Liver regeneration of living donor after liver donation for transplantation: Disparity in the left and right remnant liver.

Donor safety is crucial for living donor liver transplantation (LDLT), and sufficient liver regeneration significantly affects outcomes of living donors. This study aimed to investigate clinical factors associated with liver regeneration in living donors. The study retrospectively reviewed 380 living donors who underwent liver donation at Chang Gung Memorial Hospital in Linkou. The clinical characteristics and medical parameters of donors were analyzed and compared according to liver donation graft type. There were 355 donors (93.4%) with right hemi-liver donations and 25 donors (6.6%) with left hemi-liver donations. Left hemi-liver donors had a higher body mass index (BMI) and a larger ratio of remnant liver volume (RLV) to total liver volume (TLV). However, the 2 groups showed no significant difference in the liver regeneration ratio. The type of remnant liver (P < .001), RLV/body weight (P = .027), RLV/TLV (P < .001), serum albumin on postoperative day 7 and total bilirubin levels on postoperative day 30 were the most significant factors affecting liver regeneration in living donors. In conclusion, adequate liver regeneration is essential for donor outcome after liver donation. The remnant liver could eventually regenerate to an adequate volume similar to the initial TLV before liver donation. However, the remnant left hemi-liver had a faster growth rate than the remnant right hemi-liver in donors.

Where is the optimal plane to mobilize the anterior rectal wall in female patients undergoing total mesorectal excision?

BACKGROUND: Since Heald proposed the total mesorectal excision (TME) procedure, the prognosis of patients with rectal cancer has been significantly improved. But Heald did not specifically describe the anterior surgical plane in female patients. And the surgical plane for mobilizing the anterior rectal wall during TME surgery in female patients remains controversial. AIM: To investigate the anatomy of the female pelvis and identify the optimal plane for mobilizing the anterior rectal wall. METHODS: We retrospectively collected surgical procedure videos and clinical data of female patients diagnosed with middle or low rectal cancer who underwent the TME procedure between January 2020 and October 2022 across six hospitals. The patients were divided into two groups based on the surgical approach used to mobilize the anterior rectal wall: The experimental group was to open the peritoneum at the lowest point of the peritonea reflection and enter the plane for mobilizing, while the control group was cut at 0.5-1 cm above the peritoneal reflection and enter another plan. Then, we compared the preoperative and postoperative information between the two groups. We also dissected and observed ten adult female pelvises to analyze the anatomic structure and compare the entry plane between the two approaches. Finally, we researched the pathological structure between the rectum and the vagina. RESULTS: Finally, 77 cases that met the criteria were included in our study. Our observations revealed that the experimental group underwent a smooth procedure, entering the plane amidst the mesorectal fascia and adventitia of the vagina, whereas the control group entered the plane between the vaginal adventitia and muscle layers. Compared to the control group, the experimental group showed a significant decrease in intraoperative bleeding [22.5 (19.5-50) mL vs 17 (5-20) mL, P = 0.01], as well as a shorter duration of hospitalization [9 (7-11.25) d vs 7 (6-10) d, P = 0.03]. Through the examination of surgical videos and cadaveric studies, we discovered that Denonvilliers' fascia is absent in females. Additionally, pathological sections further revealed the absence of Denonvilliers' fascia in females, with only loose connective tissue present between the mesorectal fascia and adventitia of the vagina. CONCLUSION: The plane amidst the mesorectal fascia and vaginal adventitia is the optimal surgical plane to mobilize the anterior rectal wall for female patients undergoing the TME procedure.

Synergic Effect of Robot-Assisted Rehabilitation and Antispasticity Therapy: A Narrative Review.

