1. Application of reinforcement learning for effective vaccination strategies of coronavirus disease 2019 (COVID-19)

   • Alireza Beigi
   • Amin Yousefpour
   • Hadi Jahanshahi

   Regular Article 31 May 2021 Article: 609

   

2. The magnetic field effect on the improvement of the binding reaction of C-reactive protein at the microfluidic channel surface of an SPR biosensor

   • Yosra Saad
   • Marwa Selmi
   • Hafedh Belmabrouk

   Regular Article 31 May 2021 Article: 608

   

3. Correction to: Seismic glitchness at Sos Enattos site: impact on intermediate black hole binaries detection efficiency

   • A. Allocca
   • A. Berbellini
   • L. Trozzo

   Correction 31 May 2021 Article: 607

4. Correction to: Dynamical analysis and optimal harvesting of conformable fractional prey–predator system with predator immigration

   • R. Kaviya
   • P. Muthukumar

   Correction 31 May 2021 Article: 606

5. Experimental investigation of thermo-physical properties of MgO-MWCNT (75–25%)/10W40 as a new nano-lubricant

   • Mohammad Hemmat Esfe
   • Milad Goodarzi
   • Saeed Esfandeh

   Regular Article 31 May 2021 Article: 605

   

6. Abundant novel wave solutions of nonlinear Klein–Gordon–Zakharov (KGZ) model

   • Mostafa M. A. Khater
   • A. A. Mousa
   • Raghda A. M. Attia

   Regular Article 31 May 2021 Article: 604

   

7. Design of wideband single-layer metamaterial absorber in the S-band and C-band spectrum

   • Hadi Teguh Yudistira
   • Kiki Kananda

   Regular Article 29 May 2021 Article: 603

   

8. Status of direct and indirect solar desalination methods: comprehensive review

   • S. Mohsen Pourkiaei
   • Mohammad Hossein Ahmadi
   • Lingen Chen

   Review 29 May 2021 Article: 602

   

9. Model of boson and fermion particle masses

   • J. W. Moffat

   Regular Article 29 May 2021 Article: 601

10. A conformally flat four-dimensional curved generalization of the two-dimensional Misner space

    • Bidyut Bikash Hazarika

    Regular Article 29 May 2021 Article: 600

    

11. Experimental and numerical investigations of a fixed-bed distributor for obtaining the outlet fluid velocity profile

    • Puriya Mohamad-Gholy-Nejad
    • Mohammad Sadegh Hatamipour

    Regular Article 29 May 2021 Article: 599

    

12. Comparison of variance reduction methods in shielding problems with source multiplication

    • Matteo Falabino
    • Daniele Sciannandrone
    • Laurent Chabert

    Regular Article 29 May 2021 Article: 598

    

13. Enhanced magnetocaloric effect in a mixed spin-(1/2, 1) Ising–Heisenberg two-leg ladder with strong–rung interaction

    • Hamid Arian Zad
    • Nerses Ananikian

    Regular Article 29 May 2021 Article: 597

    

14. The second and third waves in India: when will the pandemic be culminated?

    • C. Kavitha
    • A. Gowrisankar
    • Santo Banerjee

    Letter to the Editor 28 May 2021 Article: 596

    

15. Dynamics and performance evaluation of a self-tuning multistable shape memory energy harvester

    • Wen-An Jiang
    • Xin-Dong Ma
    • Qin-Sheng Bi

    Regular Article 28 May 2021 Article: 595

    

16. The extremes of neutron richness

    • F. Miguel Marqués

    Review 28 May 2021 Article: 594

    

17. Transformation of electrical energy into hydrogen and its storage

    • Manfred Wanner

    Regular Article Open access 28 May 2021 Article: 593

    

18. Hydrothermal synthesis of ultrafine SnO₂ nanospheres: effect of reaction time on physical properties

    • Sahar Khajuee
    • Nafiseh Memarian

    Regular Article 28 May 2021 Article: 592

    

19. Penrose instabilities and the emergence of rogue waves in Sasa–Satsuma equation

    • M. Pradeepa
    • N. Vishnu Priya
    • M. Senthilvelan

    Regular Article 28 May 2021 Article: 591

    

20. Reconstruction method in the kinetic gravity braiding theory with shift-symmetric

    • Ruslan K. Muharlyamov
    • Tatiana N. Pankratyeva

    Regular Article 28 May 2021 Article: 590

    

21. Observation of A_1g mode at the edges of MoS₂ and its applications

    • Siddhartha Dam
    • Abhishek Thakur
    • G. Amarendra

    Regular Article 28 May 2021 Article: 589

    

22. Constantin Carathéodory axiomatic approach and Grigory Perelman thermodynamics for geometric flows and cosmological solitonic solutions

    • Iuliana Bubuianu
    • Sergiu I. Vacaru

    Regular Article 27 May 2021 Article: 588

23. Threshold dynamics of difference equations for SEIR model with nonlinear incidence function and infinite delay

    • Soufiane Bentout
    • Salih Djilali
    • Tarik Mohammed Touaoula

    Regular Article 27 May 2021 Article: 587

    

24. Pattern formations in nonlinear dynamics of hepatitis B virus

    • B. Tamko Mbopda
    • S. Issa
    • H. P. Ekobena Fouda

    Regular Article 27 May 2021 Article: 586

    

25. Thermoelastic wave propagation in a piezoelectric layered half-space within the dual-phase-lag model

    • Ethar A. A. Ahmed
    • A. R. El Dhaba
    • A. F. Ghaleb

    Regular Article 27 May 2021 Article: 585

    

