PS Particles Research Articles

Suppression and azimuthal anisotropy of prompt and nonprompt {mathrm{J}}/psi production in PbPb collisions at sqrt{{s_{_{text {NN}}}}} =2.76,mathrm{TeV}

The nuclear modification factor R_{mathrm{AA}} and the azimuthal anisotropy coefficient v_{2} of prompt and nonprompt (i.e. those from decays of b hadrons) {mathrm{J}}/psi mesons, measured from PbPb and pp collisions at sqrt{{s_{_{text {NN}}}}} =2.76,mathrm{TeV} at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta p_{mathrm{T}} >6.5,{mathrm{GeV}}/{mathrm{c}} and rapidity |{y}|<2.4, extending down to p_{mathrm{T}} =3,{mathrm{GeV}}/{mathrm{c}} in the 1.6<|{y}|<2.4 range. The v_{2} of prompt {mathrm{J}}/psi is found to be nonzero, but with no strong dependence on centrality, rapidity, or p_{mathrm{T}} over the full kinematic range studied. The measured v_{2} of nonprompt {mathrm{J}}/psi is consistent with zero. The R_{mathrm{AA}} of prompt {mathrm{J}}/psi exhibits a suppression that increases from peripheral to central collisions but does not vary strongly as a function of either y or p_{mathrm{T}} in the fiducial range. The nonprompt {mathrm{J}}/psi R_{mathrm{AA}} shows a suppression which becomes stronger as rapidity or p_{mathrm{T}} increases. The v_{2} and R_{mathrm{AA}} of open and hidden charm, and of open charm and beauty, are compared.

Swelling-diffusion-interfacial polymerized core-shell typed polystyrene/poly(3, 4-ethylenedioxythiophene) microspheres and their electro-responsive characteristics

We synthesized core-shell structured conducting polystyrene/poly(3,4-ethylenedioxythiophene) (PS/PEDOT) microspheres and examined their electro-responsive electrorheological (ER) properties under an applied electric field when dispersed in a silicone oil. Monodisperse PS particles 1.05 μm in diameter were initially fabricated via dispersion polymerization, and PS/PEDOT microspheres with average diameters of approximately 1.07 μm were prepared by a swelling-diffusion-interfacial polymerization process. The morphology of the PS/PEDOT microspheres was confirmed by both field emission scanning electron microscopy and transmission electron microscopy, while their chemical structure was characterized by Fourier transform infrared spectroscopy. Formation of particle chains in the ER fluid was directly observed by optical microscopy under an applied electric field. The rheological behavior of the PS/PEDOT particle-based ER fluid was examined using a rotational rheometer on particles dispersed in silicone oil at a volume fraction of 10%. As the electric field was strengthened, the performance of the ER fluid was also enhanced. The dielectric spectra were also well correlated to their ER effects using an LCR meter.

In-situ observation of hydrophobic micron particle impaction on liquid surface

Particle impaction on a droplet surface directly affects the particle capture by the droplet, and this phenomenon is the basic process of wet scrubbing and wet deposition. The experimental system is established to in-situ observe the behavior of micron particles impacting on the liquid surface. 50–200μm hydrophobic PMMA and PS particles were used. The particles showed two types of motion behavior, namely, submergence and oscillation, after impaction onto the liquid surface. During particle sinking, the advancing contact angle remained constant. The shape of the liquid surface met the Young–Laplace equation under the quasi-static assumption. After the angle of the three-phase line reached the critical value, the liquid surface was closed, and the particle submerged. A small bubble formed, adhering to the particle trailing surface. If the particle velocity decreases to zero before the angle of the three-phase lines reaches the critical value, the particle will reverse the direction of its motion. When the particle moves to the horizontal liquid surface, the movement ceases. Reciprocating oscillation behavior was not observed. During particle reversion, the receding contact angle gradually decreased and then remained unchanged. The large contact angle hysteresis is the main cause of failure observation in rebound motion mode in the experiment. The changing rule of the critical submergence/oscillation velocity with the particle diameter and surface tension coefficient was studied. As the particle diameter increases, the critical submergence/oscillation velocity decreases. As the surface tension coefficient increases, the critical submergence/oscillation velocity increases. The observed critical submergence/oscillation velocity in this experiment demonstrated the accuracy of the proposed model.

