Differences In Peak Intensities Research Articles

Need for complementary techniques for reliable characterization of MoS2-like layers

The observation of characteristic A1g and E2g1 peaks, at around 408 and 382 cm−1, respectively, in Raman spectroscopy is considered the evidence of 2H-structured MoS2, probably the most extensively studied transition-metal dichalcogenide. Here, using a combination of x-ray diffraction, x-ray photoelectron spectroscopy, and resonant Raman spectroscopy, we show that the detection of A1g and E2g1 modes in Raman spectra alone may not necessarily imply the presence of MoS2. A series of Mo–S films, ≈ 20-nm-thick, are grown on single-crystalline Al2O3(0001) substrates at 1073 K as a function of H2S partial pressure, pH2S (= 0, 0.01%, 0.1%, and 1% of total pressure) via ultra-high vacuum dc magnetron sputtering of a Mo target in 20 m Torr (2.67 Pa) Ar/H2S gas mixtures. In pure Ar discharges and with pH2S up to 0.1%, i.e., pH2S ≤ 2.67 × 10−3 Pa, we obtain body centered cubic (bcc), 110-textured films with lattice parameter a increasing from 0.3148 nm (in pure Ar) to 0.3151 nm (at pH2S = 2.67 × 10−4 Pa), and 0.3170 nm (at pH2S = 2.67 × 10−3 Pa), which we attribute to increased incorporation of S in the Mo lattice. With 1% H2S, i.e., pH2S = 2.67 × 10−2 Pa, we obtain 000l oriented 2H-structured MoS2.0±0.1 layers. Raman spectra of the thin films grown using 0.1% (and 1%) H2S show peaks at around 412 (408) and 380 cm−1 (382 cm−1), which could be interpreted as A1g and E2g1 Raman modes for 2H-MoS2. By comparing the Raman spectra of MoS2.0±0.1 and Mo:S thin films, we identify differences in A1g and E2g1 peak positions and intensities of defect-sensitive peaks relative to the A1g peaks that can help distinguish pure MoS2 from non-stoichiometric MoS2−x and multiphase Mo:S materials.

Statistical Framework for Identifying Differences in Similar Mass Spectra: Expanding Possibilities for Isomer Identification.

Isomeric molecules are important analytes in many biological and chemical arenas, yet their similarity poses challenges for many analytical methods, including mass spectrometry (MS). Tandem-MS provides significantly more information about isomers than intact mass analysis, but highly similar fragmentation patterns are common and include cases where no unique m/z peaks are generated between isomeric pairs. However, even in such situations, differences in peak intensity can exist and potentially contain additional information. Herein, we present a framework for comparing mass spectra that differ only in terms of peak intensity and include calculation of a statistical probability that the spectra derive from different analytes. This framework allows for confident identification of peptide isomers by collision-induced dissociation, higher-energy collisional dissociation, electron-transfer dissociation, and radical-directed dissociation. The method successfully identified many types of isomers including various d/l amino acid substitutions, Leu/Ile, and Asp/IsoAsp. The method can accommodate a wide range of changes in instrumental settings including source voltages, isolation widths, and resolution without influencing the analysis. It is shown that quantification of the composition of isomeric mixtures can be enabled with calibration curves, which were found to be highly linear and reproducible. The analysis can be implemented with data collected by either direct infusion or liquid-chromatography MS. Although this framework is presented in the context of isomer characterization, it should also prove useful in many other contexts where similar mass spectra are generated.

