number and buoyancy parameter of channel 4 yielded the minimum values of all channels owing to its higher flow rate and gradual rise in temperature. The deviation in the rate of mass flow Φ changed slightly corresponding to the various operational parameters, only the total heat flux would bring a bigger fluctuation. The tiny difference in temperatures among the observation areas on the substrate verified the positive influence of the flow distribution in matching the non-uniform heat flux.

Tonicity Can Be Expressed in Multiple Ways

We have provided a definition for tonicity 1 to eliminate many issues with the concept 2-4 in physiology education and proposed that there are multiples ways to express tonicity 1 . In this abstract, we prove this hypothesis using logical reasoning. OC 0 (the initial osmotic concentration in a solution compartment (S) before osmosis occurs) 5 is the key term to be used. If person A and B are playing a game and score 12 and 8 points, respectively, there are many ways (narrative or quantitative) to express the result of the game, such as “A won the game,” “B lost the game,” “A earned 4 more points than B,” “B had 4 points less than A,” “12 to 8” or “3 to 2.” Osmosis in an osmosis system (S 1 -m-S 2 ) can be viewed as a water-competing game between OC 0 (S 1 ) and OC 0 (S 2 ) across the membrane (m). If OC 0 (S 1 ) and OC 0 (S 2 ) equal 300 and 250 (mOsm/L), respectively, then the tonicity between S 1 and S 2 can be expressed as “S 1 is hypertonic to S 2 .” This also means that any expressions that mean “S 1 is hypertonic to S 2 ” are alternate ways to express tonicity, including 300:250, 6:5, Δ OC0 = 300 – 250 = 50 (mOsm/L), π (S 1 ): π (S 2 ), and Δ π = π (S 1 ) - π (S 2 ). These multiple expressions are not exclusive. Among these ways, “00:250” is most informative. Just like A and B can only own their points (12 and 8) and the score (12 to 8) can only be owned by the game, as we have addressed previously 1 , S 1 and S 2 own their points (OC 0 (S 1 ) and OC 0 (S 2 )) and the owner of the water-competing game (S 1 -m-S 2 ), not any solution owns tonicity. A tiny difference between the scores of “12:8” and “300:250” or “ Δ π ” is the following: “12:8” shows the result of the game, “300:250” predicts the result of osmosis or “ Δ π ” shows the result of osmosis. In fact, Δ π is the only accurate definition in a list of inconsistent, elusive definitions of tonicity in the literature we presented in a past work 2 . As long as the truth of tonicity is clear, the multiple expressions of it can be developed without confusion. Hence, it is incorrect to refer to “a solution’s tonicity” or “the tonicity of a solution,” as is commonly seen in the literature and causes great confusion 1 .

Experimental investigation on collision characteristics of dual-spray with different physical-chemical fuel properties: A case study of butanol-biodiesel fuel combination

The dual direct injection strategy can flexibly control the reactivity distributions and equivalence ratio, which shows a great potential in realizing clean and efficient combustion. However, the sprays’ collision is inevitable when the fuel sprays are injected into the combustion chamber simultaneously owing to limited in-cylinder space, which is rarely investigated. The investigation aims to explore the atomization and combustion characteristics of collision between biodiesel and butanol sprays at different injection delay times of biodiesel (0, 0.5, 1, 1.5, 2 ms). Experiments are conducted in a constant volume combustion chamber. The collision spray and combustion images are captured by optical diagnosis techniques. Several macroscopic parameters are obtained, including spray behavior, spray area, ignition delay, ignition location, flame behavior, flame lift-off length, and natural luminosity intensity. Results show that the variation of injection delay time can effectively change the spray distribution and realize the concentration stratification. The liquid-phase diffusion region increases with an increased premixed charge of butanol spray, but the total evaporation time has a tiny difference. The sprays’ collision can promote the ignition process, but the ignition location is slightly affected by the injection delay time of biodiesel. A trade-off relationship between the vapor-phase diffusion area and combustion characteristics is found. When the injection delay time exceeds 0.5 ms, a longer injection delay time can lead to a larger vapor-phase area, which causes smaller equivalent ratio, longer flame-off length, and lower luminosity intensity. However, a longer injection delay would lead to an uncomplete combustion of the n-butanol spray. At the experimental cases, the injection delay time of biodiesel should be 1/2–2/3 injection duration to realize complete combustion and small emissions.

An area-efficient sub-10 nW temperature-to-digital converter for thermopile temperature sensors

A 6.29 nW temperature-to-digital converter for IR radiation-based thermopile temperature sensors was designed and fabricated on the chip area of 0.068 mm2 using 90 nm CMOS technology. The sub-mV voltage produced by the sensor is nearly proportional to the temperature difference between the object and the environment and is converted to sub-nA current using the gate-leakage characteristics of PMOS transistors. The ratio of the sub-nA current and the reference current proportional to the sub-mV voltage difference is converted to the frequency ratio of the two current-to-frequency oscillators. Then, the digital output proportional to the tiny voltage difference can be obtained by the counters. After the two-point calibrated digital outputs are mapped to the object temperatures, the average resolution is 0.11 °C with a conversion time of 348 ms, which results in the figure of merit of 0.026 nJ × °C2. The inaccuracy of the object temperature is +0.26/−0.95 °C from −10 °C to 100 °C at the ambient temperature of 25 °C.

Wellness 911

Wellness 911

Light-colored solar-driven PANI/polyacrylonitrile fiber with low-temperature resistance for wearable heater

High-performance photothermal textiles with favorable low-temperature resistance and washing resistance demonstrate obvious superiority and growing demand. However, most photothermal conversion materials show dark color, restricting their color tunability in wearable heating garments. The light-colored solar-driven polyaniline (PANI)/polyacrylonitrile fiber with high low-temperature resistance and washing resistance is fabricated continuously via the wet-spinning method. The temperature of the solar-driven PANI/polyacrylonitrile fiber (0.5 wt%) rises from room temperature (20.00 °C) to 48.12 °C irradiated at 600 W m−2 for 10 min. Even at −30.01 °C, the equilibrium temperature of the solar-driven PANI/polyacrylonitrile fiber is maintained at 25.42 °C, demonstrating its prominent low-temperature resistance. This phenomenon is attributed to the effective and stable light absorption of PANI particles in the Vis-NIR region. The K/S value of the solar-driven PANI/polyacrylonitrile fiber is 0.08 at 700 nm, indicating the color depth is very light. Besides, the tiny temperature difference is observed after being washed 25 times, demonstrating the solar-driven PANI/polyacrylonitrile fiber possesses high washing resistance. The solar-driven PANI/polyacrylonitrile fiber can be easily woven into a bracelet or sewn into the fabric, suggesting a facile fabrication strategy overcoming the constraints of photothermal fiber color is obtained to promote the development of wearable heater.