Preparation of Photoluminescent Porous Silicon Nanoparticles by High‐Pressure Microfluidization

The use of high-shear microfluidization as a rapid, reproducible, and high-yield method to prepare nanoparticles of porous silicon (pSi) with a narrow size distribution is described. Porous films prepared by electrochemical etch of a single-crystal silicon wafer are removed from the substrate, fragmented, dispersed in an aqueous solution, and then processed with a microfluidizer, which generates high yields (57%) of pSi nanoparticles of narrow size distribution (PDI = 0.263) without a filtration step. Preparation of pSi nanoparticles via microfluidization improves yields (by 2.4-fold) and particle size uniformity (by 1.8-fold), and it lowers the total processing time (by 36-fold) over standard ultrasonication or ball milling methods. The average diameter of the nanoparticles can be adjusted over the range 150–350 nm by appropriate adjustment of processing steps. If the fluid carrier in the microfluidizer contains an oxidant for Si, the resulting pSi particles are prepared with a core–shell structure, in which an elemental Si core is encased in a silicon oxide shell. When an aqueous sodium tetraborate processing solution is used, microfluidization generates photoluminescent core–shell pSi particles with a quantum yield of 19% in a single step in less than 20 min.

Fabrication and characterization of core-shell polystyrene/polyaniline/Au composites and their catalytic properties for the reduction of 4-nitrophenol

Herein, polystyrene/polyaniline/Au (PS/PANI/Au) composites were prepared by a novel method using self-made Au(en)2Cl3 as the Au source and were used as the catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Before the preparation of PS/PANI/Au, PS microparticles were sulfonated by the copolymerization between styrene and sodium 4-styrenesulfonate (SSS). Then self-made Au(en)2Cl3 was added and Au(en)23+ species were adsorbed on the surface of sulfonated PS particles due to the electrostatic attraction. The Au(en)23+ was then reduced to Au nanoparticles in situ by aniline monomer. After the polymerization of the residual aniline monomer by ammonium persulfate (APS), the PS/PANI/Au composite catalysts were obtained. The morphology and structure of the as-prepared PS/PANI/Au composites were characterized by TEM, FT-IR, XPS and EDX. Their catalytic performance for the reduction of 4-NP by NaBH4 was evaluated by means of UV–vis spectroscopy. The as-prepared PS/PANI/Au composites are very active for the reduction of 4-NP by virtue of the interaction between Au nanoparticles and PANI shell. The catalytic reaction obeys the pseudo-first-order reaction equations and the reaction rate constants are also calculated in this paper.

On the native/nonnative speaker notion and World Englishes: Debating with K. Rajagopalan

ABSTRACT In a series of three articles published in the Journal of Pragmatics (1995, henceforth JP), the purpose of the papers is to question the division of English spoken in the world into, on one hand, "native" varieties (British English, American English. Australian English) and, on the other, "new/nonnative" varieties (Indian English, Singaporean English, Nigerian English). The JP articles are indeed groundbreaking for they mark one of the first interactions among scholars from the East with researchers in the West with regard to the growth and spread of the language as well as the roles English is made to play by its impressive number of users. The privileged position of prestige and power attributed to the inner circle varieties (USA, UK, Canada, Australia and New Zealand) is questioned. Rajagopalan (1997, motivated by his reading of the JP papers, adds another dimension to this questioning by pointing to the racial and discriminatory stance underlying the notions "native speaker" and "nonnative speaker" (henceforth, respectively NS and NNS). Rajagopalan has written extensively on the issue of nativity or "nativeness"; over the years, Schmitz has also written on the same topic. There appears, in some cases, to be a number of divergent views with regard to subject on hand on the part of both authors. The purpose of this article is to engage in a respectful debate to uncover misreading and possible misunderstanding on the part of Schmitz. Listening to one another and learning from each another are essential in all academic endeavors.

Cumulative effect of hydrophobic PLMA and surface epoxide groups in composite polymer particles on adsorption behavior of congo red and direct red-75

