Search Results (57)

The application of cellular spheroids in bone tissue engineering research has gained significant interest in the last decade. Compared to monolayer cell cultures, the 3D architecture allows for more physiological cell–cell and cell–extracellular matrix (ECM) interactions that make cellular spheroids a suitable model system to investigate the bone ECM in vitro. The use of 3D model systems requires fine-tuning of the experimental methods used to study cell morphology, ECM deposition and mineralization, and cell–ECM interactions. In this study, we use a construct made of MC3T3-E1 cellular spheroids encapsulated in an alginate hydrogel to study and characterize the deposited ECM. Spheroid shape and structure were evaluated using confocal microscopy. The deposited collagenous ECM was characterized using Second Harmonic Imaging Microscopy (SHIM), quantitative hydroxyproline (HYP) assay, and Transmission Electron Microscopy (TEM). The use of hydrogel constructs enabled easy handling and imaging of the samples, while also helping to preserve the spheroid’s stability by preventing cells from adhering to the culture dish surface. We used a non-modified alginate hydrogel that did not facilitate cell attachment and therefore functioned as an inert encapsulating scaffold. Constructs were cultured for up to 4 weeks. SHIM, HYP assay, and TEM confirmed the deposition of a collagenous matrix. We demonstrated that alginate-encapsulated bone spheroids are a convenient and promising model for studying the bone ECM in vitro. Full article

A method for characterizing carbon nanotubes (CNTs) in powder form with different packing densities in the microwave regions is proposed. The CNTs were sandwiched between two dielectric walls in (Polyvinyl Chloride) PVC and put in a waveguide shim. We measured the transmission/reflection S-parameters of the waveguide using a Vector Network Analysis (VNA), and the impacts of the PVCs on the measured S-parameters were de-embedded by microwave network analysis. Then, the well-known Nicolson–Ross–Weir (NRW) method was processed to determine the complex permittivity and permeability of the CNTs. Furthermore, we pressed the PVC to increase the packing densities of the CNTs. The results of the characterization can be employed to design microwave devices using the CNTs. Full article

Background/Objectives: Laser ablation is a promising technique for tissue-debulking in patients with symptomatic benign prostatic hyperplasia (BPH). This study evaluated the effects of focused laser ablation of the prostate (FLA) on urinary symptoms for patients with BPH. Methods: Since 2018, 62 patients had bilateral prostate FLA for prostate cancer and/or symptomatic BPH, defined as an international prostate symptom score (IPSS) ≥11, and have 6-month follow-up data. Urinary and sexual health were scored with standardized surveys while imaging defined prostate anatomy. FLA was performed as an outpatient procedure with either transrectal MRI-guided (n = 24) or transperineal ultrasound-guided (n = 38) laser fiber placement to debulk the prostate and/or ablate cancer foci plus margins. Enhanced prostate MRI was performed immediately or up to 2 days later to assess the treatment zones. Follow-up then consisted of PSA levels every 6 months and MRI at 6–12 months and then yearly combined with patient sexual/urinary surveys and clinical assessments. Results: All patients had technically successful FLA and 6-month clinical and imaging follow-up. At 6-month follow-up, mean IPSS was reduced by 43% relative to baseline (10.4 vs. 18.4), mean prostate volume was reduced by 30% (42.2 vs. 60.5 mL), and mean PSA was reduced by 58% (4.3 vs. 10.2 ng/mL). All of these changes were statistically significant (p ≤ 0.008). Compared with baseline, there was no significant change in the SHIM score at 6 months (16.0 vs. 16.8; p = 0.59). In a subset of patients for whom 12-month data were available, there were significant reductions in PSA (61%; 4.1 vs. 10.5 ng/mL; p < 0.002) and IPSS (45%; 9.9 vs. 17.9; p < 0.002), while the 12-month SHIM score was not significantly different from baseline (15.2 vs. 16.0; p = 0.27). Mean laser irradiation time was 19 min with a mean energy deposition of 13,562 J. The most frequent adverse events were prolonged urinary catheterization in 10 patients (16%) and urinary tract infection in 8 (13%). Conclusions: FLA is a safe and effective tissue-debulking technique for patients with symptomatic BPH. This outpatient procedure requires minimal procedure time and can be performed without the need for operating rooms or cystoscopy. Our results are consistent with those of previous studies indicating that FLA preserves sexual function. Full article

