Effects of Polarizer-Analyzer Configurations for FTIR Spectroscopy: Implications for Multiple Polarization Algorithms.

Polarized Fourier transform infrared (p-FTIR) spectroscopy is a widely used technique for determining orientational information in thin organic materials. Conventionally, a single polarizer is placed in the path of the incident light (termed the polarizer). Occasionally, a second polarizer is also placed after the sample (referred to as the analyzer). However, this polarizer-analyzer configuration has the potential to induce polarization-dependent variances in the final spectra beyond those that are expected, i.e., the squared-cosine relationship of absorptance with respect to polarization angle is no longer accurate. These variances are due to changes in the polarization state of the transmitted light induced by the sample and have yet to be explored in the context of p-FTIR. Consequently, this study employs both theoretical and experimental approaches to identify the effects of including a second polarizer in p-FTIR analyses of anisotropic organic samples. For thin samples, the most significant spectral variance arising from only birefringence is observed on the shoulders of the dichroic peaks. By adopting a crossed polarizer configuration, it is shown that there is potential to identify anisotropy of samples that are generally considered too thick for p-FTIR analysis by exploiting this feature. Furthermore, the squared-cosine relationship of absorptance with respect to the polarization angle is also shown to be inapplicable when a second parallel-oriented polarizer is included. Accordingly, a function that accounts for the second polarizer is proposed for multiple polarization techniques.

Atomic-Level Engineered Cobalt Catalysts for Fenton-Like Reactions: Synergy of Single Atom Metal Sites and Nonmetal-Bonded Functionalities.

Single atom catalysts (SACs) are atomic-level-engineered materials with high intrinsic activity. Catalytic centers of SACs are typically the transition metal (TM)-nonmetal coordination sites, while the functions of coexisting non-TM-bonded functionalities are usually overlooked in catalysis. Herein, the scalable preparation of carbon-supported cobalt-anchored SACs (CoCN) with controlled Co─N sites and free functional N species is reported. The role of metal- and nonmetal-bonded functionalities in the SACs for peroxymonosulfate (PMS)-driven Fenton-like reactions is first systematically studied, revealing their contribution to performance improvement and pathway steering. Experiments and computations demonstrate that the Co─N3C coordination plays a vital role in the formation of a surface-confined PMS* complex to trigger the electron transfer pathway and promote kinetics because of the optimized electronic state of Co centers, while the nonmetal-coordinated graphitic N sites act as preferable pollutant adsorption sites and additional PMS activation sites to accelerate electron transfer. Synergistically, CoCN exhibits ultrahigh activity in PMS activation for p-hydroxybenzoic acid oxidation, achieving complete degradation within 10 min with an ultrahigh turnover frequency of 0.38 min-1, surpassing most reported materials. These findings offer new insights into the versatile functions of N species in SACs and inspire rational design of high-performance catalysts in complicated heterogeneous systems.

Extending the Depth of Focus of an Infrared Microscope Using a Binary Axicon Fabricated on Barium Fluoride.

Axial resolution is one of the most important characteristics of a microscope. In all microscopes, a high axial resolution is desired in order to discriminate information efficiently along the longitudinal direction. However, when studying thick samples that do not contain laterally overlapping information, a low axial resolution is desirable, as information from multiple planes can be recorded simultaneously from a single camera shot instead of plane-by-plane mechanical refocusing. In this study, we increased the focal depth of an infrared microscope non-invasively by introducing a binary axicon fabricated on a barium fluoride substrate close to the sample. Preliminary results of imaging the thick and sparse silk fibers showed an improved focal depth with a slight decrease in lateral resolution and an increase in background noise.

Staphylococcus aureus surface attachment selectively influences tolerance against charged antibiotics.