Industrial application of hydrophobic materials is numerous particularly as adsorption beads to remove organic pollutants. In this research combined effect of hydrophobicity and reactive epoxide group on the adsorption behavior of dye molecules by composite polymer particles was investigated. Lauryl methacrylate (LMA) a poor water soluble long chain vinyl monomer is commercially available. Polystyrene/poly(LMA-divinyl benzene) or PS/P(LMA-DVB) composite seed particles were first prepared by slightly modified activated swelling of micron-sized PS seed particles utilizing either water or water-ethanol dispersion medium. The influence of poly(vinyl alcohol) (PVA) as steric stabilizer on the size and size distribution was evaluated. The poor solubility of LMA in the continuous phase hindered the homogeneous swelling of PS particles even in the presence of ethanol (5% w/w) and resulted in fairly polydispersed PS/P(LMA-DVB) composite seed particles. The composite seed particles were then functionalized with epoxide group by seeded polymerization of glycidyl methacrylate (GMA) to produce PS/P(LMA-DVB)/PGMA composite polymer particles. The epoxide functionalized PS/P(LMA-DVB)/PGMA composite polymer particles were used to adsorb two kinds of azo dyes, congo red (CR) and direct red-75 (DR-75). The effects of initial dye concentration at 303 and 323K on adsorption behavior were investigated and the adsorption was explained by adsorption isotherms. Temperature dependent adsorption measurements were also carried out at identical initial dye concentration. The adsorption results showed that inclusion of reactive epoxide group on/near the surface of hydrophobic PS/P(LMA-DVB) composite seed particles improved the adsorption capacity of dye molecules.

Robust fabrication of fluorine-free superhydrophobic steel mesh for efficient oil/water separation

A facile and environmentally friendly method was reported for the fabrication of superhydrophobic steel mesh by depositing with dual-scale Polystyrene@Silica (PS@SiO2) particles coated with hexadecyltrimethoxysilane (HDTMS), which provided 3D multi-scale hierarchical rough surface structure with low surface energy to perform the superhydrophobic effect. PS particles of ~1 μm and ~200 nm were first synthesized via dispersion polymerization and emulsion polymerization, respectively. The obtained PS particles were then used as template for the silification using tetraethyl orthosilicate as the precursor. After treated with HDTMS, the PS@SiO2 particles were deposited on steel mesh forming dual-sized hierarchical structures. The as-prepared film exhibited excellent water repellence with a water contact angle of 161.6° ± 1.1° and water contact angle hysteresis of 3.4°. It also showed efficient and rapid oil/water separation ability and could be repeatedly used for at least 5 times. This facile synthesis strategy for fabricating multifunctional steel mesh provides potential applications in large-scale oil–water separation.

Relating Nanoparticle Shape and Adhesiveness to Performance as Flotation Collectors

Cationic polystyrene-core-poly(n-butyl methacrylate)-shell (PS–PB) nanoparticles perform as flotation collectors as they spontaneously adsorb onto 43 μm glass beads in water, promoting glass bead attachment to air bubbles. Under our flotation conditions at room temperature, polystyrene is a hard plastic, whereas, with glass transition near room temperature, poly(n-butyl methacrylate) is a soft polymer. Colloidal probe atomic force microscopy measurements revealed that the pull-off forces and the work of adhesion of PS–PB nanoparticles to glass were significantly higher than observed with harder PS particles. Glass bead recovery in laboratory flotation experiments increased significantly with thickness of the soft PB shells on the PB–PS core/shell nanoparticles. Ninety-two nm Janus particles consisting of one PS and one PB lobe were also very effective collectors. We propose that high nanoparticle/glass bead adhesion minimizes nanoparticle removal by bead/bead collisions (nanoscale ball milling) during mix...

Examination of ion beam induced damage on polymer surface using Ar clusters

The damage of polymer surfaces caused by the high energy primary ion beams of TOF‐SIMS was examined using Ar cluster ions. Polymer damage, the damage of secondary ions detected from the polystyrene surface and the damage layer formed by the Bi3 primary ion beam have previously been studied. In this study, the damage observed in the secondary ions was studied by using Ar cluster primary ions. The secondary ions were mainly classified into two types, ions reflecting the polystyrene structure and cyclized ions, generated by excessive energy, which are not useful for qualitative analysis. The layer damaged by irradiation of the Bi3 primary ion regarding PS samples was confirmed using Ar cluster sputtering beams. The depth of the layer that has chemical damage in the PS main chain caused by 30 kV Bi3++ (ion dose: 5 × 1012 ions/cm2) irradiation was approximately 50–60 nm. The Ar cluster ion sputter rate in PS decreases with the Bi3 ion irradiation. Micro PS particles that are not able to be detected by a conventional TOF‐SIMS measurement can be effectively analyzed by accumulating the secondary ions over the static limit using Ar cluster sputtering. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Characterization of the sulfonated PEEK/sulfonated nanoparticles composite membrane for the fuel cell application

Emulsion polymerization and post sulfonation methods are used to prepare polystyrene nanoparticles with a uniform size and particle size distribution, and sulfonated poly(etheretherketone) (sPEEK) for the fabrication of composite membranes. The polystyrene particles are functionalized with sulfonation reagents in order to enhance the proton conductivity. This study compares the performance of polymer electrolyte membrane fuel cells with different amounts of sulfonated nanoparticles and sulfonation reaction time of the PEEK polymer. The optimum composition of PS-SO3H particles is determined based on the mechanical properties, the behavior of water in the membrane, and the level of proton conductivity. The composite membrane has higher levels of proton conductivity than the pure sPEEK membrane. An increase in the content of PS particles increases the proton conductivity due to the incorporation of hydrophilic nanoparticles. These properties enable the composite membranes to become candidates for proton exchange membrane fuel cell applications.