26. Complete noncommutativity in a cosmological model with radiation

    • G. Oliveira-Neto
    • L. Fazza Marcon

    Regular Article 27 May 2021 Article: 584

    

27. Structural, optical, and radiation shielding features for a series of borate glassy system modified by molybdenum oxide

    • Y. S. M. Alajerami
    • Mohamed A. Morsy
    • M. K. A. Karim

    Regular Article 26 May 2021 Article: 583

    

28. Light pressure across all scales: editorial

    • Andrea Macchi
    • Onofrio M. Maragò

    Editorial 26 May 2021 Article: 582

29. A multi-field tachyon-quintom model of dark energy and fate of the universe

    • Muhamad Zahid Mughal
    • Iftikhar Ahmad

    Regular Article 26 May 2021 Article: 581

    

30. Numerical simulation of mixed convection in a lid-driven trapezoidal cavity with flexible bottom wall and filled with a hybrid nanofluid

    • Bader Alshuraiaan
    • Ioan Pop

    Regular Article 26 May 2021 Article: 580

    

31. Tachyon model of Tsallis holographic dark energy

    • Yang Liu

    Regular Article 26 May 2021 Article: 579

    

32. Determination of pH distribution through pH-related properties in deacidified model paper

    • Izabela Vajová
    • Katarína Vizárová
    • Svetozár Katuščák

    Regular Article 25 May 2021 Article: 578

    

33. Changes in blood–brain barrier permeability characterized from electroencephalograms with a combined wavelet and fluctuation analysis

    • A. N. Pavlov
    • A. P. Khorovodov
    • J. Kurths

    Regular Article 25 May 2021 Article: 577

    

34. Environmental effects on structural asymmetry in extragalactic radio sources and quasar/galaxy unification

    • C. I. Onah
    • A. A. Ubachukwu
    • F. C. Odo

    Regular Article 25 May 2021 Article: 576

    

35. \(P-v\) criticality, phase structure and extended thermodynamics of AdS ABG black holes

    • Benoy Kumar Singh
    • Raj Pal Singh
    • Dharm Veer Singh

    Regular Article 24 May 2021 Article: 575

    

36. On transverse progressive waves in Yang–Mills fields

    • Alexander S. Rabinowitch

    Regular Article 24 May 2021 Article: 574

37. A proper surface of section to study a new Hénon–Heiles potential with additional singular gravitational terms

    • Juan F. Navarro

    Regular Article 24 May 2021 Article: 573

    

38. In nonlinear optics, fluid dynamics and plasma physics: symbolic computation on a (2+1)-dimensional extended Calogero–Bogoyavlenskii–Schiff system

    • Yuan Shen
    • Bo Tian
    • Tian-Yu Zhou

    Regular Article 24 May 2021 Article: 572

    

39. Squeezing in the quantum Rabi model with parametric nonlinearity

    • V. Yogesh
    • Prosenjit Maity

    Regular Article 24 May 2021 Article: 571

    

40. A study of warm inflation model inspired by some inhomogeneous dark energy fluids

    • Rabia Saleem
    • Farooq Mehmood

    Regular Article 22 May 2021 Article: 570

    

41. Generalized Einstein–Power Maxwell theory in 2+1-dimensions

    • Z. Amirabi

    Regular Article 22 May 2021 Article: 569

42. Spin-based transport properties of Cs₂WX₆ (X = Cl, Br) ferromagnets for spin-injected thermoelectric current

    • Malak Azmat Ali
    • Rehan Ullah
    • G. Murtaza

    Regular Article 21 May 2021 Article: 568

    

43. Investigation of the structure and radiation shielding properties of borate/Y₂O₃ glasses

    • Z. A. Alrowaili
    • T. A. Taha
    • K. M. A. Saron

    Regular Article 21 May 2021 Article: 567

    

44. Distributions of magnetic field and current in pinching plasma flows: effect of axial magnetic field

    • D. G. Solyakov
    • Yu. Ye. Volkova
    • D. V. Yeliseyev

    Regular Article 20 May 2021 Article: 566

    

45. Probing Szekeres’ colliding sandwich gravitational waves

    • Kamran Qadir Abbasi
    • Ibrar Hussain
    • Asghar Qadir

    Regular Article 20 May 2021 Article: 565

    

46. Measuring entanglement of a rank-2 mixed state prepared on a quantum computer

    • A. R. Kuzmak
    • V. M. Tkachuk

    Regular Article 20 May 2021 Article: 564

    

47. Erratum to: Constraining theories of gravity by GINGER experiment

    • Salvatore Capozziello
    • Carlo Altucci
    • Raffaele Velotta

    Erratum 20 May 2021 Article: 563

48. CO₂ emissions of nuclear power and renewable energies: a statistical analysis of European and global data

    • Friedrich Wagner

    Regular Article Open access 20 May 2021 Article: 562

    

49. Homotopy perturbation and Adomian decomposition methods for modeling the nonplanar structures in a bi-ion ionospheric superthermal plasma

    • S. A. El-Tantawy
    • Shaukat Ali Shan
    • Nasser Bin Turki

    Regular Article 19 May 2021 Article: 561

    

50. Nonlinear interaction underlying flow structure transition of inclined oil–water two-phase countercurrent flow

    • Weikai Ren
    • Ningde Jin

    Regular Article 19 May 2021 Article: 560