BACKGROUND: Stroke and spinal cord injury are neurological disorders that cause disability and exert tremendous social and economic effects. Robot-assisted training (RAT), which may reduce spasticity, is widely applied in neurorehabilitation. The combined effects of RAT and antispasticity therapies, such as botulinum toxin A injection therapy, on functional recovery remain unclear. This review evaluated the effects of combined therapy on functional recovery and spasticity reduction. MATERIALS AND METHODS: Studies evaluating the efficacy of RAT and antispasticity therapy in promoting functional recovery and reducing spasticity were systemically reviewed. Five randomized controlled trials (RCTs) were included. The modified Jadad scale was applied for quality assessment. Functional assessments, such as the Berg Balance Scale, were used to measure the primary outcome. Spasticity assessments, such as the modified Ashworth Scale, were used to measure the secondary outcome. RESULTS: Combined therapy improves functional recovery in the lower limbs but does not reduce spasticity in the upper or lower limbs. CONCLUSIONS: The evidence supports that combined therapy improves lower limb function but does not reduce spasticity. The considerable risk of bias among the included studies and the enrolled patients who did not receive interventions within the golden period of intervention are two major factors that should be considered when interpreting these results. Additional high-quality RCTs are required.

Wearable and wireless performance evaluation system for sports science with an example in badminton.

Two capacitive sensing units were designed, fabricated, and embedded into two corresponding fingerstalls through microelectronic and additive manufacturing with flexible materials and ergonomic considerations in this study. The sensing units were routed to an adaptor, which in turn was routed to a transmission port (comprising a signal converter and a Bluetooth module), realizing a wearable and wireless force sensing system for sports science applications as the objective. The collected capacitive signals were converted through a preliminarily established database, indicating local force distributions on finger segments. Practical examinations with badminton actions (forehand cross-net shots) were conducted by players to show the effectiveness of the proposed system as an application example. Statistical and quantified results reflected the visual observations on valid shots (67% and 39% for the professional and amateur players, respectively) and well-controlled racket-holding attitude (19.69% and 35.31% force application difference between the first two segments of the index finger of the professional and amateur player, respectively). These proved that the proposed system outperforms existing similar systems in the market and is able to not only classify players with different skill levels but also distinguish attitude stability and controllability, showing scientific evidence in sports science for the first time.

Elastic Moduli of Avian Eggshell.

We analyze 700 freshly-laid eggs from 58 species (22 families and 13 orders) across three orders of magnitude in egg mass. We study the elastic moduli using three metrics: (i) effective Young's modulus, EFEM, by a combined experimental and numerical method; (ii) elastic modulus, Enano, by nanoindentation, and (iii) theoretical Young's modulus, Etheory. We measure the mineral content by acid-base titration, and crystallographic characteristics by electron backscatter diffraction (EBSD), on representative species. We find that the mineral content ranges between 83.1% (Zebra finch) and 96.5% (ostrich) and is positively correlated with EFEM-23.28 GPa (Zebra finch) and 47.76 GPa (ostrich). The EBSD shows that eggshell is anisotropic and non-homogeneous, and different species have different degrees of crystal orientation and texture. Ostrich eggshell exhibits strong texture in the thickness direction, whereas chicken eggshell has little. Such anisotropy and inhomogeneity are consistent with the nanoindentation tests. However, the crystal characteristics do not appear to correlate with EFEM, as EFEM represents an overall "average" elasticity of the entire shell. The experimental results are consistent with the theoretical prediction of linear elasticity. Our comprehensive investigation into the elastic moduli of avian eggshell over broad taxonomic scales provides a useful dataset for those who work on avian reproduction.

Thalidomide suppresses angiogenesis and immune evasion via lncRNA FGD5-AS1/miR-454-3p/ZEB1 axis-mediated VEGFA expression and PD-1/PD-L1 checkpoint in NSCLC.

