Normal Kinetics Research Articles

Corrosion of iron in liquid uranium hexafluoride at 80 °C. Part I: Normal and abnormal experimental kinetics

The results reported here are the first on pure iron corrosion in liquid UF6 at 80 °C. Two kinetic behaviours have been observed: one led to micrometric scales (from micron to hundreds of microns after several months) and the other one to hundreds of nanometers for several months. The higher corrosion kinetics resulted in the presence of impurities such as NOxF complexes formed by interaction between the medium and the reactor material. These NOxF catalysed the corrosion reaction leading to a corrosion mechanism controlled by the cathodic reaction rate. Effect of impurities in UF6 coming from experimental conditions or nature of uranium ore should then be systematically and carefully checked. Whatever the corrosion kinetics and the presence of impurities, the nature of the layer was identical: a duplex fluoride scale composed of an iron rich layer, FeF2, and a uranium rich layer evolving over time from U2F9 to UF5.

Cutting Edge: Redundant Roles for MHC Class II-, CD1d-, and MR1-restricted T Cells in Clearing Bartonella Infection.

The importance of unconventional T cells for mucosal immunity is firmly established but for systemic bacterial infection remains less well defined. In this study, we explored the role of various T cell subsets in murine Bartonella infection, which establishes persistent bacteremia unless controlled by antibacterial Abs. We found that αβ T cells are essential for Ab production against and clearance of B. taylorii, whereas MHC class I (MHC-I)- or MHC class II (MHC-II)-deficient mice eliminated B. taylorii infection with normal kinetics. Similarly, animals lacking either CD1d or MR1 suppressed bacteremia with normal kinetics. Interestingly, mice with a combined deficiency of either MHC-II and CD1d or MHC-II and MR1 failed to clear the infection, indicating that the combination of CD1d- and MR1-restricted T cells can compensate for the lack of MHC-II in this model. Our data document a previously underappreciated contribution of unconventional T cells to the control of systemic bacterial infection, supposedly as helper cells for antibacterial Ab production.

Polish Society of Biomechanics Morecki&Fidelus Award Winner: Comparison of two polymers PDO and PLLA/PCL in application of urological stent for the treatment of male urethral stenosis.

Purpose: The primary objective of the conducted research was to develop an urological stent design for the treatment of male ure-thral stenosis. Given the variable loading conditions inside the urethra, the proposed stent should maintain normal tissue kinetics and obstruct the narrowed lumen. The suitable selection for the stent material significantly influences the regeneration and proper remodeling of the urethral tissues. Methods: In this work, the mechanical characteristics of some polymer materials were studied, including: polydi-oxanone (PDO) and poly(L-lactide) (PLLA)/polycaprolactone (PCL) composite. The obtained mechanical properties for static tensile testing of the materials, allowed the determination of such parameters as Young's modulus (E), tensile strength (R m) and yield strength (R e). Subsequently, the design of a urological stent was developed, for which a numerical analysis was carried out to check the behaviour of the stent during varying loads prevailing in the urethra. Result: The research indicated that PDO has better mechanical properties than the proposed PLLA/PCL composite. The numerical analysis results suggested that the developed stent design can be successfully used in the treatment of male urethral stenosis. The obtained stress and strain distributions in the numerical analysis confirm that the PDO material can be used as a material for an urological stent. Conclusions: The biodegradable polymers can be successfully used in urology. Their advantages over solid materials are their physicochemical properties, the ability to manipulate the rate and time of degradation and the easy availability of materials and manufacturing technology.

Transition from Sequential to Concerted Proton-Coupled Electron Transfer of Water Oxidation on Semiconductor Photoanodes.

Accelerating proton transfer has been demonstrated as key to boosting water oxidation on semiconductor photoanodes. Herein, we study proton-coupled electron transfer (PCET) of water oxidation on five typical photoanodes [i.e., α-Fe2O3, BiVO4, TiO2, plasmonic Au/TiO2, and nickel-iron oxyhydroxide (Ni1-xFexOOH)-modified silicon (Si)] by combining the rate law analysis of H2O molecules with the H/D kinetic isotope effect (KIE) and operando spectroscopic studies. An unexpected and universal half-order kinetics is observed for the rate law analysis of H2O, referring to a sequential proton-electron transfer pathway, which is the rate-limiting factor that causes the sluggish water oxidation performance. Surface modification of the Ni1-xFexOOH electrocatalyst is observed to break this limitation and exhibits a normal first-order kinetics accompanied by much enhanced H/D KIE values, facilitating the turnover frequency of water oxidation by 1 order of magnitude. It is the first time that Ni1-xFexOOH is found to be a PCET modulator. The rate law analysis illustrates an effective strategy for modulating PCET kinetics of water oxidation on semiconductor surfaces.

