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Because of the prevalent time-delay characteristics in real-world phenomena, this paper investigates the existence of mild solutions for diffusion equations with time delays and the Hilfer fractional derivative. This derivative extends the traditional Caputo and Riemann–Liouville fractional derivatives, offering broader practical applications. Initially, we constructed Banach spaces required to handle the time-delay terms. To address the challenge of the unbounded nature of the solution operator at the initial moment, we developed an equivalent continuous operator. Subsequently, within the contexts of both compact and non-compact analytic semigroups, we explored the existence and uniqueness of mild solutions, considering various growth conditions of nonlinear terms. Finally, we presented an example to illustrate our main conclusions.

We primarily investigate the existence of solutions for fractional neutral integro-differential equations with nonlocal initial conditions, which are crucial for understanding natural phenomena. Taking into account factors such as neutral type, fractional-order integrals, and fractional-order derivatives, we employ probability density functions, Laplace transforms, and resolvent operators to formulate a well-defined concept of a mild solution for the specified equation. Following this, by using fixed-point theorems, we establish the existence of mild solutions under more relaxed conditions.

Fractional integrodifferential diffusion equations play a significant role in describing anomalous diffusion phenomena. In this paper, we study the existence and uniqueness of mild solutions to these equations. Firstly, we construct an appropriate resolvent family, through which the related equicontinuity, strong continuity, and compactness properties are studied using the convolution theorem of Laplace transform, the probability density function, the Cauchy integral formula, and the Fubini theorem. Then, we construct a reasonable mild solution for the considered equations. Finally, we obtain some sufficient conditions for the existence and uniqueness of mild solutions to the considered equations by some fixed point theorems.

We obtain a new maximum principle of the periodic solutions when the corresponding impulsive equation is linear. If the nonlinear is quasi-monotonicity, we study the existence of the minimal and maximal periodic mild solutions for impulsive partial differential equations by using the perturbation method, the monotone iterative technique and the method of upper and lower solution. We give an example in last part to illustrate the main theorem.

AIM: To analyze the characteristics of choroidal neovascularization(CNV)in neovascular age-related macular degeneration(nARMD)patients and the outcome of intravitreal anti-vascular endothelial growth factor(VEGF)treatment by using optical coherence tomography angiography(OCTA). METHODS: A prospective cohort study was carried out, which included 37 eyes of 29 patients with nARMD in West China Hospital during May to December 2017. OCTA scans was conducted to all patients before treatment, 1d, 1wk, 1mo and 3-6mo after treatment. The analysis was performed to evaluate the morphological characteristics, lesion area, parafoveal superficial vessel density and perfusion area of CNV before and after treatment. RESULTS: Among all the subjects, immature structure, small branches, and capillaries responded well to anti-VEGF treatment. Compared with the mean lesion area in nARMD patients before treatment(1.27±1.88mm2), there was significant reduction(1.13±1.79 mm2)1d after treatment, which meant CNV lesion decreased 1d after treatment, and stabilized 1mo later(P=0.001). Obvious decrease was observed both in parafoveal superficial vessel density(P=0.003)and perfusion area(P=0.015)3mo after treatment in nARMD patients. CONCLUSION: OCTA, a non-invasive diagnostic examination, clearly identified tiny structures of CNV, quantified the lesion area and displayed specific vasculature in nARMD patients. Furthermore, retinal microcirculation can be detected using OCTA, which provides an effective approach of monitoring the progression and treatment effect of nARMD.

In this paper, a generalized Gronwall inequality is demonstrated, playing an important role in the study of fractional differential equations. In addition, with the fixed-point theorem and the properties of Mittag–Leffler functions, some results of the existence as well as asymptotic stability of square-mean S-asymptotically periodic solutions to a fractional stochastic diffusion equation with fractional Brownian motion are obtained. In the end, an example of numerical simulation is given to illustrate the effectiveness of our theory results.

In this paper, we investigate a class of nonautonomous fractional diffusion equations (NFDEs). Firstly, under the condition of weighted Hölder continuity, the existence and two estimates of classical solutions are obtained by virtue of the properties of the probability density function and the evolution operator family. Secondly, it focuses on the continuity and an estimate of classical solutions in the sense of fractional power norm. The results generalize some existing results on classical solutions and provide theoretical support for the application of NFDE.

