Design of a Soft Sensor Based on Long Short-Term Memory Artificial Neural Network (LSTM) for Wastewater Treatment Plants.

Assessment of wastewater effluent quality in terms of physicochemical and microbial parameters is a difficult task; therefore, an online method which combines the variables and represents a final value as the quality index could be used as a useful management tool for decision makers. However, conventional measurement methods often have limitations, such as time-consuming processes and high associated costs, which hinder efficient and practical monitoring. Therefore, this study presents an approach that underscores the importance of using both short- and long-term memory networks (LSTM) to enhance monitoring capabilities within wastewater treatment plants (WWTPs). The use of LSTM networks for soft sensor design is presented as a promising solution for accurate variable estimation to quantify effluent quality using the total chemical oxygen demand (TCOD) quality index. For the realization of this work, we first generated a dataset that describes the behavior of the activated sludge system in discrete time. Then, we developed a deep LSTM network structure as a basis for formulating the LSTM-based soft sensor model. The results demonstrate that this structure produces high-precision predictions for the concentrations of soluble X1 and solid X2 substrates in the wastewater treatment system. After hyperparameter optimization, the predictive capacity of the proposed model is optimized, with average values of performance metrics, mean square error (MSE), coefficient of determination (R2), and mean absolute percentage error (MAPE), of 23.38, 0.97, and 1.31 for X1, and 9.74, 0.93, and 1.89 for X2, respectively. According to the results, the proposed LSTM-based soft sensor can be a valuable tool for determining effluent quality index in wastewater treatment systems.

An Initial Proteomic Analysis of Biogas-Related Metabolism of Euryarchaeota Consortia in Sediments from the Santiago River, México.

In this paper, sediments from the Santiago River were characterized to look for an alternative source of inoculum for biogas production. A proteomic analysis of methane-processing archaea present in these sediments was carried out. The Euryarchaeota superkingdom of archaea is responsible for methane production and methane assimilation in the environment. The Santiago River is a major river in México with great pollution and exceeded recovery capacity. Its sediments could contain nutrients and the anaerobic conditions for optimal growth of Euryarchaeota consortia. Batch bioreactor experiments were performed, and a proteomic analysis was conducted with current database information. The maximum biogas production was 266 NmL·L-1·g VS-1, with 33.34% of methane, and for proteomics, 3206 proteins were detected from 303 species of 69 genera. Most of them are metabolically versatile members of the genera Methanosarcina and Methanosarcinales, both with 934 and 260 proteins, respectively. These results showed a diverse euryarcheotic species with high potential to methane production. Although related proteins were found and could be feeding this metabolism through the methanol and acetyl-CoA pathways, the quality obtained from the biogas suggests that this metabolism is not the main one in carbon use, possibly the sum of several conditions including growth conditions and the pollution present in these sediments.

Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type on the Dorsal Foot in a Senior Woman: A Case Report.

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT) is a rare variant of the cutaneous B-cell lymphomas, with rapid growth and poor prognosis. Here, we report a case of PCDLBCL-LT on the foot in a senior woman. An 81-year-old woman presented with a rapidly growing mass on her left foot, and discoloration in both lower legs over the past 2 months was analyzed. Physical examination revealed hyperpigmented macules and papules on both lower extremities and a 3.0 × 2.0 × 0.5-cm, gray-dark nodule on the dorsal surface of the left foot. Histologic observation of the punch biopsy specimen revealed a sheet of atypical large centroblast/immunoblast-like lymphocytes; diffusely and evenly distributed in the dermis; with the immunophenotypes of CD45-positive, CD20-positive, Melan A-negative, Sox10-negative, S-100-negative, and CK20-negative; and a very high Ki-67 proliferative index (>90%). Further punch biopsy specimens of papules in the patient's lower extremities and bone marrow did not reveal atypical lymphoid tissues. Positron emission tomography/computed tomography did not show any metastatic lesions in distant organs and lymph nodes. The lesion was diagnosed as PCDLBCL-LT stage T1N0M0. The patient was treated with four cycles of combined therapy of rituximab and cyclophosphamide, hydroxydaunorubicin, vincristine (Oncovin), and prednisolone and the tumor was further treated with local radiotherapy. The tumor size was significantly shrunken. Primary cutaneous diffuse large B-cell lymphoma, leg type is a rare entity on the foot, characterized by a confluent sheet of diffuse large centroblast- and or immunoblast-like B cells with B-cell immunophenotyping. The combined therapy of rituximab and cyclophosphamide, hydroxydaunorubicin, vincristine (Oncovin), and prednisolone is the first-line treatment regimen, with increased survival.