BACKGROUND: Non-small cell lung cancer (NSCLC) accounts for about 80-85% of total lung cancer cases. Identifying the molecular mechanisms of anti-tumor drugs is essential for improving therapeutic effects. Herein, we aim to investigate the role of thalidomide in the tumorigenicity of NSCLC. METHODS: The A549 xenograft nude mouse model was established to explore therapeutic effects of thalidomide. The expression of FGD5-AS1 was evaluated in carcinomatous and paracarcinomatous tissues from NSCLC patients as well as NSCLC cell lines. CCK-8 assay was performed to assess cell viability. The invasive capacity was examined using transwell assay. The tube formation assay was applied to determine cell angiogenesis. Flow cytometry was subjected to validate CD8+ T cell activity. The FGD5-AS1/miR-454-3p/ZEB1 regulatory network was analyzed using luciferase reporter, RIP and ChIP assays. RESULTS: Thalidomide reduced tumor growth and angiogenesis and increased CD8+ T cell ratio in a mouse model. Enhanced expression of FGD5-AS1 was positively correlated with the poor survival of NSCLC patients. Knockdown of FGD5-AS1 notably suppressed the proliferation, invasion and angiogenesis of cancer cells as well as the apoptosis of CD8+ T cells. Thalidomide targeted FGD5-AS1 to exert its anti-tumor activity in NSCLC. FGD5-AS1 acted as a sponge of miR-454-3p to upregulate ZEB1, thus increasing the expression of PD-L1 and VEGFA. Simultaneous overexpression of FGD5-AS1 and silencing of miR-454-3p reversed thalidomide-mediated anti-tumor effects in NSCLC. CONCLUSION: Thalidomide inhibits NSCLC angiogenesis and immune evasion via FGD5-AS1/miR-454-3p/ZEB1 axis-mediated regulation of VEGFA expression and PD-1/PD-L1 checkpoint.

Prenatal exposure to air pollutants and childhood atopic dermatitis and allergic rhinitis adopting machine learning approaches: 14-year follow-up birth cohort study.

The incidence of childhood atopic dermatitis (AD) and allergic rhinitis (AR) is increasing. This warrants development of measures to predict and prevent these conditions. We aimed to investigate the predictive ability of a spectrum of data mining methods to predict childhood AD and AR using longitudinal birth cohort data. We conducted a 14-year follow-up of infants born to pregnant women who had undergone maternal examinations at nine selected maternity hospitals across Taiwan during 2000-2005. The subjects were interviewed using structured questionnaires to record data on basic demographics, socioeconomic status, lifestyle, medical history, and 24-h dietary recall. Hourly concentrations of air pollutants within 1 year before childbirth were obtained from 76 national air quality monitoring stations in Taiwan. We utilized weighted K-nearest neighbour method (k = 3) to infer the personalized air pollution exposure. Machine learning methods were performed on the heterogeneous attributes set to predict allergic diseases in children. A total of 1439 mother-infant pairs were recruited in machine learning analysis. The prevalence of AD and AR in children up to 14 years of age were 6.8% and 15.9%, respectively. Overall, tree-based models achieved higher sensitivity and specificity than other methods, with areas under receiver operating characteristic curve of 83% for AD and 84% for AR, respectively. Our findings confirmed that prenatal air quality is an important factor affecting the predictive ability. Moreover, different air quality indices were better predicted, in combination than separately. Combining heterogeneous attributes including environmental exposures, demographic information, and allergens is the key to a better prediction of children allergies in the general population. Prenatal exposure to nitrogen dioxide (NO2) and its concatenation changes with time were significant predictors for AD and AR till adolescent.

Intravoxel incoherent motion diffusion-weighted imaging to differentiate hepatocellular carcinoma from intrahepatic cholangiocarcinoma.

