Absorbent Foam Research Articles

Valorization of rambutan (Naphelium lappaceum L.) peel: an enzymatic approach toward a biopolymer absorbent foam

Valorization of rambutan (Naphelium lappaceum L.) peel: an enzymatic approach toward a biopolymer absorbent foam

Comparing Outcomes Between Standard Mepilex and Mepilex Silver for Tracheotomy Dressings.

The purpose of the study is to compare the incidence of early postoperative tracheotomy stoma wound complications in pediatric patients using a silver-impregnated barrier dressing (Mepilex Ag) versus a standard absorbent foam dressing (standard Mepilex). This is a prospective, non-blinded, randomized trial of pediatric patients undergoing tracheotomy at a tertiary care children's hospital. Patients were randomized to receive Mepilex Ag versus standard Mepilex tracheostoma dressings following tracheotomy. All patients received standard postoperative wound care and daily stomal examination. Wound related complications, breakdown, granulation, and infection were recorded for the first 7 days after surgery. A non-inferiority study design was used to test the hypothesis that the Mepilex group had a non-inferior wound complication rate (within 10% margin) compared to the Mepilex Ag group. Eighty-two patients were enrolled; 52 received Mepilex Ag, and 30 received standard Mepilex. There was no difference between the groups with respect to age, sex, race, surgical indication, or postoperative length of stay. Non-inferiority testing demonstrated that the Mepilex standard cohort had no more than 10% greater stomal wound complication rate than that of Mepilex Ag dressing group (p = 0.0108). Standard Mepilex was found to be non-inferior to Mepilex Ag in the prevention of tracheotomy stomal wound complications. Standard Mepilex may be used effectively in the postoperative period, potentially reducing costs to caregivers and the institution. Further work is needed to analyze additional factors that could contribute to poor postoperative stoma healing such as bacterial colonization. Randomized Controlled Trial, Level 2 Laryngoscope, 2024.

Analgesic effects of ibuprofen soft and flexible absorbent foam dressing after colorectal surgery: A single-center comparative study

Abstract Background Postoperative wound care and pain management are crucial components of the postoperative recovery process. This study aims to evaluate whether the analgesic effects of the ibuprofen soft and flexible absorbent foam dressing are superior to those of traditional gauze after colorectal surgery. Materials and Methods Data pertaining to patients who underwent colorectal surgery between May 2021 and January 2022 were extracted from the electronic medical records database archive of a single institution. The ibuprofen soft and flexible absorbent foam dressing was applied to 62 patients for postoperative wound care, whereas gauze was used for 78 patients. Primary outcome measurements included the count of dressings, visual analog scale pain scores, analgesic dosage, complications, and length of hospitalization. Results The mean pain score on the 5th day postoperation was significantly lower for the ibuprofen group (2.03 ± 1.55) than for the control group (2.63 ± 1.72, p = 0.035). The mean dosage (mg) of parecoxib on the 3rd day postoperation was significantly lower for the ibuprofen group (2.58 ± 12.27) than for the control group (10.26 ± 21.80, p = 0.01). The cumulative number of dressing changes during the 1st week postoperation was significantly lower for the ibuprofen group (mean ± standard deviation, 3.00 ± 0.98) than for the control group (7.55 ± 2.68, p < 0.001). No significant differences were observed in the complication rate or length of hospitalization between the groups. Conclusions The ibuprofen soft and flexible absorbent foam dressing can either enhance the analgesic effect during postoperative recovery or reduce the cost and dressing time associated with postoperative wound care.