The threat of infection during implant placement surgery remains a considerable burden for millions of patients worldwide. To combat this threat, clinicians employ a range of anti-infective strategies and practices. One of the most common interventions is the use of prophylactic antibiotic treatment during implant placement surgery. However, these practices can be detrimental by promoting the resilience of biofilm-forming bacteria and enabling them to persist throughout treatment and re-emerge later, causing a life-threatening infection. Thus, it is of the utmost importance to elucidate the events occurring during the initial stages of bacterial surface attachment and determine whether any biological processes may be targeted to improve surgical outcomes. Using gene expression analysis, we identified a cellular mechanism of S. aureus which modifies its cell surface charge following attachment to a medical grade titanium surface. We determined the upregulation of two systems involved in the d-alanylation of teichoic acids and the lysylation of phosphatidylglycerol. We supported these molecular findings by utilizing synchrotron-sourced attenuated total reflection Fourier-transform infrared microspectroscopy to analyze the biomolecular properties of the S. aureus cell surface following attachment. As a direct consequence, S. aureus quickly becomes substantially more tolerant to the positively charged vancomycin, but not the negatively charged cefazolin. The present study can assist clinicians in rationally selecting the most potent antibiotic in prophylaxis treatments. Furthermore, it highlights a cellular process that could potentially be targeted by novel technologies and strategies to improve the outcome of antibiotic prophylaxis during implant placement surgery. STATEMENT OF SIGNIFICANCE: The antibiotic tolerance of bacteria in biofilm is a well-established phenomenon. However, the physiological adaptations employed by Staphylococcus aureus to increase its antibiotic tolerance during the early stages of surface attachment are poorly understood. Using multiple techniques, including gene expression analysis and synchrotron-sourced Fourier-transform infrared microspectroscopy, we generated insights into the physiological response of S. aureus following attachment to a medical grade titanium surface. We showed that this phenotypic transition enables S. aureus to better tolerate the positively charged vancomycin, but not the negatively charged cefazolin. These findings shed light on the antibiotic tolerance mechanisms employed by S. aureus to survive prophylactically administered antibiotics and can help clinicians to protect patients from infections.

Vancomycin tolerance of adherent Staphylococcus aureus is impeded by nanospike-induced physiological changes.

Bacterial colonization of implantable biomaterials is an ever-pervasive threat that causes devastating infections, yet continues to elude resolution. In the present study, we report how a rationally designed antibacterial surface containing sharp nanospikes can enhance the susceptibility of pathogenic bacteria to antibiotics used in prophylactic procedures. We show that Staphylococcus aureus, once adhered to a titanium surface, changes its cell-surface charge to increase its tolerance to vancomycin. However, if the Ti surface is modified to bear sharp nanospikes, the activity of vancomycin is rejuvenated, leading to increased bacterial cell death through synergistic activity. Analysis of differential gene expression provided evidence of a set of genes involved with the modification of cell surface charge. Synchrotron-sourced attenuated Fourier-transform infrared microspectroscopy (ATR-FTIR), together with multivariate analysis, was utilized to further elucidate the biochemical changes of S. aureus adhered to nanospikes. By inhibiting the ability of the pathogen to reduce its net negative charge, the nanoengineered surface renders S. aureus more susceptible to positively charged antimicrobials such as vancomycin. This finding highlights the opportunity to enhance the potency of prophylactic antibiotic treatments during implant placement surgery by employing devices having surfaces modified with spike-like nanostructures.

Structural and Thermal Diffusivity Analysis of an Organoferroelastic Crystal Showing Scissor-Like Two-Directional Deformation Induced by Uniaxial Compression.

