Investigating the potential of yacon (Smallanthus sonchifolius) juice in the development of organic apple-based snacks.

This study investigates the potential of yacon (Smallanthus sonchifolius) juice for the development of prebiotic-rich organic apple-based snacks. Yacon syrup, primarily composed of fructan, inulin, fructooligosaccharides (FOS), and free sugars, represents a promising nutraceutical product. Its great potential in food processing, particularly as an innovative source of prebiotics, has been demonstrated both in vitro and in vivo since it is fermented specifically by lactobacilli and bifidobacteria. Our objective was to explore the feasibility of employing vacuum impregnation process to incorporate yacon juice into organic apples, followed by hot air drying for the formulation of dried organic apple-based snacks with health-enhancing attributes. We assessed the prebiotic and physicochemical characteristics of the impregnated snacks, also considering 50 days of storage at room temperature. Vacuum impregnation and air drying produced dried apple slices impregnated with yacon juice with good quality and stability. Higher levels of fructan (16-fold difference compared to non-impregnated apples) in the apple slices increased their prebiotic potential, promoting the growth and viability of cells within simulated intestinal fluid, including strains of Bifidobacterium animalis subsp. lactis BB -12, Bifidobacterium breve DSM 20091, Bifidobacterium longum subsp. infantis DSM 20088, Lacticaseibacillus rhamnosus GG and Lacticaseibacillus rhamnosus C112, even after prolonged storage. Remarkably, the physicochemical parameters of the impregnated and dried apple slices remained nearly constant and akin to the control samples. Therefore, the combination of vacuum impregnation and air drying has the potential to be used to produce enriched prebiotic organic apple snacks, providing consumers with additional health benefits, including enhanced gut health, with its associated implications, and increased satiety. This innovation could contribute to the development of health-promoting food products with improved nutritional profiles.

Recent studies on alternative technologies for deep-fat frying.

Deep fat fried food products have been considered as a vital dietary contributor to certain chronic diseases, including the risk of atherosclerosis, cancer and hypertension. Hence, many food industries are focusing on low fat fried products to attract consumers. In general, oil is absorbed during deep fat frying, and this century old process is used for preparing various kinds of fried food products such as potato chips, banana chips, savory snacks, etc. Vacuum frying, electric field frying and two-stage frying technologies have been developed as an alternatives to traditional frying. These two technologies are suitable for most fried products; however, they may not be suitable for sugar based fruits as they can lead to the formation of browning reactions, which are generally considered unacceptable. This review aims to cover recent work done in the area of vacuum frying and two-stage frying, including the role of pre-treatment and post-treatment novel methods. Additionally, emphasis has been given on recent innovations to improve the quality of vacuum and two-stage frying, particularly concerning the reduction of oil uptake in fried food products.

Development and evaluation of a vacuum impregnation system for enhancement of biochemical properties of food materials.

Vacuum impregnation is a novel methodology for adding various substances to porous foods. This study aimed to develop a cost effective automate system for vacuum impregnation of food materials to enhance their nutritional, functional and sensory properties depending on the functionality of the impregnation solution. The developed vacuum impregnation system includes a vacuum chamber, vacuum pump and an automation setup for creating and maintaining vacuum conditions, feeding impregnated solutions to the samples and releasing vacuum. Fresh-cut spinach leaves were impregnated with ascorbic acid (AsA) and calcium chloride (Cacl2) (10% concentration) in the setup in order to test the effect of the process on some biochemical properties. Statistical analysis revealed significant effect of vacuum impregnation on the biochemical properties (total soluble solids, total phenolic content, flavonoid content and free radical scavenging activity) and color of spinach leaves during storage up to 4 days. Impregnation process showed significant increase in the total phenolic and flavonoid content of the spinach leaves. Increment up to 78% in antioxidant activity was seen for the uncoated impregnated leaves as compared to 59% activity in untreated samples. Thus, products with desired parameters can be produced with this process with minimal impact on their properties at a lower cost and in a shorter time period.