Tunning Silver@Gold core@shell incorporated in poly (vinyl alcohol) via laser ablation: Antibacterial activity and cell viability behavior for wound healing

This study aims to bio-modulate Poly (vinyl alcohol) crosslinked by silver and gold nanoparticles fabricated by one-step laser ablation. The optical, cell viability, and antibacterial characterization of the fabricated films have been studied via different techniques. FTIR and XRD were used to investigate the molecular structures of the polymer matrix of Polyvinyl Alcohol incorporating gold and silver (Ag-Au NPs) created by laser ablation. XRD data illustrate the semicrystalline structure of PVA, with two hump peaks at 2θ = 8.52° and 2θ = 20.17° that are decreased when loaded with Ag-Au nanoparticles at different laser ablation times. The FT-IR spectra demonstrated a variation in the intensity of different peaks compared to the spectrum of the Polyvinyl Alcohol. This suggests that PVA and Ag-Au nanoparticles interacted and complexed in semicrystalline areas. The optical energy gap (Eg) reduces from 5.55 eV to 5.00 eV during direct transition and from 4.79 eV to 3.10 eV during indirect transition. The cell viability value for sample S2 was 91.7 ± 5.8%, indicating that both nanocomposites are biocompatible. S2 represents the high values of the inhibition zone, which make it preferred in antibacterial applications. The results demonstrate that Polyvinyl Alcohol/metal composite materials have excellent cell viability and antibacterial properties, implying that they may be suggested in antibacterial utilizations.

Structural Analysis of Phosphorylation Proteoforms in a Dynamic Heterogeneous System Using Flash Oxidation Coupled In-Line with Ion Exchange Chromatography.

Protein posttranslational modifications (PTMs) are key modulators of protein structure and function that often change in a dynamic fashion in response to cellular stimuli. Dynamic PTMs are very challenging to structurally characterize using modern techniques, including covalent labeling methods, due to the presence of multiple proteoforms and conformers together in solution. We have coupled an ion exchange high-performance liquid chromatography separation with a flash oxidation system [ion exchange chromatography liquid chromatography-flash oxidation (IEX LC-FOX)] to successfully elucidate structural changes among three phosphoproteoforms of ovalbumin (OVA) during dephosphorylation with alkaline phosphatase. Real-time dosimetry indicates no difference in the effective radical dose between peaks or across the peak, demonstrating both the lack of scavenging of the NaCl gradient and the lack of a concentration effect on radical dose between peaks of different intensities. The use of IEX LC-FOX allows us to structurally probe into each phosphoproteoform as it elutes from the column, capturing structural data before the dynamics of the system to reintroduce heterogeneity. We found significant differences in the residue-level oxidation between the hydroxyl radical footprint of nonphosphorylated, monophosphorylated, and diphosphorylated OVA. Not only were our data consistent with the previously reported stabilization of OVA structure by phosphorylation, but local structural changes were also consistent with the measured order of dephosphorylation of Ser344 being removed first. These results demonstrate the utility of IEX LC-FOX for measuring the structural effects of PTMs, even in dynamic systems.

Evaluation of roasting and storage conditions as a strategy to improve the sensory characteristics and shelf life of coffee.

Coffee is one of the most consumed products worldwide. Among the varieties of this product, specialty coffee is a type of coffee that has been growing in the world market. This paper aims to assess the effects that the conditions derived from coffee roasting at different altitude levels have on the quality of the product. It was discovered that processing coffee at a higher altitude level yielded a smaller increase in bitterness. This led to a better Specialty Coffee Association (SCA) score in cupping and, consequently, to better preservation of the coffee quality. The storage time affected the aroma by associating roaster aromas with older coffees. Although the assessed origins had the same NIR spectra, differences in peak intensity lead to variations in the flavor and aroma of the coffee. Furthermore, although green beans prolong quality allowing a SCA score of 84.73 ± 2.81 after 4 months of storage, roasted coffee at higher altitudes could also maintain the quality between production and consumption (SCA score of 80.22 ± 0.91 after 2 months). Finally, this research found that the instrumental equipment helped to find minor changes in the sensorial profile, and with these changes correlated with the sensorial panel, the best conditions to preserve coffee quality were found.

