Abstract Background. Tumors are the second most common cause of death in humans worldwide, second only to cardiovascular and cerebrovascular diseases. Although methods and techniques for the treatment of tumors continue to improve, the effect is not satisfactory. These may lack effective therapeutic targets. This study aimed to evaluate the value of SNHG12 as a biomarker in the prognosis and clinical characteristics of various cancer patients. Methods. We analyzed SNHG12 expression and plotted the survival curves of all cancer samples in the TCGA database using the GEPIA tool. Then, we searched for eligible papers up to April 1, 2019 in databases. Next, the data were extracted from studies examining SNHG12 expression, overall survival and clinicopathological features in patients with malignant tumors. We used Review Manager 5.3 and Stata 15 software to analyze the statistical data. Results. In the TCGA database, abnormally high expression of SNHG12 in tumor samples indicates that the patient has a poor prognosis. Results of meta-analysis is that SNHG12 high expression is related to low overall survival (HR=2.72, 95% CI=1.95-3.8, P<0.00001), high tumor stage (OR=3.94, 95% CI=2.80-5.53, P<0.00001), high grade (OR=2.04, 95% CI=1.18-3.51, P=0.01), distant metastasis (OR=2.20, 95% CI=1.40-3.46, P=0.0006), tumor size (OR=2.79, 95% CI=1.89-4.14, P<0.00001) and lymph node metastasis (OR=2.66, 95%CI=1.65-4.29, P<0.0001). Conclusions . Our study confirmed that the high expression level of SNHG12 is closely related to the clinicopathological characteristics and prognosis of patients and is a new predictive biomarker for various cancer patients.
Glioma relies on glycolysis to obtain energy and sustain its survival under low glucose microenvironment in vivo. The mechanisms on glioma cell glycolysis regulation are still unclear. Signaling mediated by Double-stranded RNA-activated protein kinase (PKR) - like ER kinase (PERK) is one of the important pathways of unfolded protein response (UPR) which is comprehensively activated in cancer cells upon the hypoxic and low glucose stress. Here we show that PERK is significantly activated in human glioma tissues. PERK silencing results in decreased glioma cell viability and ATP/lactate production upon low glucose stress, which is mediated by partially blocked AKT activation and subsequent inhibition of Hexokinase II (HK2)'s mitochondria translocation. More importantly, PERK silenced glioma cells show decreased tumor formation capacity. Our results reveal that PERK activation is involved in glioma glycolysis regulation and may be a potential molecular target for glioma treatment.
Some insects, such as bees, wasps, and bugs, have specialized coupling structures to synchronize the wing motions in flight. Some others, such as ladybirds, are equipped with coupling structures that work only at rest. By locking elytra into each other, such structures provide hindwings with a protective cover to prevent contamination. Here, we show that the coupling may play another significant role: contributing to energy absorption in falls, thereby protecting the abdomen against mechanical damage. In this combined experimental, numerical and theoretical study, we investigated free falls of ladybirds (Coccinella septempunctata), and discovered that upon collision to the ground, the coupling may fail and the elytra may unlock. This unlocking of the coupling increased the energy absorption by 33%, in comparison to when the elytra remain coupled. Using micro-computed tomography scanning, we developed comparative models that enabled us to simulate impact scenarios numerically. Our results showed that unlocking of the coupling, here called elytra splitting, reduces both the peak impact force and rebound velocity. We fabricated the insect-inspired coupling mechanism using 3D printing and demonstrated its application as a damage preventing on system for quadcopters in accidental collisions.
The trap-jaw ant Odontomachus monticola manipulates its hollow mandibles to generate extremely high speeds to impact various objects through a catapult mechanism, making the violent collision occur between the mandible and the impacted objects, which increases the risk of structural failure. However, how the ant balances the trade-off between the powerful clamping and impact resistance by using this hollow structure remains elusive. In this combined experimental and theoretical investigation, we revealed that the hollowness ratio of the mandible plays an essential role in counterbalancing the trade-off. Micro-CT and high-speed images suggest that the hollow mandibles facilitate a high acceleration to 10^5 m/s^2Â for an enormous clamping force. However, this hollowness might challenge the structural strength while collision occurs. We found that under the same actuating energy, the von Mises stress of the object collided by the natural mandible striking can reach up to 2.9 times that generated by the entirely solid mandible. We defined the efficiency ratio of the von Mises stress on the impacted object to that on the mandible and found the hollow mandible achieves a more robust balance between powerful clamping and impact resistance compared to the solid mandible.
Nectarivorous insects are endowed with specific mouthparts, which provide an inspiration for the design of micropumps. We combined the postmortem examination and high-speed imaging to observe the kinematics of the honeybee's tongue. We found an asynchronization between the tongue movement and the glossa hair erection. We propose a physical model to describe the feeding process considering the trade-off between nectar-intake volume and energy consumption. This asynchronization is validated to be effective in maximizing the nectar-intake amount by theoretically figuring out the optimal moment when the glossal hairs began to erect. Our results reveal that the honeybee not only develops a subtle tongue with erectable glossal hairs but also preforms a highly evolved scheduled coordination between tongue movements and hair erection, which could serve as valuable models for developing miniature pumps that are both extendable and have dynamic surfaces.
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