A two-directional ferroelastic deformation in organic crystals is unprecedented owing to its anisotropic crystal packing, in contrast to isotropic symmetrical packing in inorganic compounds and polymers. Thereby, finding and constructing multidirectional ferroelastic deformations in organic compounds is undoubtedly complex and at once calls for deep comprehension. Herein, we demonstrate the first example of a two-directional ferroelastic deformation with a unique scissor-like movement in single crystals of trans-3-hexenedioic acid by the application of uniaxial compression stress. A detailed structural investigation of the mechanical deformation at the macroscopic and microscopic levels by three distinct force measurement techniques (including shear and three-point bending test), single crystal X-ray diffraction techniques, and polarized synchrotron-FTIR microspectroscopy highlighted that mechanical twinning promoted the deformation. The presence of two crystallographically equivalent faces and the herringbone arrangement promoted the two-directional ferroelastic deformation. In addition, anisotropic heat transfer properties in the parent and the deformed domains were investigated by thermal diffusivity measurement on all three axes using microscale temperature-wave analysis (µ-TWA). A correlation between the anisotropic structural arrangement and the difference in thermal diffusivity and mechanical behavior in the two-directional organoferroelastic deformation could be established. The structural and molecular level information from this two-directional ferroelastic deformation would lead to a more profound understanding of the structure-property relationship in multidirectional deformation in organic crystals.

A biocompatible electrolyte enables highly reversible Zn anode for zinc ion battery.

Progress towards the integration of technology into living organisms requires power devices that are biocompatible and mechanically flexible. Aqueous zinc ion batteries that use hydrogel biomaterials as electrolytes have emerged as a potential solution that operates within biological constraints; however, most of these batteries feature inferior electrochemical properties. Here, we propose a biocompatible hydrogel electrolyte by utilising hyaluronic acid, which contains ample hydrophilic functional groups. The gel-based electrolyte offers excellent anti-corrosion ability for zinc anodes and regulates zinc nucleation/growth. Also, the gel electrolyte provides high battery performance, including a 99.71% Coulombic efficiency, over 5500 hours of long-term stability, improved cycle life of 250 hours under a high zinc utilization rate of 80%, and high biocompatibility. Importantly, the Zn//LiMn2O4 pouch cell exhibits 82% capacity retention after 1000 cycles at 3 C. This work presents a promising gel chemistry that controls zinc behaviour, offering great potential in biocompatible energy-related applications and beyond.

Changes in Dental Biofilm Proteins' Secondary Structure in Groups of People with Different Cariogenic Situations in the Oral Cavity and Using Medications by Means of Synchrotron FTIR-Microspectroscopy.

This work unveils the idea that the cariogenic status of the oral cavity (the presence of active caries lesions) can be predicted via a lineshape analysis of the infrared spectral signatures of the secondary structure of proteins in dental biofilms. These spectral signatures that work as natural markers also show strong sensitivity to the application in patients of a so-called modulator-a medicinal agent (a pelleted mineral complex with calcium glycerophosphate). For the first time, according to our knowledge, in terms of deconvolution of the complete spectral profile of the amide I and amide II bands, significant intra- and intergroup differences were determined in the secondary structure of proteins in the dental biofilm of patients with a healthy oral cavity and with a carious pathology. This allowed to conduct a mathematical assessment of the spectral shifts in proteins' secondary structure in connection with the cariogenic situation in the oral cavity and with an external modulation. It was shown that only for the component parallel ß-strands in the amide profile of the biofilm, a statistically significant (p < 0.05) change in its percentage weight (composition) was registered in a cariogenic situation (presence of active caries lesions). Note that no significant differences were detected in a normal situation (control) and in the presence of a carious pathology before and after the application of the modulator. The change in the frequency and percentage weight of parallel ß-strands in the spectra of dental biofilms proved to be the result of the presence of cariogenic mutans streptococci in the film as well as of the products of their metabolism-glucan polymers. We foresee that the results presented here can inherently provide the basis for the infrared spectral diagnosis of changes (shifts) in the oral microbiome driven by the development of the carious process in the oral cavity as well as for the choice of optimal therapeutic treatments of caries based on microbiome-directed prevention measures.

Quantifying the effects of pre-roasting on structural and functional properties of yellow pea proteins.