The Effect of Surgical Approach and Hip Offset Reconstruction on Gait Biomechanics Following Total Hip Arthroplasty

BackgroundThis study aimed to examine how hip offset (HO) and surgical approach affect gait biomechanics following total hip arthroplasty (THA). MethodsThere were 55 THA patients assigned to 3 groups based on surgical approach (ANT: anterior, LAT: lateral, or POS: posterior) and HO difference (large HO: >5 millimeters (mm), small HO; <5 mm, or normal; between +3 mm and –3 mm). Kinematics and kinetics were recorded using motion capture and force plate data. Group differences were assessed using statistical parametric mapping. ResultsThe ANT group demonstrated more normal sagittal plane kinematics and kinetics. No frontal plane kinematic differences were found, but the LAT group displayed more normal frontal plane kinetics. The LAT group displayed a slower walking speed than the ANT group, and the LAT and POS groups used a shorter stride/step length than the control group. The large HO group showed fewer differences in sagittal plane kinematics and kinetics than the small HO and normal groups. No frontal plane kinematic differences were observed, but the normal group demonstrated more significant differences than the large HO and small HO groups. No significant differences were found between any of the HO patient groups. ConclusionAnterior and lateral approaches led to more normal gait biomechanics in sagittal kinematics and frontal kinetics, respectively, but only the ANT group exhibited spatiotemporal gait parameters within normal ranges. Hip offset differences greater or less than 5 mm do not significantly change gait patterns. Surgical approach plays a greater role than HO reconstruction in producing more normal gait biomechanics following THA.

Effects of the intrinsic energy on kinetics of bio-molecules in multidimensional landscape model

The intrinsic energy G, which is crucial for distinguishing the chemical activity of bio-molecules, plays a significant role. Various factors affecting intrinsic energy differ from simple correlations observed in the inorganic field or small organic molecular systems. To gain deeper insights into the dynamic properties within a multidimensional landscape, typical components associated with intrinsic energy, such as the pulling force F, activity distance ΔQ‡, and configurational symmetry, have been investigated. The pulling force primarily affects the x coordination and provides a quantitative measure of dynamic properties. On the other hand, estimating the influence of ΔQ‡ and configurational symmetry on intrinsic energy is complex due to their connection with configuration fluctuation properties. In this study, a statistical method was employed to investigate the fluctuation. By comparing the mean waiting time ⟨t⟩, significant differences between normal kinetics and dynamic disorder were revealed. Our findings offer a novel perspective for examining the role of intrinsic energy or potential energy in bio-molecules.

Outer-arm dynein light chain LC1 is required for normal motor assembly kinetics, ciliary stability, and motility.

Light chain 1 (LC1) is a highly conserved leucine-rich repeat protein associated with the microtubule-binding domain of the Chlamydomonas outer-dynein arm γ heavy chain. LC1 mutations in humans and trypanosomes lead to motility defects, while its loss in oomycetes results in aciliate zoospores. Here we describe a Chlamydomonas LC1 null mutant (dlu1-1). This strain has reduced swimming velocity and beat frequency, can undergo waveform conversion, but often exhibits loss of hydrodynamic coupling between the cilia. Following deciliation, Chlamydomonas cells rapidly rebuild cytoplasmic stocks of axonemal dyneins. Loss of LC1 disrupts the kinetics of this cytoplasmic preassembly so that most outer-arm dynein heavy chains remain monomeric even after several hours. This suggests that association of LC1 with its heavy chain-binding site is a key step or checkpoint in the outer-arm dynein assembly process. Similarly to strains lacking the entire outer arm and inner arm I1/f, we found that loss of LC1 and I1/f in dlu1-1 ida1 double mutants resulted in cells unable to build cilia under normal conditions. Furthermore, dlu1-1 cells do not exhibit the usual ciliary extension in response to lithium treatment. Together, these observations suggest that LC1 plays an important role in the maintenance of axonemal stability.

