Total Relaxation Research Articles

Translational Dynamics of Cations and Anions in Ionic Liquids from NMR Field Cycling Relaxometry: Highlighting the Importance of Heteronuclear Contributions.

NMR field cycling relaxometry is a powerful method for determining the rotational and translational dynamics of ions, molecules, and dissolved particles. This is in particular true for ionic liquids (ILs) in which both ions carry NMR sensitive nuclei. In the IL triethylammonium bis(trifluoromethanesulfonyl)imide ([TEA][NTf2]), there are 1H nuclei at the [TEA]+ cations and 19F nuclei at the [NTf2]- anions. Moreover, the high viscosity of this IL leads to frequency-dependent relaxation rates, leaving the so-called extreme narrowing regime. Both the rotational and the translational dynamics of the constituents of ILs can be obtained by separating the contributions of intra- and intermolecular relaxation rates. In particular, the translational dynamics can be obtained separately by applying the so-called "low-frequency approach" (LFA), utilizing the fact that the change in the total relaxation rates at low frequencies results solely from translational motions. However, for systems containing multiple NMR active nuclei, heteronuclear interactions can also affect their relaxation rates. For [TEA][NTf2], the intermolecular relaxation rate is either the sum of 1H-1H cation-cation and 1H-19F cation-anion interactions or the sum of 19F-19F anion-anion and 19F-1H anion-cation interactions. Due to the lack of available experimental information, the 1H-19F heteronuclear intermolecular contribution has often been neglected in the past, assuming it to be negligible. Employing a suitable set of ILs and by making use of isotopic H/D substitution, we show that the 1H-19F heteronuclear intermolecular contribution in fact cannot be neglected and that the LFA cannot be applied to the total 1H and total 19F relaxation rates.

Abstract We095: Using Human Cardiac Organoids to Elucidate the Cardioprotective Potential of Mitochondrial-Targeted Therapies in a Preclinical Model of Diabetic Cardiomyopathy

Introduction: Mitochondrial dysregulation is implicated in many complications of type 2 diabetes (T2D). Mitochondrial-targeted therapies SkQ1, AP39 and SS31 limit renal T2D complications. We sought to obtain the first evidence of the cardioprotective potential of SkQ1, AP39 and SS31 in T2D, using a human induced pluripotent stem cell (iPSC)-derived 3D multicellular cardiac organoid model of diabetic cardiomyopathy. Methods: Human cardiac organoids (foreskin-2 cell-line) generated from human iPSC-derived cardiomyocytes, cardiac fibroblasts and endothelial cells were subjected to 5.55mM glucose (control) or T2D-like conditions (20mM glucose, fatty acids, endothelin-1 and cortisol) for 4 days with supplementation of either SkQ1 (50nM), AP39 (50nM) or SS31 (1µM) on day 2. On day 4, endpoint parameters were evaluated in cardiac organoids, including contractile function (captured via Olympus IX71), mitochondrial superoxide levels (MitoSOX assay), mitochondrial membrane potential (TMRM assay), and cellular injury (lactate dehydrogenase; LDH). Data are expressed as mean±SEM (fold control) with n =4-6 from 2-3 independent experiments. One-way ANOVA with Dunnett`s post hoc analysis was performed with P<0.05 considered significant. Results: After 4 days, T2D-conditions increased total contraction duration (1.55±0.10-fold control), time-to-peak (1.71±0.11-fold control, indicative of systolic dysfunction) and relaxation duration (1.46±0.13-fold control, indicative of diastolic dysfunction) in cardiac organoids. All 3 functional parameters were attenuated by AP39 (to 1.15±0.06, 1.32±0.09 and 1.04±0.04-fold control, respectively), or by SS31 (to 1.10±0.05, 1.12±0.15 and 1.09±0.12-fold control, respectively; all P<0.05), but not SkQ1. T2D-conditions increased mitochondrial superoxide (2.68±0.16-fold control), which was blunted by all 3 interventions, SkQ1 to 2.00±0.29, AP39 to 1.82±0.16 and SS31 to 1.89±0.17 (all P<0.05). Cellular injury was evident in T2D cardiac organoids (2.07±0.23-fold control), which was again limited by SkQ1 (to 1.06±0.11), AP39 (to 1.18±0.09) or SS31 (to 1.08±0.07), all P<0.05. Conclusion: These findings in human cardiac organoids highlight the cardioprotective potential of mitochondrial-targeted therapies to limit T2D-induced cardiac dysfunction, mitochondrial dysregulation and cellular injury, potentially facilitating clinical progression of candidates such as AP39 and SS31 as new therapies for patients with diabetic cardiomyopathy.