Hierarchical Co3S4 nanostructure coupling with macroporous nickel foam: A robust interfacial solar evaporator for efficient desalination and sustainable freshwater production

Interfacial solar water evaporation (ISWE) technology provides a green, energy-saving and economical way to sustainably produce freshwater from various water sources for addressing the impending water shortage. However, the low evaporation rate, complex manufacturing process and harmful surface salt accumulation for ISWE are still challenging and considerably restricted the practical applications. Herein, we design and fabricate a robust ISWE based on the hierarchical Co3S4 nanostructure as a photothermal absorber and three-dimensional (3D) nickel foam (NF) as a primary structure with macroporous networks. The as-fabricated Co3S4/NF not only introduces sufficient photothermal centers to convert solar energy into heat, but also provides abundant channels for water transportation and steam escape. The Co3S4/NF evaporator exhibits a high evaporation rate of 1.56 kg m−2 h−1 and a photothermal conversion efficiency up to 94.18 % under one-sun illumination. Moreover, such evaporator shows the long-term durability and good salt-resistant ability, which can sustainably produce freshwater from various water sources including seawater, saline water, lake water and other contaminated water. The photothermal Co3S4/NF evaporator would provide a promising platform for the production of drinkable water in a safe and sustainable manner.

Driveline dressings used in heartmate patients and local complications: A retrospective cohort

BackgroundPatients with long-term ventricular assist devices (VAD) are predisposed to infection, bleeding, and pressure injuries at the insertion of the driveline. There is no consensus on a driveline dressing protocol. Chlorhexidine is often used to clean the driveline exit site and has been associated with lower rates of infection. For driveline coverage, bacteriostatic agents and transparent film have shown good results, but are costly. The same issue was associated with anchorage devices. ObjectivesThe purpose of this study was to evaluate the types of dressings used in the driveline of patients using HeartMate (HM) and to describe the incidence density of local complications (infection, bleeding, and pressure injury) within 30 days postoperatively. MethodsA retrospective cohort study was conducted and included 22 patients admitted to the Intensive Care Unit after implantation of HM II and III in a Brazilian private hospital. ResultsSeveral types of dressings were used in the drivelines. There were 22 different types of dressings. Dressing type 6 (Chlorhexidine, Excilon, Gauze and IV3000) were the most used (45.4%). Subjects using the Flexi-Trak anchoring device had a higher rate of local bleeding (50.0%) and those who used the Hollister device had more infection (61.1%) and pressure injury associated with a medical device (11.1%), compared to others. Infection was the primary complication (45.4%), followed by local bleeding (27.7%). ConclusionDespite the high variability of products used in the driveline of patients using HeartMate, the dressing made with chlorhexidine, silver-impregnated absorbent foam and transparent film, and the use of anchoring devices was the most frequently used. Infection was the most common complication.

Novel reusable catalytic poly(4-styrenesulfonate-co-glycidylmethacrylate) foams for adsorption and photodegradation of the model pollutant dye methylene blue based on aromatic-aromatic interactions

With the aim of achieving new highly porous, water-insoluble solid adsorbents for pollutants in water whose adsorption mechanism is based on aromatic-aromatic interactions, solid materials bearing charged aromatic groups have been developed from a family of copolymers of sodium styrene sulfonate and glycidyl methacrylate synthesized by free radical copolymerization both in DMF and in DMF/H2O, with comonomer molar ratio ranging between 0.2 and 0.8. The copolymers have been rationally designed to furnish hydrophilic functional negatively charged aromatic rings to allow aromatic-aromatic interaction with cationic aromatic pollutants, and hydrophobic functional monomers able to trigger crosslinking reactions through ring opening of epoxy groups by thermal treatment. All these copolymers form hydrogels in water. However, foams with closed cell structure were formed with the copolymer synthesized in DMF at a 0.2/0.8 NaSS/GMA molar ratio in the feed upon thermal treatment for 5–15 min at 270 °C, that resulted in non-soluble, elastic, hard, and fragile solid materials. Volume expansion stood around 30-fold the original volume, and porosity of the resulting expanded objects reached values higher than 73 %. Due to the large surface area of these foams and the presence of the benzene sulfonate moieties, the materials showed maximum adsorption capacity of around 200 mg of the model dye methylene blue per g of material, with a high adsorption rate. Interestingly, the absorbent foams showed catalytic activity towards photodegradation of the dye and allowed reusing the materials for at least six cycles.

