Exfoliation in a low boiling point solvent and electrochemical applications of MoO₃

• Matangi Sricharan,
• Bikesh Gupta,
• Sreejesh Moolayadukkam and
• H. S. S. Ramakrishna Matte

Beilstein J. Nanotechnol. 2020, 11, 662–670, doi:10.3762/bjnano.11.52

• (AFM; Agilent 5500). Samples for FESEM and AFM were prepared by dripping 10 µL of MoO3 dispersion (diluted 100 times) onto a Si/SiO2 (300 nm) substrate while samples for TEM were prepared by dripping 10 µL of the diluted dispersion on a 300 mesh lacey carbon grid. Raman spectra (Horiba LABRam HR) of

• + in the presence of UV light. This was further confirmed using Raman spectroscopy and UV–vis spectroscopy (Supporting Information File 1, Figure S5). The Raman spectra of bulk and exfoliated MoO3 in 2-butanone, IPA and an IPA/H2O mixture are shown in Figure 2e. Bulk and exfoliated MoO3 in 2-butanone

• has strong Raman peaks at 278, 334, 662, 816 and 992 cm−1, which are in good agreement with orthorhombic α-MoO3, suggesting that the exfoliated MoO3 retained its chemical structure [13]. Additionally, the increase in full width at half maximum (FWHM) from 4 cm−1 (bulk) to 8 cm−1 (exfoliated in 2

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

• Marta Bartel,
• Katarzyna Markowska,
• Marcin Strawski,
• Krystyna Wolska and
• Maciej Mazur

Beilstein J. Nanotechnol. 2020, 11, 620–630, doi:10.3762/bjnano.11.49

• [10][11][12][13][14][15][16][17]. The resulting composites exhibit a double function, they support the metal nanoparticles and prevent their aggregation. For example, polystyrene microspheres have been decorated with silver nanoparticles and were used as catalysts, Raman-enhancing materials

Soybean-derived blue photoluminescent carbon dots

• Shanshan Wang,
• Wei Sun,
• Dong-sheng Yang and
• Fuqian Yang

Beilstein J. Nanotechnol. 2020, 11, 606–619, doi:10.3762/bjnano.11.48

• due to the Raman scattering of the water [35]. The annealed-CDs show no PL under irradiation with UV–vis light. Note that the sharp peaks in Figure 3b represent the Raman scattering of water (solvent) only, indicating that there is no photoluminescence emission from the annealed-CDs under excitation

• at various wavelengths. The Raman scattering of the annealed CDs has a relatively low yield. The Raman peaks can be only observed when the gain or slit bandwidth of the instrument is increased to compensate for the low fluorescence signal. In contrast to the annealed-CDs, the LA-CDs-10%, which are

• peaks in the photoluminescence spectrum are from the water Raman scattering. The broad peaks of the emissions at 418, 422 and 436 nm have much weaker intensities than the water Raman scattering, suggesting that the PL intensity from laser-ablated Teflon is negligible. Thus, both the HTC-CDs and the LA

Adsorptive removal of bulky dye molecules from water with mesoporous polyaniline-derived carbon

• Hyung Jun An,
• Jong Min Park,
• Nazmul Abedin Khan and
• Sung Hwa Jhung

Beilstein J. Nanotechnol. 2020, 11, 597–605, doi:10.3762/bjnano.11.47

• on the enrichment of carbon (or successive removal of heteroatoms such as nitrogen and oxygen) with increasing pyrolysis temperature [42][43]. The best adsorbent (vide infra) KOH-900 was analyzed further with Raman spectroscopy. As shown in Supporting Information File 1, Figure S1, KOH-900 is

Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• field is extremely important is surface-enhanced Raman scattering (SERS), where Raman spectra can be enhanced by several orders of magnitude. However, there are many other areas where it is possible to increase the efficiency of equipment by increasing the electromagnetic field around metal

Nanoarchitectonics: bottom-up creation of functional materials and systems

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2020, 11, 450–452, doi:10.3762/bjnano.11.36