Study on Quality Changes of Kelp Gel Edible Granules during Storage.

The kelp gel edible granules developed utilizing the gel properties of alginate are prone to quality deterioration if improperly stored during the storage process. This study comprehensively investigated the quality changes of kelp gel edible granules stored at 4 °C and 25 °C by evaluating indicators such as total bacterial count, coliform bacteria, pH, relaxation time, color difference, appearance, texture characteristics, gel strength, and sensory scoring. The results showed that during the storage at 4 °C, the total bacterial count remained within the national standard range, the hardness and chewiness increased, the gel strength first increased and then decreased, the partial exudation of the bound water in the product occurred, and the sensory score slightly decreased, with an overall minor change in quality. During the storage at 25 °C, significant quality changes were observed, with the total bacterial count exceeding the national standard on the 20th day; additionally, the hardness, chewiness, and gel strength all initially increased and then decreased, both the bound water and the restrained water in the product exuded, the moisture stability decreased, and the sensory score significantly decreased between 16 to 20 days. The spoilage of the product was characterized by a significant water loss, reduction in volume, color change from bright green to dark yellow-brown, and a distinct smell of decaying algae. No coliform bacteria was detected in all products during the storage period. In summary, the shelf life endpoint of the product stored at 25 °C is 16 days, and the shelf life of the product stored at 4 °C is greater than 20 days. Storage at 4 °C can better maintain product quality, extend the shelf life, and effectively maintain the overall color of the product.

Clogauite, PbBi4Te4S3, a new member of the aleksite series

AbstractClogauite, ideally PbBi4Te4S3 is the new n = 1 member of the aleksite series, PbnBi4Te4Sn+2, where n is the homologue number. Clogauite is named from the type locality, the Clogau gold mine, Dolgellau Gold belt, Gwynedd, North Wales, United Kingdom. The mineral and name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2023–062). The aleksite series is an accretional homologous series in which each member is derived from the same 5-atom tetradymite archetype. Clogauite crystallises in the trigonal crystal system (space group: P$\bar{3}$m1, #164). Three distinct polytypes of clogauite are recognised, corresponding to identical chemistry but different layer sequences, expressed as (57), (5559) and (557.559), respectively, in reference to the number of atoms in individual layer sequences. These are clogauite-12H, a = 4.277(4) Å, c = 23.46(14) Å, V = 371.598 Å3 and Z = 1; clogauite-24H, a = 4.278(4) Å, c = 46.88(31) Å, V = 743.053 Å3 and Z = 2; and clogauite-36H, a = 4.278(4) Å, c = 70.36(32) Å, V = 1115.283 Å3 and Z = 3. Clogauite is opaque, with a pale grey colour in reflected light. Reflectance is higher than tetradymite or galena. Bireflectance and anisotropy are strong. Structural data were determined from measurement of atomic-scale HAADF STEM imaging showing the internal arrangement of component atoms and characteristic selected area electron diffraction patterns for each polytype. The structures were then further constrained from ab initio total energy calculations and structure relaxation using density functional theory (DFT) using the measured parameters as input data. The relaxed crystal structure for each polytype was modelled to generate crystallographic information files (cif). STEM and electron diffraction simulations based on the crystallographic information data obtained from the DFT calculations show an excellent match to the empirical measurements.

Quantitative 23Na magnetic resonance imaging in the abdomen at 3 T

ObjectivesTo assess the feasibility of sodium-23 MRI for performing quantitative and non-invasive measurements of total sodium concentration (TSC) and relaxation in a variety of abdominal organs.Materials and methodsProton and sodium imaging of the abdomen was performed in 19 healthy volunteers using a 3D cones sequence and a sodium-tuned 4-rung transmit/receive body coil on a clinical 3 T system. The effects of B1 non-uniformity on TSC measurements were corrected using the double-angle method. The long-component of 23Na T2* relaxation time was measured using a series of variable echo-times.ResultsThe mean and standard deviation of TSC and long-component 23Na T2* values were calculated across the healthy volunteer group in the kidneys, cerebrospinal fluid (CSF), liver, gallbladder, spleen, aorta, and inferior vena cava.DiscussionMean TSC values in the kidneys, liver, and spleen were similar to those reported using 23Na-MRI previously in the literature. Measurements in the CSF and gallbladder were lower, potentially due to the reduced spatial resolution achievable in a clinically acceptable scan time. Mean long-component 23Na T2* values were consistent with previous reports from the kidneys and CSF. Intra-population standard error was larger in smaller, fluid-filled structures due to fluid motion and partial volume effects.