Light-induced gradual activation of photosystem II in dark-grown Norway spruce seedlings

Gymnosperms, unlike angiosperms, are able to synthesize chlorophyll and form photosystems in complete darkness. Photosystem I (PSI) formed under such conditions is fully active, but photosystem II (PSII) is present in its latent form with inactive oxygen evolving complex (OEC). In this work we have studied light-induced gradual changes in PSII function in dark-grown cotyledons of Norway spruce (Picea abies) via the measurement of chlorophyll a fluorescence rise, absorption changes at 830nm, thermoluminescence glow curves (TL) and protein analysis. The results indicate that in dark-grown cotyledons, alternative reductants were able to act as electron donors to PSII with inactive OEC. Illumination of cotyledons for 5min led to partial activation of PSII, which was accompanied by detectable oxygen evolution, but still a substantial number of PSII centers remained in the so called PSII-QB-non-reducing form. Interestingly, even 24h long illumination was not sufficient for the full activation of PSII centers. This was evidenced by a weak attachment of PsbP protein and the absence of PsbQ protein in PSII particles, the absence of PSII supercomplexes, the suboptimal maximum yield of PSII photochemistry, the presence of C band in TL curve and also the presence of up-shifted Q band in TL in DCMU-treated cotyledons. This slow light-induced activation of PSII in dark-grown cotyledons could contribute to the prevention of PSII overexcitation before the light-induced increase in PSI/PSII ratio allows effective operation of linear electron flow.

Controlled Release of Dexamethasone From an Intravitreal Delivery System Using Porous Silicon Dioxide

PurposeThe current study aims to evaluate a porous silicon-based drug delivery system meant for sustained delivery of dexamethasone (Dex) to the vitreous and retina.MethodsDexamethasone was grafted covalently into the pore walls of fully oxidized porous silicon particles (pSiO2-COO-Dex), which then was evaluated for the pharmacological effect of the payload on cultured ARPE19 cells before intravitreal injection. The Dex release profile was investigated in a custom designed dynamic dissolution chamber to mimic the turnover of vitreous fluid in rabbit eyes. Ocular safety, in vivo release, and pharmacodynamics were evaluated in rabbit eyes, and the human VEGF-induced rabbit retinal vascular permeability model.ResultsLoading efficiency of Dex was 69 ± 9 μg per 1 mg of the pSiO2-COO-Dex particles. Dynamic in vitro release demonstrated a sustained mode when compared to free Dex, with the drug half-life extended by 5 times. The released Dex was unaltered and biologically active. In vivo drug release in rabbit eyes revealed a mode similar to the release seen in vitro, with a vitreous half-life of 11 days. At 2 and 4 weeks after a single intravitreal injection of pSiO2-COO-Dex particles (mean 2.71 ± 0.47 mg), intravitreal 500 ng of VEGF did not induce significant retinal vessel dilation or fluorescein leakage, while these events were observed in the eyes injected with empty pSiO2 particles or with free Dex. The retinal vessel score from fluorescein angiography for the control eyes was double the score for the eyes injected with pSiO2-COO-Dex. No adverse reaction was observed for the eyes injected with drug-loaded pSi particles during the course of the study.ConclusionsThe porous silicon-based Dex delivery system (pSiO2-COO-Dex) can be administered safely into vitreous without toxicity. Dex release from the porous silicon particles was sustained for 2 months and was effective against VEGF-induced retinal vessel reaction.

Large-Scale Synthesis of Monodisperse Red Blood Cell (RBC)-Like Polymer Particles.

Red blood cell (RBC)-like particles have shown great interest as a model for the understanding of the cell behavior and as promising biomaterials in targeted drug delivery. In this study, a simple and versatile route was proposed for the large-scale synthesis of monodisperse and well-defined RBC-like PS particles using divinylbenzene (DVB) as the cross-linker and ethanol as reaction medium. RBC-like particles were obtained due to the asymmetric shrinkage of a cross-linked network during the phase separation process. An ordered self-assembly monolayer with the concave facing up at the air-water interface was also demonstrated.