A challenge test on Pseudomonas spp. as spoiling microorganism in fish fillets.

Fish fillets are highly susceptible to spoilage, with Pseudomonas spp. bacteria being among the main culprits. To maintain products' quality and safety, it is important to control the load of these microorganisms and understand their growth potential in fish fillets. However, setting up challenge tests might be hard due to the difficulty of differentiating intentionally inoculated bacteria from those already present on the fillets. To overcome this obstacle, a pilot study using Pseudomonas aeruginosa, a clinically significant bacterial species that is rare in food, was conducted. Vacuum-packed Northern cod, salmon, and plaice fish fillets were experimentally inoculated and subjected to trials at both refrigeration (4 °C) and thermal abuse temperatures (from +4 °C to +6 °C and then to +8 °C). The results showed that the growth potential of Pseudomonas aeruginosa in all the fish fillets was less than 0.5 Log10 CFU/g. This confirms that vacuum packaging could reduce the multiplication of Pseudomonas spp. in the fish fillets and underlines as it is crucial to have fish fillets containing initial loads of Pseudomonas between 104-105 CFU/g or lower at the beginning of the shelf life in order to control the deterioration rate of the product. This study provides a basis for developing further challenge tests for Pseudomonas spp. in the fish industry and highlights the importance of controlling initial loads of Pseudomonas to prevent product deterioration during the shelf life.

The pectus care guidelines: best practice consensus guidelines from the joint specialist societies SCTS/MF/CWIG/BOA/BAPS for the treatment of patients with pectus abnormalities.

Pectus defects are a group of congenital conditions found in approximately 1 in 250 people, where the sternum is depressed back towards the spine (excavatum), protrudes forwards (carinatum) or more rarely is a mixture of both (arcuatum or mixed defects). For the majority of patients, it is well tolerated, but some patients are affected psychologically, physiologically or both. The deformity becomes apparent at a young age due to the growth of the ribs and the cartilage that links them to the sternum. The majority of defects are mild and are well tolerated, i.e. they do not affect activity and do not cause psychological harm. However, some young people develop lower self-esteem and depression, causing them to withdraw from activities (such as swimming, dancing) and from interactions that might 'expose' them (such as sleepovers, dating, going to the beach and wearing fashionable clothes). This psychological harm occurs at a crucial time during their physical and social development. A small number of patients have more extreme depression of their sternum that impedes their physiological reserve, which can occur when engaging in strenuous exercise (such as running) but can also limit moderate activity such as walking and climbing stairs. The effects can be so extreme that symptoms occur at rest or cause life-threatening compression of the major blood vessels and organs. The group of patients with physiological impairment usually also suffer from low self-esteem and depression. This paper summarizes the current evidence for the different treatment strategies for this condition, including supportive care, psychological support and non-surgical techniques including bracing and vacuum bell therapy. We also consider surgical techniques including the Ravitch procedure, the Nuss procedure (minimally invasive repair of pectus excavatum), pectus implants and other rare procedures such as Pectus Up. For the majority of patients, supportive care is sufficient, but for a minority, a combination of the other techniques may be considered. This paper also outlines best practice guidance for the delivery of such therapies, including standardized assessment, consent to treatment, audit, quality assurance and long-term support. All the interventions have risks and benefits that the patient, parents and clinicians need to carefully consider and discuss when deciding on the most appropriate course. We hope this evidence review of 'Best Practice for Pectus' will make a significant contribution to those considerations and help all involved, from patients to national policy makers, to deliver the best possible care.

Enhanced consolidation and removal of accumulated flocculants in dredged soil via leaching with vacuum preloading.