Dynamics of Hot Exciton Relaxation in Conjugated Polymer Chain

Hot excitons are formed after photoexcitation of conjugated polymer chains. Hot excitons relax and convert into cold excitons with the aid of vibrational modes. In this study, the dynamics of such conversion is studied within the strong coupling regime. It has been found that the magnitudes of electronic coupling integrals for hot exciton relaxation are mostly due to exchange interactions between the interacting units. During relaxation, hot excitons oscillate back and forth between two different sites until they lose their extra energy. The time step for each oscillation has been found as small as 0.3 fs. It has also been found that photoexcited states in conjugated polymer chains do not necessarily localize at their initial location formed. Monte-Carlo simulations show that hot excitons can sustain their coherent motion along the conjugated backbone to some extent before total relaxation.

Cardioneuroablation for asystolic reflex syncope with or without the use of extra cardiac vagal stimulation-one year follow-up results

Abstract Background Extra-Cardiac Vagal Stimulation (ECVS) during cardioneuroablation (CNA) has been introduced to confirm total vagal denervation – a clear intra-procedural end-point. However, whether the use of ECVS is associated with better outcome than simple intra-procedural assessment of CNA-induced changes in basic ECG parameters, has not been established. Purpose To compare one-year efficacy of CNA performed with versus without ECVS. Methods This retrospective analysis included 90 patients (age: 37±12 years, 39 males) divided into 2 groups: ECVS(+) (n=41, general anesthesia and total muscle relaxation, settings: 50 Hz, 0.05 ms, 1 V/kg (<70V) for 5 s) and ECVS(-) group (n=49, light sedation). CNA strategy was the same in all patients and was based on presumed anatomical localization of ganglionated plexi, combined with identification of ablation targets at sites with fragmented bipolar atrial electrograms. The end-point in the ECVS (+) group was complete vagal denervation, confirmed by ECVS, whereas in the ECVS (-) group - significant (>30%) acceleration of sinus rate. The primary endpoint was syncope recurrence during one-year follow-up. Results Both groups were comparable concerning clinical and demographic parameters. Primary endpoint occurred in 4 (10%) patients in the ECVS(+) group and in 7 (14%) patients in the ECVS(-) group (p=0.7481) (Figure). No complications were reported. Conclusions These preliminary results suggest that the use of ECVS only slightly improves the one-year CNA efficacy, however, prospective larger studies and longer follow-up are needed to confirm these initial findings.

Experimental study of rotational relaxation for D2(1,12) in collisions with N2.

The rotational relaxation behavior of D2(1,12) in a D2-N2 mixture was investigated using coherent anti-Stokes Raman scattering (CARS) technique. The rovibrational level v = 1 and J = 12 of D2 was selectively excited through stimulated Raman pumping while monitoring the temporal evolution of population for D2(1, J ≤ 12) molecules using time-resolved CARS spectroscopy. The results demonstrate that the rotational relaxation processes of D2(1,12) encompass both multi-quantum relaxation and continuous single-quantum relaxation. When α, the molar ratio of N2, is less than 0.5, D2(1,12) predominantly undergoes a single quantum relaxation process transition. However, when α ≥ 0.5, the multi-quantum relaxation mechanism gradually predominates. The total rotational relaxation rate coefficients of D2(1,12) collisions with N2 and D2 at 295K were determined to be 3.974 × 10-14 and 1.179 × 10-14cm3s-1, respectively. The temperature dependence of rotational relaxation rate of D2(1,12) was investigated within the temperature range of 295-453K. With increasing temperature, the dominant relaxation process exhibited an accelerated behavior, while the minor relaxation process remained largely unaffected. The rotational temperature of the D2molecule at various N2 molar ratios was determined through the utilization of Boltzmann plots. The rotational temperature undergoes a rapid decline within 2 μs, corresponding to the near-resonant rotation-vibration relaxation process of D2(1,12) collisions with N2. The system reaches a quasi-equilibrium state when the delay time is 3 μs. The findings of this study can serve as a valuable empirical basis for further validation of the kinetic theory and simulation.