Influence of silicon particle morphology on laser-induced plasma properties

In this work, Si particles of varying sizes and a bulk Si wafer are exposed to high-energy nanosecond-pulsed laser excitation. The subsequent laser-induced plasma is characterized using a suite of diagnostic techniques, including spatiotemporal species imaging via high-speed videography and high-resolution gated spectroscopy. The intensity and location of various species in the plasma (e.g., Si I and Si II) are tracked as a function of time over two time regimes, 2–10 μs and 20–80 μs, and show differences in impurities and peak intensities between the various particle sizes and compared to the Si wafer. Electron densities under these conditions decrease from ≈1.8 to 0.8 × 1017 cm−3 from 2 to 8 μs, while plasma excitation temperatures determined from the Boltzmann method range from 9200 to 8000 K over the same time window. The powdered Si samples have characteristically larger and more intense plasmas than the wafer sample. The laser-induced air-shock from energetic materials (LASEM) method was employed on these materials, in concert with their acoustic response, to establish their relative microsecond energy releases. While the powders have similar laser-induced shock velocities, they appear to have differences in their acoustic response which roughly scales as a function of plasma carbon content. The proposed reasons for these shock and acoustic trends are discussed, which include particle size and morphology, surface impurities, and dispersion and flow within the plasma.

Synchrotron Fourier-Transform Infrared Microspectroscopy: Characterization of in vitro polarized tumor-associated macrophages stimulated by the secretome of inflammatory and non-inflammatory breast cancer cells

Studies suggested that the pathogenesis of inflammatory breast cancer (IBC) is related to inflammatory manifestations accompanied by specific cellular and molecular mechanisms in the IBC tumor microenvironment (TME). IBC is characterized by significantly higher infiltration of tumor-associated macrophages (TAMs) that contribute to its metastatic process via secreting many cytokines such as TNF, IL-6, IL-8, and IL-10 that enhance invasion and angiogenesis. Thus, there is a need to first understand how IBC-TME modulates the polarization of TAMs to better understand the role of TAMs in IBC. Herein, we used gene expression signature and Synchrotron Fourier-Transform Infrared Microspectroscopy (SR-μFTIR) to study the molecular and biochemical changes, respectively of in vitro polarized TAMs stimulated by the secretome of IBC and non-IBC cells. The gene expression signature showed significant differences in the macrophage's polarization-related genes between stimulated TAMs. FTIR spectra showed absorption bands in the region of 1700–1500 cm−1 attributed to the amide I ν(C=O), & νAS (CN), δ (NH), and amide II ν(CN), δ (NH) proteins bands. Moreover, three peaks of different intensities and areas were detected in the lipid region of the νCH2 and νCH3 stretching modes positioned within the 3000–2800 cm−1 range. The PCA analysis for the second derivative spectra of the amide regions discriminates between stimulated IBC and non-IBC TAMs. This study showed that IBC and non-IBC TMEs differentially modulate the polarization of TAMs and SR-μFTIR can determine these biochemical changes which will help to better understand the potential role of TAMs in IBC.

Analysis of indole and indazole amides synthetic cannabinoids by differential Raman spectroscopy based on ANN.

A simple, rapid, accurate, and non-destructive method was developed for the determination of cannabinoids, combining principal component analysis and multi-layer perceptron neural network to classify indole and indazole amide synthetic cannabinoids. Under the experimental conditions of this study, 25 experimental samples were successfully classified into two categories as the final classification, which guaranteed 96% correct rate. First, the samples were manually classified and divided into two categories according to the difference in peak position and peak intensity of the differential Raman characteristic peaks at 650-540 cm-1 , etc. Fisher's discriminant method (FDA) and principal component analysis (PCA) were used to analyze the experimental data. Fisher's discriminant analysis was used to formulate two classification functions to discriminate the results of manual classification, and the overall accuracy rate of classification reached 88%. Principal component analysis was used to reduce the dimensionality of the data, which could reduce the influence of redundant data on the experimental results. The original data, FDA-processed data and PCA-processed data, and artificial neural network algorithm (ANN-MLP/RBF) were combined to build a classification model. In the MLP model, the classification accuracy of the original data, FDA-processed data, and PCA-processed data was 80%, 92%, and 96% respectively, and the overall accuracy of the sample classification was 89.33%. In the RBF model, the accuracy of sample classification was 76%, 84%, and 92% respectively, and the overall accuracy of sample classification was 84%. Differential Raman spectroscopy could be used to distinguish 25 kinds of synthetic cannabinoids, and finally, the samples were divided into two categories. The PCA + MLP model was the best for processing spectral data. Based on the perspective of multivariate data, this study demonstrated that the method could be used for rapid and non-destructive testing of indole and indazole amide synthetic cannabinoids and that an efficient and non-destructive classification model was obtained. This method could be used for rapid detection and inspection of drugs in the field of forensic science.