The vacuum preloading coupling flocculation treatment is a widely employed method for reinforcing soils with high water content in practical construction. However, uneven distribution and accumulation of flocculants pose significant damage to the soil environment and result in uneven soil consolidation, leading to severe issues in subsequent soil development and exploitation. To address these concerns, an evolved leaching with vacuum method is developed for facilitating soil consolidation while preventing the accumulation of flocculant in the soil. In this study, five model tests are conducted in which FeCl3 is chosen as the typical flocculant to promote soil consolidation, and deionized water is used for leaching. The final discharged water, settlement, water content and penetration resistance of soil are obtained to evaluate the soil reinforcement effect, while the flocculant removal effect is evaluated by the Fe3+ content in the filtrate and soil. The comprehensive reinforcement and flocculant removal effect show that this method is extremely effective compared to traditional vacuum preloading. The two leaching is clarified as the best choice, resulting in a 22% decrease in the soil water content and a 25% in soil penetration resistance, meanwhile a 12.8% removal rate of the flocculant. The test results demonstrate that leaching with vacuum preloading can contribute to promoting soil consolidation and reducing the accumulation of flocculant in the soil, ensuring the safe and eco-friendly use of the soil for future applications. The conclusions obtained are of significant theoretical value and technical support for practical construction and sustainable development.

Comprehensive infectious diabetic foot ulcer repair through multiple dressing methods, maggot therapy, and vacuum therapy after amputation: A case report study.

INTRODUCTION AND IMPORTANCE: Diabetic foot ulcers are a prevalent and challenging issue among diabetes patients, frequently leading to notable health concerns and reduced quality of life. Effectively addressing diabetic foot ulcers necessitates a comprehensive treatment strategy. CASE PRESENTATION: The 69-year-old patient with Type 2 diabetes, complicated by illiteracy and poor glycemic control, developed a foot wound that escalated to cellulitis and abscess due to diabetes and peripheral vascular disease. After angioplasty and midfoot amputation, treatment focused on wound healing with antibiotics, local anesthesia, larval therapy, vacuum-assisted closure (VAC), platelet-rich plasma (PRP) injections, and specialized dressings. A multidisciplinary team approach facilitated successful wound healing and functional improvement, highlighting the importance of comprehensive care and innovative treatments in complex diabetic foot ulcers. DISCUSSION: Diabetic foot ulcers, a frequent complication of diabetes, present notable hurdles in treatment and care. Comprehensive strategies are typically essential for managing these ulcers efficiently and averting additional issues. Recently, there has been increasing attention towards employing various dressing techniques, maggot therapy, and vacuum therapy as integral components of a holistic diabetic foot ulcer treatment approach. CONCLUSION: Employing a comprehensive method involving various dressing techniques, maggot therapy, and vacuum therapy for diabetic foot ulcers can significantly boost wound healing, curb infections, and lower the chances of additional complications.

Effect of ultrasound combined with chemical pretreatment as an innovative non-thermal technology on the drying process, quality properties and texture of cherry subjected to radio frequency vacuum drying.

To obtain high-quality cherry products, ultrasound (US) combined with five chemical pretreatment techniques were used on cherry prior to radio frequency vacuum drying (RFV), including carboxymethyl cellulose coating (CMC), cellulase (CE), ethanol (EA), isomaltooligosaccharide (IMO), and potassium carbonate + ethyl oleate (PC + AEEO). The effect of different pretreatments (US-CMC, US-CE, US-EA, US-IMO, US-(PC + AEEO)) on the drying characteristics, quality properties, texture, and sensory evaluation of cherries was evaluated. Results showed that the dehydration time and energy consumption were decreased by 4.17 - 20.83 % and 3.22 - 19.34 %, respectively, and the contents of individual sugars, soluble solid, total phenolics (TPC), natural active substances, total flavonoids (TFC), and antioxidant properties (DPPH, ABTS and FRAP) were significantly increased after US combined with five chemical treatments (P < 0.05). Moreover, the pretreatment played important role in improving texture properties and surface color retention in the dried cherries. According to the sensory evaluation analysis, the dehydrated cherries pretreated with US-CMC exhibited the highest overall acceptance, texture, crispness, color, and sweet taste showed lower off-odor, bitter taste and sour taste compared to control and other pretreatments. The findings indicate that US-CMC pretreatment is a promising technique for increasing physicochemical qualities and dehydration rate of samples, which provides a novel strategy to processing of dried cherry.