Radical Polymerization Kinetics of Hexyl Methacrylate in Dimethylsulfoxide Solution

In this study, we conducted a series of polymerization studies of hexyl methacrylate in dimethyl sulfoxide with (0.1 - 0.4) mol dm-3 of monomer and (1 10-3 – 4 10-3) mol dm-3 of benzoyl peroxide as initiators at 70 °C. Using the well-known conversion vs. time technique, the effects of initiator and monomer concentration on the rate of polymerization (Rp) were studied. An initiator of order 0.35 was obtained in accordance with theory and a divergence from normal kinetics was detected with an order of 1.53 with respect to monomer concentration. The activation energy was determined to be (72.90) kJ mol-1, which does not correspond to the value of most thermally initiated monomers. The observed value of activation energy suggests that propagation and termination reactions have equal activation energy and the difference between them is nearly zero. The average degree of polymerization (DPn) decreased as benzoyl peroxide concentration increase whereas an increase in solvent polarity has slightly increased rate of polymerization value.

Rod photoreceptor activation and deactivation in early-stage diabetic eye disease.

To infer rod phototransduction activation and deactivation characteristics in diabetics who have mild or no clinically-apparent retinopathy. Fifteen non-diabetic controls, 15 diabetics with no clinically-apparent diabetic retinopathy (NDR), and 15 diabetics with mild non-proliferative diabetic retinopathy (MDR) participated. Dark-adapted flash electroretinograms (3.2 to 4.4 log scot td-s) were recorded to assess rod activation. The a-waves were fit with a Gaussian model to derive Rmp3 (maximum photoreceptor response amplitude) and S (phototransduction sensitivity). Rod deactivation was assessed with a paired flash paradigm, in which a-waves were measured for two flashes separated by inter-stimulus intervals (ISIs) of 0.125 to 16s. The ISI needed for the a-wave amplitude of the second flash to recover to 50% of the first flash (t50) was determined. The effect of stimulus retinal illuminance on activation and deactivation was evaluated in a subset of control subjects. Analysis of variance indicated that both diabetic groups had significant log S reductions compared to controls (p < 0.001). Mean S was reduced by approximately 49% and 78% for the NDR and MDR groups, respectively. In contrast, log Rmp3 and log t50 did not differ significantly among the groups (both p > 0.08). Reducing stimulus retinal illuminance significantly reduced S, but did not significantly affect Rmax or t50. Only phototransduction sensitivity was abnormal in this sample of diabetic subjects. The normal deactivation kinetics suggests that circulating rod current is normal. These findings begin to constrain possible explanations for abnormal rod function in early diabetic retinal disease.

Baseline Kinetics of Clot Waveform Analysis of Clotting Screening Tests on Sysmex CS2500 Automated Coagulometry

Clot waveforms generated by different automated coagulometry are of immense utility in predicting the risk of bleeding or thrombosis. They are part of global hemostasis testing. Different automated analyzers use different technology for clotting screening tests. The clotting screening results depends on the instrument and the reagents used. Hence clot waveform analysis may have different kinetics based on instrument or reagents used. A baseline characteristic can help in clinical interpretation.Total 47 voluntary blood donors (23 males and 24 females) between 20-50 years age are included in the study. We have analyzed the kinetics of clot waveform of Prothrombin time (PT) using Dade Innovin, activated partial thromboplastin time (aPTT) using Actin FS &amp; Actin FSL and thrombin time (TT) on Sysmex CS2500 automated coagulometry. The baseline characteristics were analyzed and the reference intervals were determined as follows: PT using Dade Innovin reagent: 9.8 – 12.0s, its 1st derivative or maximum velocity (min1): 1.00-2.42 %/s, 2nd derivative or maximum acceleration (min2): 0.14-0.38%/s2, maximum deceleration (max2): 0.18-0.42 %/s2; aPTT using actin FSL: 26.2-34.5s, min1 2.73-6.17%/s, min2 0.41-0.95%/s2, max2 0.30-0.77 %/s2 ; aPTT using actin FS reagent: 21.2-30.5s, min1 2.73-6.33 %/s, min2 0.37-1.07 %/s2, max2 0.32-0.94 %/s2 ; TT: 16.8-19.6 s, min1 0.57-1.23 %/s, min2 0.08-0.20 %/s2, max2 0.03-0.11 %/s2 respectively. The clotting time shows an inverse moderate to weak relationship with maximum velocity, maximum acceleration and maximum deceleration. Analyzing the normal kinetics of clot waveform helps in understanding the clotting process and clinical interpretation.