Label‐free surface‐enhanced Raman spectroscopy detection of prostate cancer combined with multivariate statistical algorithm

AbstractThe purpose of this study was to detect human plasma for screening prostate cancer (PCa) and benign prostatic hyperplasia (BPH) based on surface‐enhanced Raman spectroscopy (SERS) and multivariate statistical algorithms. The test was to detect 106 plasma samples, which originated from 39 normal subjects, 26 patients with PCa and 41 patients with BPH. Significant differences in peak intensity at 495, 636, 1135, 1205, and 1675 cm−1 can be observed from the difference spectrogram, which contributes to initially distinguish the cancer group from the normal group. Then, the multivariate statistical techniques, including principal component analysis (PCA) and linear discriminant analysis (LDA) diagnostic algorithms, as well as recursive weighted partial least square (PLS) method and support vector machine (SVM) algorithm, were used to analyze the spectral data. For PCa versus normal group and BPH versus normal group, the classification accuracy of PCA‐LDA was 96.80% and 97.50%, respectively, and the classification accuracy of PLS‐SVM was 100.00% and 100.00%, respectively. In the diagnosis of PCa and BPH, the sensitivity, specificity and accuracy of PCA‐LDA were 65.40%, 75.60%, and 71.06% respectively, and the area under the curve (AUC) value of the receiver operating characteristic (ROC) curve was 0.788, while the sensitivity, specificity and accuracy of PLS‐SVM were 88.46%, 87.80%, and 88.06%, respectively, and the AUC value was 0.881. The diagnostic results of PLS‐SVM are better than PCA‐LDA, which supported that PLS‐SVM algorithm has greater potential than PCA‐LDA algorithm in the pre‐diagnosis and screening of PCa.

Enantiodetection of Chiral Molecules via Two-Dimensional Spectroscopy.

Enantiodetection of chiral molecules is important to chemical reaction control and biological function designs. Traditional optical methods of enantiodetection rely on the weak magnetic-dipole or electric-quadrupole interactions, and in turn suffer from the weak signal and low sensitivity. We propose a new optical enantiodetection method to determine the enantiomeric excess via two-dimensional (2D) spectroscopy of the chiral mixture driven by three electromagnetic fields. The quantities of left- and right-handed chiral molecules are reflected by the intensities of different peaks on the 2D spectrum, separated by the chirality-dependent frequency shifts resulting from the relative strong electric-dipole interactions between the chiral molecules and the driving fields. Thus, the enantiomeric excess can be determined via the intensity ratio of the peaks for the two enantiomers.

Lymphatic filarial serum proteome profiling for identification and characterization of diagnostic biomarkers.