High-efficiency terahertz-wave generation based on extended interaction oscillator with strongly-coupled 2π mode operation.

A slow-wave structure improvement for enhancing the 2π-mode electronic efficiency is embodied in the validation of an extended interaction oscillator (EIO), which has an electronic efficiency of 6.52% at 0.22 THz from particle-in-cell (PIC) calculations. A 2π-mode bi-periodic slow-wave structure (BPSWS) with staggered long and short slots is utilized for optimizing the circuit performance. The proposed BPSWS has the capability of combining the respective advantages for both π and 2π-mode in terms of coupling performance and output performance, thus supporting a strongly-coupled 2π-mode with higher coupling capability. Compared with the typical mono-periodic SWS (MPSWS), the adopted strongly-coupled 2π-mode effectively improves the characteristic impedance M2R/Q by 103% to 66.79 Ω, the coupling coefficient by 66% to 0.497, and the normalized wave-amplitude by 22%. Accordingly, 503 W of average output power can be derived for the BPSWS-EIO with a 25.7 kV and 0.3 A sheet beam injected. Cold-test experiments were conducted, confirming that the 0.22 THz structure exhibits commendable fabrication precision and consistency and thus demonstrates the expected frequency response.

Obstetric factors and neonatal outcomes of depressed skull fractures in newborns.

PURPOSE: To determine the obstetric factors affecting the development of depressed skull fracture in neonates. MATERIALS AND METHODS: This was a retrospectively cohort study on neonates born between July 2016 and August 2021. Neonates diagnosed with depressed skull fractures within one week of birth through X-ray and/or brain ultrasonography were included, and their mothers' obstetric characteristics were reviewed. RESULTS: There were 12 cases in 6791 live births. Five women were over 35 years old. All except two were nulliparous. Five cases were delivered from labor induction and others presented with spontaneous labor. Except for two cases, delivery occurred within an hour after full cervical dilatation. Two cases were assisted by vacuum. None displayed fetal distress signs such as low Apgar scores below 7, meconium staining, and umbilical cord pH under 7.2. All depressed fractures were found in the right parietal area. Three cases resulted in focal hyperechoic lesion in brain ultrasonography and two of them showed small hemorrhage-like lesion in magnetic resonance imaging. All depressed skull fractures improved within 6 months in followed X-rays or ultrasonography. CONCLUSIONS: There was no definitely associated obstetric condition for depressed skull fracture of neonates although nulliparous women were majority of the affected cases.

Air inflow into vacuum-type immobilization devices impacts setup errors.

We aimed to determine the impact of air inflow into vacuum-type immobilization devices (VIDs) on setup errors. We assigned 70 patients undergoing radiotherapy for head and neck cancer to groups V (n = 34) or N (n = 36) according to whether the VIDs were deflated weekly or not deflated during treatment, respectively. We calculated systematic errors (Σ) as the standard deviations (SDs) of mean errors, and random errors (σ) as the root mean square of SDs in each patient. We compared overall means (µ), SDs (SDoverall), random errors and systematic errors. We also measured temporary pressure changes in VIDs to determine the influence of pressure changes in VIDs on setup errors. The µ was within 0.20 mm and 0.2° in both groups, whereas SDoverall significantly differed between them. The SDoverall differed the most in the Roll axes of groups N (0. 87°) and V (0.58°). The Σ and σ values were lower in all axes of group V than in group N. Despite the initial deflation target of - 70 kPa, the pressure in VIDs reached - 5 kPa at the end of treatment. However, weekly deflation apparently maintained pressure at - 20 kPa. Effective pressure control in VIDs can reduce patient-by-patient variation and improve setup reproducibility for individual patients, consequently resulting in small variations among overall setup errors.

Negative Pressure Wound Therapy in Pharyngocutaneous Fistula.