The Effect of Guided Imagery and Progressive Muscle Relaxation on Sedation in Patients Undergoing Noninvasive Mechanical Ventilation

Mental imagery and relaxation are noninvasive methods and can easily be used by the patient. Accordingly, this study aimed to detect the effect of guided mental imagery (GI) and progressive muscle relaxation (PMR) on sedation in patients undergoing noninvasive mechanical ventilation (NIV). This clinical trial study was carried out in the Shahid Modarres Hospital in 2022 and encompassed 80 patients with COVID-19 undergoing NIV, who were assigned to two intervention and control groups. The sedation survey scale was used to collect the required data. Before the intervention, the two groups completed the questionnaires, and then the relaxation program was presented during four sessions for the intervention group. This study included 80 patients with a mean age (± SD) of 59.59 ± 9.27 years. The Quade nonparametric ANCOVA revealed the significant impact of intervention on the post values of Total score (p-value < 0.001), Tolerance (p-value < 0.001), Calmness (p-value < 0.001), Ventilator synchrony (p-value < 0.001), face relaxation (p-value < 0.001), Consciousness (p-value = 0.009) and Awakeness (p-value = 0.020). The study findings demonstrated the effectiveness of relaxation program in promoting sedation in patients undergoing NIV. Accordingly, intensive care unit (ICU) nurses at our institution are encouraged to use PMR and GI to sedation of patients under NIV.

Modification mechanism of calcium lignosulfonate on cementing cement

During the construction of coalbed methane extraction wells, cementing cement sheath is crucial for the stability and sealing of surface wells. One effective method to enhance these properties is the addition of lignosulfonate. However, the mechanism of the effect of calcium lignosulfonate on the whole process of cement hydration is still unclear. In this paper, the water distribution and variation characteristics of calcium lignosulfonate modified cement paste were revealed by low-field nuclear magnetic resonance technology, and the hydration ion experiment of modified cement was carried out to obtain the variation characteristics of hydration ions of modified cementing cement. Finally, the formation mechanism of hydration products was clarified by analyzing the phase change of modified cement stone. The results indicate that the cement paste’s hydration process can be divided into four stages: dissolution, crystallization, acceleration, and decline. During the dissolution stage, calcium lignosulfonate’s air entraining effect maintains the cement paste in a stable suspension state. In the crystallization stage, calcium lignosulfonate’s electro-repulsion delays the formation of hydration products and the hydration process. During the acceleration stage, the addition of calcium lignosulfonate reduces bound water formation in the cement slurry’s flocculation structure, and the released filled water participates more in the hydration reaction, reducing the total relaxation signal’s increasing trend. In the decline stage, the cement paste has solidified, and the system’s water is primarily in the porous medium. The research results have practical guiding significance for the addition of calcium lignosulfonate in cementing operations.

Phonon-mediated ultrafast energy- and momentum-resolved hole dynamics in monolayer black phosphorus.

The electron-phonon scattering plays a crucial role in determining the electronic, transport, optical, and thermal properties of materials. Here, we employ a non-Markovian stochastic Schrödinger equation (NMSSE) in momentum space, together with abinitio calculations for energy bands and electron-phonon interactions, to reveal the phonon-mediated ultrafast hole relaxation dynamics in the valence bands of monolayer black phosphorus. Our numerical simulations show that the hole can initially remain in the high-energy valence bands for more than 100fs due to the weak interband scatterings, and its energy relaxation follows single-exponential decay toward the valence band maximum after scattering into low-energy valence bands. The total relaxation time of holes is much longer than that of electrons in the conduction band. This suggests that harnessing the excess energy of holes may be more effective than that of electrons. Compared to the semiclassical Boltzmann equation based on a hopping model, the NMSSE highlights the persistence of quantum coherence for a long time, which significantly impacts the relaxation dynamics. These findings complement the understanding of hot carrier relaxation dynamics in two-dimensional materials and may offer novel insights into harnessing hole energy in photocatalysis.

