[Tibiotalocalcaneal Arthrodesis: Comparison of Fixation Methods, Mid-Term Clinical Results]. / Tibiotalokalkaneální artrodéza: srovnání metod fixace, strednedobé klinické výsledky.

PURPOSE OF THE STUDY The authors focused on the topic of tibiotalocalcaneal arthrodesis. It is a surgical procedure used to manage severe comprehensive ankle and hindfoot pathology. The scope of surgery and the negative impact on the walking stereotype are offset by preserving a weight-bearing and pain-free limb. The purpose of the study was to evaluate the group of patients who had undergone surgery at the First Department of Orthopaedic Surgery, St. Anne s University Hospital Brno and to identify the most suitable fixation for arthrodesis. It also aimed to compare the outcomes achieved by the authors with those reported by other departments. MATERIAL AND METHODS The group included patients operated on at the authors department between 2011 and 2021. The surgery was indicated in patients with severe concomitant arthritis of the upper and lower ankle, complex hindfoot instability, Charcot arthropathy. Contraindications included acute infection, decompensated diabetes and heavy smoking. The study compares fixation using a lateral plate, a retrograde nail and a retrograde nail with fibula acting as biological plate. The patients were scored preoperatively and postoperatively using the AOFAS Ankle-Hindfoot Score. Statistical analysis of the results was also carried out. RESULTS The group included 23 patients, of whom a lateral plate was opted for in 7 patients, a retrograde nail in 8 patients and a retrograde nail with fibula used as a biological plate in 8 patients. The patients of the group were followed up for the period ranging from 0.5 to 9 years after surgery. Serious complications were observed by the authors in 6 patients of the group. The failure of osteosynthesis material was reported in 2 cases with lateral plating fixation. A stress fracture above the apex of the nail developed in 2 cases. A serious infection was observed by the authors in 1 patient. The method associated with the lowest incidence of complications was the fixation with a retrograde nail and fibula used as a biological plate. DISCUSSION The forms of fixation for tibiotalocalcaneal arthrodesis have recently advanced considerably, the methods of fixation for arthrodesis in particular. The modern implants enable to compress the individual structures, to provide stable fixation and potentially to avoid long-term plaster cast fixation. Nonetheless, these surgical procedures are associated with a high complication rate. Currently, there is no consensus in international studies on the optimal fixation for arthrodesis. Numerous papers describe complications including postoperative infections, failure of osteosynthesis material and fractures close to osteosynthesis material. The number and the type of complications observed by the authors in their group of patients were similar to those reported by other authors. CONCLUSIONS Tibiotalocalcaneal arthrodesis is a surgical procedure reserved exclusively for patients indicated based on strict criteria and should be performed by an experienced team able to cope with potential complications. In the followed-up group of patients, the optimal method of fixation for arthrodesis appeared to be the fixation with a retrograde nail and fibula used as a biological plate. Key words: tibiotalocalcaneal arthrodesis, retrograde nail, lateral ankle plate, ankle instability, ankle arthrosis, biological plate.

[Intramedullary Nailing in Managing Diaphyseal Metastases of Long Bones: Retrospective Study Comparing the Expected Survival and the Actual Survival of Patients]. / Intramedulární hreb v lécbe metastatického postizení diafýz dlouhých kostí: retrospektivní studie s ohledem na srovnání prognózy doby dozití a reálné prezití pacientu.

