Nanomechanical Resonators: Toward Atomic Scale.

The quest for realizing and manipulating ever smaller man-made movable structures and dynamical machines has spurred tremendous endeavors, led to important discoveries, and inspired researchers to venture to previously unexplored grounds. Scientific feats and technological milestones of miniaturization of mechanical structures have been widely accomplished by advances in machining and sculpturing ever shrinking features out of bulk materials such as silicon. With the flourishing multidisciplinary field of low-dimensional nanomaterials, including one-dimensional (1D) nanowires/nanotubes and two-dimensional (2D) atomic layers such as graphene/phosphorene, growing interests and sustained effort have been devoted to creating mechanical devices toward the ultimate limit of miniaturization─genuinely down to the molecular or even atomic scale. These ultrasmall movable structures, particularly nanomechanical resonators that exploit the vibratory motion in these 1D and 2D nano-to-atomic-scale structures, offer exceptional device-level attributes, such as ultralow mass, ultrawide frequency tuning range, broad dynamic range, and ultralow power consumption, thus holding strong promises for both fundamental studies and engineering applications. In this Review, we offer a comprehensive overview and summary of this vibrant field, present the state-of-the-art devices and evaluate their specifications and performance, outline important achievements, and postulate future directions for studying these miniscule yet intriguing molecular-scale machines.

Correlation of Histomorphological Findings with Bacteriological Index in Leprosy Patients.

BACKGROUND & OBJECTIVE: Leprosy is characterized by various clinicopathological forms depending on the host's body. Therefore, the correlation of histopathological findings with bacteriological index is helpful in diagnosing, classification, and monitoring the treatment. We aimed to analyze the histomorphological findings correlation with the bacteriological index in different types of leprosy. Then, study the histopathological spectrum of leprosy. METHODS: We carried out a histomorphological study of skin biopsies obtained from 100 new patients tested clinically in OPD (Out Patients Department) on the basis and calculation of bacteriological index on a slit-skin smear. The histomorphological findings correlation with the bacteriological index was to be found in different types of leprosy. RESULTS: In the histopathological studies, 52% of the patients were diagnosed with borderline tuberculoid (BT) followed by 20% with borderline lepromatous (BL), 13% with lepromatous leprosy (LL), 8% with tuberculoid (TT), 4% with histoid Hansen's disease, and 3% with mid-borderline (BB). On the clinical and histopathological examinations, correlation was found for 80% of the cases. Considering the correlation of histopathological features with the bacteriological index, 63% of the cases showed good correlation which was comparable with that of other studies. CONCLUSION: Because of the underlying symptoms of leprosy, there is a difference between different types of leprosy and the clinical and environmental perceptions. Thus, the correlation of clinical, histopathological, and bacteriological indices could be more helpful in the diagnosis of leprosy rather than considering only one parameter.