Single Active Nanoelectromechanical Tuning Fork Front-End Radio-Frequency Receiver

Nanoelectromechanical systems (NEMS) offer the potential to revolutionize fundamental methods employed for signal processing in today's telecommunication systems,1-4 owing to their spectral purity and the prospect of integration with existing technology. In this work, we present a novel, front-end receiver topology based on a single-device silicon nanoelectromechanical mixer-filter. The operation is demonstrated by using the signal amplification in a field effect transistor (FET) merged into a tuning fork resonator. The combination of both a transistor and a mechanical element into a hybrid unit enables on-chip functionality and performance in silicon previously unachievable. Signal mixing, filtering and demodulation are experimentally demonstrated at very high frequencies (>100 MHz), maintaining a high quality factor of Q=800, and stable operation at near ambient pressure (0.1 atm) and room temperature (T=300 K). The results show that ultimately miniaturized, silicon NEMS can be utilized to realize multi-band, single-chip receiver systems based on NEMS mixer-filter arrays with reduced system complexity and power consumption

TECHNOLOGIES AND TECHNICAL EQUIPMENT FOR HEMP FIBER CROP

Hemp is not a crop prohibited or restricted by law, only that such a plantation must be authorized and monitored by the Ministry of Health, the Ministry of Internal Affairs and the Ministry of Agriculture and Rural Development.The paper will present the partial results obtained in a research project in which a piece of equipment for harvesting green hemp stems was grounded and made in order to process these stems to obtain fibers. The purpose of this paper is to present a review of existing mechanical harvesting systems for hemp fiber crops with special reference to hemp

Phase-locked loop based on nanoelectromechanical resonant-body field effect transistor

We demonstrate the room-temperature operation of a silicon nanoelectromechanical resonant-body field effect transistor (RB-FET) embedded into phase-locked loop (PLL). The very-high frequency resonator uses on-chip electrostatic actuation and transistor-based displacement detection. The heterodyne frequency down-conversion based on resistive FET mixing provides a loop feedback signal with high signal-to-noise ratio. We identify key parameters for PLL operation, and analyze the performance of the RB-FET at the system level. Used as resonant mass detector, the experimental frequency stability in the ppm-range translates into sub atto-gram (10(-18) g) sensitivity in high vacuum. The feedback and control system are generic and may be extended to other mechanical resonators with transistor properties, such as graphene membranes and carbon nanotubes. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758991

Sustained Nano-Mechanical Oscillation of a Resonant-Body Transistor by Frequency-Modulated Heterodyne Phase-Locked-Loop

Many applications based on resonant nanoelectromechanical systems (NEMS) require monitoring their natural frequency of oscillation over time with high precision, e.g. for gas sensing or nanomechanical mass spectrometry. In this study, we integrate a very-high frequency, nanomechanical resonant-body field-effect transistor into a frequency-modulated phase-locked loop (FM-PLL) which operates analog, requires only one frequency source, and simultaneously exploits the low-noise displacement detection based on FM-demodulation with resonant transistors. We demonstrate sustained mechanical oscillation of a 120 MHz doubly-clamped nano-resonator (54 nm thick, 158 nm wide, 2.65 μm long) by using the FM-PLL in vacuum and in air, reaching a frequency stability in the low ppm-range at room temperature

COMPOUND NATURAL SOURCE OF NUTRIENTS AND HUMUS FOR PLANTS AND SOIL

Composting is the biological decomposition of biodegradable solid waste under controlled conditions in a state that is sufficiently stable to allow trouble-free storage and handling and that is satisfactorily matured for safe use in agriculture. When mineral fertilizers are not available or are too expensive, compost is the most important source to provide plant nutrients and adjust soil condition. Many people today appreciate compost as a natural source of nutrients and humus. The paper will present the partial results obtained in a research project in which a biohumus loosening plant was based and built. The use of the biohumus loosening plant aims to adjust the natural decomposition process, ensure good conditions for the composting process, especially air (oxygen), water, and a good composition of the material introduced into the piles, and monitor them for get a quality product.Â

Inferring fine-scale spatial structure of the brown bear (Ursus arctos) population in the Carpathians prior to infrastructure development

Landscape genetics is increasingly being used in landscape planning for biodiversity conservation by assessing habitat connectivity and identifying landscape barriers, using intraspecific genetic data and quantification of landscape heterogeneity to statistically test the link between genetic variation and landscape variability. In this study we used genetic data to understand how landscape features and environmental factors influence demographic connectedness in Europe’s largest brown bear population and to assist in mitigating planned infrastructure development in Romania. Model-based clustering inferred one large and continuous bear population across the Carpathians suggesting that suitable bear habitat has not become sufficiently fragmented to restrict movement of individuals. However, at a finer scale, large rivers, often located alongside large roads with heavy traffic, were found to restrict gene flow significantly, while eastern facing slopes promoted genetic exchange. Since the proposed highway infrastructure development threatens to fragment regions of the Carpathians where brown bears occur, we develop a decision support tool based on models that assess the landscape configuration needed for brown bear conservation using wildlife corridor parameters. Critical brown bear corridors were identified through spatial mapping and connectivity models, which may be negatively influenced by infrastructure development and which therefore require mitigation. We recommend that current and proposed infrastructure developments incorporate these findings into their design and where possible avoid construction measures that may further fragment Romania’s brown bear population or include mitigation measures where alternative routes are not feasible

Translation of the Fugl-Meyer assessment into Romanian: Transcultural and semantic-linguistic adaptations and clinical validation