PURPOSE OF THE STUDY The paper focuses on the potential use of nail osteosynthesis in diaphyseal metastases of long bones. The purpose of the paper is to assess the outcomes of intramedullary osteosynthesis in pathologic and impending pathologic fractures, to evaluate patient survival and potential complications. MATERIAL AND METHODS The retrospective study evaluated a cohort of 42 patients (19 men and 23 women) in whom intramedullary osteosynthesis was performed for complete pathologic fracture (28 patients) or impending pathologic fracture (14 patients) between 2010 and 2019. Of the total number of 42 patients, 31 patients' lower limbs were affected, namely by 17 pathologic fractures and 14 impending fractures. There were 11 humerus fractures. The mean age was 61.8 years (range 41-84 years). In the followed-up cohort, the patient survival after osteosynthesis with intramedullary nails, complications occurred and post-operative mobility of the patient were assessed. The functional outcomes were evaluated using the Musculoskeletal Tumor Society (MSTS) scoring system. The unpaired Mann-Whitney test was used to test the significance of the difference in functional outcomes and survival between the followed-up groups. Survival longer than 6 months was evaluated using Fisher's exact test. The level of statistical significance used for the test was p 0.05. RESULTS The investigated indicator was patient survival, which was 11.3 months (range 1-50 months) on average. In the group of impending fractures, the mean survival was 13.5 months. In the group of pathologic fractures, the survival was 10 months. The functional outcome in 16 followed-up patients at three months after intramedullary osteosynthesis according to the MSTS score was 46.9% (30-66.7%). At the level of significance of p 0.05, the statistically significant difference in the functional outcomes between the group with preventive intramedullary osteosynthesis and the group with nail osteosynthesis of the pathologic fracture was not confirmed (p=0.952). When comparing the patient survival after nail osteosynthesis with impending pathologic fracture and the survival of patients with pathologic fracture, a statistically significant difference in survival between these two groups (p=0.520) was not confirmed. The patient survival of longer than 6 months was 71% in the group of impending fractures and 40% in the group of pathologic fractures. DISCUSSION The occurrence of pathologic fracture is associated with increased pain, loss of function, and according to some authors, a higher risk of death. Surgical treatment options include intramedullary osteosynthesis, plate osteosynthesis with cement filling, implantation of an intercalary spacer, and implantation of tumor endoprostheses. When deciding on a surgical procedure, an account is taken of the expected survival of the patient. In patients with an expected survival of up to 6 months, intramedullary osteosynthesis is indicated as a palliative surgical intervention. The most common complications include implant failure and metastatic progression. CONCLUSIONS Intramedullary osteosynthesis is the method of choice in treating pathologic fractures or impending pathologic diaphyseal fractures of long bones in patients with an expected predicted survival of up to 6 months. Intramedullary osteosynthesis aims to reduce pain and enable early verticalization. The study confirmed the importance of preventive intramedullary osteosynthesis and its effect on survival compared to the survival of patients with a pathologic fracture. Key words: skeletal metastases, diaphyseal metastases, intramedullary osteosynthesis, pathologic fracture, impending fracture.

The impact of waiting time for orthopaedic consultation on pain levels in individuals with osteoarthritis: a systematic review and meta-analysis.

OBJECTIVE: Time spent waiting for access to orthopaedic specialist health services has been suggested to result in increased pain in individuals with osteoarthritis (OA). We assessed whether time spent on an orthopaedic waiting list resulted in a detrimental effect on pain levels in patients with knee or hip OA. METHODS: We searched Ovid MEDLINE, EMBASE and EBSCOhost databases from inception until September 2021. Eligible articles included individuals with OA on an orthopaedic waitlist and not receiving active treatment, and reported pain measures at two or more time points. Random-effects meta-analysis was used to estimate the pooled effect of waiting time on pain levels. Meta-regression was used to determine predictors of effect size. RESULTS: Thirty-three articles were included (n = 2,490 participants, 67 ± 3 years and 62% female). The range of waiting time was 2 weeks to 2 years (20.8 ± 18.8 weeks). There was no significant change in pain over time (effect size = 0.082, 95% CI = -0.009, 0.172), nor was the length of time associated with longitudinal changes in pain over time (ß = 0.004, 95% CI = -0.005, 0.012). Body mass index was a significant predictor of pain (ß = -0.043, 95% CI = -0.079, 0.006), whereas age and sex were not. CONCLUSIONS: Pain remained stable for up to 1 year in patients with OA on an orthopaedic waitlist. Future research is required to understand whether pain increases in patients waiting longer than 1 year.

[Long-Term Results of Total Knee Replacement Using P.F.C. Sigma System with an All-Polyethylene Tibial Component]. / Dlouhodobé výsledky totální náhrady kolenního kloubu P.F.C. Sigma s celopolyetylenovou tibiální komponentou.