In this article, we consider the stability for elliptic problems that have degenerate coercivity in their principal part, $$\displaylines{ -\text{div}\Big(\frac{|\nabla u|^{p-2}\nabla u}{(1+|u|)^{\theta(p-1)}}\Big) +|u|^{q-1}u=f,\quad x\in\Omega, \cr u(x)=0,\quad x\in \partial\Omega, }$$ where $\theta>0$, $\Omega\subseteq \mathbb{R}^N$ is a bounded domain. Let K be a compact subset in $\Omega$ with zero r-capacity ($pr(p-1)[1+\theta(p-1)]/(r-p)$, and $u_n$ is the sequence of solutions of the corresponding problems with datum $f_n$. Then $u_n$ converges to the solution u.

This paper deals with the existence and uniqueness of periodic solutions, S-asymptotically periodic solutions, and other types of bounded solutions for some fractional evolution equations with the Weyl-Liouville fractional derivative defined for periodic functions. Applying Fourier transform we give reasonable definitions of mild solutions. Then we accurately estimate the spectral radius of resolvent operator and obtain some existence and uniqueness results.

Local integral estimates as well as local nonexistence results for a class of quasilinear equations -Δpu=σP(u)+ω for p>1 and Hessian equations Fk-u=σP(u)+ω were established, where σ is a nonnegative locally integrable function or, more generally, a locally finite measure, ω is a positive Radon measure, and P(u)~exp⁡αuβ with α>0 and β≥1 or P(u)=up-1.

We use a monotone iterative method in the presence of lower and upper solutions to discuss the existence and uniqueness of mild solutions for the initial value problem $$displaylines{ u'(t)+Au(t)= f(t,u(t),Tu(t)),quad tin J,; t eq t_k,cr Delta u |_{t=t_k}=I_k(u(t_k)) ,quad k=1,2,dots ,m,cr u(0)=x_0, }$$ where $A:D(A)subset Eo E$ is a closed linear operator and $-A$ generates a strongly continuous semigroup $T(t)(tgeq 0)$ in $E$. Under wide monotonicity conditions and the non-compactness measure condition of the nonlinearity f, we obtain the existence of extremal mild solutions and a unique mild solution between lower and upper solutions requiring only that $-A$ generate a strongly continuous semigroup.

The periodic boundary value problem is discussed for a class of fractional evolution equations. The existence and uniqueness results of mild solutions for the associated linear fractional evolution equations are established, and the spectral radius of resolvent operator is accurately estimated. With the aid of the estimation, the existence and uniqueness results of positive mild solutions are obtained by using the monotone iterative technique. As an application that illustrates the abstract results, an example is given.

We mainly study the fractional evolution equation in an ordered Banach space 𝑋𝐶𝐷𝑎0+𝑢(𝑡)+𝐴𝑢(𝑡)=𝑓(𝑡,𝑢(𝑡),𝐺𝑢(𝑡)) , 1

We investigate the initial value problem for a class of fractional evolution equations in a Banach space. Under some monotone conditions and noncompactness measure conditions of the nonlinearity, the well-known monotone iterative technique is then extended for fractional evolution equations which provides computable monotone sequences that converge to the extremal solutions in a sector generated by upper and lower solutions. An example to illustrate the applications of the main results is given.

Oscillation characteristics in a cavity are investigated under real experimental conditions through unsteady numerical simulations of the time-evolving oscillatory damping of a high-Mach-number freestream over a two-dimensional forward-facing cavity. The post-disturbance flow field is taken as the initial condition. Temporal variations in the flow field and wall resistance coefficient are obtained. The forward-facing cavity experiences underdamped oscillatory behavior when subjected to disturbances. The convergence of the oscillations is influenced by the cavity volume, with significant reductions in cavity damping observed when stagnation regions develop within the cavity. During the initial phase of disturbance, each oscillation cycle consists of gas injection and jet phases. In the former, external gas stagnates within the cavity, resulting in a gradual increase in internal density and pressure. High-temperature regions extend from the external flow into the cavity, and bow shocks approach the cavity wall, adversely affecting aerodynamic drag reduction and thermal protection for aircrafts. In the jet phase, the flow field structure resembles the opposing jet. As the gas is expelled, the internal cavity pressure decreases, forming a cold jet that envelops the cavity's surface. The temperature within the boundary layer on the surface decreases, and bow shocks are pushed away from the wall, resulting in thermal-protection and drag-reduction effects. Transitions between phases induce instability in the internal flow states within the cavity. During the transition from the gas injection phase to the jet phase, the wall drag coefficient reaches its peak value; the reverse transition results in the lowest wall drag coefficient. [ABSTRACT FROM AUTHOR]