An innovative synthetic support for immunocytochemical assessment of cytologically indeterminate (Bethesda III) thyroid nodules.

Fine needle aspiration (FNA) is the procedure of choice in the evaluation of thyroid nodules. Nodules with indeterminate cytological categories, Bethesda III and IV, pose challenges in clinical practice and are frequently submitted to diagnostic surgery. CytoFoam Core (CFCS) uses an absorbent foam device inserted into the needle hub to collect the cytological sample aspirated during FNA. Specimen is formalin-fixed and paraffin-embedded. Assessing diagnostic efficacy of CFCS, compared to traditional cytology, in re-evaluating thyroid nodules classified as Bethesda III, using post-surgical histology as reference standard. Retrospective study on 89 patients with a first indeterminate cytological report who were referred to the Department of Endocrinology of Regina Apostolorum Hospital (Albano L. Rome, Italy) for a second FNA. FNA was performed after at least one month under ultrasound guidance with a 23G needle according to the established procedure. During the second procedure, both traditional cytological (TC) smears and a single-pass CFCS specimen were obtained for each patient. On CFCS samples immunocytochemical staining for Galectin-3, HBME-1, and CK-19 was also performed. 51 patients eventually underwent surgery, and their histological diagnoses were compared to the TC and CFCS reports. Four parameters were evaluated: inadequacy rate, rate of persistent indeterminate (Bethesda III and IV) reports, rate of malignancy in persistently indeterminate nodules, and rate of cancer in lesions cytologically classified as malignant. Non-diagnostic samples were 6 (11.8%) in TC vs 3 (5.9%) in CFCS (p=0.4). Persistent indeterminate samples were 31 (60.8%) in TC vs 19 (37.2%) in CFCS (p=0.01). Rate of malignancy in persistently indeterminate nodules was 8/19 (42.1%) in CFCS vs 9/31 (29%) in TC group (p=0.3). Nine/51 (17.6%) samples were classified as benign by TC vs 21/51 (41.2%) samples by CFCS (p<0.01). All nodules resulted benign at post-surgical evaluation. Five/51 (9.8%) samples were classified as suspicious for malignancy/malignant in TC group against 8/51 (15.7%) samples in CFCS (p=0.5). Post-surgical evaluation confirmed malignancy in all these cases. CFCS demonstrated greater diagnostic accuracy than TC in repeat FNA assessment of cytologically indeterminate nodules. CFCS increased the conclusive diagnosis rate and decreased the number of cytologically indeterminate cases.

Experimental and numerical investigation of G-UHPC based novel multi-layer protective slabs under contact explosions

Geopolymer based ultra-high performance concrete (G-UHPC) has been recognized as a ‘eco-friendly’ form of ultra-high performance concrete owing to its beneficial characteristics, e.g. waste utilization, reduction in carbon dioxide emission, low energy consumption, superior mechanical behavior and adjustable hardening time. Thus, G-UHPC is well suitable for the rapid construction of blast-resistant structures. In this study, four slabs, including a reference normal strength concrete (NSC) slab and three novel multi-layered composite slabs fabricated by G-UHPC, steel wire mesh (SWM) and energy absorber foam materials, were tested on their blast resistance against contact explosions and the corresponding numerical simulations were carried out. Four failure patterns (crater, crater and spalling, breach-perforation and breach-punching) were quantitatively characterized. The G-UHPC slab reinforced with SWM exhibited superior blast resistance as compared to the referenced NSC specimen. The low stiffness and shear strength of the energy absorber foam materials were the main reasons for the breach-punching failure mode. The acoustic impedance and compressibility of the energy absorber foam materials must be reasonably considered to achieve a positive effect on the blast resistance of the concrete slabs. The developed finite element mode could effectively predict the failure characteristics of the specimens.