• TiO2 and ZnO nanoparticles exhibit distinct and useful properties [35]. Other examples include a self-assembled MoS2-based composite that was developed for energy conversion and storage purposes [36], a silver-nanoparticle/cellulose-nanofiber composite that was applied for surface-enhanced Raman

Electrochemically derived functionalized graphene for bulk production of hydrogen peroxide

• Munaiah Yeddala,
• Pallavi Thakur,
• Anugraha A and
• Tharangattu N. Narayanan

Beilstein J. Nanotechnol. 2020, 11, 432–442, doi:10.3762/bjnano.11.34

• (see Figure 2a). In order to test the durability of the materials in acidic medium, chronoamperometry studies were carried out in 0.5 M H2SO4 at 0.45 V vs RHE for 3 h. The EEG samples were studied (before and after chronoamperometry) using Raman and FTIR spectroscopy along with the electrochemical

• performance in 0.1 M KOH solution, and the data is given in Figure 5. In Figure 5a, the Raman spectra of EEG before and after 3 h of chronoamperometry are shown, which show no appreciable change in either the peak position or peak intensity. This indicates that no additional defects are created during the

• experiment. The important Raman peaks are marked in the figure and the shoulder peak in “G” is due to the additional single phonon intra-valley scattering process (named as D’) which is due to the presence of defects. However, the FTIR spectrum (see Figure S4b) shows evidence for the formation of OH

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• -enhanced Raman spectroscopy [4]. Ion beam formation of nanoscale ripples has emerged as a versatile method to imprint uniaxial magnetic anisotropy [5] and to control the magnetic texture of thin films [6]. Formation of self-assembled surface nanoripple structures by monoatomic off-normal ion irradiation

An advanced structural characterization of templated meso-macroporous carbon monoliths by small- and wide-angle scattering techniques

• Felix M. Badaczewski,
• Marc O. Loeh,
• Torben Pfaff,
• Dirk Wallacher,
• Daniel Clemens and
• Bernd M. Smarsly

Beilstein J. Nanotechnol. 2020, 11, 310–322, doi:10.3762/bjnano.11.23

• obtained from only the SANS analysis of the empty and DPX-filled samples. Here the non-accessibility (black) is much more pronounced. The available surface area for DPX adsorption is less than 50% for all carbon samples. Microstructural characterization Figure 6 depicts the Raman raw data of the monolithic

• with regard to the relationship between meso- and macroporosity and the sp2-hybridized atomic structure, the latter being determined by the carbon source. Based on porosity analysis (Hg porosimetry and physisorption), small-angle neutron scattering, wide-angle X-ray scattering and Raman spectroscopy we

• (empty samples) (SPhys.,Ar/SSANS,empty). (B) Ratios based only on SANS analysis of the empty and DPX-filled carbon samples (SSANS,filled/SSANS,empty). Raman data, WAXS data and fits (lines) of the WAXS data (open circles). Microstructural parameters describing the size and disorder of graphene-like

Rational design of block copolymer self-assemblies in photodynamic therapy

• Maxime Demazeau,
• Laure Gibot,
• Anne-Françoise Mingotaud,
• Patricia Vicendo,
• Clément Roux and
• Barbara Lonetti

Beilstein J. Nanotechnol. 2020, 11, 180–212, doi:10.3762/bjnano.11.15

Simple synthesis of nanosheets of rGO and nitrogenated rGO

• Pallellappa Chithaiah,
• Madhan Mohan Raju,
• Giridhar U. Kulkarni and
• C. N. R. Rao

Beilstein J. Nanotechnol. 2020, 11, 68–75, doi:10.3762/bjnano.11.7

• ° does not appear indicating that the precursors were directly converted into rGO and N-rGO nanosheets. Figure 2 shows the Raman spectra of the rGO and N-rGO nanosheets. The Raman spectrum of the rGO sample (Figure 2a) shows D, G and 2D band at, respectively, 1362, 1594 and 2880 cm−1. The spectrum of the