Pharyngocutaneous fistula (PCF) is an abnormal connection between the pharynx and skin that can occur after laryngectomy surgery. It can have a significant negative impact on patient recovery, delaying wound healing, requiring prolonged nil-per-oral (NPO) status, and reducing quality of life. Traditionally, the management of PCF has relied on conservative measures or surgical intervention. However, negative pressure wound therapy (NPWT) offers a promising alternative approach. This case study involves three patients who underwent laryngectomy and developed postoperative PCF. All patients received NPWT with a modified suction catheter and low negative pressure (20-40 mmHg). With NPWT, all patients achieved complete wound closure, with healing times ranging from two weeks to six weeks. This suggests that NPWT may significantly accelerate PCF healing compared to traditional methods. However, maintaining an airtight dressing on the neck region can be challenging. This study highlights the potential of NPWT for faster PCF closure after laryngectomy. Further research is needed to optimize NPWT application techniques, explore the impact on long-term outcomes, and establish guidelines for broader clinical use.

Stiffness calibration of qPlus sensors at low temperature through thermal noise measurements.

Non-contact atomic force microscopy (nc-AFM) offers a unique experimental framework for topographical imaging of surfaces with atomic and/or sub-molecular resolution. The technique also permits to perform frequency shift spectroscopy to quantitatively evaluate the tip-sample interaction forces and potentials above individual atoms or molecules. The stiffness of the probe, k, is then required to perform the frequency shift-to-force conversion. However, this quantity is generally known with little precision. An accurate stiffness calibration is therefore mandatory if accurate force measurements are targeted. In nc-AFM, the probe may either be a silicon cantilever, a quartz tuning fork (QTF), or a length extensional resonator (LER). When used in ultrahigh vacuum (UHV) and at low temperature, the technique mostly employs QTFs, based on the so-called qPlus design, which actually covers different types of sensors in terms of size and design of the electrodes. They all have in common a QTF featuring a metallic tip glued at the free end of one of its prongs. In this study, we report the stiffness calibration of a particular type of qPlus sensor in UHV and at 9.8 K by means of thermal noise measurements. The stiffness calibration of such high-k sensors, featuring high quality factors (Q) as well, requires to master both the acquisition parameters and the data post-processing. Our approach relies both on numerical simulations and experimental results. A thorough analysis of the thermal noise power spectral density of the qPlus fluctuations leads to an estimated stiffness of the first flexural eigenmode of ≃2000 N/m, with a maximum uncertainty of 10%, whereas the static stiffness of the sensor without tip is expected to be ≃3300 N/m. The former value must not be considered as being representative of a generic value for any qPlus, as our study stresses the influence of the tip on the estimated stiffness and points towards the need for the individual calibration of these probes. Although the framework focuses on a particular kind of sensor, it may be adapted to any high-k, high-Q nc-AFM probe used under similar conditions, such as silicon cantilevers and LERs.

Prevention of the Quality Degradation of Antarctic Krill (Euphausia superba) Meal through Two-Stage Drying.

To achieve a krill meal of high quality, a two-stage drying involving hot-air drying and vacuum drying was investigated. Five experimental groups were established according to the different drying conditions in the second stage, including 95 °C and 101 kPa, 95 °C and 60 kPa, 75 °C and 101 kPa, 75 °C and 60 kPa, and 75 °C and 20 kPa. The results showed that reducing the drying temperature and vacuum pressure in the second stage had a significant impact on the drying characteristics, sensory quality, and bioactive compounds of krill meal. Among all five groups, the drying condition of 75 °C and 60 kPa maintained a high drying rate while preserving a phospholipid content of 30.01 mg/kg and an astaxanthin content of 37.41 mg/kg. It also effectively reduced the isomerization of astaxanthin and the oxidation of unsaturated fatty acids. These results suggested that the two-stage drying method may contribute to the production of high-quality krill meal.

Development of an Apple Snack Enriched with Probiotic Lacticaseibacillus rhamnosus: Evaluation of the Refractance Window Drying Process on Cell Viability.