The present study aimed to explore the value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in differentiating hepatocellular carcinoma (HCC) from intrahepatic cholangiocarcinoma (ICC). This study included 65 patients with malignant hepatic nodules (55 with HCC, 10 with ICC), and 17 control patients with normal livers. All patients underwent IVIM-DWI scans on a 3.0 T magnetic resonance imaging (MRI) scanner. The standard apparent diffusion coefficient (ADC), pure diffusion coefficient (Dslow), pseudo-diffusion coefficient (Dfast), and perfusion fraction (f) were obtained. Differences in the parameters among the groups were analysed using one-way ANOVA, with p < 0.05 indicating statistical significance. Receiver operating characteristic (ROC) curve analysis was used to compare the efficacy of each parameter in differentiating HCC from ICC. ADC, Dslow, Dfast, f significantly differed among the three groups. ADC and Dslow were significantly lower in the HCC group than in the ICC group, while Dfast was significantly higher in the HCC group than in the ICC group; f did not significantly differ between the HCC and ICC groups. When the cut-off values of ADC, Dslow, and Dfast were 1.27 × 10-3 mm2/s, 0.81 × 10-3 mm2/s, and 26.04 × 10-3 mm2/s, respectively, their diagnostic sensitivities for differentiating HCC from ICC were 98.18%, 58.18%, and 94.55%, their diagnostic specificities were 50.00%, 80.00%, and 80.00%, and their areas under the ROC curve (AUCs) were 0.687, 0.721, and 0.896, respectively. Dfast displayed the largest AUC value. IVIM-DWI can be used to differentiate HCC from ICC.

A Correlative Study Between IVIM-DWI Parameters and the Expression Levels of Ang-2 and TKT in Hepatocellular Carcinoma.

BACKGROUND: Noninvasive evaluation of the expression of angiopoietin-2 (Ang-2) and transketolase (TKT) in hepatocellular carcinoma (HCC) is of great significance for the clinical development of individualized treatment plans. However, the correlation between intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) and the expression of Ang-2 and TKT has not been reported. We sought to investigate the correlations between IVIM-DWI parameters and Ang-2 and TKT expression levels in HCCs. METHODS: Conventional non-enhanced magnetic resonance imaging (MRI) and IVIM-DWI and dynamic contrast MRI were performed for 61 patients with HCC before surgical treatment. Various IVIM-DWI parameters, such as apparent diffusion coefficient (ADC), slow apparent diffusion coefficient (D), fast apparent diffusion coefficient (D*) and fraction of fast apparent diffusion coefficient (f), were calculated using Function-MADC software. Expression levels of Ang-2 and TKT in HCC were detected via immunohistochemical staining and classified into two grades. Independent sample t tests were used to compare differences in parameters between the two groups. The Spearman rank correlation test was used to analyze the correlations between IVIM-DWI parameters and Ang-2 and TKT expression levels in HCCs. RESULTS: The D* and f values were significantly higher in the high Ang-2 group than in the low Ang-2 group; there were no obvious between-group differences in ADC and D. Ang-2 expression was positively correlated with D* and f but not with ADC and D. The ADC and D values were significantly lower in the high TKT group than in the low TKT group, whereas the between-group differences for D* and f were not significant. TKT expression was negatively correlated with ADC and D but not with D* and f. CONCLUSIONS: IVIM-DWI can be used to evaluate Ang-2 and TKT expression in HCC.

Virus-Like Particle Systems for Vaccine Development against Viruses in the Flaviviridae Family.

Viruses in the Flaviviridae family are important human and animal pathogens that impose serious threats to global public health. This family of viruses includes emerging and re-emerging viruses, most of which are transmitted by infected mosquito or tick bites. Currently, there is no protective vaccine or effective antiviral treatment against the majority of these viruses, and due to their growing spread, several strategies have been employed to manufacture prophylactic vaccines against these infectious agents including virus-like particle (VLP) subunit vaccines. VLPs are genomeless viral particles that resemble authentic viruses and contain critical repetitive conformational structures on their surface that can trigger the induction of both humoral and cellular responses, making them safe and ideal vaccine candidates against these viruses. In this review, we focus on the potential of the VLP platform in the current vaccine development against the medically important viruses in the Flaviviridae family.

USEAQ: Ultra-fast Superpixel Extraction via Adaptive Sampling from Quantized Regions.