PURPOSE OF THE STUDY Use of an all-polyethylene (all-poly, AP) tibial component in primary total knee arthroplasty is still an attractive option considering the durability of replacement, the elimination of backside wear and the lower cost compared to modular metalbacked tibia. The purpose of the study was to evaluate the long-term results of the total knee replacement using the P.F.C. Sigma system with a monoblock all-polyethylene tibial component implanted at the 1st Orthopedic Department of the St. Anne's University Hospital and Masaryk University Brno in the period 1999-2010. MATERIAL AND METHODS In the monitored period, 911 total knee replacements using P.F.C. Sigma with an all-polyethylene tibial component were performed. This cohort of patients was evaluated at least 10 years after the primary replacement surgery. Altogether 323 knee replacements in 289 patients were evaluated. The clinical outcomes were assessed according to the Knee Society Clinical Rating System (KSS) and the Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. The replacement survival was evaluated using the Kaplan-Meier survival analysis. RESULTS In the evaluated group, the average KS was 82.6 points and the average functional score was 74.7 points. Excellent results were recorded in 213 cases, good results in 78 and satisfactory in 23 replacements. Poor clinical results were reported in 9 patients. The average range of motion was 105.8°. In 5 knees (1.5%) revision surgery was performed for infection complications, 3 cases were complicated due to periprosthetic fractures, 4 replacements were revised due to anterior knee pain and 8 knees showed a limited range of motion. Only 1 replacement was revised for aseptic loosening, with no need for reimplantation of the component. The survivorship of the implant was 98.5 % at the follow-up of 12.8 years, including the reasons of reimplantation. DISCUSSION Total knee replacement with an all-polyethylene tibial component is not so popular as the metal-backed modular implants. The all-polyethylene tibial component has certain advantages: lower unit costs, no backside wear, no liner dislocation, possibility of conservative bone resection. On the other hand, this type of implant is not modular and augmentations or longer stems cannot be used. Even though this type of endoprosthesis is recommended exclusively for elderly patients with a lower level of activity, the current mid- and long-term results show that indications for all-poly implants are much broader. CONCLUSIONS The total knee replacement with an all-polyethylene tibial component shows very good long-term clinical outcomes with an excellent survival rate. The all-poly design is cost-effective and may be used not only in elderly patients. Key words: total knee replacement, all-polyethylene tibial component, long-term results.

Targeting eotaxin-1 and CCR3 receptor alleviates enteric neuropathy and colonic dysfunction in TNBS-induced colitis in guinea pigs.

BACKGROUND: The accumulation of eosinophils is mediated by the chemokine receptor-3 (CCR3)-eotaxin axis. Increased expression of eotaxin and its receptor is associated with inflammatory bowel disease (IBD). Activation of eosinophils causes the release of cationic proteins that are neurotoxic such as eosinophil-derived neurotoxin (EDN). Damage to enteric neurons alters neurally controlled functions of the gut correlated with intestinal inflammation. We hypothesized that inhibition of the CCR3-eotaxin axis will prevent inflammation-induced functional changes to the gastrointestinal tract. METHODS: Hartley guinea pigs were administered with trinitrobenzene sulfonate (TNBS; 30 mg/kg in 30% ethanol) intrarectally to induce colitis. A CCR3 receptor antagonist (SB 328437 [SB3]) was injected intraperitoneally 1 hour postinduction of colitis. Animals were euthanized 7 days post-treatment and colon tissues were collected for ex vivo studies. The EDN-positive eosinophils in the colon, indicating eosinophil activation, were quantified by immunohistochemistry. Effects of SB3 treatment on gross morphological damage, enteric neuropathy, and colonic dysmotility were determined by histology, immunohistochemistry, and organ bath experiments. KEY RESULTS: The number of EDN-positive eosinophils was significantly increased in the lamina propria in close proximity to myenteric ganglia in inflamed colon. The TNBS-induced inflammation caused significant damage to colonic architecture and inhibition of colonic motility. Treatment with SB3 antagonist attenuated inflammation-associated morphological damage in the colon, reduced infiltration of EDN-positive eosinophils and restored colonic motility to levels comparable to control and sham-treated guinea pigs. CONCLUSION & INFERENCES: This is the first study demonstrating that inhibition of CCR3-eotaxin axis alleviates enteric neuropathy and restores functional changes in the gut associated with TNBS-induced colitis.

3D-printed polymer antiresonant waveguides for short-reach terahertz applications.

In this work, we present a 3D-printed waveguide that provides effective electromagnetic guidance in the THz regime. The waveguide is printed using low-cost polycarbonate and a conventional fused deposition modeling printer. Light guidance in the hollow core is achieved through antiresonance, and it improves the energy effectively transported to the receiver compared to free space propagation. Our demonstration adds to the field of 3D-printed terahertz components, providing a low-cost way of guiding terahertz radiation.

Short-Chain Fatty Acids Regulate Cytokines and Th17/Treg Cells in Human Peripheral Blood Mononuclear Cells in vitro.