Porous Silicon's Photoactivity in Water: Insights into Environmental Fate.

Interest in porous silicon (pSi) (and, more broadly, silicon nanoparticles (NPs)) has increased along with their concomitant use in various commercial and consumer products, yet little is known about their behavior in the natural environment. In this study, we have investigated the photosensitization, optical, and surface properties of pSi as a function of time in aqueous systems. Samples were prepared via an anodic electrochemical etching procedure, resulting in pSi particles with diameters of ca. 500 nm, composed of a porous network of Si nanocrystallites of 2-4 nm. Initially, pSi particles generated significant amounts of (1)O2, yet they rapidly lost much of this ability due to the formation of an oxide layer on the surface, as determined by X-ray photoelectron spectroscopy, which likely prevented further photosensitization events. Addition of natural organic matter (NOM) did not significantly impact pSi's photosensitization abilities. The pSi lacked any intrinsic bactericidal properties on Escherichia coli and did not produce enough (1)O2 to considerably affect populations of a model virus, PR772, highlighting its relatively benign nature toward microbial communities. Results from this study suggest that the photoactivity of pSi is unlikely to persist in aqueous systems and that it may instead behave more similarly to silica particles from an environmental perspective.

TEF30 Interacts with Photosystem II Monomers and Is Involved in the Repair of Photodamaged Photosystem II in Chlamydomonas reinhardtii.

The remarkable capability of photosystem II (PSII) to oxidize water comes along with its vulnerability to oxidative damage. Accordingly, organisms harboring PSII have developed strategies to protect PSII from oxidative damage and to repair damaged PSII. Here, we report on the characterization of the THYLAKOID ENRICHED FRACTION30 (TEF30) protein in Chlamydomonas reinhardtii, which is conserved in the green lineage and induced by high light. Fractionation studies revealed that TEF30 is associated with the stromal side of thylakoid membranes. By using blue native/Deriphat-polyacrylamide gel electrophoresis, sucrose density gradients, and isolated PSII particles, we found TEF30 to quantitatively interact with monomeric PSII complexes. Electron microscopy images revealed significantly reduced thylakoid membrane stacking in TEF30-underexpressing cells when compared with control cells. Biophysical and immunological data point to an impaired PSII repair cycle in TEF30-underexpressing cells and a reduced ability to form PSII supercomplexes after high-light exposure. Taken together, our data suggest potential roles for TEF30 in facilitating the incorporation of a new D1 protein and/or the reintegration of CP43 into repaired PSII monomers, protecting repaired PSII monomers from undergoing repeated repair cycles or facilitating the migration of repaired PSII monomers back to stacked regions for supercomplex reassembly.

Rheology, morphology, and mechanical properties of reactive compatibilized polypropylene/polystyrene blends via Friedel–Crafts alkylation reaction in the presence of clay

Attempts were made to study the effect of reactive compatibilization via Friedel–Crafts alkylation reaction, using AlCl3 as a catalyst, on rheology, morphology, and mechanical properties of polypropylene/polystyrene (PP/PS) blends in the presence of an organoclay (Cloisite 15A). During the reactive compatibilization process, PS showed much more degradation than that of PP in the presence of AlCl3. It was found that the effect of generation of PP‐g‐PS copolymer at the interface of the PP/PS blend dominates the effects of degradation of PS and PP phases, which manifested itself by increased toughness as well as uniform dispersion of the dispersed PS particles in the PP matrix. Generation of PP‐g‐PS copolymer was confirmed by using Fourier‐transform infrared analysis. By using rheological and X‐ray diffraction analyses, it was shown that the clay had higher affinity to PS than that of PP. It was also shown that the clay located at the interface of PP and PS phases, leading to increased relaxation time of the deformed PS dispersed particles, exhibited higher dispersion in PP/PS blend, which resulted in higher ductility of the blend. By using the results of rheological studies, it was concluded that during reactive compatibilization of the blend nanocomposite, the clay migrated into the dispersed PS phase, which was confirmed by scanning electron microscopy analysis. It was demonstrated that the rheological studies have a reliable sensitivity to the clay partitioning and phase morphology of the studied blends and blend nanocomposites. J. VINYL ADDIT. TECHNOL., 24:18–26, 2018. © 2015 Society of Plastics Engineers