High-Intensity Focused Ultrasound (HIFU) provides comparable oncologic, erectile, and urinary outcomes to standard-of-care options for localized prostate cancer. This study reports the largest United States series of HIFU in veterans for both primary and salvage therapies. We retrospectively analyzed the outcomes of 43 veterans treated at the Michael E. DeBakey Veterans Affairs Medical Center from 2018 to 2022. Primary endpoints included prostate-specific antigen (PSA) reduction and local recurrence rates. Secondary endpoints included 30-day complications, Sexual Health Inventory for Men (SHIM), and American Urological Association Symptom Score (AUASS). In our study, 31 veterans (72.1%) received primary treatment and 12 (27.9%) received salvage therapy, with a median follow-up of 23 and 25 months, respectively. Median PSA nadir was 0.16 for primary and 0.12 for salvage groups, with PSA reduction stable over 30 months. Local recurrence occurred in 16.1% of primary and 16.6% of salvage patients. SHIM scores and AUASS were not statistically different before and after HIFU therapy. Short- and intermediate-term results suggest HIFU is a safe and effective treatment option with excellent potency and preserved urinary function, as well as adequate oncological control for primary and salvage therapies for localized prostate cancer in veterans. Full article

Most Nuclear Power Plants (NPPs) are designed for baseload operations, maintaining a steady power output at 100%, except during planned maintenance and refueling. However, in countries like France, Slovakia, and Korea, where nuclear power is a major source of electricity, integrating nuclear energy with intermittent renewables is crucial for stable power generation. This integration necessitates daily power adjustments by NPPs in response to grid demands, a process known as a Load Follow Operation (LFO). Such a process introduces strong interdependencies between thermal–hydraulic and neutron–kinetic parameters, coupled with the three-dimensional movement of Control Element Assemblies (CEAs) and Xenon dynamics, which pose safety challenges due to shifts in core power distribution. To address these complexities, a multi-physics approach is employed using the multi-physics package RELAP5/3DKIN and implementing two strategies. The first strategy uses a mechanical shim, adjusting the reactor power exclusively through CEAs. The second strategy combines CEA movement with adjustments in soluble boron concentration. Both strategies are evaluated against axial offset and 3D power peaking safety limits to ensure compliance with operational safety requirements. Full article

Acoustic analysis of voice enables objective assessment of voice to diagnose changes in voice characteristics, and track the progress of therapy. In contrast to subjective assessment, objective measurements provide mathematical results referring to specific parameters and can be analyzed statistically. Changes in the voice of patients with partial deafness (PD) were not widely described in the literature, and recent studies referred to the voice parameters measured in this group of patients only using the multi-dimensional voice program (MDVP) by Kay Pentax. This paper describes the results of acoustic analysis of voice in patients with PD using VOXplot, and compares the results with those achieved with MDVP. Background/Objectives: The purpose of this study was a VOXplot objective analysis of voice in individuals with PD and to assess consistency with results obtained using MDVP and with perceptual assessment. Methods: Voice samples from 22 post-lingual PD individuals were recorded. They included continuous speech (cs) and sustained vowels (sv). The control group consisted of 22 healthy individuals with no history of voice or hearing dysfunction. The samples were analyzed with MDVP followed by VOXplot version 2.0.0 Beta. Statistical analysis was performed using a t-test paired with two samples for means. All individuals were also subjected to a perceptual voice assessment using the GRBAS by Hirano. Results: Differences were observed in 13 VOXplot parameters measured in voice samples of adults with PD compared with those in the control group. Both multiparametric indices, AVQI and ABI, showed a statistical increase. When it comes to MDVP parameters correlating with breathiness, all of them (shim dB, APQ, NHR, SPI, and NSH) increased in patients with partial deafness, reflecting a breathy voice. Only one increase in the SPI was not statistically significant. Seven MDVP parameters correlating with hoarseness were elevated, and five (Jitt%, vF0, Shim dB, APQ, and NHR) showed a statistically significant increase. Correlations were found of VOXplot and MDVP parameters with perceptual voice assessment. Conclusions: Both programs for objective assessment showed voice abnormalities in patients with PD compared with the control groups. There was a poor to moderate level of consistency in the results achieved using both systems. Correlations were also found with GRBAS assessment results. Full article