PurposeThe Fugl-Meyer Assessment (FMA) scale, which is widely used and highly recommended, is an appropriate tool for evaluating poststroke sensorimotor and other possible somatic deficits. It is also well-suited for capturing a dynamic rehabilitation process. The aim of this study was to first translate the entire sensorimotor FMA scale into Romanian using the transcultural and semantic-linguistic adaptations of its official afferent protocols and to then validate it using the preliminary clinical evaluation of inter- and intra-rater reliability and relevant concurrent validity.MethodsThrough three main steps, we completed a standardized procedure for translating FMA's official afferent evaluation protocols into Romanian and their transcultural and semantic-linguistic adaptation for both the upper and lower extremities. For relevant clinical validation, we evaluated 10 patients after a stroke two times: on days 1 and 2. All patients were evaluated simultaneously by two kinesi-physiotherapists (generically referred to as KFT1 and KFT2) over the course of 2 consecutive days, taking turns in the roles of an examiner and observer, and vice versa (inter-rater). Two scores were therefore obtained and compared for the same patient, i.e., being afferent to an inter-rater assay by comparing the assessment outcomes obtained by the two kinesi-physiotherapists, in between, and respectively, to the intra-rater assay: based on the evaluations of the same kinesi-physiotherapist, in two consecutive days, using a rank-based method (Svensson) for statistical analysis. We also compared our final Romanian version of FMA's official protocols for concurrent validity (Spearman's rank correlation statistical method) to both of the widely available assessment instruments: the Barthel Index (BI) and the modified Rankin scale (mRS).ResultsSvensson's method confirmed overall good inter- and intra-rater results for the main parts of the final Romanian version of FMA's evaluation protocols, regarding the percentage of agreement (≥80% on average) and for disagreement: relative position [RP; values outside the interval of (−0.1, 0.1) in only two measurements out of the 56 comparisons we did], relative concentration [RC; values outside the interval of (−0.1, 0.1) in only nine measurements out of the same 56 comparisons done], and relative rank variation [RV; all values within an interval of (0, 0.1) in only five measurements out of the 56 comparisons done]. High correlation values were obtained between the final Romanian version of FMA's evaluation protocols and the BI (ρ = 0.9167; p = 0.0002) for FMA–upper extremity (FMA-UE) total A-D (motor function) with ρ = 0.6319 and for FMA-lower extremity (FMA-LE) total E-F (motor function) with p = 0.0499, and close to the limit, with the mRS (ρ = −0.5937; p = 0.0704) for FMA-UE total A-D (motor function) and (ρ = −0.6615; p = 0.0372) for FMA-LE total E-F (motor function).ConclusionsThe final Romanian version of FMA's official evaluation protocols showed good preliminary reliability and validity, which could be thus recommended for use and expected to help improve the standardization of this assessment scale for patients after a stroke in Romania. Furthermore, this endeavor could be added to similar international translation and cross-cultural adaptations, thereby facilitating a more appropriate comparison of the evaluation and outcomes in the management of stroke worldwide

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Developmental Dysplasia of the Hip: How Many Risk Factors Are Needed?

Developmental dysplasia of the hip (DDH) is a progressive condition that lacks clear diagnostic and management protocols, due to insufficient data. While some advocate for universal screening, others recommend using risk factors as landmarks. In this study, we aimed to assess the risk factors associated with DDH incidence among a large population. We conducted a retrospective single-center multifactorial study between January 2019 and March 2022, including 3720 children who were investigated anamnestically, clinically, and through an ultrasound scan. We classified them into two groups: the control group with 3300 healthy children and the study group with 420 newborns diagnosed with DDH. Our analysis identified several risk factors associated with DDH, including gender, prematurity, non-vertex birth presentation, oligohydramnios, gestational diabetes, maternal hypertension, family history, associated deformities, and swaddling. We found that every DDH patient had at least two risk factors. Based on our findings, we recommend that children who present two or more risk factors for DDH be mandatorily evaluated sonographically, as well as children with clinical signs. DDH screening is recommended for each newborn for the long-term benefits of early detection and treatment

Vitamin D—A Risk Factor for Bone Fractures in Children: A Population-Based Prospective Case–Control Randomized Cross-Sectional Study

Background: Vitamin D is an essential component in calcium metabolism. Seasonality, advanced age, sex, dark skin pigmentation, and limited exposure to sunlight were reported as causes of vitamin D deficiency. This study aims to determine whether children with lower levels of vitamin D suffer more fractures than those with sufficient levels. Materials and Methods: Our institution underwent a prospective case–control randomized cross-sectional single-blinded study that included 688 children. They were split into two groups: the study group and the control group. The study group received supplements of vitamin D and calcium for 6 months. Another reference cohort was observed, which comprised 889 patients in the pediatric ward for different respiratory or gastroenterological conditions without a history of fractures. This group was used for age–sex matching tests. Results: Logistic regression showed that with every one unit increase of vitamin D level, the chance of having a middle third fracture in both bones of the forearm decreased by 7% (OR 1.07); distal third fracture incidence decreased by 1.03 times; middle third radius fracture incidence decreased by 1.03 times; distal third radius fracture incidence decreased by 1.06 times. The risk of having a distal third both-bone forearm fracture increased by 1.06 times with every year of age. Comparing the healing process, we noticed an improvement in bony callus formation for patients in the study group. Conclusions: Dosing the serum level of 25-OH-vitamin D should be taken into consideration for pediatric low-energy trauma fractures. Supplementing with vitamin D and calcium throughout childhood can be a solution for healthy bones. Our preliminary results show that the normal level of vitamin D in children should start at 40 ng/mL