Roasting could modify the protein structure/conformation, contributing to changes in functional properties. Here we investigated the effects of pre-roasting on the extraction efficiency, structural and functional properties of pea protein concentrates and isolates (PPC and PPI) produced from yellow split peas. The shorter roasting times (150 °C, 10 and 20 min) had little effect on protein yields and could increase the solubility of PPC or PPI by âˆ¼ 12% at pH 7 and enhance the solubility of PPI by âˆ¼ 12% (10-min roasting) and âˆ¼ 24% (20-min roasting) at pH 3. However, a longer duration of pre-roasting (150 °C, 30 min) significantly reduced the extraction efficiency of PPC and PPI by âˆ¼ 30% and âˆ¼ 61%, respectively. Meanwhile, pre-roasting had minor effects on SDS-PAGE profiles and the secondary structures of pea proteins but significantly altered tertiary structures by reducing free sulfhydryl groups, increasing disulfide bonds and surface hydrophobicity. As for the emulsifying properties, pre-roasting improved the emulsion ability index (EAI) of PPC and PPI but decreased the emulsion stability index (ESI) of PPC and had no significant effect on PPI. Moreover, PPC and PPI with shorter pre-roasting duration (10 and 20 min) had endothermic peaks and showed a slight decrease in the denaturation temperature (Td) and the onset temperature (To), respectively. Overall, the study demonstrated that controlled pre-roasting at 150 °C for 10 min and 20 min altered protein structures (mainly tertiary structures), improving the solubility and EAI of pea proteins at pH 7, while retaining their thermal properties in comparison to unroasted samples.

Transforming Spirulina maxima Biomass into Ultrathin Bioactive Coatings Using an Atmospheric Plasma Jet: A New Approach to Healing of Infected Wounds.

The challenge of wound healing, particularly in patients with comorbidities such as diabetes, is intensified by wound infection and the accelerating problem of bacterial resistance to current remedies such as antibiotics and silver. One promising approach harnesses the bioactive and antibacterial compound C-phycocyanin from the microalga Spirulina maxima. However, the current processes of extracting this compound and developing coatings are unsustainable and difficult to achieve. To circumvent these obstacles, a novel, sustainable argon atmospheric plasma jet (Ar-APJ) technology that transforms S. maxima biomass into bioactive coatings is presented. This Ar-APJ can selectively disrupt the cell walls of S. maxima, converting them into bioactive ultrathin coatings, which are found to be durable under aqueous conditions. The findings demonstrate that Ar-APJ-transformed bioactive coatings show better antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, these coatings exhibit compatibility with macrophages, induce an anti-inflammatory response by reducing interleukin 6 production, and promote cell migration in keratinocytes. This study offers an innovative, single-step, sustainable technology for transforming microalgae into bioactive coatings. The approach reported here has immense potential for the generation of bioactive coatings for combating wound infections and may offer a significant advance in wound care research and application.

Characterization of K562 cells: uncovering novel chromosomes, assessing transferrin receptor expression, and probing pharmacological therapies.

Human erythroleukemic K562 cells represent the prototypical cell culture model of chronic myeloid leukemia (CML). The cells are pseudo-triploid and positive for the Philadelphia chromosome. Therefore, K562 cells have been widely used for investigating the BCR/ABL1 oncogene and the tyrosine kinase inhibitor, imatinib-mesylate. Further, K562 cells overexpress transferrin receptors (TfR) and have been used as a model for targeting cytotoxic therapies, via receptor-mediated endocytosis. Here, we have characterized K562 cells focusing on the karyotype of cells in prolonged culture, regulation of expression of TfR in wildtype (WT) and doxorubicin-resistant cells, and responses to histone deacetylase inhibition (HDACi). Karyotype analysis indicates novel chromosomes and gene expression analysis suggests a shift of cultured K562 cells away from patient-derived leukemic cells. We confirm the high expression of TfR on K562 cells using immunofluorescence and cell-surface receptor binding radioassays. Importantly, high TfR expression is observed in patient-derived cells, and we highlight the persistent expression of TfR following doxorubicin acquired resistance. Epigenetic analysis indicates that permissive histone acetylation and methylation at the promoter region regulates the transcription of TfR in K562 cells. Finally, we show relatively high expression of HDAC enzymes in K562 cells and demonstrate the chemotoxic effects of HDACi, using the FDA-approved hydroxamic acid, vorinostat. Together with a description of morphology, infrared spectral analysis, and examination of metabolic properties, we provide a comprehensive characterization of K562 cells. Overall, K562 cell culture systems remain widely used for the investigation of novel therapeutics for CML, which is particularly important in cases of imatinib-mesylate resistance.