We present a novel and highly efficient superpixel extraction method called USEAQ to generate regular and compact superpixels in an image. To reduce the computational cost of iterative optimization procedures adopted in most recent approaches, the proposed USEAQ for superpixel generation works in a one-pass fashion. It firstly performs joint spatial and color quantizations and groups pixels into regions. It then takes into account the variations between regions, and adaptively samples one or a few superpixel candidates for each region. It finally employs maximum a posteriori (MAP) estimation to assign pixels to the most spatially consistent and perceptually similar superpixels. It turns out that the proposed USEAQ is quite efficient, and the extracted superpixels can precisely adhere to boundaries of objects. Experimental results show that USEAQ achieves better or equivalent performance compared to the stateof- the-art superpixel extraction approaches in terms of boundary recall, undersegmentation error, achievable segmentation accuracy, the average miss rate, average undersegmentation error, and average unexplained variation, and it is significantly faster than these approaches.

Aortic remodelling after thoracic endovascular aortic repair for acute and subacute type B aortic dissection.

BACKGROUND: Thoracic endovascular aortic repair (TEVAR) in the current era has gained widespread acceptance as the modality of choice for the treatment of complicated aortic dissection (AD). However, reports on clinical results of TEVAR treatment of AD patients are mainly comparisons and analyses of results between patients in the acute and chronic phases, few reports have described the postoperative aortic remodelling of patients with subacute AD after TEVAR. The aim of this study was to investigate aortic remodelling after TEVAR in acute and subacute Stanford type B AD patients. METHODS: The clinical data of 38 Stanford type B AD patients who received TEVAR treatment in our hospital between July 2012 and December 2017 were retrospectively analysed. The maximum diameters of the aorta, the mean diameters of the true lumens (TLs) and the false lumens (FLs) of the aorta in the dissection range before and after TEVAR treatment were measured. All diameters between different groups or in the same group before and after therapy were compared using nonparametric tests. Count data were examined using the χ2 test. RESULTS: The 38 patients were 31.0-82.0 years old with a mean age of 57.0±11.0 years, including 31 men and 7 women, with 22 patients in the acute phase and 16 patients in the subacute phase. Among the 38 patients included in this study, 7 (18.4%) patients had endoleaks after treatment. No perioperative deaths occurred. Analyses of computed tomography angiography measurement results showed that the baseline maximum diameters of the aorta, TLs and FLs before TEVAR between the acute and subacute groups were not significantly different (P=0.193, P=0.301 and P=0.067, respectively). After TEVAR treatment, the maximum diameters of the aorta and the diameters of the FLs were different between the two groups (P=0.005 and P=0.012), but the diameters of the TLs were not (P=0.069). The diameters of the TLs increased, and those of FLs decreased significantly in the acute and subacute groups after TEVAR (P<0.001, P<0.001, P<0.001 and P=0.007, respectively); the maximum diameters of the aorta decreased significantly in the acute group (P<0.001), but they did not change obviously in the subacute group (P=0.121). CONCLUSIONS: TEVAR offers satisfactory results for the treatment of type B AD. Acute AD may be associated with better aortic remodelling compared to subacute AD after TEVAR.

Techno-economic and resource analysis of hydroprocessed renewable jet fuel.