Short-chain fatty acids (SCFAs) have been recognized as mediators of immune responses, including pathways of cytokine production. In this study, we investigated the immune-regulatory effects of SCFAs on human peripheral blood mononuclear cells (PBMCs) from buffy coat of healthy donors. PBMCs were exposed to varying concentrations of individual SCFAs or of their mixtures of acetate, propionate and butyrate. The productions of interleukin (IL) IL-1ß, IL-2, IL-6, IL-10, IL-17, IL-21, IL-23 and transforming growth factor beta 1 (TGF-ß1) were assessed. T cell differentiation after exposure to SCFAs was also examined. Compared with lipopolysaccharide (LPS)-stimulated cells (controls), SCFAs slightly decreased TGF-ß1 production and reduced IL-6 production; butyrate was more effective than acetate or propionate. SCFAs particularly butyrate caused the induction of CD4+CD25+ regulatory T cells (Treg) rather than Th17 cells. SCFAs may up-regulate the production of anti-inflammatory cytokines in PBMCs, resulting in the induction of CD4+CD25+ Treg cells.

Short-Chain Fatty Acids Regulate Secretion of IL-8 from Human Intestinal Epithelial Cell Lines in vitro.

Short-chain fatty acids (SCFAs) including acetate, propionate and butyrate play an important role in the physiological functions of epithelial cells and colonocytes, such as immune response regulation. Human intestinal epithelial cells (IECs) contribute in intestinal immune response via different ways, such as production of different immune factors including Interleukin (IL) IL-8, which act as chemoattractant for neutrophils, and subsequently enhance inflammation. Therefore, we aimed to evaluate the effects of SCFAs on IECs viability and production of IL-8 in vitro. SCFAs were co-cultured with either normal intestinal epithelial (T4056) or adenocarcinoma derived (HT-29) cell lines for 24-96 h in the presence of E.coli lipopolysaccharides (LPS). Cell viability, proliferation, production of IL-8 and expression of IL-8 mRNA were determined in the cell cultures. The result showed that 20 mM of SCFAs was non-cytotoxic to T4056 and enhanced their growth, whereas the growth of HT-29 was inhibited. The SCFAs down regulated LPS-stimulated IL-8 secretion with different response patterns, but no obvious effects on the release of IL-8 from non LPS- stimulated cells. In conclusion, SCFAs showed regulatory effect on release of LPS-stimulated IL-8 as well as the expression of mRNA of IL-8; these might explain the anti-inflammatory and anti-carcinogenic mechanism of SCFAs.

Short-chain fatty acids produced by synbiotic mixtures in skim milk differentially regulate proliferation and cytokine production in peripheral blood mononuclear cells.

Short chain fatty acids (SCFAs) are major products of prebiotic fermentation and confer human health benefits such as immune-regulation. In this study, reconstituted skim milk supplemented with prebiotics (RSMP) including inulin, hi-maize or ß-glucan was fermented by probiotic strains of Lactobacillus spp. and Bifidobacteria spp. After 24 h of fermentation, probiotics growth and SCFAs production were investigated and the produced SCFAs were extracted. Inulin and Lactobacillus rhamnosus GG ATCC 53013 (LGG) combination released highest concentrations of SCFAs compared to LGG and hi-maize or ß-glucan. Extracted SCFAs were then used for in vitro immune modulation study in human peripheral blood mononuclear cells (PBMCs). In lipopolysaccharide (LPS)-stimulated PBMCs, SCFAs particularly butyrate down-regulated tumor necrosis factor alpha, interleukin (IL)-12, interferon gamma (IFN-γ) and transforming growth factor beta-1 (TGF-ß1), and up-regulated IL-4, IL-10, while no significant effect was noted in non-LPS-stimulated PBMCs. The results indicate that SCFAs regulated cytokine milieu in LPS-stimulated PBMCs to anti-inflammatory cytokines.

Waveguide lasers in ytterbium-doped tantalum pentoxide on silicon.

A waveguide laser in an ytterbium-doped tantalum pentoxide film is reported. The waveguide is formed of a rib of sputtered tantalum pentoxide on top of oxidized silicon with an over-cladding of silica. Emission at a wavelength of 1025 nm was achieved with an absorbed pump power threshold and slope efficiency of ≈29 mW and 27%, respectively, for a cavity formed by a high reflector mirror and an estimated 12% Fresnel reflection from the bare end-face at the output.

Maca reduces blood pressure and depression, in a pilot study in postmenopausal women.