• -hybridized carbon atoms in the rGO domains. The 2D-band is the second order of the D-band. The Raman results are consistent with previous reports [5]. Thermogravimetric analysis (TGA) was carried out to investigate the thermal stability of the rGO and N-rGO nanosheets. The study was performed in an oxygen

• and 600 °C as well. The corresponding XRD patterns, Raman spectra and SEM images are given in Figure S1 and Figure S2, respectively, in Supporting Information File 1. In order to understand the supercapacitor behavior of rGO and H-rGO (hydrogen-treated rGO) samples, we have carried out cyclic

Synthesis of amorphous and graphitized porous nitrogen-doped carbon spheres as oxygen reduction reaction catalysts

• Maximilian Wassner,
• Markus Eckardt,
• Andreas Reyer,
• Thomas Diemant,
• Michael S. Elsaesser,
• R. Jürgen Behm and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2020, 11, 1–15, doi:10.3762/bjnano.11.1

• ) and (101) crystal planes of the graphite lattice. All Raman spectra (Figure 6 and Table 3) of the N-doped carbon spheres show two bands at ca. 1350 cm−1 (D band) and ca. 1600 cm−1 (G band). The G band is due to the E2g in-plane vibration mode of the graphite lattice and hence assigned to the sp2

• nitriding temperature, the microporosity increases strongly (Figure 9) and additionally we found a slight increase of the amount of graphenic structures in the catalysts, as indicated by the peak narrowing in the XRD patterns and the decreasing AD/AG ratio in the Raman signals. These structural changes may

• method of Brunauer, Emmett, and Teller in a relative pressure range of p/p0 0.01 to 0.3. The ratio of micropore surface area to external surface area was calculated by the t-plot method (thickness curve: carbon black STSA, fitted thickness range: 0.4–0.6 nm). Raman spectroscopy measurements were

Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

• Jingran Zhang,
• Tianqi Jia,
• Yongda Yan,
• Li Wang,
• Peng Miao,
• Yimin Han,
• Xinming Zhang,
• Guangfeng Shi,
• Yanquan Geng,
• Zhankun Weng,
• Daniel Laipple and
• Zuobin Wang

Beilstein J. Nanotechnol. 2019, 10, 2483–2496, doi:10.3762/bjnano.10.239

• surface-enhanced Raman scattering (SERS) substrates. Recently, in order to obtain a higher enhancement factor at a lower detection limit, hierarchical structures, including nanostructures and nanoparticles, appear to be viable SERS substrate candidates. Here we describe a novel method integrating the

• solution on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multiple Ag nanoparticles on the surface of a plane and with multiple micro/nanostructures are studied with COMSOL software

• sensitive, hierarchical SERS substrate. Keywords: Ag nanoparticles; hierarchical substrates; malachite green molecules; nanoindentation; nanostructures; R6G; SERS; Introduction Surface-enhanced Raman scattering (SERS) has triggered significant research interest due to its suitability as an analytical tool

Semitransparent Sb₂S₃ thin film solar cells by ultrasonic spray pyrolysis for use in solar windows

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Lothar Weinhardt,
• Monika Blum,
• Clemens Heske,
• Wanli Yang,
• Ilona Oja Acik and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 2396–2409, doi:10.3762/bjnano.10.230

• pattern of the vacuum-annealed sample matched orthorhombic Sb2S3 (ICDD PDF 01-075-4012). The Raman spectrum of the as-deposited Sb2S3 layer contains two broad bands (Figure 1e), which are characteristic of amorphous Sb2S3 [28][46]. After vacuum annealing, characteristic narrower bands of Sb2S3 are

• detected, which is an expected result when crystalline Sb2S3 is formed [28][46][49]. No traces of additional phases were detected by either XRD or Raman in any glass/ITO/TiO2/Sb2S3 samples. Chlorine, which could originate from the SbCl3 precursor, was not detected by energy-dispersive X-ray spectroscopy