738 A RARE CASE OF UNICUSPID AORTIC VALVE WITH SEVERE STENOSIS AND REGURGITATION: CLINICAL PRESENTATION AND MANAGEMENT

Abstract A 19-year-old Pakistani migrant, who arrived in our country on foot, presented at emergency department with angina and worsening dyspnoea on exertion. The patient reported an unclear history of aortic valve disease. Clinical examination revealed a 6/6L systolic murmur with thrill. The electrocardiogram showed sinus rhythm and signs of left ventricular hypertrophy. Chest X-ray reported cardiomegaly and signs of congestion. Troponin I HS was mildly elevated (39 ng/L, n.v. &amp;lt; 18 ng/L). The patient was admitted to our Cardiology department. Transthoracic echocardiography revealed a mildly dilated left ventricle (LV), with severe hypertrophy, normal kinetics and systolic function (EF 63%), dilated ascending aorta (diam. 41 mm) and severe aortic steno-insufficiency. Transesophageal echocardiography was then performed, revealing a highly calcified, unicuspid unicommissural aortic valve with severe stenosis and regurgitation. A separate origin of left coronary ostia was also documented. The patient was referred to urgent cardiac surgery. A modified Bentall procedure (mechanical valve and prosthetic conduit) was performed with reimplantation of the coronary ostia. Due to a post-surgical complete atrioventricular block, a dual-chamber pacemaker (DDD) was implanted. Follow-up echocardiography showed reduction of LV volumes and wall thickness and normal prosthetic function. Unicuspid aortic valve is a very rare congenital disease, with a prevalence of about 0.02% in the adult population and is frequently associated with ascending aorta dilatation. The treatment is aortic valve replacement. Complete atrioventricular block can occur after surgery, requiring cardiac pacing.

493 A CASE REPORT OF SUBACUTE INFLAMMATORY HEART DISEASE WITH AN ATYPICAL ONSET

Abstract Background Inflammatory heart disease is a heterogeneous process with variegate clinical manifestations. The acute phase is characterized by a sudden injury involving cardiomyocytes, cardiac conduction system and/or pericardium, with different pathophysiological implications. Case Summary A 26-year-old previously healthy woman presented for worsening fatigue and bradycardia. The ECG at admission showed total heart block with infra-Hisian escape rhythm, heart rate was 36 bpm. She reported no history of tick bite or recent inflammatory event; body temperature was 36,8 °C. Laboratory assessment showed persistently raised troponin (28943 -&amp;gt; 32632 ng/l), C-reactive protein was 0,70 mg/l, white blood cells 4,86×10^3/µl, procalcitonin 0,03 µg/l, interleukin-6 was 60,5 pg/ml (n.v. &amp;lt;28,0) and NT-pro-BNP was 312 pg/ml. Borrelia, Salmonella, Ricketsiae, Toxoplasma screening was negative for acute infection as well as any other viral serology. Comprehensive laboratory autoimmunity assessment was negative. Echocardiography revealed normal biventricular volume and kinetics, no valvulopathies and no pericardial effusion. Coronary angiogram was normal. The cardiac magnetic resonance showed extensive oedema and contextual late gadolinium enhancement predominantly in the interventricular septum and mid segment of the anterior wall. Serum angiotensin-converting enzyme concentration was normal. Due to persistent heart block, after 5 days the patient underwent endomyocardial biopsy that showed slight oedema and mild fibrosis without lymphocytic infiltration nor histochemical findings suggestive of active myocarditis. Granulomas were absent. Viral analysis on myocardium was negative. An intermediate dose of steroids was started with a progressive restoration of 1:1 atrioventricular conduction and shortening of QRS up to incomplete right bundle branch block, hence the patient was discharged without pacemaker implantation. Discussion In heart inflammatory diseases with bradyarrhythmic onset, atrioventricular conduction may be restored with targeted therapy. Multimodality assessment is crucial in the diagnostic and therapeutic work-up of these cases.