Retrieving the Coassembly Pathway of Composite Cellulose Nanocrystal Photonic Films from their Angular Optical Response.

Aqueous suspensions of cellulose nanocrystals (CNCs) are known to self-assemble into a chiral nematic liquid crystalline phase, leading to solid-state nanostructured colored films upon solvent evaporation, even in the presence of templating agents. The angular optical response of these structures, and therefore their visual appearance, are completely determined by the spatial arrangement of the CNCs when the drying suspension undergoes a transition from a flowing and liquid crystalline state to a kinetically arrested state. Here, it is demonstrated how the angular response of the final film allows for retrieval of key physical properties and the chemical composition of the suspension at the onset of the kinetic arrest, thus capturing a snapshot of the past. To illustrate this methodology, a dynamically evolving sol-gel coassembly process is investigated by adding various amounts of organosilica precursor, namely, 1,2-bis(trimethoxysilyl)ethane. The influence of organosilica condensation on the kinetic arrest can be tracked and thus explains the angular response of the resulting films. The a posteriori and in situ approach is general; it can be applied to a variety of additives in CNC-based films and it allows access to key rheological information of the suspension without using any dedicated rheological technique.

Nanosilver and Nano Zero-Valent Iron Exposure Affects Nutrient Exchange Across the Sediment-Water Interface.

To examine how nanoparticles influence biogeochemical cycles in streams, we studied the acute impact of nanosilver (nAg) and nanoparticulate zero-valent iron (nZVI) exposure on nutrient and oxygen exchange across the sediment-water interface of two streams (agricultural canal and wetland) that differed in their water quality and sediment characteristics. At the agricultural site, nAg increased oxygen consumption and decreased N2 flux rates from that observed in control incubations. nZVI caused sediment-water systems from both streams to go hypoxic within 1.5 h of exposure. N2 flux rates were at least an order of magnitude higher in nZVI treatments as compared to control. Water column nitrate and nitrite concentrations were not impacted by nZVI exposure but total dissolved phosphorus concentrations were higher in cores treated with nZVI. nAg and nZVI exposure to surface water ecosystems can disrupt ecological function across the sediment-water interface.

The development of chiral nematic mesoporous materials.

Cellulose nanocrystals (CNCs) are obtained from the sulfuric acid-catalyzed hydrolysis of bulk cellulose. The nanocrystals have diameters of ~5-15 nm and lengths of ~100-300 nm (depending on the cellulose source and hydrolysis conditions). This lightweight material has mostly been investigated to reinforce composites and polymers because it has remarkable strength that rivals carbon nanotubes. But CNCs have an additional, less explored property: they organize into a chiral nematic (historically referred to as cholesteric) liquid crystal in water. When dried into a thin solid film, the CNCs retain the helicoidal chiral nematic order and assemble into a layered structure where the CNCs have aligned orientation within each layer, and their orientation rotates through the stack with a characteristic pitch (repeating distance). The cholesteric ordering can act as a 1-D photonic structure, selectively reflecting circularly polarized light that has a wavelength nearly matching the pitch. During CNC self-assembly, it is possible to add sol-gel precursors, such as Si(OMe)4, that undergo hydrolysis and condensation as the solvent evaporates, leading to a chiral nematic silica/CNC composite material. Calcination of the material in air destroys the cellulose template, leaving a high surface area mesoporous silica film that has pore diameters of ~3-10 nm. Importantly, the silica is brilliantly iridescent because the pores in its interior replicate the chiral nematic structure. These films may be useful as optical filters, reflectors, and membranes. In this Account, we describe our recent research into mesoporous films with chiral nematic order. Taking advantage of the chiral nematic order and nanoscale of the CNC templates, new functional materials can be prepared. For example, heating the silica/CNC composites under an inert atmosphere followed by removal of the silica leaves highly ordered, mesoporous carbon films that can be used as supercapacitor electrodes. The composition of the mesoporous films can be varied by using assorted organosilica precursors. After removal of the cellulose by acid-catalyzed hydrolysis, highly porous, iridescent organosilica films are obtained. These materials are flexible and offer the ability to tune the chemical and mechanical properties through variation of the organic spacer. Chiral nematic mesoporous silica and organosilica materials, obtainable as centimeter-scale freestanding films, are interesting hosts for nanomaterials. When noble metal nanoparticles are incorporated into the pores, they show strong circular dichroism signals associated with their surface plasmon resonances that arise from dipolar coupling of the particles within the chiral nematic host. Fluorescent conjugated polymers show induced circular dichroism spectra when encapsulated in the chiral nematic host. The porosity, film structure, and optical properties of these materials could enable their use in sensors. We describe the development of chiral nematic mesoporous silica and organosilica, demonstrate different avenues of host-guest chemistry, and identify future directions that exploit the unique combination of properties present in these materials. The examples covered in this Account demonstrate that there is a rich diversity of composite materials accessible using CNC templating.