Vibrational anharmonicity of A-band related optical center and its temperature dependence studied by femtosecond laser excitation in bulk natural diamond

Unusual A-band spectra with well-resolved quasi-periodical phonon progressions of multiple peaks (N\(\sim \)9) were excited in a natural diamond by 515-nm, 300-fs laser pulses at variable pre-heating temperatures of 24-200oC. The non-radiative multi-phonon part of the relaxation path was comparable with the total relaxation energy (zero-phonon line energy), pointing out some extended defects (e.g., dislocations) as the recombination center of the A-band emission. The derived temperature dependences of the peak intensities, separations and half-widths of the separate spectral peaks in the A-band phonon progressions indicate the different trends for vibration-free zero-phonon transition and vibration-related lower-energy transitions to high vibrational levels of the bottom state – lower thermal damping and more softened phonon for the zero-phonon transition, also implying the extended defect origin of the A-band photoluminescence.

Kinetic relaxation and nucleation of Bose stars in self-interacting wave dark matter

We revisit kinetic relaxation and soliton/boson star nucleation in fuzzy scalar dark matter featuring short-ranged self-interactions Hint=−λ|ψ|4/2m2, alongside gravitational self-interactions. We map out the full curve of nucleation timescale for both repulsive (λ&lt;0) and attractive (λ&gt;0) short-ranged self-interaction strength and in doing so reveal two new points. Firstly, besides the two usual terms, ∝G2 and ∝λ2, in the total relaxation rate Γrelax, there is an additional cross term ∝Gλ arising due to interference between gravitational and short-ranged self-interaction scattering amplitudes. This yields a critical repulsive interaction strength λcr≃−2πGm2/v02, at which the relaxation rate is smallest and serves as the transition point between typical net attractive self-interaction (λ≳λcr) and net repulsive self-interaction (−λ≳−λcr). Secondly, while in the net attractive regime, nucleation timescale is similar to inverse relaxation timescale τnuc∼Γrelax−1; in the net repulsive regime, nucleation occurs at a delayed time τnuc∼(λ/λcr)Γrelax−1. We confirm our analytical understanding by performing 3D field simulations with varying average mass density ρ¯, box size L and grid size N. Published by the American Physical Society 2024

Intraoperative goal-directed fluid therapy in neurosurgical patients: A systematic review.

Perioperative fluid management is critical in neurosurgery as over perfusion can lead to brain edema whereas under perfusion may lead to brain hypoperfusion or ischemia. We aimed to determine the effectiveness of intraoperative goal-directed fluid therapy (GDFT) in patients undergoing intracranial surgeries. We searched MEDLINE, Cochrane, and PubMed databases and forward-backward citations for studies published between database inception and February 22, 2024. Randomized controlled trials where intraoperative GDFT was performed in neurosurgery and compared to the conventional regime were included in the study. GDFT was compared with the conventional regime as per primary outcomes - total intraoperative fluid requirement, serum lactate, hemodynamics, brain relaxation, urine output, serum biochemistry, and secondary outcomes - intensive care unit and hospital length of stay. The quality of evidence was assessed with the Cochrane risk of bias tool. This study is registered on PROSPERO (CRD42024518816). Of 75 records identified, eight were eligible, the majority of which had a low to moderate risk of overall bias. In four studies, more fluid was given in the control group. No difference in postoperative lactate values was noted in 50% of studies. In the remaining 50%, lactate was more in the control group. Three out of four studies did not find any significant difference in the incidence of intraoperative hypotension, and four out of six studies did not find a significant difference in vasopressor requirement. The majority of studies did not show significant differences in urine output, brain relaxation, and length of stay between both groups. None found any difference in acid base status or electrolyte levels. GDFT, when compared to the conventional regime in neurosurgery, showed that the total volume of fluids administered was lesser in the GDFT group with no increase in serum lactate. There was no difference in the hemodynamics, urine output, brain relaxation, urine output, length of stay, and biochemical parameters.

Bandwidth of quantized surface plasmons: competition between radiative and nonradiative damping effects.