Effects of activity distance on dynamics of bio-molecules in the multidimensional potential energy model

Activity distance, which is commonly used to describe the transformation from a bound state to a transition state in the potential energy landscape model, is the key factor in the bio-molecular system to study dynamic properties. Adopted both in phenomenological theory and the statistical model, activity distance is the fundamental parameter to describe the kinetic characteristics of bio-molecules and is usually connected with the change in the pulling force F. The effects of activity distance Δx‡ are easy to be detected in a single dimensional landscape model because the force only expresses the mechanical work −Fx, which mainly overlaps with the fluctuation of the configuration of bio-molecules. However, as the force cannot affect the transformation directly in the multidimensional landscape model, the deflection angle φ is introduced in our work to discuss the pulling force, which has partial effects on the Q dimension. By comparing the mean waiting time ⟨t⟩ under the conditions of normal kinetics and dynamic disorder, in this study, we show the typical results from the effects of activity distance on the multidimensional potential energy model.

Safety of Novel Inpatient High Dose Methotrexate Protocol with Reduced Length of Hospital Stay

Introduction: High dose methotrexate (HD-MTX) treatment needs close monitoring, forced diuresis using intravenous hydration to ensure rapid drug clearance, and leucovorin rescue. Delayed clearance can result in serious adverse events such as severe mucositis and pancytopenia. Most institutions keep patients hospitalized until complete drug clearance, which can take up to 4-5 days on average (Binder, A et al.). Patients who exhibit normal drug clearance kinetics exhibit no increase in toxicity. Method: We developed modified protocol at Regions Hospital where patients can be discharged if their initial post-infusion methotrexate drug levels demonstrate normal clearance kinetics [< 5 mM (micromoles/L) at 24 hours or < 1 mM at 48 hours], they are able to maintain adequate oral hydration and have no evidence of renal or hepatic dysfunction. Patients are prescribed oral leucovorin at discharge to complete 7 days of treatment. Many institutions use a protocol that involves serial methotrexate drug level monitoring each day until the level is below 0.1-0.05 mM. We conducted a retrospective chart review to determine if the modified protocol is comparable to the commonly used standard protocol in terms of safety. We summarized patient- and cycle-specific characteristics and assessed the incidence of renal, hepatic, gastrointestinal, and hematologic toxicities among patients treated with HD-MTX (defined as ≥ 1000 mg/m2). Results: We retrospectively reviewed medical records of 53 patients who received intravenous methotrexate in our institution between 2015-2019. Only 29 patients had received HD-MTX (defined as ≥ 1000 mg/m2). Median age was 65 years [33-86], 55.2% (n=16) were male. HD MTX was given for B-cell lymphoma with high risk for CNS recurrence in 15 patients (51.7%), primary CNS lymphoma in 12 patients (41.4%) and acute lymphocytic lymphoma in 2 patients (6.9%). Median MTX dosage was 9 g [4-18]. Median 24-hour MTX-level was 3.78 mM and 48- hour MTX-level was 0.39 mM. (Tables 1-2). Of the total number of 156 cycles, grade III or more of hematological, hepatic, and renal toxicities were reported in (9.6%, 1.3% and 0%) respectively. There was no increase from low grade (0, I, II) to high grade (III, IV) toxicities. Mucositis was not reported after any of these cycles; however, febrile neutropenia occurred after 4 cycles (2.4%). Overall, there was no increase in toxicity compared to toxicity of historical protocol (Stoller RG. et al.). Length of hospital stay (LOS) was 3 days [1-79] comparing with 4-5 days to what reported historically. (Table 2). Conclusion: Our date suggests that patients who received high dose methotrexate can be safely discharged early if they exhibit normal drug clearance kinetics with in the first 48 hours after infusion, maintain normal renal function and continue oral hydration and leucovorin as outpatient. Adopting this protocol may have an economic benefit by shortening the length of hospitalization by 1-2 days. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Combined Genetic Ablation of CD54 and CD58 in CAR Engineered Cytotoxic Lymphocytes Effectively Averts Allogeneic Immune Cell Rejection