Linearly Polarized Infrared Spectroscopy for the Analysis of Biological Materials.

The analysis of biological samples with polarized infrared spectroscopy (p-IR) has long been a widely practiced method for the determination of sample orientation and structural properties. In contrast to earlier works, which employed this method to investigate the fundamental chemistry of biological systems, recent interests are moving toward "real-world" applications for the evaluation and diagnosis of pathological states. This focal point review provides an up-to-date synopsis of the knowledge of biological materials garnered through linearly p-IR on biomolecules, cells, and tissues. An overview of the theory with special consideration to biological samples is provided. Different modalities which can be employed along with their capabilities and limitations are outlined. Furthermore, an in-depth discussion of factors regarding sample preparation, sample properties, and instrumentation, which can affect p-IR analysis is provided. Additionally, attention is drawn to the potential impacts of analysis of biological samples with inherently polarized light sources, such as synchrotron light and quantum cascade lasers. The vast applications of p-IR for the determination of the structure and orientation of biological samples are given. In conclusion, with considerations to emerging instrumentation, findings by other techniques, and the shift of focus toward clinical applications, we speculate on the future directions of this methodology.

Translocation and fate of nanospheres in pheochromocytoma cells following exposure to synchrotron-sourced terahertz radiation.

The routes by which foreign objects enter cells is well studied; however, their fate following uptake has not been explored extensively. Following exposure to synchrotron-sourced (SS) terahertz (THz) radiation, reversible membrane permeability has been demonstrated in eukaryotic cells by the uptake of nanospheres; nonetheless, cellular localization of the nanospheres remained unclear. This study utilized silica core-shell gold nanospheres (AuSi NS) of diameter 50 ± 5 nm to investigate the fate of nanospheres inside pheochromocytoma (PC 12) cells following SS THz exposure. Fluorescence microscopy was used to confirm nanosphere internalization following 10 min of SS THz exposure in the range 0.5-20 THz. Transmission electron microscopy followed by scanning transmission electron microscopy energy-dispersive spectroscopic (STEM-EDS) analysis was used to confirm the presence of AuSi NS in the cytoplasm or membrane, as single NS or in clusters (22% and 52%, respectively), with the remainder (26%) sequestered in vacuoles. Cellular uptake of NS in response to SS THz radiation could have suitable applications in a vast number of biomedical applications, regenerative medicine, vaccines, cancer therapy, gene and drug delivery.

On surface composition and stability of ß-carotene microcapsules comprising pea/whey protein complexes by synchrotron-FTIR microspectroscopy.

This study aims to elucidate the stability of spray dried ß-carotene microcapsules by identifying their surface composition using synchrotron-Fourier transform infrared (FTIR) microspectroscopy. To investigate the impact of enzymatic cross-linking and polysaccharide addition on heteroprotein, three wall materials were prepared: pea/whey protein blends (Con), cross-linked pea/whey protein blends (TG), and cross-linked pea/whey protein blends-maltodextrin complex (TG-MD). The TG-MD exhibited the highest encapsulation efficiency (>90 %) after 8 weeks of storage followed by TG and Con. Chemical images obtained using synchrotron-FTIR microspectroscopy confirmed that the TG-MD displayed the least amount of surface oil, followed by TG and Con, due to increasing amphiphilic ß-sheet structure of the proteins led by cross-linking and maltodextrin addition. Both enzymatic cross-linking and polysaccharide addition improved the stability of ß-carotene microcapsules, demonstrating that pea/whey protein blends with maltodextrin can be utilised as a hybrid wall material for enhancing the encapsulation efficiency of lipophilic bioactive compounds in foods.