We investigate the damping effects of coherent electron oscillations on the bandwidth of a quantized nanoparticle plasmon resonance. The nanoparticle (NP) is treated as a two-level quantum system, and the total relaxation time involves both the population relaxation time associated with radiative processes and the collisional relaxation time associated with nonradiative processes that result in dephasing/decoherence of electron oscillations. We describe the optical response of NPs to an external electromagnetic field by the optical Bloch equations employing the density matrix formalism to capture the quantum description nature of dipolar plasmon resonance and suggest a generalized criterion for the validity of dipole approximation. Then we explore the competition between the radiative and nonradiative damping in determining the plasmon bandwidth of two typical NP models; metallic nanospheres and dielectric core-metal shell NPs (nanoshells). We show that the frequency of plasmon resonance, in addition to the NP size, plays an important role in the competition between the damping mechanisms. Consequently, the damping processes are significantly influenced by the factors that determine the resonance frequency, such as the core size, the dielectric constant of the medium, and the shell thickness (for nanoshells). For both models of NPs, we identify the optimum parameters that achieve a narrower plasmon bandwidth (minimal damping), which is a prerequisite for advanced sensing and medical applications. We demonstrate excellent agreement of the simulated spectral features of the plasmon resonance with previously reported experimental results for a single NP where the inhomogeneous broadening of the plasmon line is excluded. For NP ensembles where inhomogeneous broadenings and interface chemical effects are significant, our theoretical approach successfully predicts the overall trend of size-dependent damping rates.

Comprehensive analysis of early-stage hydration and microstructure evolution in Sufflaminate cement: Insights from low-field NMR and isothermal calorimetry

This study presented a comprehensive investigation of the early hydration reaction and microstructure evolution of sulfoaluminate cement (SAC) using low-field nuclear magnetic resonance (LF-NMR) and isothermal calorimetry (IC). LF-NMR, combined with total relaxation signal and transverse relaxation time (T2), was employed to characterize the evolution of evaporation water (EW) and the degree of hydration (αlf) during the initial stage of SAC hydration. The hydration process was divided into four phases. The relative content of different EW types within the paste was investigated, and the pore structure and specific surface area evolution of SAC paste were studied based on the T2. The heat release of hydration of SAC was measured using IC, and the hydration kinetics was fitted with the JMAK model. The results demonstrated that the early hydration reaction of SAC was a multidimensional controlled process influenced by various factors. Also, the crystallization nucleation rate of hydration products was inversely related to w/c. Furthermore, a successful nonlinear fitting between the weighted average of T2 and the hydration degree (αt) obtained from IC was established, providing a standard reference curve for studying hydration degree and microstructure. Finally, the hydration products and microstructure were investigated using, SEM, and TG, and the evolution of the compressive strength of SAC was also analyzed. This work gave valuable insights into SAC's early hydration behavior and microstructural development, which can contribute to a better understanding of its performance and potential applications.

Occurrence state and nuclear magnetic resonance relaxation characteristics of confined water in quartz nanopores

Water in the shale obstructs the enrichment and transportation of shale gas, so it is crucial to identify the occurrence mechanism of water in shale. In this work, molecular dynamics (MD) simulation had been performed to explore the occurrence state, dynamic characteristics, and nuclear magnetic resonance (NMR) relaxation properties of confined water in shale inorganic nanopores (quartz). The results show that the number of adsorbed layers, diffusion coefficients (D) and rotational correlation time (τ c) of water in quartz pores are strongly influenced by pore width (H). Layer analysis of water held in confinement indicates that the D value increases and the τc value decreases as the water approaches the centre of the pore. Furthermore, varying occurrence states lead to different NMR relaxation mechanisms. With the increase of H, the transverse relaxation time of adsorbed water is basically stable at 10−1 s. Finally, an exponential formula for evaluating pore size distribution is established. The total thickness of the water layer with the ratio of the intramolecular relaxation rate to the total relaxation rate less than 40% is defined as the thickness of the adsorbed water film.