The objective of this study was to develop a dried apple snack enriched with probiotics, evaluate its viability using Refractance Window (RWTM) drying, and compare it with conventional hot air drying (CD) and freeze-drying (FD). Apple slices were impregnated with Lacticaseibacillus rhamnosus and dried at 45 °C using RWTM and CD and FD. Total polyphenol content (TPC), color (∆E*), texture, and viable cell count were measured, and samples were stored for 28 days at 4 °C. Vacuum impregnation allowed for a probiotic inoculation of 8.53 log CFU/gdb. Retention values of 6.30, 6.67, and 7.20 log CFU/gdb were observed for CD, RWTM, and FD, respectively; the population in CD, RWTM remained while FD showed a decrease of one order of magnitude during storage. Comparing RWTM with FD, ∆E* was not significantly different (p < 0.05) and RWTM presented lower hardness values and higher crispness than FD, but the RWTM-dried apple slices had the highest TPC retention (41.3%). Microstructural analysis showed that RWTM produced a smoother surface, facilitating uniform moisture diffusion and lower mass transfer resistance. The effective moisture diffusion coefficient was higher in RWTM than in CD, resulting in shorter drying times. As a consequence, RWTM produced dried apple snacks enriched with probiotics, with color and TPC retention comparable to FD.

Facial tightening using a novel vacuum-assisted microneedle fractional radiofrequency system: A prospective, randomized, split-face study.

BACKGROUND: The microneedle fractional radiofrequency system (MFRS) is able to rejuvenate facial appearance by heating and coagulating certain depth of skin tissue. OBJECTIVE: To evaluate the safety and efficacy of a novel vacuum-assisted MFRS for facial contour tightening. METHODS: This prospective, randomized, split-face study included 21 patients who underwent three treatments with a vacuum-assisted MFRS at 1-month intervals. Half of the face was treated with the MFRS; the other half was untreated (control). Facial volume changes and wrinkles were objectively measured using a three-dimensional imaging system and VISIA-CR. RESULTS: Volume changes of the treated midface were -0.24 ± 0.75, -0.59 ± 0.92, and -0.55 ± 0.65 mL at 1, 3, 6 months follow-up; however, measurements of the control side were 0.08 ± 0.70, -0.08 ± 0.53, and - 0.10 ± 0.86 mL, indicating significant reductions (p < 0.05). The number of facial wrinkles on the treated side was significantly reduced to 12.44 ± 4.85 at 3 months and sustained at 6 months (11.11 ± 4.100) compared to the control side (14.89 ± 5.26 and 13.22 ± 4.44, respectively; p < 0.05). No long-term side effects occurred. CONCLUSION: The vacuum-assisted MFRS is safe and effective and is recommended for improving facial tightening and reducing wrinkles. This technology is sufficient to ensure the insertion depth, thus helping to improve the treatment accuracy and safety. The MFRS provides sustained effects for at least 6 months.

Infusion of active compound into sliced button mushrooms through vacuum impregnation to improve functionality: Comparing response surface methodology and artificial neural network.

The present study explores the infusion of active compounds (ascorbic acid and calcium lactate) into sliced button mushrooms (Agaricus bisporus) to increase the nutritional value and reduce the browning effect of sliced mushrooms using the vacuum impregnation (VI) technique. The aim was to functionalize the vacuum-infused sliced mushrooms and evaluate the physicochemical properties of button mushrooms for diversifying food use. The central composite design was implemented to determine the optimized condition for the process with four independent factors, that is, immersion time (IT) 30-90 min, solution temperature (ST) 35-55°C, solution concentration (SC) 4%-12%, and vacuum pressure (VP) 50-170 mbar. The optimum VI processes obtained were ST-40°C, SC-8%, VP-140 mbar, and IT-65 min with a desirability function of 0.77. Statistically, two models (response surface methodology [RSM] and artificial neural network [ANN]) were employed to compare the better performance for the prediction of VI operational process parameters. The RSM model showed a better prediction of VI process parameters than the ANN model, with a higher R2 value (0.9228 vs. 0.8160) and lower root mean square error value (1.4004 vs. 2.1751), χ2 (2.4491 vs. 5.2762), mean absolute error (1.1177 vs. 1.1611), and absolute average deviation (4.3532 vs. 5.6746) for water loss. A similar pattern was observed for solute gain, ascorbic acid, titratable acidity, color change, firmness, and pH. Therefore, the VI process was found to be an effective method for enhancing the nutritional properties of sliced mushrooms. These findings concluded that the RSM model is more efficient for better prediction with good accuracy of the VI process than the ANN model.