Mosquito's eyes inspired, hydrophobic and multifunctional coating on flexible polyurethane (PU) foam: highly efficient oil spills remediation and exceptional flame-retardant performance

Inspired by the structure of mosquito's compound eyes, a hydrophobic flexible polyurethane (PU) foam composite (named as PU@SiO2/ADP) with good flame-retardant property was fabricated by coating aluminum diethylhypophosphite (ADP) and in situ-formed SiO2 nanoparticles. Owning to considerable surface roughness of stacked SiO2 nanoparticles and intrinsic hydrophobicity of ADP, the water contact angle (WCA) of modified PU foam increased from 113° to 133°. The absorption capacity of modified foam to oils and organic solvents was also evaluated. The results showed that the absorption ratios of the modified PU to dichloromethane reached 69 g/g. The oil-water separation results proved that PU@SiO2/ADP foam could rapidly and selectively absorb oils or organic solvents from the water surface even under turbulent flow conditions. Fabricated hydrophobic PU maintained excellent oil absorption properties after 10 absorption-squeezing cycles, demonstrating good recyclability. The modified PU foam also showed high flame retardancy. The surface treatment method applied in this research not only provides an effective strategy for fabricating a promising absorbent PU foam for oil spill treatment, but also brings a promising prospect for enhancing the flame-retardant performance of these absorbent polymer composites. This work provides support and reference for the improvement of similar materials in future works.

A novel sound absorber foam based on ethylene propylene diene monomer (EPDM) to absorb low‐frequency waves: Influence of EPDM ethylene content

AbstractIn this study, a partially reticulated foam was fabricated based on ethylene propylene diene monomer rubber to absorb low‐frequency acoustic waves. The effect of ethylene content was studied on the cellular structure, viscoelastic behavior, and sound abortion characteristics. High airflow resistivity of the developed partially reticulated structure, as well as highly deformable cell walls of EPDM foams, led to large dissipation of sound energy at low and medium frequencies. Samples with lower ethylene content which exhibited lower storage modulus and larger pore sizes showed higher viscose motions with superior sound absorption. The foam sample with the lowest ethylene content offered the best sound absorption coefficient with a sharp peak as high as 0.91 within the 500–2500 Hz frequency range. The results imply the role of ethylene content as a molecular structure tool to optimize the acoustic absorption potential of EPDM foam. Besides, the foam samples showed considerable insulation performance, yielding a sound reduction index equal to 26–29 dB. The absorption and reflection of the sound waves were integrated to provide the insulation. Thus, a developed lightweight insulator with high resistance to harsh environmental conditions and great low‐frequency sound absorption could be achieved by structural engineering.

Far- and Near Range Measurements with a Synthetic Aperture Radar for Educational Purposes and Comparison of Two Different Signal Processing Algorithms

Abstract. In this paper two simple synthetic aperture radar (SAR) methods are applied on data from a 24 GHz FMCW radar implemented on a linear drive for educational purposes. The data of near and far range measurements are evaluated using two different SAR signal processing algorithms featuring 2D-FFT and frequency back projection (FBP) method (Moreira et al., 2013). A comparison of these two algorithms is performed concerning runtime, image pixel size, azimuth and range resolution. The far range measurements are executed in a range of 60 to 135 m by monitoring cars in a parking lot. The near range measurement from 0 to 5 m are realised in a measuring chamber equipped with absorber foam and nearly ideal targets like corner reflectors. The comparison of 2D-FFT and FBP algorithm shows that both deliver good and similar results for the far range measurements but the runtime of the FBP algorithm is up to 150 times longer as the 2D-FFT runtime. In the near range measurements the FBP algorithm displays a very good azimuth resolution and targets which are very close to each other can be separated easily. In contrast to that the 2D-FFT algorithm has a lower azimuth resolution in the near range, thus targets which are very close to each other, merge together and cannot be separated.