Allogeneic cell therapies hold promise to be cost effective with scaled manufacturing for multi-dosing and on-demand off-the-shelf availability. A critical consideration for allogeneic cell products is their ability to persist, maintain function and avoid rejection by the patient's immune system. Genetic knockout (KO) of beta-2-microglobulin (B2M) leads to complete loss of cell-surface human leukocyte antigen (HLA) class I expression and efficiently abrogates CD8+ T-cell reactivity. However, loss of HLA class I triggers NK cell-mediated missing-self recognition and manipulation of B2M must therefore be combined with other immune-modulating strategies to limit recipient NK cell reactivity. We hypothesized that rejection by the patient's immune system can be diminished in primary CAR T cells, iPSC-derived T (iT) and NK (iNK) cells by reverse-engineering common tumor escape mechanisms. The adhesion molecules CD54 and CD58 are both present at the target cell side of the immune synapse, and loss of either of these molecules have previously been reported to elicit immune escape. Here, we show that the combined deletion of CD54 and CD58 in allogeneic immune effector cells makes them resistant to rejection by recipient immune cells through unidirectional reduced synapse formation (Figure 1A). HLA class I down-regulation by B2M silencing in primary T and NK cells triggered potent cytotoxicity by resting allogeneic NK cells. This response was mostly driven by educated NK cells expressing either NKG2A or killer cell immunoglobulin-like receptors (KIR) binding to HLA-E and HLA-C, respectively. However, over-expression of HLA-E or single HLA-C ligands in a K562 screening model only shut down the specific response of the NK cell subset carrying the cognate inhibitory receptor, resulting in only partial resistance to NK cells at the bulk level. Notably, the introduction of HLA-E was particularly detrimental in donors with expanded NKG2C+ NK cell subsets, due to its stimulatory effect through the activating NKG2C receptor. In contrast, combined deletion of CD54 and CD58 in target cells uniquely decreased the response of all tested NK cell subsets and showed universal reduction across NK cell populations from 18 healthy donors (Figure 1B). To delineate the mechanisms behind the increased resistance of target cells carrying these edits, we studied NK cell-target cell interactions at the single cell level by confocal microscopy in microchips. Allogeneic NK cells formed fewer conjugates and failed to form productive immune synapses with CD54-/-CD58-/- target cells, supporting the notion that they are more resistant to NK-cell mediated killing by unidirectional altered adhesion. We next introduced these edits in primary B2M-/- T cells engineered to express a second generation CAR19 from the TRAC locus. Corroborating the K562 screen, CD54-/-CD58-/-B2M-/- CAR-T cells had a selective survival advantage over B2M-/- CAR T cells and HLA-E-over-expressing B2M-/- CAR T cells in conventional mixed lymphocyte reaction (MLR) assays in vitro. Furthermore, we established an in vivo model to probe the effect of different genetic edits on the persistence of allogeneic cell therapy products. To this end, a mixed population of B2M-/- CAR T cells additionally bearing either CD54 and/or CD58 KO, HLA-E over-expression, or no further edits were infused into mice harboring allogeneic healthy donor PBMC. We found that CD54-/-CD58-/-B2M-/- CAR T cells had significantly better in vivo persistence compared to both B2M-/- CAR T cells and HLA-E+B2M-/- CAR T cells in the presence of PBMC from healthy donors (Figure 1B). Although multiplexed editing is feasible in primary CAR T cells, the iPSC platform has an unmatched capacity for homogenously introducing multiple immune-evasion strategies for off-the-shelf cell therapy. Similar to primary CAR T cells, multiplexed edited CD54-/-CD58-/-B2M-/-CIITA-/- iNK cells showed normal growth kinetics and were resistant to rejection by activated allogeneic NK cells in MLR assays. Together, these data demonstrate that reverse-engineering of common tumor escape mechanisms, which render target cells less susceptible to immune synapse formation, is an effective strategy to avert immune rejection of allogeneic CAR T and iPSC-derived CAR NK cells. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Serpin-loaded extracellular vesicles promote tissue repair in a mouse model of impaired wound healing