Lymphatic Filariasis (LF) affects more than 863 million people in tropical and subtropical areas of the world, causing high morbidity and long illnesses leading to social exclusion and loss of wages. A combination of drugs Ivermectin, Diethylcarbamazine citrate and Albendazole is recommended by WHO to accelerate the Global Programme to Eliminate Lymphatic Filariasis (GPELF). To assess the outcome of GPELF, to re-evaluate and to formulate further strategies there is an imperative need for high quality diagnostic markers. This study was undertaken to identify Lymphatic Filarial biomarkers which can detect LF infections in asymptomatic cases and would also serve as indicators for differentiating among different clinical stages of the disease. A combination of Fourier-transform infrared spectroscopy (FT-IR), MMP zymography, SDS-PAGE, classical 2DE along with MALDI-TOF/MS was done to identify LF biomarkers from serum samples of different stages of LF patients. FT-IR spectroscopy coupled with univariate and multivariate analysis of LF serum samples, revealed significant differences in peak intensity at 3300, 2950, 1645, 1540 and 1448 cm-1 (p<0.05). The proteomics analysis results showed that various proteins were differentially expressed (p<0.05), including C-reactive protein, α-1-antitrypsin, heterogeneous nuclear ribonucleoprotein D like, apolipoproteins A-I and A-IV in different LF clinical stages. Functional pathway analysis suggested the involvement of differentially expressed proteins in vital physiological pathways like acute phase response, hemostasis, complement and coagulation cascades. Furthermore, the differentiation between different stages of LF cases and biomarkers identified in this study clearly demonstrates the potential of the human serum profiling approach for LF detection. To our knowledge, this is the first report of comparative human serum profiling in different categories of LF patients.

Rapid identification of flaxseed oil based on portable fiber optic Raman spectroscopy combined with an oil microscopy method.

To explore a fast, simple, and accurate method to identify adulteration in flaxseed oil, the Raman spectral data of 130 samples containing flaxseed, canola, cottonseed, and adulterated oils were obtained using a portable fiber optic Raman spectrometer. The Raman spectral results showed that the Raman spectra of the flaxseed and canola oils had noticeable peak shifts, whereas the peak positions of the flaxseed and cottonseed oils were relatively similar. Clear peak intensity differences were observed in the flaxseed, cottonseed, and canola oils, mainly at 868cm-1 , 1022cm-1 , 1265cm-1 , and 1655cm-1 , with Raman shift intensities in the following order: Iflaxseed oil >Icottonseed oil >Icanola oil . Similarly, the peak intensity of the flaxseed and adulterated oils also exhibited certain differences (at 868cm-1 , 1022cm-1 , 1265cm-1 , and 1655cm-1 ), and the Raman shift intensity tended to decrease gradually with the increasing content of canola and cottonseed oils in the flaxseed oil. Additionally, the results of Raman spectroscopy combined with the "oil microscopy" method exhibited large variations in the radar patterns of the flaxseed, canola, and cottonseed oils, whereas the radar patterns of the flaxseed and adulterated oils closely resembled each other. The results indicated that Raman spectroscopy in combination with oil microscopy more effectively revealed the subtle differences in the Raman shift intensity, serving as a more visual and comprehensive approach for differentiating the quality variations between pure flaxseed oil and other oil species and adulterated oil. PRACTICAL APPLICATION: This study analyzed the Raman spectra of flaxseed, canola, cottonseed, and adulterated oils using fiber optic Raman spectroscopy. Combined with the oil microscopy method for comprehensive evaluation and analysis, it is feasible to effectively identify the quality differences among flaxseed, canola, cottonseed, and adulterated oils.

Biogenic VOCs Emission Profiles Associated with Plant-Pest Interaction for Phenotyping Applications.