Objectives: To evaluate the effect of bio-electromagnetic energy regulation (BEMER) therapy on erectile dysfunction (ED) in patients with multiple sclerosis (MS). Methods: A triple-blind randomized clinical trial was conducted in two different centers. Fifty-two male participants with MS were randomly allocated into two groups. Patients received either three weeks of BEMER with pelvic floor exercises or sham BEMER with pelvic floor exercises. The primary measure was the International Index of Erectile Function—Erectile Function (IIEF-EF). Secondary measures included the Sexual Health Inventory for Men (SHIM), Erection Hardness Scale (EHS), Arizona Sexual Experience Scale (AXES), Modified Fatigue Impact Scale (MFIS), and Multiple Sclerosis, Intimacy, and Sexuality Questionnaire (MSISQ-19). Results: Compared to the sham BEMER group, the BEMER group showed better improvements in the IIEF-EF (mean difference [MD]: −6.9, p < 0.001), SHIM (MD: −6.1, p < 0.001), EHS (MD: −0.4, p = 0.022), AXES (MD: 2.9, p = 0.030), MSISQ-19 (MD: 15.0, p < 0.001), and MFIS (MD: 31.0, p < 0.001). Conclusions: BEMER therapy improved erectile function and sexual satisfaction and reduced fatigue in patients with MS after three weeks of intervention. Long-term follow-up studies are warranted to ascertain the sustained benefits of BEMER therapy for MS-related ED. Full article

Finite element modelling of multi-bolted foundation connections used for the foundation of heavy machinery or equipment is presented. Connections made using different types of shims, with particular emphasis on polymer–steel shims, are investigated. The stiffness characteristics for the adopted models of multi-bolted foundation connections at the installation stage are described and compared. It is shown that the use of polymer–steel shims can result in a significant improvement in the stiffness of a multi-bolted foundation connection compared to a connection with a polymer shim, and in achieving a multi-bolted foundation connection with a stiffness similar to that of a connection with a steel shim (at a sufficiently low polymer layer thickness). Full article

(1) Background: Since the introduction of the purpose-built Single Port (SP) robotic platform, there has been an ongoing debate regarding its advantages compared to the established multi-port (MP) system. The goal of this present study is to compare the perioperative, oncological, and functional outcomes of SP Extraperitoneal robotic radical prostatectomy (RARP) versus that of MP Transperitoneal RARP approach at a high-volume tertiary center. (2) Methods: Based on a retrospective review of the prospectively maintained IRB-approved database, 925 patients successfully underwent RARP by a single experienced robotic surgeon. A 4:1 propensity-matched analysis based on the baseline prostate cancer International Society of Urological Pathology (ISUP) Grade Group, clinical stage, and preoperative Prostate Specific Antigen (PSA) was performed, which yielded a cohort of 606 patients—485 in the SP EP and 121 in the MP TP approaches. Of note, the SP EP approach also included the traditional Extraperitoneal (n = 259, 53.4%) and the novel Transvesical (TV) approaches (n = 226, 46.6%). (3) Results: The overall operative time was slightly longer in the SP cohort, with a mean of 198.9 min compared to 181.5 min for the MP group (p < 0.001). There were no intraoperative complications with the MP approach and only one during the SP approach. The SP EP technique demonstrated significant benefits, encompassing reduced intraoperative blood loss (SP 125.1 vs. MP 215.9 mL), shorter length of hospital stay (SP 12.6 vs. MP 31.9 h), reduced opioid use at the time of discharge (SP 14.4% vs. MP 85.1%), and an earlier Foley catheter removal (SP 6 vs. MP 8 days). From an oncological perspective, the rate of positive surgical margins remained comparable across both groups (p = 0.84). Regarding functional outcomes, the mean continence rates and Sexual Health Inventory for Men (SHIM) scores were identical between the two groups at 6 weeks, 3 months, and 6 months respectively. (4) Conclusion: SP EP RARP demonstrates similar performance to MP TP RARP in terms of oncologic and functional outcomes. However, SP EP RARP offers several advantages in reducing the overall hospital stay, decreasing postoperative pain and hence the overall opioid use, as well as shortening the time to catheter removal, all of which translates to reduced morbidity and facilitates the transition to outpatient surgery. Full article