Chronic metabolic diseases such as diabetes are characterized by delayed wound healing and a dysregulation of the inflammatory phase of wound repair. Our study focuses on changes in the payload of extracellular vesicles (EVs) communicating between immune cells and stromal cells in the wound bed, which regulate the rate of wound closure. Adoptive transfer of EVs from genetically defined mouse models are used here to demonstrate a functional and molecular basis for differences in the pro-reparative biological activity of diabetic (db/db) vs. wildtype EVs in wound healing. We identify several members of the Serpin family of serine protease inhibitors that are absent in db/db EVs, then we overexpress Serpin A1, F2 and G1 in EVs to evaluate their effect on wound healing in db/db mice. Serpins have an important role in regulating levels of elastase, plasmin and complement factors that coordinate immune cell signaling in full thickness wounds in a diabetic model. Here, we establish a novel therapeutic approach by engineering the payload of EVs based on proteomic analysis. Serpin-loaded EVs were used to rescue the Serpin deficiency identified by proteomics and promote wound healing in db/db mice, as well as evaluated how EVs affected extracellular matrix remodeling and the resolution of tissue injury. Therefore, we propose that the identification of EV payloads that are downregulated in diabetic wounds can be systematically analyzed for their functional activity and potential as a therapeutic, based on whether their re-expression in engineered EVs restores normal kinetics of tissue repair in chronic wounds.Graphical

Comparison of Inflammatory Markers Changes in Patients Who Used Postoperative Prophylactic Antibiotics within 24 Hours after Spine Surgery and 5 Days after Spine Surgery.

C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), and white blood cell (WBC) count are inflammatory markers used to evaluate postoperative infections. Although these markers are non-specific, understanding their normal kinetics after surgery may be helpful in the early detection of postoperative infections. To compliment the recent trend of reducing the duration of antibiotic use, this retrospective study investigated the inflammatory markers of patients who had received antibiotics within 24 hours after surgery according to the Health Insurance Review & Assessment Service guidelines and compared them with those of patients who had received antibiotics for 5 days, which was proven to be non-infectious. We enrolled 74 patients, divided into two groups. Patients underwent posterior lumbar interbody fusion (PLIF) at a single institution between 2019 and 2020. Group A included 37 patients who received antibiotics within 24 hours after the PLIF procedure, and group B comprised 37 patients who had used antibiotics for 5 days. A 1 : 1 nearest-neighbor propensity-matched analysis was used. The clinical variables included age, sex, medical history, body mass index, estimated blood loss, and operation time. Laboratory data included CRP, ESR, and WBC, which were measured preoperatively and on postoperative days (POD) 1, 3, 5, and 7. CRP dynamics tended to decrease after peaking on POD 3, with a similar trend in both groups. The average CRP level in group B was slightly higher than that in group A; however, the difference was not statistically significant. Multiple linear regression analysis revealed operation time, number of fused levels, and estimated blood loss as significant predictors of a greater CRP peak value (r²=0.473, p<0.001) in patients. No trend (a tendency to decrease from the peak value) could be determined for ESR and WBC count on POD 7. Although slight differences were observed in numerical values and kinetics, sequential changes in inflammatory markers according to the duration of antibiotic administration showed similar patterns. Knowledge of CRP kinetics allows the assessment of the degree of difference between the clinical and expected values.

Initiated Chemical Vapor Deposition (iCVD) of Bio-Based Poly(tulipalin A) Coatings: Structure and Material Properties

A solvent-free route of initiated chemical vapor deposition (iCVD) was used to synthesize a bio-renewable poly(α-Methylene-γ-butyrolactone) (PMBL) polymer. α-MBL, also known as tulipalin A, is a bio-based monomer that can be a sustainable alternative to produce polymer coatings with interesting material properties. The produced polymers were deposited as thin films on three different types of substrates—polycarbonate (PC) sheets, microscopic glass, and silicon wafers—and characterized via an array of characterization techniques, including Fourier-transform infrared (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), ultraviolet visible spectroscopy (UV–vis), differential scanning calorimetry (DSC), size-exclusion chromatography (SEC), and thermogravimetric analysis (TGA). Optically transparent thin films and coatings of PMBL were found to have high thermal stability up to 310 °C. The resulting PMBL films also displayed good optical characteristics, and a high glass transition temperature (Tg~164 °C), higher than the Tg of its structurally resembling fossil-based linear analogue-poly(methyl methacrylate). The effect of monomer partial pressure to monomer saturation vapor pressure (Pm/Psat) on the deposition rate was investigated in this study. Both the deposition rate and molar masses increased linearly with Pm/Psat following the normal iCVD mechanism and kinetics that have been reported in literature.