Pest attacks on plants can substantially change plants’ volatile organic compounds (VOCs) emission profiles. Comparison of VOC emission profiles between non-infected/non-infested and infected/infested plants, as well as resistant and susceptible plant cultivars, may provide cues for a deeper understanding of plant-pest interactions and associated resistance. Furthermore, the identification of biomarkers—specific biogenic VOCs—associated with the resistance can serve as a non-destructive and rapid tool for phenotyping applications. This research aims to compare the VOCs emission profiles under diverse conditions to identify constitutive (also referred to as green VOCs) and induced (resulting from biotic/abiotic stress) VOCs released in potatoes and wheat. In the first study, wild potato Solanum bulbocastanum (accession# 22; SB22) was inoculated with Meloidogyne chitwoodi race 1 (Mc1), and Mc1 pathotype Roza (SB22 is resistant to Mc1 and susceptible to pathotype Roza), and VOCs emission profiles were collected using gas chromatography-flame ionization detection (GC-FID) at different time points. Similarly, in the second study, the VOCs emission profiles of resistant (‘Hollis’) and susceptible (‘Alturas’) wheat cultivars infested with Hessian fly insects were evaluated using the GC-FID system. In both studies, in addition to variable plant responses (susceptibility to pests), control treatments (non-inoculated or non-infested) were used to compare the VOCs emission profiles resulting from differences in stress conditions. The common VOC peaks (constitutive VOCs) between control and infected/infested samples, and unique VOC peaks (induced VOCs) presented only in infected/infested samples were analyzed. In the potato-nematode study, the highest unique peak was found two days after inoculation (DAI) for SB22 inoculated with Mc1 (resistance response). The most common VOC peaks in SB22 inoculated with both Mc1 and Roza were found at 5 and 10 DAI. In the wheat-insect study, only the Hollis showed unique VOC peaks. Interestingly, both cultivars released the same common VOCs between control and infected samples, with only a difference in VOC average peak intensity at 22.4 min retention time where the average intensity was 4.3 times higher in the infested samples of Hollis than infested samples of Alturas. These studies demonstrate the potential of plant VOCs to serve as a rapid phenotyping tool to assess resistance levels in different crops.

Label-free detection of bladder cancer and kidney cancer plasma based on SERS and multivariate statistical algorithm

In this study, we mainly aimed to investigate the diagnostic potential of surface-enhanced Raman spectroscopy for bladder cancer and kidney cancer which are the most common cancers of the urinary system, and evaluate the classification ability of three statistical algorithms: principal component analysis-linear discriminate analysis (PCA-LDA), partial least square-random forest (PLS-RF), and partial least square-support vector machine (PLS-SVM). The plasma of 26 bladder cancer patients, 38 kidney cancer patients and 39 normal subjects was mixed with the same volume of silver nanoparticles, respectively, and then high-quality SERS signal was obtained. The SERS spectra in the range of 400–1800 cm−1 were compared and analyzed. There were some significant differences in SERS peak intensity, which may reflect the changes in the content of some biomacromolecules in the plasma of cancer patients. Based on the three algorithms of PCA-LDA, PLS-RF and PLS-SVM, the classification accuracy of SERS spectra of plasma from cancer patients and normal subjects was 98.1%, 100% and 100%, respectively.In addition, the classification accuracy of the three diagnostic algorithms to classify the SERS spectra of bladder cancer and kidney cancer was 81.3%, 91.7%, and 98.4%, respectively. This exploratory work demonstrates that SERS combined with PLS-SVM algorithm has superior performance for clinical screening of bladder cancer and kidney cancer through peripheral plasma.

Task-fMRI Group and Functional Connectivity Analysis of the Brain During Faradarmani Consciousness Field Connection

Taheri Consciousness (T-Consciousness) was introduced and defined by Mohammad Ali Taheri as one of the constituent components of the Cosmos in addition to matter and energy, from which Taheri Consciousness Fields (TCFs) are derived. TCFs are not matter or energy, but they can be proven by scientific experiments. The effect of Faradarmani CF, as one TCFs, was examined in this study. Faradarmangar is a certified and trained individual who has been entrusted with the TCFs. Task fMRI has played a critical role in recognizing the specific functions of the different regions of the human brain during various cognitive activities. This study aimed to investigate the group analysis and functional connectivity in the Faradarmangars’ brains during Faradarmani CF (FCF) connection. Using task functional MRI (task-fMRI), we attempted the identification of different activated and deactivated brain regions during the TCFs connection. Clusters that showed significant differences in peak intensity between the task and rest groups were selected as seeds for seed-voxel analysis. Connectivity of group differences in functional connectivity analysis was determined following each activation and deactivation network. In this study, we report the fMRI-based representation of the FCF connection at the human brain level. The group analysis of the FCF connection task revealed activation of the frontal lobe (BA6/BA10/BA11). Moreover, seed-based functional connectivity analysis showed decreased connectivity within activated clusters and posterior Cingulate Gyrus (BA31). Moreover, we observed increased connectivity within deactivated clusters and the frontal lobe (BA11/BA47) during the FCF connection. Activation clusters, as well as the increased and decreased connectivity between different regions of the brain during the FCF connection, firstly, validates the significant effect of FCF and, secondly, indicates a distinctive pattern of connection with this non material and non-energetic field in the brain.