BACKGROUND: Biomass-derived jet fuel is an alternative jet fuel (AJF) showing promise of reducing the dependence on fossil fuel and greenhouse gas emissions. Hydroprocessed esters and fatty acids (HEFA) concept is also known as one of the pathways for producing bio jet fuel. HEFA fuel was approved by the American Society for Testing and Materials in 2011, and can be blended up to 50% with conventional jet fuel. Since then, several HEFA economic and life-cycle assessments have been published in literature. However, there have been limited analyses on feedstock availability, composition, and their impact on hydrocarbon yield (particularly jet blendstock yield) and overall process economics. RESULTS: This study examines over 20 oil feedstocks, their geographic distribution and production levels, oil yield, prices, and chemical composition. The results of our compositional analysis indicate that most oils contain mainly C16 and C18 fatty acids except pennycress, yellow grease, and mustard, which contain higher values and thus would require hydrocracking to improve jet fuel production. Coconut oil has a large content of shorter carbon fatty acids, making it a good feedstock candidate for renewable gasoline instead of jet substitutes' production. Techno-economic analysis (TEA) was performed for five selected oil feedstocks-camelina, pennycress, jatropha, castor bean, and yellow grease-using the HEFA process concept. CONCLUSION: The resource analysis indicates that oil crops currently grown in the United States (namely soybean) have relatively low oil yield when compared to oil crops grown in other parts of the world, such as palm, coconut, and jatropha. Also, non-terrestrial oil sources, such as animal fats and greases, have relatively lower prices than terrestrial oil crops. The minimum jet fuel selling price for these five resources ranges between $3.8 and $11.0 per gallon. The results of our TEA and resource studies indicate the key cost drivers for a biorefinery converting oil to jet hydrocarbons are as follows: oil price, conversion plant capacity, fatty acid profile, addition of hydrocracker, and type of hydroprocessing catalysts.

Magnetic induction of hyperthermia by a modified self-learning fuzzy temperature controller.

The aim of this study involved developing a temperature controller for magnetic induction hyperthermia (MIH). A closed-loop controller was applied to track a reference model to guarantee a desired temperature response. The MIH system generated an alternating magnetic field to heat a high magnetic permeability material. This wireless induction heating had few side effects when it was extensively applied to cancer treatment. The effects of hyperthermia strongly depend on the precise control of temperature. However, during the treatment process, the control performance is degraded due to severe perturbations and parameter variations. In this study, a modified self-learning fuzzy logic controller (SLFLC) with a gain tuning mechanism was implemented to obtain high control performance in a wide range of treatment situations. This implementation was performed by appropriately altering the output scaling factor of a fuzzy inverse model to adjust the control rules. In this study, the proposed SLFLC was compared to the classical self-tuning fuzzy logic controller and fuzzy model reference learning control. Additionally, the proposed SLFLC was verified by conducting in vitro experiments with porcine liver. The experimental results indicated that the proposed controller showed greater robustness and excellent adaptability with respect to the temperature control of the MIH system.

Design of a heart rate controller for treadmill exercise using a recurrent fuzzy neural network.

BACKGROUND AND OBJECTIVE: In this study, we developed a computer controlled treadmill system using a recurrent fuzzy neural network heart rate controller (RFNNHRC). Treadmill speeds and inclines were controlled by corresponding control servo motors. The RFNNHRC was used to generate the control signals to automatically control treadmill speed and incline to minimize the user heart rate deviations from a preset profile. METHODS: The RFNNHRC combines a fuzzy reasoning capability to accommodate uncertain information and an artificial recurrent neural network learning process that corrects for treadmill system nonlinearities and uncertainties. Treadmill speeds and inclines are controlled by the RFNNHRC to achieve minimal heart rate deviation from a pre-set profile using adjustable parameters and an on-line learning algorithm that provides robust performance against parameter variations. The on-line learning algorithm of RFNNHRC was developed and implemented using a dsPIC 30F4011 DSP. RESULTS: Application of the proposed control scheme to heart rate responses of runners resulted in smaller fluctuations than those produced by using proportional integra control, and treadmill speeds and inclines were smoother. The present experiments demonstrate improved heart rate tracking performance with the proposed control scheme. CONCLUSIONS: The RFNNHRC scheme with adjustable parameters and an on-line learning algorithm was applied to a computer controlled treadmill system with heart rate control during treadmill exercise. Novel RFNNHRC structure and controller stability analyses were introduced. The RFNNHRC were tuned using a Lyapunov function to ensure system stability. The superior heart rate control with the proposed RFNNHRC scheme was demonstrated with various pre-set heart rates.

A novel electrochemical immunosensor for highly sensitive detection of aflatoxin B1 in corn using single-walled carbon nanotubes/chitosan.