Transition from the “Burst-Like Growth” to the Normal Growth Kinetics in Free-Growing Helium Crystals

Transition from the “Burst-Like Growth” to the Normal Growth Kinetics in Free-Growing Helium Crystals

P-211 Significant differences in efficiency between two commonly used ionophore solutions for assisted oocyte activation (AOA): a prospective comparison of ionomycin and A23187

Abstract Study question Are there differences in oocyte activation rate and developmental morphokinetic after assisted oocyte activation (AOA) with either ionomycin or A23187? Summary answer Ionomycin produces greater oocyte activation rate than A23187 (43.1% vs 15.9%), while the morphokinetic pattern of parthenotes’ development is similar between both Ca2+ ionophores. What is known already Fertilization failure (FF) after ICSI is often due to a male factor, such as the alteration of sperm-borne oocyte activating factors or globozoospermia. AOA can restore fertilization rate by stimulating transient spikes of Ca2+ in the cytoplasm of the oocyte, but its efficiency and effect on embryo development are not fully characterized. Here, the efficiency of two AOA preparation and protocols commonly used in clinical practice is compared using parthenogenetically activated human oocytes. The objective is to identify the most appropriate protocol for AOA and to compare the morphokinetic pattern of the generated parthenotes up to expanded blastocyst (tB). Study design, size, duration Prospective study involving 120 human oocytes from 66 women from March 2019 to November 2021. Oocytes were activated with two AOA protocols after mock ICSI: i) A23187 (ready-to-use solution, GM508 CultActive (Gynemed) n = 69), and ii) Ionomycin (homemade solution, 10 µmol/L, n = 51). Oocyte activation and development were analyzed in both groups; further, the morphokinetic patterns were compared; videos of embryos obtained with donor oocytes and sperm (n = 39) were used as comparator of normal developmental kinetics. Participants/materials, setting, methods Oocytes were injected with latex microspheres to simulate ICSI, followed by AOA. A23187 was used according to manufacturer specification. For ionomycin, three incubations of seven minutes each were performed. Resulting parthenotes (1PN) were incubated in a time-lapse system for 160h. Activation and developmental rates, tPNf (pronucleus fading), t2, t3, t4, t5, t8 (from 1st division to 8-cell), tsB (blastulation onset) and tB (blastocyst expansion) were compared using Student’s T-test and ANOVA. Statistical significance: p-value &amp;lt;0.05. Main results and the role of chance Ionomycin resulted in a significantly higher oocyte activation rate (22/51, 43.1%) than A23187 (11/69, 15.9%), p = 0.0009. In the ionomycin group, 81.8% (18/22) of parthenotes reached the 2-cell stage, 45.5% (10/22) reached the 5-cell stage, and 18.2% (4/22) reached the pseudo-blastocyst stage, as expected for these pseudo-embryos lacking the contribution of the sperm. In the A23187 group, 54.5% (6/11) reached the 2-cell stage, 27.3% (3/11) the 5-cell stage, and none formed pseudo-blastocysts. While the number of parthenotes progressing through development is much lower for A23187, the expected poor development of human parthenotes past activation and corresponding low numbers did not allow to reach statistical significance (p &amp;gt; 0.05). tPNf was significantly different among the 3 groups compared: 47.4±37.5h (n = 11, A23187), 27.7±23.8h (n = 21, ionomycin) and 23.3±4.6h (n = 39, control), p = 0.0019; with ionomycin presenting an average tPNf similar to the one obtained by ICSI. Among activated oocytes, the morphokinetic pattern in the ionomycin and A23187 groups was very similar to the one obtained in the control group (p &amp;gt; 0.05 at all timings). As an example, the t5 in the 3 groups was 58.5±12.6h (n = 3, A23187), 45.6±21.8h (n = 10, ionomycin), and 49.5±12.4h (n = 34, control), p = 0.29. Limitations, reasons for caution The low number of parthenotes progressing past 2-cells limit the possibility to extract solid conclusions regarding the morphokinetic patterns after AOA. The efficiency of activation using the two tested protocol is however confirmed. Wider implications of the findings The use of homemade ionomycin solutions is an effective option for the treatment of fertilization failures where assisted oocyte activation is indicated. Caution should be exerted when using GM508 Cultactive to investigate fertilization failures of oocyte origin. Trial registration number not applicable