• phase composition were characterized by XRD (Rigaku Ultima IV, θ-2θ, Cu Kα1 λ = 1.5406 Å, 40 kV, 40 mA, step 0.02°, 5° min−1, Si strip detector D/teX Ultra) and Raman spectroscopy (Horiba Labram HR 800, backscattering mode, ≈143 µW µm−2). The elemental composition of glass/ITO/TiO2/Sb2S3 samples and

Deterministic placement of ultra-bright near-infrared color centers in arrays of silicon carbide micropillars

• Stefania Castelletto,
• Abdul Salam Al Atem,
• Faraz Ahmed Inam,
• Hans Jürgen von Bardeleben,
• Sophie Hameau,
• Ahmed Fahad Almutairi,
• Gérard Guillot,
• Shin-ichiro Sato,
• Alberto Boretti and
• Jean Marie Bluet

Beilstein J. Nanotechnol. 2019, 10, 2383–2395, doi:10.3762/bjnano.10.229

• micro-PL was performed using the Micro-Raman spectrometer LabRAM HR Evolution from HORIBA, equipped with a 785 nm laser. The laser is focused via a 100× 0.9 NA objective on the pillars and on the area with no pillars (gap) at the irradiation depth. The emitted photoluminescence is collected with the

• University. We thank Prof B. Gibson for the access to the laboratories at the ARC Centre of Excellence for Nanoscale Biophotonics. We thank RMIT University Micro Nano Research facility for the use of the Horiba Raman system. S.-I.S. acknowledges JSPS KAKENHI Grant Numbers 17KK0137 and JP18H01483. A.F.A

Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation

• Nadra Bohli,
• Meryem Belkilani,
• Juan Casanova-Chafer,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2019, 10, 2364–2373, doi:10.3762/bjnano.10.227

• attachment of 1-hexadecanethiol on the Au-MWCNT sensor layer. The corresponding S–H stretch vibration mode band is found at 2360 cm−1 [27][28][29][30]. Moreover, other techniques were used for thiol monolayer characterisation. In previous work [31][32], different thiol chains were characterized by Raman

Integration of sharp silicon nitride tips into high-speed SU8 cantilevers in a batch fabrication process

• Nahid Hosseini,
• Matthias Neuenschwander,
• Oliver Peric,
• Santiago H. Andany,
• Jonathan D. Adams and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2019, 10, 2357–2363, doi:10.3762/bjnano.10.226

• ], high-resolution electrochemical and nanoelectrical imaging [7][8], Raman spectroscopy [9], nanoindentation [10], nanomechanical machining [11], plasmonic applications [12][13] and microscale grapping [14]. In parallel with the development of AFM cantilevers made out of traditional materials (e.g

The role of Ag⁺, Ca²⁺, Pb²⁺ and Al³⁺ adions in the SERS turn-on effect of anionic analytes

• Stefania D. Iancu,
• Andrei Stefancu,
• Vlad Moisoiu,
• Loredana F. Leopold and
• Nicolae Leopold

Beilstein J. Nanotechnol. 2019, 10, 2338–2345, doi:10.3762/bjnano.10.224

• -Napoca, Romania 10.3762/bjnano.10.224 Abstract In our recent studies we highlighted the role of adsorbed ions (adions) in turning on the surface-enhanced Raman scattering (SERS) effect in a specific mode for anionic and cationic analytes. In this work, we emphasize the role of Ag+, Ca2+, Pb2+ and Al3

• of higher affinities to the silver surface as indicated by the SERS spectra of corresponding mixed solutions. Keywords: adion-specific adsorption model; cation bridging; Raman; surface enhanced Raman scattering (SERS); Introduction Surface-enhanced Raman scattering (SERS) is an ultrasensitive

• +–halide–organic molecule is formed that allows a charge transfer between the metal surface and the molecule leading to a resonant Raman scattering effect [6][7][8]. Evidence for surface complexes were provided by several SERS experiments on silver electrodes [3][8], but also on colloidal silver