OBJECTIVE: Lepidium meyenii (Maca) has been used for centuries for its fertility-enhancing and aphrodisiac properties. In an Australian study, Maca improved anxiety and depressive scores. The effects of Maca on hormones, lipids, glucose, serum cytokines, blood pressure, menopausal symptoms and general well-being in Chinese postmenopausal women were evaluated. METHODS: A randomized, double-blind, placebo-controlled, cross-over study was conducted in 29 postmenopausal Hong Kong Chinese women. They received 3.3 g/day of Maca or placebo for 6 weeks each, in either order, over 12 weeks. At baseline, week 6 and week 12, estradiol, follicle stimulating hormone (FSH), sex hormone binding globulin (SHBG), thyroid stimulating hormone (TSH), full lipid profiles, glucose and serum cytokines were measured. The Greene Climacteric, SF-36 Version 2, Women's Health Questionnaire and Utian Quality of Life Scales were used to assess the severity of menopausal symptoms and health-related quality of life. RESULTS: There were no differences in estradiol, FSH, TSH, SHBG, glucose, lipid profiles and serum cytokines amongst those who received Maca as compared to the placebo group; however, significant decreases in diastolic blood pressure and depression were apparent after Maca treatment. CONCLUSIONS: Maca did not exert hormonal or immune biological action in the small cohort of patients studied; however, it appeared to reduce symptoms of depression and improve diastolic blood pressure in Chinese postmenopausal women. Although results are comparable to previous similar published studies in postmenopausal women, there might be a cultural difference among the Chinese postmenopausal women in terms of symptom reporting.

Fluence and polarisation dependence of GaAs based Lateral Photo-Dember terahertz emitters.

We characterise THz output of lateral photo-Dember (LPD) emitters based on semi-insulating (SI), unannealed and annealed low temperature grown (LTG) GaAs. Saturation of THz pulse power with optical fluence is observed, with unannealed LTG GaAs showing highest saturation fluence at 1.1 ± 0.1 mJ cm(-2). SI-GaAs LPD emitters show a flip in signal polarity with optical fluence that is attributed to THz emission from the metal-semiconductor contact. Variation in optical polarisation affects THz pulse power that is attributed to a local optical excitation near the metal contact.

A metamolecule antenna for coplanar waveguides.

We report on a metamolecule antenna, based on a fish-scale design but augmented with two split-ring resonators (SRRs) placed within the fish-scale loops. The properties of the antenna resonator, with and without additional SRRs, were examined using finite element method simulations (COMSOL Multiphysics). The simulation findings were subsequently confirmed experimentally, using a vector network analyser coupled to an antenna-loaded coplanar waveguide (CPW). The addition of SRRs to the fish-scale meta-molecule leads to a demonstrably large increase in microwave-absorption. It is shown that the fish-scale/SRR/CPW combination performs as a microwave antenna. Simulations of the antenna gain and far-field emission are presented and discussed.

Investigation of the role of the lateral photo-Dember effect in the generation of terahertz radiation using a metallic mask on a semiconductor.

Pulses of coherent terahertz radiation can be efficiently generated by a lateral diffusion current after ultrafast generation of photo-carriers near a metal interface on the surface of a semiconductor, this is known as the lateral photo-Dember effect. We investigate how the emission depends on the pump spot position, size, power and how it is affected by the application of an applied external bias. We study the role of the metallic mask and how it suppresses emission from the carriers diffusing under it due to a reduction of available radiation states both theoretically and experimentally.

Myeloid derived suppressor cells and their role in diseases.

Myeloid derived suppressor cells (MDSCs) are a heterogeneous population of myeloid progenitors that can play a major role in tumour development and chronic inflammation. The importance of the suppressive function ofMDSCs was first suggested by studies involving cancer patients and cancer-bearing mice. In addition, recent studies have demonstrated that MDSCs can also be involved in many other pathological conditions. MDSCs have unique ways of abrogatingan immune response in addition to those utilised by other immune-suppressive cell types, for example via the induction of arginase-1 and consequent upregulation in reactive oxygen species (ROS) production. Due to their heterogeneity,they further can express a variety of lineage markers, which overlap with other myeloid cell types such as Gr1,CD11b, MHCIIlo, Ly6C and Ly6G, making it difficult to identify them by surface phenotype alone. The disparity between mouse and human MDSCs further complicates the identification of these elusive cell populations. In this review, we will summarise the recent updates on the methods for eliciting and studying different MDSC subsets, including newly proposed surface phenotypes, as well as insights into how their function is being characterised in both mice and humans. In addition, exciting new discoveries suggesting their involvement across a number of different pathological settings, such as sepsis, autoimmunity and Leishmaniasis, will be discussed.

Terahertz emission by diffusion of carriers and metal-mask dipole inhibition of radiation.