Iridescent Chiral Nematic Cellulose Nanocrystal/Polymer Composites Assembled in Organic Solvents.

We describe an approach to prepare polymer composites with chiral nematic photonic structures through the self-assembly of cellulose nanocrystal (CNC) dispersions in organic solvents. Contrary to previous reports, we demonstrate that dispersions of neutralized sulfated CNCs in polar organic media readily form lyotropic chiral nematic liquid crystalline phases. We have investigated the effect of the neutralizing base on the CNC self-assembly, observing chiral nematic ordering for all counterions studied. The self-assembly of the organic CNC dispersions can be exploited to prepare iridescent polymeric composites simply by casting the CNC dispersion with a suitable polymer soluble in the organic solvent. Photonic properties of the composite films can be easily controlled by either varying the ratio of CNCs to polymer or adding salts.

Chiral nematic stained glass: controlling the optical properties of nanocrystalline cellulose-templated materials.

Chiral nematic mesoporous materials decorated with metal nanoparticles have been prepared using the templated self-assembly of nanocrystalline cellulose (NCC). By adding small quantities of ionic compounds to aqueous dispersions of NCC and tetramethoxysilane (TMOS), the helical pitch of the chiral nematic structure could be manipulated in a manner complementary to the ratio of NCC/TMOS previously demonstrated by our group. We have studied the transformation of these ion-loaded composites into high surface area mesoporous silica and carbon films decorated with metal nanoparticles through calcination and carbonization, respectively. This general and straightforward approach to prepare chiral nematic metal nanoparticle assemblies may be useful in a variety of applications, particularly for their chiral optical properties.

Inhibition of enzyme activity by nanomaterials: potential mechanisms and implications for nanotoxicity testing.

The objective of this study was to investigate whether nanoparticle-exposure affects enzyme function and to determine the mechanisms responsible. Silicon, Au, and CdSe nanoparticles were synthesized in house and their physicochemical properties were characterized. The activity of purified lactate dehydrogenase (LDH) was inhibited or abolished by all nanoparticles tested. Inhibition was dependent upon particle core and surface-functional group composition. Inhibition of LDH was absent in crude tissue homogenates, in the presence of albumin, and at the isoelectric point of the protein, indicating that nanoparticles bind non-specifically to abundant proteins via a charge interaction. Circular dichroism spectroscopy suggests that the structure of LDH may be altered by nanoparticles in a manner different from that of bulk controls. We present new data on the specific physicochemical properties of nanoparticles that may lead to bioactivity and highlight a number of potentially serious problems with common nanotoxicity testing methods.

Photothermal Response of Photoluminescent Silicon Nanocrystals.

We demonstrate that silicon nanocrystals (Si-NCs) exhibiting relatively high near-IR photoluminescent quantum yields also exhibit a notable photothermal (PT) response. The PT effect has been quantified as a function of NC size, defect concentration, and irradiating energy, suggesting that the origin of the PT response is a combination of carrier thermalization and defect-mediated heating. The PT effect observed under NIR irradiation suggests that Si-NCs could find use in combined in vivo PL imaging and PT therapy.

Size-dependent reactivity in hydrosilylation of silicon nanocrystals.

We present an investigation into the influence of nanocrystal size on the reactivity of silicon nanocrystals (Si-NCs) in near-UV photochemical hydrosilylation. The size-dependent reactivity of Si-NCs with photoluminescence (PL) in the visible and near-infrared regions was evaluated using PL and Fourier-transform infrared (FTIR) spectroscopy, and small-angle X-ray scattering (SAXS). Under near-UV excitation, Si-NCs with PL in the visible spectral region react faster than Si-NCs with near-IR PL, allowing partial separation of a mixture of Si-NC sizes through hydrosilylation. This is attributed to quantum size effects in the exciton-mediated mechanisms proposed for this reaction.

Sol-gel precursors for group 14 nanocrystals.

The synthesis of Group 14 nanocrystals with controlled size dispersity and composition is an area of considerable interest due to their size-dependent optical and electronic properties, thought to enable their use in a wide range of applications such as fluorophores for biological imaging and photovoltaics. In this review, the use of sol-gel derived polymers as precursors for oxide-embedded Group 14 nanocrystals is presented. This versatile approach can yield tangible quantities of both oxide-embedded and freestanding materials with controllable size, narrow size distributions, and tailorable composition.

An investigation into near-UV hydrosilylation of freestanding silicon nanocrystals.

We present a study of the photochemical hydrosilylation of freestanding silicon nanocrystals (Si-NCs) using a near-UV source. The impact of reaction with alkenes and alkynes was studied using in situ photoluminescence (PL) spectroscopy, allowing measurement of both changes in intensity and PL maxima during the reaction. Understanding this behavior is important for the utilization of these materials in a number of applications where hydrosilylation is a leading method to functionalize Si-NCs. Changes in the PL were studied and shown arise from the influence of oxidation as well as the Si-C bond formation. Hydrosilylation with a range of conjugated alkynyl species was studied to understand how the introduction of these species to the NC surface can quench the PL from Si-NCs. These results were explained in context of the free-radical and exciton-mediated mechanisms for photochemical hydrosilylation proposed for Si-NCs. Materials in this study were characterized by Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), selected electron area diffraction (SAED), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA) and dynamic light scattering (DLS).

Coordination polymers from the self-assembly of silver(I) salts and two nonlinear aliphatic dinitrile ligands, cis-1,3-cyclopentanedicarbonitrile and cis-1,3-bis(cyanomethyl)cyclopentane: synthesis, structures, and photoluminescent properties.

Six coordination polymers with aliphatic dinitrile ligands, {[Ag(cpdcn)2]ClO4}n (6a), {[Ag(cpdcn)2]PF6}n (6b), {[Ag(cpdcn)2]SbF6}n (6c, cpdcn = cis-1,3-cyclopentanedicarbonitrile), {[Ag(bcmcp)2] ClO4}n (7a), {[Ag(bcmcp)2]PF6}n (7b), {[Ag(bcmcp)2]SbF6}n, (7c, bcmcp = cis-1,3-bis(cyanomethyl)cyclopentane) have been synthesized and structurally characterized by IR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray crystallography. Both ligands used in this study are meso-compounds; while the ligand cpdcn is structurally rigid, the ligand bcmcp has greater conformational flexibility. X-ray crystallography has revealed that structures 6a-c consist of chiral 1D-polymers. The structure of complexes 7a and 7b are best described as a 2D chiral (4,4) square mesh with 3-fold parallel interpenetration. Surprisingly, complex 7c was characterized to be an achiral 1D coordination polymer. The synthesis of the ligands, IR spectra of the free and coordinated CN groups, DSC and TGA, and the photoluminescent properties of complexes 6a-c and 7a-c are also discussed.

Iron/iron oxide nanoparticle sequestration of catalytic metal impurities from aqueous media and organic reaction products.

A host of transition metal ions (Co2+, Cu2+, Ni2+, RuX+, RhX+, Pd2+, Ag+, and Pt4+) were sequestered from aqueous media upon exposure to FexOy@Fe nanoparticles. Concentrations were lowered from approximately 100 ppm to below 40 ppb. This technique was extended to the removal of catalytic ions from the products of a "Click" cycloaddition and a Heck coupling in organic solvents. Residual metal concentrations in organic reaction products matched or exceeded pharmaceutical standards.