Long-term results of treatment of achalasia cardia by combined balloon dilation. The role of high-resolution manometry in the diagnosis of achalasia. Endoscopic and manometric parallels

The aim. To analyze the results of treatment of achalasia cardia by balloon dilatation with an accent on hydrodilatation, to compare the types of achalasia cardia according to high-resolution manometry with endoscopic semiotics and to evaluate the effectiveness of endoscopic balloon dilatation depending on the type of achalasia. Materials and methods. The article details an additional method of endoscopic balloon dilatation of the cardia - hydrodilatation (42 patients). The results of endoscopic balloon dilatation were analyzed according to high-resolution manometry data (37 patients). High-resolution manometry data were also evaluated in correlation with endoscopic efficacy criteria (11 patients). Results. Hydrodilatation is used as an additional method after pneumodilatation to increase efficiency of treatment (39 patients) or as an independent method (3 patients) with a combination of achalasia cardia and cicatricial changes of the esophageal-gastric junction, as well as after surgery on the cardia. The combined balloon dilatation technique gives good immediate results in 89.7% (35/39), as an independent method - 100%. Of the total number of patients, 90.5% (38/42) completed the course of endoscopic dilatation with good results, despite the fact that this is a more complex group of patients resistant to standard intervention - balloon pneumodilatation. It is not known which high-resolution manometry data should be used to assess the effectiveness of balloon dilatation: the dilatation efficiency is 75% according to the resting pressure of the lower esophageal sphincter, 83.3% according to the total relaxation pressure, 66.7% according to the cumulative analysis, strictly adhering to the reference values, and 100% according to the tendency to lower pressure. Conclusion. Endoscopic balloon dilatation is a highly effective minimally invasive method of treating achalasia cardia. Hydrodilatation is used to improve the results of endoscopic treatment. For an objective assessment of the effectiveness of balloon dilatation, high-resolution manometry should be performed before and after treatment.

Benefits of Segmental Spinal Anaesthesia in Patients Undergoing Laproscopic Cholecystectomy: A Retrospective Study

Background: Segmental Spinal anaesthesia (SA) is reported to be having excellent results in terms of post-operative pain, analgesia requirement, relatively less complications and reduced hospital stay. General anaesthesia (GA) is the anaesthetic technique of choice for laparoscopic cholecystectomy (LC). The main reasons for selecting spinal anaesthesia (SA) as the first choice for laparoscopic cases were its advantages like total muscle relaxation, a conscious patient, economical, relatively uneventful recovery after, pain free early postoperative period and the protection from potential complications of general anaesthesia. Materials and Methods: It is a retrospective study conducted between October 2020 and September 2022. 160 Patients in study group undergoing laparoscopic abdominal procedures were operated under Spinal Anesthesia. In study group 45 patients had acute cholecystitis and 115 underwent elective cholecystectomy were included. 100 Patients who were operated under General anesthesia were kept as control. Results: Out of 160 patients, 105 patients were females, average age was 43.8 years and 55 male patients with average age was 39.2 years laparoscopic cholecystectomy was performed in all patients. Out of 160 patients 45(28.12%) of had acute cholecystitis. 32 (20%) patients HAD hypotension, 35 (21.88%) observed anxiety, neck or shoulder pain, and 1 (0.62%) patient required conversion because of anxiety, despite sedation where as one patient required conversion to general anaesthesia due to failure of SA effect. Conclusions: Laparoscopic surgery done with the patient under spinal anaesthesia has several advantages general anaesthesia. Laparoscopic cholecystectomy using spinal anaesthesia is a better alternative as there is no intubation related airway obstruction. There was excellent muscle relaxation; decreased surgical bed oozing, economical, pain free early post-operative period. A little risk of unrecognised hypoglycaemia was observed in a ..........

Advanced insight on the water dynamics of anisotropic hydrogels by field-cycling nuclear magnetic resonance: Application of 3-Tau model

Fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry is used to investigate an anisotropic polygalacturonate hydrogel formed by the diffusion of calcium ions from an external reservoir (external gelation). Such a hydrogel has a gradient of polymer density accompanied by a gradient of the mesh size of its 3D network. The NMR relaxation process is dominated by the interaction of proton spins between water molecules located at polymer interfaces and in nanoporous spaces. The FFC NMR experiment provides the spin-lattice relaxation rate R1ω as a function of Larmor frequency ω producing dispersion (NMRD) curves that are highly sensitive to the dynamics of the protons at the surfaces. The hydrogel is sliced into three parts and the NMR profile for each hydrogel slice is measured. The NMRD data for each slice is interpreted using the 3-Tau Model with the aid of user-friendly fitting software called 3TM. The key fit parameters include three nano-dynamical time constants and the average “mesh size” which collectively determine the bulk water and water surface layer contribution to the total relaxation rate. The results are consistent with independent studies where comparison is possible.