Investigations of human brain disorders are frequently conducted in rodent models using magnetic resonance imaging. Due to the small specimen size and the increase in signal-to-noise ratio with the static magnetic field strength, dedicated small-bore animal scanners can be used to acquire high-resolution data. Ultra-high-field (≥7 T) whole-body human scanners are increasingly available, and they can also be used for animal investigations. Dedicated sensors, in this case, radiofrequency coils, are required to achieve sufficient sensitivity for the high spatial resolution needed for imaging small anatomical structures. In this work, a four-channel transceiver coil array for rat brain imaging at 7 T is presented, which can be adjusted for use on a wide range of differently sized rats, from infants to large adults. Three suitable array designs (with two to four elements covering the whole rat brain) were compared using full-wave 3D electromagnetic simulation. An optimized static B₁⁺ shim was derived to maximize B₁⁺ in the rat brain for both small and big rats. The design, together with a 3D-printed adjustable coil housing, was tested and validated in ex vivo rat bench and MRI measurements. Full article

The influence of fabrication and assembly errors on the surface distortion due to gravity of a 2 m primary mirror and its correction method are presented. The effect of fabrication errors on the surface distortion is verified by Monte Carlo analysis. The results show that, within the 46.3% confidence interval, the surface accuracy root mean square (RMS) caused by fabrication errors is more than 5.0 nm (indicator requirement). The sensitivity of mirror surface accuracy to the matching relationship between the flexible support axial assembly position and the inherent properties (neutral surface and center of gravity) of the mirror were analyzed. Then, the correction principle of the RMS was proposed based on the analysis result. The surface accuracy RMS of surface gravity distortion is sensitive to fabrication and assembly errors, which can be effectively corrected using a flexible support mounting technique. This new flexible support mounting technique replaces the conventional method with flexible supports having shims so that adjustments can be made during testing to counteract the gravitational distortion of the mirror surface. Astigmatic aberration due to gravitational changes is effectively reduced by selecting a suitable thickness of shim, and the relationship between the astigmatism and the thickness of shim was investigated using the finite element analysis method. Finally, the finite element analysis results showed that the optimal surface gravity accuracy of the mirror assembly could be obtained by adjusting the shim, while the other performance of the assembly was not affected. Full article

This study focuses on investigating the newly proposed sliding–rolling friction composite seismic isolation bearing. It begins by establishing the dynamic equilibrium equation for the structure. Subsequently, this paper proposes a calculation model for the sliding–rolling friction composite seismic isolation bearing, integrating fundamental theories of structural dynamic response analysis and numerical solution methods. Utilizing finite element analysis software ABAQUS (2021), the mechanical properties of the seismic isolation bearing are comprehensively assessed. Through this evaluation, the optimal parameters of the seismic isolation bearing are determined. The findings reveal that the optimal parameters include a friction coefficient (μ) of 0.04, four U-type dampers at 45° angles, a width of 60 mm, five balls, and two shims. Full article