A camphene-camphor-polymer composite material for the production of superhydrophobic absorbent microporous foams

In a recently published paper (doi.org/10.3390/molecules26113116) on self-propelled motion of objects on the water surface, we described a novel surface-active plastic material obtained by dissolution of camphor and polypropylene in camphene at 250 ^circC. The material has wax-like mechanical properties, can be easily formed to any moldable shape, and allows for longer and more stable self-propelled motion if compared with pure camphor or pure camphene or of a camphene-camphor wax. Here we use scanning electron microscopy to visualize and characterize the microporous structure of the solid polypropylene foam formed in the plastic for different polypropylene contents. The topology of foams remaining in the material after camphor and camphene molecules have been removed through evaporation or dissolution is similar to polypropylene foams obtained using thermally-induced phase separation. We show that the foams have a superhydrophobic surface but strongly absorb non-polar liquids, and suggest an array of potential scientific and industrial applications.

Evaluation of the effect of microphone cavity geometries on acoustic imaging in wind tunnels

Aeroacoustic measurements performed by flush-mounted microphone arrays on the walls of closed-section wind tunnels are contaminated by the hydrodynamic pressure fluctuations of the wall’s boundary layer. This study evaluates three different microphone cavity geometries for mitigating this issue. Their improvement to the signal-to-noise ratio (SNR) and the accuracy of their acoustic imaging results are compared to a flush-mounted microphone array. The four geometries include: (1) an array of flush-mounted microphones as the baseline, (2) a cylindrical hard-plastic cavity with a countersink, (3) a conical cavity made of melamine acoustic absorbing foam, and (4) a conical cavity with star-shaped protrusions, also made of melamine. The three arrays with cavities were covered with a steel-wire cloth to reduce the boundary layer fluctuations at the microphone while the baseline array was uncovered. Two sound sources were tested in an aeroacoustic wind tunnel for assessing the performance of the different cavities: a speaker placed outside the flow and a distributed sound source generated by a flat plate inside of the flow. When using conventional frequency domain beamforming, both cavities made of melamine offer up to a 30 dB increase in SNR with respect to the flush-mounted case, followed by the hard-walled cavity with up to a 20 dB increase. This is a 20 dB improvement when compared to the single microphone cases. The melamine cavities also provide cleaner acoustic source maps and accurate spectral estimations for a wider frequency range. The effect of cavity placement and geometry on the coherence, which affects the beamforming analysis of the acoustic signal was negligible for all cases. Distributed sound source measurements using the three arrays agreed with predictions using the Brooks, Pope, and Marcolini (BPM) model, showing that the cavities could detect vortex shedding that was undetectable by the flush array.

Effect of Absorbent Foam Filling on Mechanical Behaviors of 3D-Printed Honeycombs.

Polylactic acid (PLA) hexagonal honeycomb structures were fabricated by using 3D-printing technology. By filling with absorbent polymethacrylimide (PMI) foam, a novel absorbent-foam-filled 3D-printed honeycomb was obtained. The in-plane (L- and W-direction) and out-of-plane (T-direction) compressive performances were studied experimentally and numerically. Due to absorbent PMI foam filling, the elastic modulus, compressive strength, energy absorption per unit volume, and energy absorption per unit mass of absorbent-foam-filled honeycomb under L-direction were increased by 296.34%, 168.75%, 505.57%, and 244.22%, respectively. Moreover, the elastic modulus, compressive strength, energy absorption per unit volume, and energy absorption per unit mass, under W-direction, also have increments of 211.65%, 179.85, 799.45%, and 413.02%, respectively. However, for out-of-plane compression, the compressive strength and energy absorption per unit volume were enhanced, but the density has also been increased; thus, it is not competitive in energy absorption per unit mass. Failure mechanism and dimension effects of absorbent-foam-filled honeycomb were also considered. The approach of absorbent foam filling made the 3D-printed honeycomb structure more competitive in electromagnetic wave stealth applications, while acting simultaneously as load-carrying structures.