Terahertz (THz) radiation can be generated by ultrafast photo-excitation of carriers in a semiconductor partly masked by a gold surface. A simulation of the effect taking into account the diffusion of carriers and the electric field shows that the total net current is approximately zero and cannot account for the THz radiation. Finite element modelling and analytic calculations indicate that the THz emission arises because the metal inhibits the radiation from part of the dipole population, thus creating an asymmetry and therefore a net current. Experimental investigations confirm the simulations and show that metal-mask dipole inhibition can be used to create THz emitters.

Cytokine profile and induction of T helper type 17 and regulatory T cells by human peripheral mononuclear cells after microbial exposure.

The immunomodulatory effects of probiotics were assessed following exposure of normal peripheral blood mononuclear cells (PBMC), cord blood cells and the spleen-derived monocyte/macrophage cell line CRL-9850 to Lactobacillus acidophilus LAVRI-A1, Lb. rhamnosus GG, exopolysaccharides (EPS)-producing Streptococcus thermophilus St1275, Bifidobacteriun longum BL536, B. lactis B94 and Escherichia coli TG1 strains. The production of a panel of pro- and anti-inflammatory cytokines by PBMC following bacterial stimulation was measured, using live, heat-killed or mock gastrointestinal tract (GIT)-exposed bacteria, and results show that (i) all bacterial strains investigated induced significant secretion of pro- and anti-inflammatory cytokines from PBMC-derived monocytes/macrophages; and (ii) cytokine levels increased relative to the expansion of bacterial cell numbers over time for cells exposed to live cultures. Bifidobacteria and S. thermophilus stimulated significant concentrations of transforming growth factor (TGF)-ß, an interleukin necessary for the differentiation of regulatory T cells (T(reg) )/T helper type 17 (Th17) cells and, as such, the study further examined the induction of Th17 and T(reg) cells after PBMC exposure to selected bacteria for 96 h. Data show a significant increase in the numbers of both cell types in the exposed populations, measured by cell surface marker expression and by cytokine production. Probiotics have been shown to induce cytokines from a range of immune cells following ingestion of these organisms. These studies suggest that probiotics' interaction with immune-competent cells produces a cytokine milieu, exerting immunomodulatory effects on local effector cells, as well as potently inducing differentiation of Th17 and T(reg) cells.

Inflammatory mediators hold the key to dendritic cell suppression and tumor progression.

Cancer has long been considered a disease that is associated with immune tolerance. Its connection with inflammation initially appears paradoxical. During the last decade, it has become increasingly clear that immune infiltrates form an integral part of tumor and critically contribute to its development and progression. In the tumor milieu, a variety of inflammatory mediators, such as cytokines (IL- 6, IL-10, VEGF, TGFß, M-CSF and GM-CSF), chemokines (CCL20 and CXCL8), hormones (prostanoids like PGE2), reactive oxygen species and cellular constituents (gangliosides), are continuously produced. These mediators represent a critical interface between immune and neoplastic compartments. Not only do they continuously support tumor survival and expansion, but suppress the function of immune cells, notably, dendritic cells - the powerful antigen presenting cells that are crucial for induction of tumor-specific immune responses. This review summarizes such a dual role of inflammatory factors and discusses the controversies associated with specific mediators including IL-10, GM-CSF and ROS in tumor and immune modulation. Identifying the inflammatory signature of cancer patients hence represents a critical task for individualized immunotherapy in the future.

Waveguide mode filters fabricated using laser-induced forward transfer.

Titanium (Ti)-in-diffused lithium niobate waveguide mode filters fabricated using laser-induced forward transfer followed by thermal diffusion are presented. The mode control was achieved by adjusting the separation between adjacent Ti segments thus varying the average value of the refractive index along the length of the in-diffused channel waveguides. The fabrication details, loss measurements and near-field optical characterization of the mode filters are presented. Modeling results regarding the device performance are also discussed.

Numerical simulation of optical Stark effect saturable absorbers in mode-locked femtosecond VECSELs using a modified two-level atom model.

The interaction of an optical pulse with a quantum well saturable absorber is simulated using a semi-classical two-level-atom model which has been modified to approximate spectral hole burning in the carrier distribution. Saturable absorption behaviour is examined in the limit where pulse duration approaches the carrier-carrier scattering time. For long pulses bleaching dominates the absorber response but as the pulse duration approaches the carrier-carrier scattering timescale an additional pulse shaping mechanism becomes active, allowing the absorber to continue to shorten pulses beyond the limit set by bleaching. Examination of the spectral and temporal absorption profiles suggests that intense pulses experience additional pulse shortening from the optical Stark effect.