A sensitive electrochemical immunosensor for aflatoxin B1 (AFB1) detection based on single-walled carbon nanotubes/chitosan was presented. The immunosensor was based on an indirect competitive binding to a fixed amount of anti-AFB1 between free AFB1 and AFB1-bovine serum albumin, which conjugate immobilized on covalently functionalized nanotubes/chitosan laid on the glass carbon electrode. Then, the anti-mouse immunoglobulin G secondary antibody labeled with alkaline phosphatase was bound to the electrode surface through reacting with primary antibody. Finally, alkaline phosphatase catalyzes the hydrolysis of the substrate α-naphthyl phosphate, which produced electrochemical signal. Compared with conventional methods, the established immunosensor was more sensitive and simple. Under optimal conditions, this method could quantitatively detect AFB1 from 0.01 to 100 ng mL(-1) with a detection limit of 3.5 pg mL(-1). Moreover, the immunosensor was successfully applied to assay AFB1 in corn powder, which showed good correlation with the results obtained from high performance liquid chromatography.

A Molecular Phylogeny of the Lichen Genus Lecidella Focusing on Species from Mainland China.

The phylogeny of Lecidella species is studied, based on a 7-locus data set using ML and Bayesian analyses. Phylogenetic relationships among 43 individuals representing 11 Lecidella species, mainly from mainland China, were included in the analyses and phenotypical characters studied and mapped onto the phylogeny. The Lecidella species fall into three major clades, which are proposed here as three informal groups-Lecidella stigmatea group, L. elaeochroma group and L. enteroleucella group, each of them strongly supported. Our phylogenetic analyses support traditional species delimitation based on morphological and chemical traits in most but not all cases. Individuals considered as belonging to the same species based on phenotypic characters were found to be paraphyletic, indicating that cryptic species might be hidden under these names (e.g. L. carpathica and L. effugiens). Potentially undescribed species were found within the phenotypically circumscribed species L. elaeochroma and L. stigmatea. Additional sampling across a broader taxonomic and geographic scale will be crucial to fully resolving the taxonomy in this cosmopolitan genus.

Atomic-layer-deposited silver and dielectric nanostructures for plasmonic enhancement of Raman scattering from nanoscale ultrathin films.

Plasmonic silver nanostructures and a precise ZnO cover layer prepared by capacitively coupled plasma atomic layer deposition (ALD) were exploited to enhance the Raman scattering from nanoscale ultrathin films on a Si substrate. The plasmonic activity was supported by a nanostructured Ag (nano-Ag) layer, and a ZnO cover layer was introduced upon the nano-Ag layer to spectrally tailor the localized surface plasmon resonance to coincide with the laser excitation wavelength. Because of the optimized dielectric environment provided by the precise growth of ZnO cover layer using ALD, the intensity of Raman scattering from nanoscale ultrathin films was significantly enhanced by an additional order of magnitude, leading to the observation of the monoclinic and tetragonal phases in the nanoscale ZrO2 high-K gate dielectric as thin as ∼6 nm on Si substrate. The excellent agreement between the finite-difference time-domain simulation and experimental measurement further confirms the so-called [absolute value]E(->)[absolute value](4) dependence of the surface-enhanced Raman scattering. This technique of plasmonic enhancement of Raman spectroscopy, assisted by the nano-Ag layer and optimized dielectric environment prepared by ALD, can be applied to characterize the structures of ultrathin films in a variety of nanoscale materials and devices, even on a Si substrate with overwhelming Raman background.

Self-Assembled Epitaxial Core-Shell Nanocrystals with Tunable Magnetic Anisotropy.

Epitaxial core-shell CoO-CoFe2 O4 nanocrystals are fabricated by using pulsed laser deposition with the aid of melted material (Bi2 O3 ) addition and suitable lattice mismatch provided by substrates (SrTiO3 ). Well aligned orientations among nanocrystals and reversible core-shell sequence reveal tunable magnetic anisotropy. The interfacial coupling between core and shell further engineers the nanocrystal functionality.