Modeling of coupled heat transfer in a windowed volumetric solar receiver

A two-dimensional coupled heat transfer model with Monte-Carlo ray tracing (MCRT) method is developed to analyze the heat transfer in windowed volumetric solar receiver. The local thermal non-equilibrium (LTNE) effects in ceramic foam absorber and spectral selectivity of quartz window are considered. With the solar absorption term calculated by the MCRT, the P1-approximation for thermal radiative exchange in the foam absorber is examined by comparing with the MCRT. In the model based on P1-approximation, net radiation method (NRM) and MCRT are applied to calculate the thermal radiative exchange between the window and absorber. The effects of porosity and cell size of the absorber foam on temperature distribution and thermal efficiency are investigated. The results show that for heat transfer in foam absorber at a highest temperature below 1727 K, the P1-approximation underestimates the absorber temperature by about 27 K and overestimates the window temperature by 106–133 K. And the thermal efficiency is underestimated by about 2.1% using the P1-approximation. There is small difference between the temperature in the absorber predicted by different models, but the NRM cannot predict the axial temperature gradient in the window. Under a constant air mass flow rate, within the absorber foam with the cell size range of 2–4 mm and porosity range of 0.7–0.9, a higher thermal efficiency can be reached at a larger cell size or a lower porosity.

A novel hydroxofluorographene-coated melamine foam for efficient and repeatable oil removal from water.

With the frequent occurrence of oil spill accidents and the continuous discharge of oily water during oil production and transportation, effective oil removal from environmental water by adsorption still faces severe challenges. Here, a novel absorbent hydroxofluorographene-coated melamine foam, namely G(OH)F@MF, with high affinity to oils was fabricated via stepwise assembly. The G(OH)F@MF absorbent achieved effective removal of various oils within 1 min with relatively high adsorption capacities for petrol (89.34 g/g), lubricating oil (89.60 g/g), and peanut oil (104.79 g/g). Furthermore, it could be regenerated by simply squeezing and reused for more than 10 times with an adsorption capacity exceeding 37.12 g/g. In addition, the results indicated that the G(OH)F@MF absorbent was suitable for oil cleanup at a wide range of pH values (4-12) and temperatures (5-45 °C). The adsorption performance of the material was stable in the presence of natural organic matter and even in different water environments. This study can provide a novel sorbent and method for the green, rapid, recyclable, and stable removal of oils from environmental water.

Effect of Y-Methacryloxypropyltrimethoxysilane (MPS) and Tetraethoxysilane (TEOS) Towards Preparation of Oil Absorbent Foams from Polyvinyl Alcohol (PVA) Reinforced with Microfibrillated Cellulose (MFC)

Increasing usage of foams in various industry sectors had causing serious disposal problems once it reaches the end of its life-cycle. Herein, PVA-MFC foam was prepared by freeze-drying using polyvinyl alcohol (PVA) and microfibrillated cellulose (MFC) as a reinforced material from sugarcane bagasse (SCB). In this study, the PVA-MFC foam was chemically silylated with Y-methacryloxypropyltrimethoxysilane (MPS) and tetraethoxysilane (TEOS). The wetting ability and mechanical strength of the silylated _2,20PVA-MFC foam was greatly enhanced compared with unmodified _2,20PVA-MFC foam. The silane chemicals (MPS and TEOS) had been confirmed grafted on _2,20PVA-MFC foam due to the presence of Si-C and Si-O-C stretching vibration as showed in Fourier Transform Infrared (FTIR) spectra and cloud-like coating of porous pore was observed in scanning electron microscopy (SEM) images. The silylated _2,20PVA-MFC foam (MPS and TEOS) exhibited a series of desirable properties such as lower swelling ratio and high absorption capacity of solvents and oils but had low thermal stability in thermogravimetric (TGA) analysis. The characterization of _2,20PVA-MFC foam using TEOS was further investigated. A significant difference in morphology was clearly observed between the unmodified and silylated _2,20PVA-MFC-TEOS foam through field emission scanning electron microscopy (FESEM) images. The X-ray photoelectron (XPS) analysis of silylated _2,20PVA-MFC-TEOS foam confirmed the presence of C, O and trace amount of Si elements. These synthesized _2,20PVA-MFC foam could be a promising material for broad range of polymer foam applications.

A multicentre, observational evaluation of the product characteristics of two absorbent foam dressings.