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Wireless localization and target sensing both rely on precise extraction of parameters such as signal amplitude, propagation delay, and Doppler shift from the received signals. Due to the high multi-path resolution and strong penetration, both localization and sensing can be achieved through identical UWB waveforms. In this paper, we try to properly allocate resources for localization and sensing to fully exploit the potential of UWB systems. Considering the complexity of the multi-slot networks, we derive the Fisher Information Matrix (FIM) expressions for single-slot and dual-slot integrated sensing and localization (ISAL) networks, respectively, and propose two resource optimization schemes, namely the step-by-stepscheme and the integrated scheme, respectively. The numerical results show that: (i) for the sensing-resource-limited networks with relatively uniform node distribution, the energy allocated to each step in the step-by-step scheme satisfies the relationship energy for clock offset < energy for radar localization < energy for target sensing; (ii) in the multi-slot ISAL networks, more energy will be allocated to the time slots where the networks are relatively sensing-resource-limited; (iii) the step-by-step scheme is more suitable for the sensing-resource-abundant networks, while the integrated scheme is more suitable for the sensing-resource-limited networks. [ABSTRACT FROM AUTHOR]

Location-based service based on wireless cooperative localization networks is becoming ubiquitous nowadays. However, since the fact that most location network nodes are resource-limited, recent investigations focus on the proper network scheduling strategies that can significantly enhance the system performance, including but not limited to localization accuracy and energy efficiency. In addition to the current efficient nondata-aided strategies, we find that some silent nodes, called "eavesdroppers," can be helpful to the localization task without transmitting any signals. In this paper, we first formulate the eavesdropping scheduling policy in practical asynchronous cooperative wireless localization networks. Then, we perform resource optimization in different eavesdropping-based strategies. Both two-slot and multislot strategies are considered, and three types of listening modes are designed from a practical point of view. Numeric results show that, for the scenario with a blocked propagation path, the localization error of networks with dedicated eavesdroppers is only 21% of the conventional networks. Besides, the system with eavesdropping anchors could improve the localization performance by 70%. The result could provide meaningful insights into the practical low-complexity location network deployment and development. [ABSTRACT FROM AUTHOR]

BACKGROUND: To obtain new environmentally friendly fungicides, we used the natural product pimprinine as the lead compound, and designed and synthesized two series of ring‐opening derivatives of pimprinine containing amide/thioamide. We then studied their antifungal activity against six common plant pathogenic fungi in vitro. RESULTS: Most of the target compounds have good antifungal activity against six important plant pathogenic fungi in vitro. At a concentration of 50 μg ml−1, compound 3o showed prominent antifungal effects on Alternaria solani and Rhioctornia solani, with inhibition rates of 91.8% and 97.4%, and a 50% effective concentration (EC50) of 6.2255 and 0.6969 μg ml−1 respectively. The EC50 of compound 3o against Alternaria solani was significantly lower than that of boscalid (13.0380 μg ml−1) and flutriafol (11.9057 μg ml−1). In addition, compound 3o had good antifungal activity against Sclerotinia sclerotiorum, cucumber powdery mildew, cucumber Botrytis cinerea and Phytophthora capsici in vivo; the antifungal activity of compound 3o against cucumber Botrytis cinerea is 91.7%. At the same time, docking results for highly active compound 3o with the presumed target succinate dehydrogenase and the molecular docking prediction scores of all compounds further indicate its possible antifungal activity mechanism. CONCLUSION: The designed and optimized derivative 3o of ring‐opening pimprinine has good antifungal activity and can be used as a new antifungal drug for further research. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Pimprinine and streptochlorin are indole alkaloids derived from marine or soil microorganisms. In our previous study, they were promising lead compounds due to their potent bioactivity in preventing many phytopathogens, but further structural modifications are required to improve their antifungal activity. In this study, pimprinine and streptochlorin were used as parent structures with the combination strategy of their structural features. Three series of target compounds were designed and synthesized. Subsequent evaluation for antifungal activity against six common phytopathogenic fungi showed that some of thee compounds possessed excellent effects, and this is highlighted by compounds 4a and 5a, displaying 99.9% growth inhibition against Gibberella zeae and Alternaria Leaf Spot under 50 μg/mL, respectively. EC50 values indicated that compounds 4a, 5a, 8c, and 8d were even more active than Azoxystrobin and Boscalid. SAR analysis revealed the relationship between 5-(3′-indolyl)oxazole scaffold and antifungal activity, which provides useful insight into the development of new target molecules. Molecular docking models indicate that compound 4a binds with leucyl-tRNA synthetase in a similar mode as AN2690, offering a perspective on the mode of action for the study of its antifungal activity. These results suggest that compounds 4a and 5a could be regarded as novel and promising antifungal agents against phytopathogens due to their valuable potency. [ABSTRACT FROM AUTHOR]