Crystal growth and physico-chemical characterization of methyl ammonium chloride doping on the characteristics of potassium dihydrogen phosphate crystal for nonlinear optical applications

• The KDP and MACKDP single crystals were grown by the slow evaporation method. • The UV–Vis-NIR spectrums reveal that the title compounds can be used as nonlinear optical materials. • KDP and MACKDP crystal belong to the soft material category. • Third-order nonlinear optical susceptibility (χ 3 ) was found to be 5.391 × 10 −8 esu and 5.412 × 10 −8 esu for KDP and MACKDP, respectively. Potassium dihydrogen phosphate (KDP) and Methyl ammonium chloride doped KDP (MACKDP) were made into nonlinear optical single crystals using the ambient temperature slow evaporation method. An examination of powder X-ray diffraction reveals that the reflection lines of the doped KDP crystal are almost identical to those of the pure parent chemical KDP, with just a little difference in peak intensity. The space group and lattice parameters of the crystal structure were determined using XRD measurements on a single crystal. FTIR spectrum studies indicated the existence of numerous functional groups due to the shifting of peak positions. According to the results of UV–Vis-NIR testing, the UV cutoff wavelength for pure KDP is 381 nm and for methyl ammonium chloride doped potassium dihydrogen phosphate crystal is 383 nm. Growing crystals have reduced permittivity and dielectric loss tangent at increasing frequencies and temperatures. There were 1.12 times more correlated second harmonic (SHG) powers in the doped crystal than there were in pure KDP, according to the Kurtz and Perry approach. Thermogravimetric and differential thermal analysis were used to evaluate the thermal properties of an KDP doped MACKDP crystals. Vickers microhardness experiments have examined the impact of methyl ammonium chloride mixing on the hardness parameters of KDP crystal. The encouraging third-order nonlinear properties were examined employing a Z-scan technique using an Nd: YAG laser at 532 nm. To be considered a viable choice for nonlinear optical devices, the title material must exhibit a wide range of noteworthy physicochemical and optical nonlinear features.

A direct method for detecting proteins in body fluids by Surface-Enhanced Raman Spectroscopy under native conditions

Surface enhanced Raman spectroscopy (SERS) is widely used in biomolecular detection. However, maintaining the native structure of proteins while obtaining sensitive and reproducible SERS signals of unlabeled proteins remains a challenge. In this study, dichloromethane (DCM) and CaCl2 were used to optimize the aggregation of Ag nanoparticles (AgNPs), and several proteins were analyzed comprehensively. Calcium ions removed citrate ions outside AgNPs, inducing hot spots and achieving high-sensitivity SERS signals of proteins. Furthermore, 20 random samples of 0.5 μg/mL hemoglobin were analyzed by this method. The obtained spectra showed good repeatability and a high quality. Using the peak intensity of DCM as internal parameter, the differences in peak intensities at the same position were analyzed to distinguish different proteins and evaluate changes in protein structure. Subsequently, the protein content in protein mixtures and serum was quantified and a good linear relationship between peak intensity and protein concentration was obtained. This method shows great promise in the fields of food testing and clinical diagnosis.