Application of vacuum-sealing drainage in buttonhole-related arteriovenous fistula infection: A case report.

Few studies have reported the application of vacuum-sealing drainage of infected dialysis vascular access wounds. Herein, we present a case of buttonhole-related arteriovenous fistula infection treated with vacuum-sealing drainage. A 53-year-old female hemodialysis patient was hospitalized with an inflamed arteriovenous fistula. The patient underwent non-tunneled catheterization for dialysis and was treated with moxifloxacin and vancomycin for staphylococcal infection. On Day 3, the skin overlying the inflamed fistula was ulcerated, resulting in severe hemorrhage. Emergency surgery was performed along with vacuum-sealing drainage for fistula reconstruction. Vacuum-sealing drainage accelerated the recovery of the wound without complications. No further access complications occurred during over a 3-year follow-up.

Influence of the Advanced One-Step Mixing System Under Non-Vacuum on the Mechanical Properties of Acrylic Bone Cement.

Background: The specific aim of this study was to evaluate the mechanical properties of cement prepared with the advanced one-step mixing system and whether the addition of vacuum conditions yielded an appreciable improvement in the biomechanical strength or overall quality of bone cement. Methods: The advanced one-step mixing system was used. Twelve specimens were prepared by mixing under vacuum conditions and 12 specimens were prepared by mixing without a vacuum. Radiographs of cement specimens were analyzed to determine the porosity of the test region. Tensile testing of the specimens was performed with a loading rate of 2.54mm/min at room temperature. The ultimate tensile strength (UTS) and the tensile elastic modulus (E) were determined for each sample. Results: The UTS of the bone cement samples mixed under vacuum conditions were not significantly different than those mixed without vacuum (vacuum: 39±6MPa; non-vacuum: 35±6MPa; p=0.637). The E of samples mixed under vacuum conditions was significantly higher than the bone cement mixed without vacuum (vacuum: 2.78±0.06GPa; non-vacuum: 2.63±0.15GPa; p=0.019). Radiographic images showed samples mixed under vacuum conditions contained fewer defects than the samples mixed without vacuum (vacuum: 3.5%±3.3% (range: 0.0%-9.0%); non-vacuum: 6.9%±1.0% (range: 4.6%-8.2%)). Conclusion: Mixing bone cement with the advanced one-step mixing system under vacuum conditions does not produce an appreciable difference in the UTS of the bone cement in a bench biomechanical testing model compared to the bone cement mixed without vacuum. It does, however, create a less porous cement mixture with a higher E compared to cement mixed without vacuum. Level of Evidence: V.

Pulsed THz radiation under ultrafast optical discharge of vacuum photodiode.

In this paper, we first present an experimental demonstration of terahertz radiation pulse generation with energy up to 5 pJ under the electron emission during ultrafast optical discharge of a vacuum photodiode. We use a femtosecond optical excitation of metallic copper photocathode for the generation of ultrashort electron bunch and up to 45 kV/cm external electric field for the photo-emitted electron acceleration. Measurements of terahertz pulses energy as a function of emitted charge density, incidence angle of optical radiation and applied electric field have been provided. Spectral and polarization characteristics of generated terahertz pulses have also been studied. The proposed semi-analytical model and simulations in COMSOL Multiphysics prove the experimental data and allow for the optimization of experimental conditions aimed at flexible control of radiation parameters.