Erratum to "The Possibility of Changing the Wettability of Material Surface by Adjusting Gravity".

[This corrects the article DOI: 10.34133/2020/2640834.].

The Possibility of Changing the Wettability of Material Surface by Adjusting Gravity.

The contact angle, as a vital measured parameter of wettability of material surface, has long been in dispute whether it is affected by gravity. Herein, we measured the advancing and receding contact angles on extremely low contact angle hysteresis surfaces under different gravities (1-8G) and found that both of them decrease with the increase of the gravity. The underlying mechanism is revealed to be the contact angle hysteresis and the deformation of the liquid-vapor interface away from the solid surface caused by gradient distribution of the hydrostatic pressure. The real contact angle is not affected by gravity and cannot measured by an optical method. The measured apparent contact angles are angles of inclination of the liquid-vapor interface away from the solid surface. Furthermore, a new equation is proposed based on the balance of forces acting on the three-phase contact region, which quantitatively reveals the relation of the apparent contact angle with the interfacial tensions and gravity. This finding can provide new horizons for solving the debate on whether gravity affects the contact angle and may be useful for the accurate measurement of the contact angle and the development of a new contact angle measurement system.

Defining the regulatory role of programmed cell death 4 in laryngeal squamous cell carcinoma.

Programmed cell death 4 (PDCD4) is decreased in many different kinds of malignant tumors. EMT endows tumor cells invasive and metastatic properties. However, few studies have determined the role of PDCD4 in the regulation of EMT in the context of laryngeal carcinoma. We examined the relationship between PDCD4 and EMT-associated proteins E-cadherin and N-cadherin using laryngeal carcinoma tissues. Gene manipulation was used to define the regulatory capacity of PDCD4. We report that PDCD4 and E-cadherin/N-cadherin expression were significantly changed in the carcinoma tissues, and their expression was associated with pathological grade, metastatic state, and clinical stage. The suppression of PDCD4 (and consequently, E-cadherin) was concomitant with increased proliferation and G2-phase arrest, decreased apoptosis, and increased cell invasion. PDCD4 upregulation reversed the above-mentioned results. In nude mice, PDCD4 knockdown increased tumor growth and pathological features, confirming the tumorigenic role of PDCD4. Finally, PDCD4 silencing was associated with dysregulation of the carcinogenic Wnt-ß-catenin and the STAT3-miR-21 signaling pathways. This study revealed a dynamic regulatory relationship between PDCD4 and critical factors for EMT, establishing a broad, functional role for PDCD4 in laryngeal carcinoma, which may be propagated by the STAT3-miR-21 pathway. These findings provide new information on an EMT-associated target that may lead to a novel therapy.

Cisplatin-induced necroptosis in TNFα dependent and independent pathways.

Cisplatin is a chemotherapeutic drug for treatment of many solid tumors. It has been shown to induce apoptosis and/or necrosis in different types of cancer cells. However, the underlying mechanisms remain elusive. In this study, we provide evidences that cisplatin induces necroptosis in receptor-interacting protein 3 (RIP3)-expressing cell lines, but not in cell lines lacking RIP3 protein expression. Deficiency of core components of necroptotic pathway, RIP1, RIP3, or mixed lineage kinase domain-like protein (MLKL) blocked cisplatin-induced cell death in L929 cells. This phenomenon is dependent on RIP1/RIP3/MLKL necrosome formation and translocation to mitochondria-associated membrane (MAM), but only partially via autocrine production of tumor necrosis factor α (TNFα). