Shedding Light on Colorectal Cancer: An In Vivo Raman Spectroscopy Approach Combined with Deep Learning Analysis.

Raman spectroscopy has emerged as a powerful tool in medical, biochemical, and biological research with high specificity, sensitivity, and spatial and temporal resolution. Recent advanced Raman systems, such as portable Raman systems and fiber-optic probes, provide the potential for accurate in vivo discrimination between healthy and cancerous tissues. In our study, a portable Raman probe spectrometer was tested in immunosuppressed mice for the in vivo localization of colorectal cancer malignancies from normal tissue margins. The acquired Raman spectra were preprocessed, and principal component analysis (PCA) was performed to facilitate discrimination between malignant and normal tissues and to highlight their biochemical differences using loading plots. A transfer learning model based on a one-dimensional convolutional neural network (1D-CNN) was employed for the Raman spectra data to assess the classification accuracy of Raman spectra in live animals. The 1D-CNN model yielded an 89.9% accuracy and 91.4% precision in tissue classification. Our results contribute to the field of Raman spectroscopy in cancer diagnosis, highlighting its promising role within clinical applications.

Synthesis, Crystal Structure, and Broadband Emission of (CH3)3SSnCl3.

We report here on the synthesis, crystal structure, optoelectronic and vibrational properties, as well as the DFT calculations of the novel trimethylsulfonium tin trichloride (CH3)3SSnCl3. The air-stable compound is prepared by reacting the (CH3)3SCl and SnCl2 solid precursors in evacuated silica tubes at 100 °C. According to powder X-ray diffraction and Rietveld refinement, it crystallizes at room temperature in the orthorhombic space group Pbca (No. 61) with isolated pyramids of [SnCl3]- and (CH3)3S+ units. UV-vis reflectance and photoluminescence spectroscopies reveal a direct energy band gap of 3.85 eV, accompanied by a broad Stokes-shifted luminescence signal. Photoexcitation of the compound at room temperature and at -196 °C results in broadband luminescence with weak magenta emission centered at 400 nm using an excitation at 250 nm. First principal calculations provide insight into the physical properties through the electron and phonon density of states. Multitemperature Raman spectroscopy and differential scanning calorimetry reveal a reversible phase transition at ca. 70 °C that affects the vibrational modes of the [SnCl3]-. By dissolving (CH3)3SSnCl3 in dimethylformamide in ambient air for a week, oxidation of tin occurs in the "defect" perovskite ((CH3)3S)2SnCl6. The crystal structure of ((CH3)3S)2SnCl6 is also determined with high accuracy via single-crystal X-ray diffraction (cubic space group Pa-3 (No. 205)) and compared with (CH3)3SSnCl3 via Hirshfeld surface analysis.

Trimethylsulfonium Lead Triiodide: An Air-Stable Hybrid Halide Perovskite.

We report on the synthesis, characterization, and optoelectronic properties of the novel trimethylsulfonium lead triiodide perovskite, (CH3)3SPbI3. At room temperature, the air-stable compound adopts a hexagonal crystal structure with a 1D network of face-sharing [PbI6] octahedra along the c axis. UV-vis reflectance spectroscopy on a pressed pellet revealed a band gap of 3.1 eV, in agreement with first-principles calculations, which show a small separation between direct and indirect band gaps. Electrical resistivity measurements on single crystals indicated that the compound behaves as a semiconductor. According to multi-temperature single-crystal X-ray diffraction, synchrotron powder X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry, two fully reversible structural phase transitions occur at -5 and ca. -100 °C with reduction of the unit cell symmetry to monoclinic as temperature decreases. The role of the trimethylsulfonium cation regarding the chemical stability and optoelectronic properties of the new compound is discussed in comparison with APbI3 (A = Cs, methylammonium, and formamidinium cation), which are most commonly used in perovskite solar cells.

Structural Stability, Vibrational Properties, and Photoluminescence in CsSnI3 Perovskite upon the Addition of SnF2.

The CsSnI3 perovskite and the corresponding SnF2-containing material with nominal composition CsSnI2.95F0.05 were synthesized by solid-state reactions and structurally characterized by powder X-ray diffraction. Both materials undergo rapid phase transformation upon exposure to air from the black orthorhombic phase (B-γ-CsSnI3) to the yellow orthorhombic phase (Y-CsSnI3), followed by irreversible oxidation into Cs2SnI6 within several hours. The phase transition occurs at a significantly lower rate in the SnF2-containing material rather than in the pure perovskite. The high hole-carrier concentration of the materials prohibits the detection of Raman signals for B-γ-CsSnI3 and induces a very strong plasmonic reflectance in the far-IR. In contrast, far-IR phonon bands and a rich Raman spectrum are observed for the Y-CsSnI3 modification below 140 cm-1 with weak frequency shift gradients versus temperatures between -95 and +170 °C. Above 170 °C, the signal is lost due to B-α-CsSnI3 re-formation. The photoluminescence spectra exhibit residual blue shifts and broadening as a sign of structural transformation initiation.

Dynamic Stereochemical Activity of the Sn(2+) Lone Pair in Perovskite CsSnBr3.

Stable s(2) lone pair electrons on heavy main-group elements in their lower oxidation states drive a range of important phenomena, such as the emergence of polar ground states in some ferroic materials. Here we study the perovskite halide CsSnBr3 as an embodiment of the broader materials class. We show that lone pair stereochemical activity due to the Sn(2+) s(2) lone pair causes a crystallographically hidden, locally distorted state to appear upon warming, a phenomenon previously referred to as emphanisis. The synchrotron X-ray pair distribution function acquired between 300 and 420 K reveals emerging asymmetry in the nearest-neighbor Sn-Br correlations, consistent with dynamic Sn(2+) off-centering, despite there being no evidence of any deviation from the average cubic structure. Computation based on density functional theory supports the finding of a lattice instability associated with dynamic off-centering of Sn(2+) in its coordination environment. Photoluminescence measurements reveal an unusual blue-shift with increasing temperature, closely linked to the structural evolution. At low temperatures, the structures reflect the influence of octahedral rotation. A continuous transition from an orthorhombic structure (Pnma, no. 62) to a tetragonal structure (P4/mbm, no. 127) is found around 250 K, with a final, first-order transformation at 286 K to the cubic structure (Pm3̅m, no. 221).

Reentrant Structural and Optical Properties and Large Positive Thermal Expansion in Perovskite Formamidinium Lead Iodide.

The structure of the hybrid perovskite HC(NH2 )2 PbI3 (formamidinium lead iodide) reflects competing interactions associated with molecular motion, hydrogen bonding tendencies, thermally activated soft octahedral rotations, and the propensity for the Pb2+ lone pair to express its stereochemistry. High-resolution synchrotron X-ray powder diffraction reveals a continuous transition from the cubic α-phase (Pm3‾ m, #221) to a tetragonal ß-phase (P4/mbm, #127) at around 285 K, followed by a first-order transition to a tetragonal γ-phase (retaining P4/mbm, #127) at 140 K. An unusual reentrant pseudosymmetry in the ß-to-γ phase transition is seen that is also reflected in the photoluminescence. Around room temperature, the coefficient of volumetric thermal expansion is among the largest for any extended crystalline solid.

Co-assembled MoS2-TiO2 Inverse Opal Photocatalysts for Visible Light-Activated Pharmaceutical Photodegradation.

Heterostructured photocatalytic materials in the form of photonic crystals have been attracting attention for their unique light harvesting ability that can be ideally combined with judicious compositional modifications toward the development of visible light-activated (VLA) photonic catalysts, though practical environmental applications, such as the degradation of pharmaceutical emerging contaminants, have been rarely reported. Herein, heterostructured MoS2-TiO2 inverse opal films are introduced as highly active immobilized photocatalysts for the VLA degradation of tetracycline and ciprofloxacin broad-spectrum antibiotics as well as salicylic acid. A single-step co-assembly method was implemented for the challenging incorporation of MoS2 nanosheets into the nanocrystalline inverse opal walls. Compositional tuning and photonic band gap engineering of the MoS2-TiO2 photonic films showed that integration of low amounts of MoS2 nanosheets in the inverse opal framework maintains intact the periodic macropore structure and enhances the available surface area, resulting in efficient VLA antibiotic degradation far beyond the performance of benchmark TiO2 films. The combination of broadband MoS2 visible light absorption and photonic-assisted light trapping together with the enhanced charge separation that enables the generation of reactive oxygen species via firm interfacial coupling between MoS2 nanosheets and TiO2 nanoparticles is concluded as a competent approach for pharmaceutical abatement in water bodies.

Extended Analysis of Raman Spectra Using Artificial Intelligence Techniques for Colorectal Abnormality Classification.

Raman spectroscopy (RS) techniques are attracting attention in the medical field as a promising tool for real-time biochemical analyses. The integration of artificial intelligence (AI) algorithms with RS has greatly enhanced its ability to accurately classify spectral data in vivo. This combination has opened up new possibilities for precise and efficient analysis in medical applications. In this study, healthy and cancerous specimens from 22 patients who underwent open colorectal surgery were collected. By using these spectral data, we investigate an optimal preprocessing pipeline for statistical analysis using AI techniques. This exploration entails proposing preprocessing methods and algorithms to enhance classification outcomes. The research encompasses a thorough ablation study comparing machine learning and deep learning algorithms toward the advancement of the clinical applicability of RS. The results indicate substantial accuracy improvements using techniques like baseline correction, L2 normalization, filtering, and PCA, yielding an overall accuracy enhancement of 15.8%. In comparing various algorithms, machine learning models, such as XGBoost and Random Forest, demonstrate effectiveness in classifying both normal and abnormal tissues. Similarly, deep learning models, such as 1D-Resnet and particularly the 1D-CNN model, exhibit superior performance in classifying abnormal cases. This research contributes valuable insights into the integration of AI in medical diagnostics and expands the potential of RS methods for achieving accurate malignancy classification.

Synthesis, characterization and photocatalytic evaluation of visible light activated C-doped TiO2 nanoparticles.

We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO(2) (C-TiO(2)) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO(2) nanoparticles crystallize in anatase phase despite the low calcination temperature of 350 °C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO(2). Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO(2), whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO(2) nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (λ > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO(2), behavior that is attributed to the incorporation of carbon into the titania lattice.

Magnetic Metal Oxide-Based Photocatalysts with Integrated Silver for Water Treatment.

In this review, the most recent advances in the field of magnetic composite photocatalysts with integrated plasmonic silver (Ag) is presented, with an overview of their synthesis techniques, properties and photocatalytic pollutant removal applications. Magnetic attributes combined with plasmonic properties in these composites result in enhancements for light absorption, charge-pair generation-separation-transfer and photocatalytic efficiency with the additional advantage of their facile magnetic separation from water solutions after treatment, neutralizing the issue of silver's inherent toxicity. A detailed overview of the currently utilized synthesis methods and techniques for the preparation of magnetic silver-integrated composites is presented. Furthermore, an extended critical review of the most recent pollutant removal applications of these composites via green photocatalysis technology is presented. From this survey, the potential of magnetic composites integrated with plasmonic metals is highlighted for light-induced water treatment and purification. Highlights: (1) Perspective of magnetic properties combined with plasmon metal attributes; (2) Overview of recent methods for magnetic silver-integrated composite synthesis; (3) Critical view of recent applications for photocatalytic pollutant removal.

Raman Spectroscopy: A Personalized Decision-Making Tool on Clinicians' Hands for In Situ Cancer Diagnosis and Surgery Guidance.

Accurate in situ diagnosis and optimal surgical removal of a malignancy constitute key elements in reducing cancer-related morbidity and mortality. In surgical oncology, the accurate discrimination between healthy and cancerous tissues is critical for the postoperative care of the patient. Conventional imaging techniques have attempted to serve as adjuvant tools for in situ biopsy and surgery guidance. However, no single imaging modality has been proven sufficient in terms of specificity, sensitivity, multiplexing capacity, spatial and temporal resolution. Moreover, most techniques are unable to provide information regarding the molecular tissue composition. In this review, we highlight the potential of Raman spectroscopy as a spectroscopic technique with high detection sensitivity and spatial resolution for distinguishing healthy from malignant margins in microscopic scale and in real time. A Raman spectrum constitutes an intrinsic "molecular finger-print" of the tissue and any biochemical alteration related to inflammatory or cancerous tissue state is reflected on its Raman spectral fingerprint. Nowadays, advanced Raman systems coupled with modern instrumentation devices and machine learning methods are entering the clinical arena as adjunct tools towards personalized and optimized efficacy in surgical oncology.

Structuring efficient photocatalysts into bespoke fiber shaped systems for applied water treatment.

In this study, structured photocatalytic systems were successfully developed by a facile method based on Alginate molds and a wet-spinning/cross-linking technique, yielding commercial photocatalyst (Degussa P25) in the form of all-ceramic hollow fibers (HFs). Taking advantage of alginate's exceptional sorption properties, copper augmented HFs were also developed. The structured photocatalysts were thoroughly characterised by a variety of techniques, including nitrogen adsorption, SEM/EDS, XRD, XPS and Raman. Synthesis and heat treatment parameters were found to affect the fibers' properties, allowing their optimization. Treatment at 600 °C under Ar was found to produce the best performing photocatalysts in terms mechanical stability, resistance to attrition and photocatalytic performance. Ca-Alginate precursors led to structures with increased mechanical stability, while Cu-Alginate decorated the surface of the photocatalyst with highly dispersed copper nanoparticles, in the state of metallic and CuO. The developed materials were photo-catalytically active, while the copper decorated ceramic HFs exhibited the highest MO adsorption and photocatalytic degradation performance, reaching a MO removal of 73.4%. The synergestic effect of adsorption on the MO degradation performance was also noticed. Moreover, the copper addition facilitated the photocatalytic process by improving the electron-hole separation and inhibiting the recombination effects. The presence of carbon residue was also beneficial, enhancing the MO sorption on the photocatalysts. It is noteworthy that the structured photocatalysts retained their efficiency for at least four photocatalytic cycles. The prepared ceramic HFs exhibited enhanced mechanical properties and excellent resistance to attrition after subsequent cycles, rendering them excellent candidates for application in industrial wastewater processes.

Photocatalysis as an advanced reduction process (ARP): The reduction of 4-nitrophenol using titania nanotubes-ferrite nanocomposites.

TiO2 photocatalysis is an advanced process, employed worldwide for the oxidation of organic compounds, that leads to significant technological applications in the fields of health and environment. The use of the photocatalytic approach in reduction reactions seems very promising and can open new horizons for green chemistry synthesis. For this purpose, titanium dioxide nanotubes (TNTs) were developed in autoclave conditions using TiO2 P25 as a precursor material. Based on these nanotubular substrates, TiO2/CoFe2O4 (TCF) nanocomposites were further obtained by wet impregnation method. The materials were thoroughly characterized and their structural, textural, vibrational, optoelectronic and magnetic properties were determined. The composite materials combine absorbance in the visible optical range and high BET surface area values (˜100 m2/g), showing extremely high yield in the photocatalytic reduction of 4-nitrophenol (4-NP), exceeding 94% within short illumination time (only 35 min). The developed nanocomposites were successfully reused in consecutive photocatalytic experiments and were easily removed from the reaction medium using magnets. Both remarkable recycling ability and high-performance stability in the photocatalytic reduction of nitrophenol were observed, thus justifying the significant economic potential and industrial perspectives for this advanced reduction process.

Copper nanowire coated carbon fibers as efficient substrates for detecting designer drugs using SERS.

Miniature Surface Enhanced Raman Scattering (SERS) sensors were fabricated by coating the carbon fiber microelectrodes with copper nanowires. The coating procedure, based on anodizing the copper wire in ultrapure water followed by cathodic deposition of the anode-derived material onto carbon fiber electrodes, provides a "clean" copper nanowire network. The developed miniature (10µm in diameter and 2mm in length) and nanoscopically rough SERS substrates are applicable in drug sensing, as shown by the detection and resolving of a range of seized designer drugs in trace amounts (microliter volumes of 10-10-10-12M solutions). The copper nanowire modified carbon microfiber substrates could also find further applications in biomedical and environmental sensing.

High performance sulfur, nitrogen and carbon doped mesoporous anatase-brookite TiO2 photocatalyst for the removal of microcystin-LR under visible light irradiation.

Carbon, nitrogen and sulfur (C, N and S) doped mesoporous anatase-brookite nano-heterojunction titania photocatalysts have been synthesized through a simple sol-gel method in the presence of triblock copolymer Pluronic P123. XRD and Raman spectra revealed the formation of anatase and brookite mixed phases. XPS spectra indicated the presence of C, N and S dopants. The TEM images demonstrated the formation of almost monodisperse titania nanoparticles with particle sizes of approximately 10nm. N2 isotherm measurements confirmed that both doped and undoped titania anatase-brookite materials have mesoporous structure. The photocatalytic degradation of the cyanotoxin microcystin-LR (MC-LR) has been investigated using these novel nanomaterials under visible light illumination. The photocatalytic efficiency of the mesoporous titania anatase-brookite photocatalyst dramatically increased with the addition of the C, N and S non-metal, achieving complete degradation (∼ 100 %) of MC-LR. The results demonstrate the advantages of the synthetic approach and the great potential of the visible light activated C, N, and S doped titania photocatalysts for the treatment of organic micropollutants in contaminated waters under visible light.

CO2 captured in zeolitic imidazolate frameworks: Raman spectroscopic analysis of uptake and host-guest interactions.

Zeolitic imidazolate frameworks (ZIFs) exhibit enhanced selectivity and increased CO2 uptake due to the incorporation of functional imidazolate units in their structure as well as their extensive porosity and ring flexibility. In situ Raman investigation of a representative host compound, ZIF-69, in practical CO2 pressure and temperature regimes (0-10 bar and 0-64 °C) correlates well with corresponding macroscopic CO2 sorption data and shows clear clear spectroscopic evidence of CO2 uptake. Significant positive shift of the 159 cm(-1) phenyl bending mode of the benzimidazole moiety indicates weak hydrogen bonding with CO2 in the larger cavities of the ZIF matrix. Raman spectroscopy is shown to be an easy and sensitive tool for quantifying CO2 uptake, identifying weak host-guest interactions and elucidating CO2 sorption mechanism in ZIFs.

Novel Ru(II) sensitizers bearing an unsymmetrical pyridine-quinoline hybrid ligand with extended π-conjugation: synthesis and application in dye-sensitized solar cells.

Heteroleptic ruthenium(II) sensitizers DV42 and DV51, encompassing a novel unsymmetrical pyridine-quinoline hybrid ligand with extended π-conjugation, were synthesized, characterized, and utilized in nanocrystalline dye-sensitized solar cells. Due to the extended conjugation of DV42 and DV51, the absorption of the corresponding sensitized TiO2 films extends into the red spectral range, shifted by 30-40 nm relative to the absorption of TiO2 films sensitized with the standard Z907 ruthenium(II) dye. Contact angle measurements of DV42- and DV51-sensitized TiO2 films suggest that these films are hydrophilic with contact angle values commonly observed upon sensitization with the standard N3 ruthenium(II) dye. Electrochemical studies of the novel ruthenium(II) dyes show that their first oxidation potentials lie well below the I(-)/I3(-) redox potential allowing easy regeneration. The excited-state oxidation potentials of both dyes lie above the TiO2 conduction band, permitting efficient electron injection from the excited dye molecules into the semiconductor conduction band. Liquid electrolyte dye-sensitized solar cells incorporating DV42- or DV51-sensitized TiO2 photoelectrodes afford overall power conversion efficiencies of 3.24 or 4.36% respectively. These efficiencies are up to 56% of the power conversion efficiencies attained by TiO2 photoelectrodes sensitized by the benchmark Z907 ruthenium(II) dye under similar experimental conditions.

Nanostructured titania films sensitized by quantum dot chalcogenides.

The optical and structural properties of cadmium and lead sulfide nanocrystals deposited on mesoporous TiO2 substrates via the successive ionic layer adsorption and reaction method were comparatively investigated by reflectance, transmittance, micro-Raman and photoluminescence measurements. Enhanced interfacial electron transfer is evidenced upon direct growth of both CdS and PbS on TiO2 through the marked quenching of their excitonic emission. The optical absorbance of CdS/TiO2 can be tuned over a narrow spectral range. On the other side PbS/TiO2 exhibits a remarkable band gap tunability extending from the visible to the near infrared range, due to the distinct quantum size effects of PbS quantum dots. However, PbS/TiO2 suffers from severe degradation upon air exposure. Degradation effects are much less pronounced for CdS/TiO2 that is appreciably more stable, though it degrades readily upon visible light illumination.

Influence of pyridine ligand nature and the corresponding ruthenium(II) dye molecular structure on the performance of dye-sensitized solar cells.

cis-[Ru(bpy)(2)(L(n))]Cl(2) (n = 1, L(1) = 4-carboxy-2-(2'-pyridyl)quinoline (); n = 2, L(2) = 2,2'-pyridine-4,4'-dicarboxylic acid ()); and cis-[Ru(bpy)(2)(L')(2))]Cl(2) (L' = 4-pyridinecarboxylic acid ()) complexes, with surface anchoring groups, are prepared from the reaction of cis-[Ru(bpy)(2)Cl(2)] () with the appropriate ligand (L(1), L(2), L'). Ion exchange in aqueous solution with NH(4)PF(6) gives the corresponding bis(hexafluorophosphate) derivatives cis-[Ru(bpy)(2)(L(1))](PF(6))(2) (), cis-[Ru(bpy)(2)(L(2))](PF(6))(2) () and cis-[Ru(bpy)(2)(L')(2)](PF(6))(2) (), respectively. The photo-electrochemical properties of the dyes () are investigated and the efficiency of the corresponding dye sensitized solar cells is compared to a N719 sensitized device, under similar fabrication and testing conditions.