Objective. To compare hysterectomy by transvaginal natural orifice transluminal endoscopic surgery (VNOTES) versus transumbilical laparoscopic single-site surgery (LESS) as a minimal invasive technique. Materials and Method. The women undergoing hysterectomy for benign diseases by VNOTES and LESS from January 2020 to June 2021 in a tertiary hospital in Shanghai were retrospectively analyzed. Results. 361 women were included in our study, with 228 in the VNOTES groups, 129 in the LESS groups, and 4 conversions from VNOTES to LESS technique. The length of a VNOTES hysterectomy was shorter than that of LESS (80.76 min versus 112.09 min; MD -31.34 min; 95% CI -40.24 to -22.43 min; P < 0.001). VNOTES hysterectomy has a quicker gas passage by the anus (18.80 versus 36.49 hours, MD -17.68 hours, 95% CI -20.23 to -15.14 hours, P < 0.001) and associated with a shorter length of hospital stay (2.31 versus 3.77 days, MD -1.46 days, 95% CI -1.75 to -1.17 days, P < 0.001), while with no increase in blood loss during the operation (median 50 versus 50 ml, P = 0.25). Besides, the VAS pain score in the 24th hour after the operation was lower (median 0 versus 0.5, P < 0.001) in the VNOTES group. Four unique phases of the learning curve were identified using cumulative analysis: the mean operation time of phase I was 82.81 ± 31.45 min (the initial learning curve of 43 cases), phase II was 72.48 ± 23.66 min (the acquisition of command of 91 cases), phase III was 103.77 ± 45.69 min (the further learning of 26 cases), and phase IV was 73.18 ± 26.89 min (postlearning in 68 cases). Conclusions. VNOTES is noninferior to LESS as a new minimal invasive procedure for hysterectomy, which also allows patients a faster recovery from surgery and to suffer less pain, and its efficiency and feasibility in large uterine need further exploring. [ABSTRACT FROM AUTHOR]

Abstract Streptococcus pneumoniae causes substantial mortality among children under 5-years-old worldwide. Polysaccharide conjugate vaccines (PCVs) are highly effective at reducing vaccine serotype disease, but emergence of non-vaccine serotypes and persistent nasopharyngeal carriage threaten this success. We investigated the hypothesis that following vaccine, adapted pneumococcal genotypes emerge with the potential for vaccine escape. We genome sequenced 2804 penumococcal isolates, collected 4-8 years after introduction of PCV13 in Blantyre, Malawi. We developed a pipeline to cluster the pneumococcal population based on metabolic core genes into “Metabolic genotypes” (MTs). We show that S. pneumoniae population genetics are characterised by emergence of MTs with distinct virulence and antimicrobial resistance (AMR) profiles. Preliminary in vitro and murine experiments revealed that representative isolates from emerging MTs differed in growth, haemolytic, epithelial infection, and murine colonisation characteristics. Our results suggest that in the context of PCV13 introduction, pneumococcal population dynamics had shifted, a phenomenon that could further undermine vaccine control and promote spread of AMR.

In this study, we present a simple ultraviolet (UV) light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365-nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W and 105, respectively, which were much higher than other ZnO nanostructure-based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices. [ABSTRACT FROM AUTHOR]

The mechanism for the effects of pressure on the magnetic properties and the martensitic transformation of Ni—Mn—Sn shape memory alloys is revealed by first-principles calculations. It is found that the total energy difference between paramagnetic and ferromagnetic austenite states plays an important role in the magnetic transition of Ni—Mn—Sn under pressure. The pressure increases the relative stability of the martensite with respect to the austenite, leading to an increase of the martensitic transformation temperature. Moreover, the effects of pressure on the magnetic properties and the martensitic transformation are discussed based on the electronic structure. [ABSTRACT FROM AUTHOR]