Wound healing is an intrinsic and dynamic process. Wound exudate is a normal feature of wound healing; however, when there is insufficient or excessive production, or the composition of the exudate is harmful, wound healing may be compromised with resulting psychosocial and financial implications. Therefore, the management of exudate is essential for improved patient outcomes and in the prevention of future complications. The purpose of these studies, carried out in Germany and Poland, was to observe and to evaluate the clinical performance of Cutimed® Siltec® and Cutimed Siltec B on patients' wounds. Three visits (initial visit, dressing change visit and final visit) were scheduled and documented. In all, 129 patients took part in these studies and 150 wounds were treated. The results were pooled. Positive attributes of using these dressings included a decrease in exudate, intact wound margins and a decrease in pain during dressing changes. Clinicians and patients were satisfied with the product and rated the following parameters as 'good' to 'very good': wearing comfort, ease of application and removal, absorption and retention capacity, adaptability to the affected body part, absorption and retention capacity under compression. The results from this study suggest that Cutimed Siltec and Cutimed Siltec B absorbent dressings are beneficial in wound management due to the positive attributes, and clinicians and patients showed satisfaction with these dressings.

Structured Floral Arrangement Program Benefits in Patients With Neurocognitive Disorder.

We attempted to clarify positive benefits in cognitive abilities and motivation during our cognitive intervention [structured floral arrangement (SFA) program] for patients with neurocognitive disorder due to stroke, traumatic brain injury (TBI), and other related disorders. In this SFA program, participants are required to arrange cut flowers and leaves on absorbent foam according to an instruction sheet. In a previous study of patients with schizophrenia, our SFA program encouraged participants and contributed to stimulating their visuospatial process and memory. Here, 27 patients with neurocognitive disorders participated in this study. Sixteen patients were assigned to an SFA-treated group and participated in six sessions during two phases plus to daily activities. Eleven non-treated patients engaged only daily activities during the same period. We compared Apathy Scale scores and neuropsychological scores between the SFA-treated and non-treated patients. Their mean attendance rate was more than 90% during the two phases. SFA-treated patients copied a Rey–Osterrieth complex figure more accurately than non-treated patients (p < 0.05) during the later intervention phase, whereas during the earlier phase, accuracy was comparable between treated and non-treated groups. In the SFA-treated group, recall scores also improved (p < 0.01), and the positive outcomes were maintained for about 3 months (p < 0.05). The Apathy Scale scores did not show significant change in either the SFA-treated or non-treated groups. Our present results suggest that the SFA program encouraged continuous participation to cognitive intervention and was useful for ameliorating dysfunctions in visuospatial memory and recognition in patients with neurocognitive disorder.

Microwave Nondestructive Imaging of Buried Objects Using Improved Scattered‐Field Calibration Technique

AbstractA novel microwave subsurface imaging scheme based on an improved electric field calibration technique is proposed in this paper. The proposed imaging scheme requires RF measurement system comprising of a uniform linear transmitter‐receiver antenna array wherein the region under examination is illuminated sequentially to measure the scattering parameters of the test. An appropriate imaging frequency is selected so as to minimize the errors introduced due to coupling among the coresident antennas. The electric field required for the imaging algorithm is obtained from the measured scattering parameters using the proposed calibration methodology in two subsequent steps. The first step of calibration removes the systematic errors inherent in the measured scattering parameters by using known standards such as a metal plate and absorber foam. The second calibration step transforms the calibrated scattering parameters of the test object into electric field values so as to use them in the required inverse reconstruction procedure. The transformation is based on comparison of the measured scattering parameters of a known specimen and test object under the same test environment. The imaging algorithm based on the electric field formulation uses the standard iterative distorted Born procedure. For determining the location of the buried object, a novel data interpretation scheme based on analysis of variance (ANOVA) applied to time domain reflection coefficients obtained from various antenna elements is also proposed here. The applicability including performance evaluation of the proposed imaging scheme is tested by retrieving microwave image of various standard objects buried inside sand.