The emergence of 7T clinical MRI technology has sparked our interest in its ability to discern the complex structures of the hand. Our primary objective was to assess the sensory and motor nerve structures of the hand, specifically nerves and Pacinian corpuscles, with the dual purpose of aiding diagnostic endeavors and supporting reconstructive surgical procedures. Ethical approval was obtained to carry out 7T MRI scans on a cohort of volunteers. Four volunteers assumed a prone position, with their hands (N = 8) positioned in a “superman” posture. To immobilize and maintain the hand in a strictly horizontal position, it was affixed to a plastic plate. Passive B0 shimming was implemented. Once high-resolution 3D images had been acquired using a multi-transmit head coil, advanced post-processing techniques were used to meticulously delineate the nerve fiber networks and mechanoreceptors. Across all participants, digital nerves were consistently located on the phalanges area, on average, between 2.5 and 3.5 mm beneath the skin, except within flexion folds where the nerve was approximately 1.8 mm from the surface. On the phalanges area, the mean distance from digital nerves to joints was approximately 1.5 mm. The nerves of the fingers were closer to the bone than to the surface of the skin. Furthermore, Pacinian corpuscles exhibited a notable clustering primarily within the metacarpal zone, situated on the palmar aspect. Our study yielded promising results, successfully reconstructing and meticulously describing the anatomy of nerve fibers spanning from the carpus to the digital nerve division, alongside the identification of Pacinian corpuscles, in four healthy volunteers (eight hands). Full article

A plantain pseudostem was harvested and processed on the same day. The process began with manually separating the sheaths (80.85%) and the core (19.14%). The sheaths were subjected to a mechanical shredding process using paddles, extracting 2.20% of lignocellulosic fibers and 2.12% of sap, compared to the fresh weight of the sheaths. The fibers were washed, dried, combed, and spun in their native state and subjected to a steam explosion treatment, while the sap was subjected to filtration and evaporation. In the case of the core, it was subjected to manual cutting, drying, grinding, and sieving to separate 12.81% of the starch and 6.39% of the short lignocellulosic fibers, compared to the fresh weight of the core. The surface modification method using steam explosion succeeded in removing a low proportion of hemicellulose and lignin in the fibers coming from the shims, according to what was shown by Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC), achieving increased σ_max and ε from the tensile test and greater thermal stability compared to its native state. The sap presented hygroscopic behavior by FT-IR and the highest thermal stability from TGA, while the starch from the core presented the lowest hygroscopic character and thermal stability. Although the pseudostem supplied two types of fibers, lower lignin content was identified in those from the core. Finally, the yarns were elaborated by using the fibers of the sheaths in their native and steam-exploded states, identifying differences in the processing and their respective physical and mechanical properties. Full article

The spectral quality of magnetic resonance spectroscopic imaging (MRSI) can be affected by strong magnetic field inhomogeneities, posing a challenge for 3D-MRSI’s widespread clinical use with standard scanner-equipped 2nd-order shim coils. To overcome this, we designed an empirical unified shim–RF head coil (32-ch RF receive and 51-ch shim) for 3D-MRSI improvement. We compared its shimming performance and 3D-MRSI brain coverages against the standard scanner shim (2nd-order spherical harmonic (SH) shim coils) and integrated parallel reception, excitation, and shimming (iPRES) 32-ch AC/DC head coil. We also simulated a theoretical 3rd-, 4th-, and 5th-order SH shim as a benchmark to assess the UNIfied shim–RF coil (UNIC) improvements. In this preliminary study, the whole-brain coverage was simulated by using B₀ field maps of twenty-four healthy human subjects (n = 24). Our results demonstrated that UNIC substantially improves brain field homogeneity, reducing whole-brain frequency standard deviations by 27% compared to the standard 2nd-order scanner shim and 17% compared to the iPRES shim. Moreover, UNIC enhances whole-brain coverage of 3D-MRSI by up to 34% compared to the standard 2nd-order scanner shim and up to 13% compared to the iPRES shim. UNIC markedly increases coverage in the prefrontal cortex by 147% and 47% and in the medial temporal lobe and temporal pole by 29% and 13%, respectively, at voxel resolutions of 1.4 cc and 0.09 cc for 3D-MRSI. Furthermore, UNIC effectively reduces variations in shim quality and brain coverage among different subjects compared to scanner shim and iPRES shim. Anticipated advancements in higher-order shimming (beyond 6th order) are expected via optimized designs using dimensionality reduction methods. Full article