Magnetically Cured Macroradical Epoxy as Antimicrobial Coating.

The radical-bearing epoxy monomer could be the ideal embodiment of multifunctionality in epoxy-based materials. This study demonstrates the potential of macroradical epoxies as surface coating materials. A diepoxide monomer derivatized with a stable nitroxide radical is polymerized with a diamine hardener under the influence of a magnetic field. The magnetically oriented and stable radicals in the polymer backbone render the coatings antimicrobial. The unconventional use of magnets during polymerization proved crucial in correlating the structure-property relationships with antimicrobial performance inferred from oscillatory rheological technique, polarized macro-attenuated total reflectance - infrared (macro-ATR-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The magnetic thermal curing influenced the surface morphology, resulting in a synergy of the coating's radical nature with microbiostatic performance assessed using the Kirby-Bauer test and liquid chromatography - mass spectroscopy (LC-MS). Further, the magnetic curing of blends with a traditional epoxy monomer demonstrates that radical alignment is more critical than radical density in imparting biocidal behavior. This study shows how the systematic use of magnets during polymerization could pave for probing more significant insights into the mechanism of antimicrobial action in radical-bearing polymers.

Characterization of freeze-dried oxidized human red blood cells for pre-transfusion testing by synchrotron FTIR microspectroscopy live-cell analysis.

Oxidative treatment of human red blood cells (RBCs) prior to freeze-drying appears to stabilize the RBCs to withstand dried storage at room temperature. To better understand the effects of oxidation and freeze-drying/rehydration on RBC lipids and proteins, single-cell measurements were performed by synchrotron-based Fourier transform infrared (FTIR) microspectroscopy 'live-cell' (unfixed) analysis. Lipid and protein spectral data of tert-butyl hydroperoxide (TBHP)-oxidized RBCs (oxRBCs), FDoxRBCs and control (untreated) RBCs were compared using principal component analysis (PCA) and band integration ratios. The oxRBCs and FDoxRBCs samples had similar spectral profiles that were clearly different to control RBCs. Spectral changes in the CH stretching region of oxRBCs and FDoxRBCs indicated the presence of increased saturated and shorter-chain lipids, consistent with lipid peroxidation and stiffening of the RBC membrane compared to control RBCs. The PCA loadings plot for the fingerprint region of control RBCs corresponding to the α-helical structure of hemoglobin, shows that oxRBCs and FDoxRBCs have conformational changes in the protein secondary structure to ß-pleated sheets and ß-turns. Finally, the freeze-drying process did not appear to compound or induce additional changes. In this context, FDoxRBCs could become a stable source of reagent RBCs for pre-transfusion blood serology testing. The synchrotron FTIR microspectroscopic live-cell protocol provides a powerful analytical tool to characterize and contrast the effects of different treatments on RBC chemical composition at the single cell level.

Synchrotron-Infrared Microspectroscopy of Live Leishmania major Infected Macrophages and Isolated Promastigotes and Amastigotes.

The prevalence of neglected tropical diseases (NTDs) is advancing at an alarming rate. The NTD leishmaniasis is now endemic in over 90 tropical and sub-tropical low socioeconomic countries. Current diagnosis for this disease involves serological assessment of infected tissue by either light microscopy, antibody tests, or culturing with in vitro or in vivo animal inoculation. Furthermore, co-infection by other pathogens can make it difficult to accurately determine Leishmania infection with light microscopy. Herein, for the first time, we demonstrate the potential of combining synchrotron Fourier-transform infrared (FTIR) microspectroscopy with powerful discrimination tools, such as partial least squares-discriminant analysis (PLS-DA), support vector machine-discriminant analysis (SVM-DA), and k-nearest neighbors (KNN), to characterize the parasitic forms of Leishmania major both isolated and within infected macrophages. For measurements performed on functional infected and uninfected macrophages in physiological solutions, the sensitivities from PLS-DA, SVM-DA, and KNN classification methods were found to be 0.923, 0.981, and 0.989, while the specificities were 0.897, 1.00, and 0.975, respectively. Cross-validated PLS-DA models on live amastigotes and promastigotes showed a sensitivity and specificity of 0.98 in the lipid region, while a specificity and sensitivity of 1.00 was achieved in the fingerprint region. The study demonstrates the potential of the FTIR technique to identify unique diagnostic bands and utilize them to generate machine learning models to predict Leishmania infection. For the first time, we examine the potential of infrared spectroscopy to study the molecular structure of parasitic forms in their native aqueous functional state, laying the groundwork for future clinical studies using more portable devices.