Design and facile synthesis of defect-rich C-MoS₂/rGO nanosheets for enhanced lithium–sulfur battery performance

• Chengxiang Tian,
• Juwei Wu,
• Zheng Ma,
• Bo Li,
• Pengcheng Li,
• Xiaotao Zu and
• Xia Xiang

Beilstein J. Nanotechnol. 2019, 10, 2251–2260, doi:10.3762/bjnano.10.217

• -rays as the excitation source. Raman spectra were collected using a Witec alpha 300M+ instrument with an excitation laser wavelength of 488 nm. Nitrogen adsorption–desorption isotherm measurements were conducted at 77 K using a micromeritics system (JW-BK132F). The contents of amorphous carbon, rGO and

• indicates that the annealing treatment improves the crystallinity of the composites. Figure 4b and Figure S2 (Supporting Information File 1) show the Raman spectra of pristine MoS2, and C-MoS2/rGO, C-MoS2/rGO-6, C-MoS2/rGO-4 and C-MoS2/rGO-8 composites. Two clear peaks at about 378 cm−1 and 404 cm−1 show in

• all curves of MoS2, consistent with the in-plane and out-of-plane A1g vibrations of pristine MoS2, respectively [37]. In addition to these peaks from pristine MoS2, the Raman spectra of C-MoS2/rGO, C-MoS2/rGO-6, C-MoS2/rGO-4 and C-MoS2/rGO-8 exhibit two broad bands at 1363 cm−1 (D-band) and 1587 cm−1

A novel all-fiber-based LiFePO₄/Li₄Ti₅O₁₂ battery with self-standing nanofiber membrane electrodes

• Li-li Chen,
• Hua Yang,
• Mao-xiang Jing,
• Chong Han,
• Fei Chen,
• Xin-yu Hu,
• Wei-yong Yuan,
• Shan-shan Yao and
• Xiang-qian Shen

Beilstein J. Nanotechnol. 2019, 10, 2229–2237, doi:10.3762/bjnano.10.215

• and Li5Ti4O12 fibers in Figure 4 reveals that the active particles are uniformly distributed on the surface of the fibers, in agreement with the SEM images. EDS analysis shows either Fe, C, P, and O or Ti, C, and O on the fibers. The fibers were further examined using XRD and Raman spectroscopy. The

• reductive inert atmosphere. However, TiO2 itself is a relatively stable anode material [42], so the appearance of such impurities would not affect the performance of the electrode. The Raman spectra of the two fiber materials in Figure 6 show two characteristic peaks at 1350 cm−1 and 1580 cm−1 corresponding

• 1; (d) EDS of Li4Ti5O12 at site 2. XRD patterns of LiFePO4 and Li4Ti5O12 fiber membranes. Raman spectra of LiFePO4 and Li4Ti5O12 fiber membranes. CV curves of LiFePO4 and Li4Ti5O12 fiber membrane electrodes. Charge–discharge curves of LiFePO4 and Li4Ti5O12 fiber membrane electrodes. EIS curves of

Microbubbles decorated with dendronized magnetic nanoparticles for biomedical imaging: effective stabilization via fluorous interactions

• Da Shi,
• Justine Wallyn,
• Dinh-Vu Nguyen,
• Francis Perton,
• Delphine Felder-Flesch,
• Sylvie Bégin-Colin,
• Mounir Maaloum and
• Marie Pierre Krafft

Beilstein J. Nanotechnol. 2019, 10, 2103–2115, doi:10.3762/bjnano.10.205

• microscopy (Rmean (optical, µm)), the bubble radius obtained by the acoustical method (Raman (acoustical, µm)) and the determined half-life of the bubbles (t1/2 (h)). Supporting Information Supporting Information File 324: Additional spectra. Acknowledgements The authors acknowledge the European Regional