The effect of non-ionic surfactants on the sustainable synthesis of selected MOFs

The MOFs selected in this work are NH2-MIL-53(Al), MIL-100(Fe) and UiO-66 type (Zr-BDC and NH2-Zr-BDC). We have tried to assist the sustainable synthesis of MOFs, at room temperature and in water as a solvent, with the presence of non-ionic surfactants: Pluronic F127 and P123. The parent MOFs prepared at room temperature with water solvent commonly grow in the form of agglomerates of small crystallites in all cases. The X ray diffraction patterns of surfactant templated NH2-MIL-53(Al) with F127 and MIL-100(Fe) with F127 and P123 show some differences in peak intensity indicating preferential crystal growth along one direction. This effect was confirmed by scanning and transmission electron microscopy, yielding long shaped crystals with more or less uniform morphology, notably larger than the parent MOFs. In the case of UiO-66 type (Zr-BDC and NH2-Zr-BDC) MOFs, the X ray diffraction profiles of the parent and the surfactant templated MOFs do not show noticeable difference, which might be due to the semi-amorphous nature of these MOFs. However, the scanning and transmission electron microscopy images show larger particles in surfactant templated UiO-66 type Zr-MOFs compared to their parent counterparts.

Highly precise in-plane displacement sensor based on an asymmetric fiber Fabry-Perot interferometer.

An in-plane displacement sensor based on an asymmetric extrinsic fiber Fabry-Perot interferometer (EFPI) is proposed and demonstrated. The asymmetric EFPI composed of a step-shaped external reflector and a cleaved fiber end face can be equivalent to two parallel FPIs with slightly different cavity lengths. By calculating the peak intensity difference of the two FPIs, the in-plane displacement can be demodulated with enhanced sensitivity and suppressed common mode noise. Both theoretical analyses and experimental results show that the sensitivity and the linear range of the in-plane displacement sensor are dependent on the cavity length. A displacement resolution of 5 nm and a linear range of ±7µm under the cavity length of 250 µm are achieved in the experiment. The proposed in-plane displacement sensor with a nanometric resolution and compact size can be widely used in the fields of metrology, accelerometers, and semiconductor manufacture.

Localized Surface Plasmon Resonance Effect of Gold Nanoparticles Using 3-Mercaptopropionic Acid as Capping Material for Sensing Probe

Gold nanoparticles (AuNP) has been used in a wide range of applications especially in medicine and optoelectronic applications due to its localized surface plasmon resonance (LSPR) effect. LSPR observation of AuNP solution shows that the plasmonic peak in the absorbance spectra lies in the range of visible light around 520 nm with deep red-wine color. The optical characteristic is controlled by the size and shape of the nanoparticles including its surface functionalization. Our research is focused on the adsorption study of 3-mercaptopropionate (3-MP) on AuNP (AuMP) surface synthesized by ligand exchange method and also by direct reduction method. The characterizations are conducted by use of UV-vis and FTIR spectroscopies in order to investigate the effect of LSPR. The absorbance spectra show that both experimental methods of AuMP give a similar profile of red-shifted in the plasmonic peaks in comparison to that of citrate-capped AuNP as a reference from 519 nm to 520 nm. The ligand exchange method of AuMP synthesis results in an unstable colloidal solution after being stored for a week at room temperature while the reduction method results in a stable colloidal solution of AuMP even though it has been stored for 2 months. The FTIR spectra show the difference in vibrational peak intensities between the 3-MP on AuNP and the 3-MPA as reference. The peak of carboxylate (COO-) asymmetric stretching is shifted to low frequency from 1708 cm-1 to 1632 cm-1 indicate the effect of LSPR while the shift to high frequencies for some vibrational peak intensities relates to the strong effect of chemical coordination between gold and capping material. The simulation of the vibration energy by use of the Density Functional Theory (DFT) method shows a similar tendency to that of the peak intensities along the infrared spectrum from experimental results.