Monolithic Phosphate Interphase for Highly Reversible and Stable Zn Metal Anode.

Zinc metal battery (ZMB) is promising as the next generation of energy storage system, but challenges relating to dendrites and corrosion of the zinc anode are restricting its practical application. Here, to stabilize Zn anode, we report a controlled electrolytic method for a monolithic solid-electrolyte interphase (SEI) via a high dipole moment solvent dimethyl methylphosphonate (DMMP). The DMMP-based electrolytes can generate a homogeneous and robust phosphate SEI (Zn3 (PO4 )2 and ZnP2 O6 ). Benefiting from the protecting impact of this in situ monolithic SEI, the zinc electrode exhibits long-term cycling of 4700 h and a high Coulombic efficiency 99.89 % in Zn|Zn and Zn|Cu cell, respectively. The full V2 O5 |Zn battery with DMMP-H2 O hybrid electrolyte exhibits a high capacity retention of 82.2 % following 4000 cycles under 5 A g-1 . The first success in constructing the monolithic phosphate SEI will open a new avenue in electrolyte design for highly reversible and stable Zn metal anodes.

Industrial freezing and tempering for optimal functional properties in thawed Mozzarella cheese.

Mozzarella cheese was industrially frozen (-18 °C), stored for up to six months, tempered at 4 °C for one or three weeks and the structure and functionality compared to cheese stored at 4 °C and cheese aged at 4 °C for four weeks prior to freezing. When combined with ageing or tempering, the slow industrial freezing minimised changes to the protein network as detected by confocal microscopy and arrested proteolysis. Cheese functionality improved with three weeks of tempering, with properties similar to cheese refrigerated for one month, potentially due to increased proteolysis and protein rehydration. Frozen storage induced ß-sheet and ß-turn structures, as detected by S-FTIR microspectroscopy, with longer tempering leading to structural recovery in the cheese. This study indicates the proteolysis and functionality of frozen cheese can be optimised with tempering time. It also provides new insights into heat transfer during the industrial freezing and tempering of cheese.

Single Shot Lensless Interferenceless Phase Imaging of Biochemical Samples Using Synchrotron near Infrared Beam.

Phase imaging of biochemical samples has been demonstrated for the first time at the Infrared Microspectroscopy (IRM) beamline of the Australian Synchrotron using the usually discarded near-IR (NIR) region of the synchrotron-IR beam. The synchrotron-IR beam at the Australian Synchrotron IRM beamline has a unique fork shaped intensity distribution as a result of the gold coated extraction mirror shape, which includes a central slit for rejection of the intense X-ray beam. The resulting beam configuration makes any imaging task challenging. For intensity imaging, the fork shaped beam is usually tightly focused to a point on the sample plane followed by a pixel-by-pixel scanning approach to record the image. In this study, a pinhole was aligned with one of the lobes of the fork shaped beam and the Airy diffraction pattern was used to illuminate biochemical samples. The diffracted light from the samples was captured using a NIR sensitive lensless camera. A rapid phase-retrieval algorithm was applied to the recorded intensity distributions to reconstruct the phase information. The preliminary results are promising to develop multimodal imaging capabilities at the IRM beamline of the Australian Synchrotron.