Green and scalable synthesis of nanocrystalline kuramite

• Andrea Giaccherini,
• Giuseppe Cucinotta,
• Stefano Martinuzzi,
• Enrico Berretti,
• Werner Oberhauser,
• Alessandro Lavacchi,
• Giovanni Orazio Lepore,
• Giordano Montegrossi,
• Maurizio Romanelli,
• Antonio De Luca,
• Massimo Innocenti,
• Vanni Moggi Cecchi,
• Matteo Mannini,
• Antonella Buccianti and
• Francesco Di Benedetto

Beilstein J. Nanotechnol. 2019, 10, 2073–2083, doi:10.3762/bjnano.10.202

• of nanocrystalline kuramite by means of a simpler, greener and scalable solvothermal synthesis. We exploited a multianalytical characterization approach (X-ray diffraction, extended X-ray absorption fine structure, field emission scanning electron microscopy, Raman spectroscopy and electronic

• microscopy (SEM), principal component analysis (PCA) of the wavelength dispersion spectroscopy (WDS) data, X-ray absorption spectroscopy (XAS) and Raman spectroscopy. Materials and Methods Synthesis The reactants necessary for the three syntheses are: CuCl2·2H2O (Merck), ZnCl2 (Merck), SnCl2·2H2O (Riedel-de

• ][55]. Raman spectroscopy was performed with a He–Ne laser source emitting at 632.8 nm with a laser spot on the sample of about 10 μm2. The main reference for the positions of the Raman peaks is from the RRUFF database [56]. XAS measurements at Cu and Sn K-edge (8978.9 and 29200.1 eV, respectively

Review of advanced sensor devices employing nanoarchitectonics concepts

• Katsuhiko Ariga,
• Tatsuyuki Makita,
• Masato Ito,
• Taizo Mori,
• Shun Watanabe and
• Jun Takeya

Beilstein J. Nanotechnol. 2019, 10, 2014–2030, doi:10.3762/bjnano.10.198

• devices. Of course, all important sensor activities cannot be described in this review. For example, sensors based on various advanced physical mechanisms such as plasmonic [194], dielectric sensing [195], surface-enhanced Raman scattering [196], Fabry–Pérot-based intraocular pressure [197], and/or novel

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents

• Natalia E. Gervits,
• Andrey A. Gippius,
• Alexey V. Tkachev,
• Evgeniy I. Demikhov,
• Sergey S. Starchikov,
• Igor S. Lyubutin,
• Alexander L. Vasiliev,
• Vladimir P. Chekhonin,
• Maxim A. Abakumov,
• Alevtina S. Semkina and
• Alexander G. Mazhuga

Beilstein J. Nanotechnol. 2019, 10, 1964–1972, doi:10.3762/bjnano.10.193

• nanoparticles designed for use as MRI contrast media are precisely examined by a variety of methods: powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, Mössbauer spectroscopy and zero-field nuclear magnetic resonance (ZF-NMR) spectroscopy. TEM and XRD measurements reveal

• a spherical shape of the nanoparticles with an average diameter of 5–8 nm and a cubic spinel-type crystal structure of space group Fd−3m. Raman, Mössbauer and NMR spectroscopy clearly indicate the presence of the maghemite γ-Fe2O3 phase. Moreover, a difference in the magnetic behavior of uncoated

• spectroscopy; MRI contrast agents; nanocrystalline materials; NMR spectroscopy; Raman spectroscopy; Introduction Nowadays, magnetic nanoparticles (MNPs) are widely used in biology and medicine. A large number of studies [1][2][3][4] have shown different prospects of their use for sample preparation, in

First principles modeling of pure black phosphorus devices under pressure

• Ximing Rong,
• Zhizhou Yu,
• Zewen Wu,
• Junjun Li,
• Bin Wang and
• Yin Wang

Beilstein J. Nanotechnol. 2019, 10, 1943–1951, doi:10.3762/bjnano.10.190

• orthorhombic semiconductor to a simple cubic metal with increasing pressure by performing in situ ADXRD and Raman spectroscopy with the assistance of a DAC apparatus. They also carried out first principles calculations to interpret the metallic behavior of BP under pressure. Pablo et al. investigated the