Prompt charmonia production and polarization at LHC in the NRQCD with $$k_T$$ k T -factorization. Part I: $$\psi (2S)$$ ψ ( 2 S ) meson

In the framework of kt-factorization approach, the production and polarization of prompt psi(2S) mesons in pp collisions at the LHC energies is studied. Our consideration is based on the non-relativistic QCD formalism for bound states and off-shell amplitudes for hard partonic subprocesses. The transverse momentum dependent (unintegrated) gluon densities in a proton were derived from Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were chosen in accordance with Kimber-Martin-Ryskin prescription. The non-perturbative color-octet matrix elements were first deduced from the fits to the latest CMS data on psi(2S) transverse momentum distributions and then applied to describe the ATLAS and LHCb data on psi(2S) production and polarization at 7 TeV. We perform the estimation of polarization parameters $\lambda_\theta$, $\lambda_\phi$ and $\lambda_{\theta \phi}$ which determine psi(2S) spin density matrix and demonstrate that taking into account the off-shellness of initial gluons in the color-octet contributions leads to unpolarized psi(2S) production at high transverse momenta, that is in qualitative agreement with the LHC data.

A sustained intravitreal drug delivery system with remote real time monitoring capability

Many chorioretinal diseases are chronic and need sustained drug delivery systems to keep therapeutic drug level at the disease site. Many intravitreal drug delivery systems under developing do not have mechanism incorporated for a non-invasive monitoring of drug release. The current study prepared rugate porous silicon (pSi) particles by electrochemical etching with the current frequency (K value) of 2.17 and 2.45. Two model drugs (rapamycin and dexamethasone) and two drug-loading strategies were tested for the feasibility to monitor drug release from the pSi particles through a color fundus camera. The pSi particles (k=2.45) with infiltration loading of rapamycin demonstrated progressively more violet color reflection which was negatively associated with the rapamycin released into the vitreous (r=−0.4, p<0.001, pairwise). In contrast, pSi with K value of 2.17 demonstrated progressive color change toward green and a weak association between rapamycin released into vitreous and green color abundance was identified (r=−0.23, p=0.002, pairwise). Dexamethasone was covalently loaded on to the fully oxidized pSi particles that appeared in vitreous as yellow color and fading over time. The yellow color decrease over time was strongly associated with the dexamethasone detected from the vitreous samples (r=0.7, p<0.0001, pairwise). These results suggest that engineered porous silicon particles may be used as a self-reporting drug delivery system for a non-invasive real time remote monitoring. Statement of SignificanceThe current study, for the first time, demonstrated proof of concept that engineered porous silicon photonic crystal may deliver therapeutics in a controlled fashion while at the same time might offer a noninvasive remote monitoring of its payload release in a living eye. Porous silicon photonic crystal changes color which is in association with its payload release into vitreous. With further optimization, the color change may be harnessed to inform eye care professionals of real time drug concentration in the eye and allow them to make informed decision to re-dose the patients.

Protection and Delivery of Anthelmintic Protein Cry5B to Nematodes Using Mesoporous Silicon Particles.

The ability of nano- and microparticles of partially oxidized mesoporous silicon (pSi) to sequester, protect, and deliver the anthelmintic pore-forming protein Cry5B to nematodes is assessed in vitro and in vivo. Thermally oxidized pSi particles are stable under gastric conditions and show relatively low toxicity to nematodes. Fluorescence images of rhodamine-labeled pSi particles within the nematodes Caenorhabditis elegans and Ancylostoma ceylanicum show that ingestion is dependent on particle size: particles of a 0.4 ± 0.2 μm size are noticeably ingested by both species within 2 h of introduction in vitro, whereas 5 ± 2 μm particles are excluded from C. elegans but enter the pharynx region of A. ceylanicum after 24 h. The anthelmintic protein Cry5B, a pore-forming crystal (Cry) protein derived from Bacillus thuringiensis, is incorporated into the pSi particles by aqueous infiltration. Feeding of Cry5B-loaded pSi particles to C. elegans leads to significant intoxication of the nematode. Protein-loaded particles of size 0.4 μm display the highest level of in vitro toxicity toward C. elegans on a drug-mass basis. The porous nanostructure protects Cry5B from hydrolytic and enzymatic (pepsin) degradation in simulated gastric fluid (pH 1.2) for time periods up to 2 h. In vivo experiments with hookworm-infected hamsters show no significant reduction in worm burden with the Cry5B-loaded particles, which is attributed to slow release of the protein from the particles and/or short residence time of the particles in the duodenum of the animal.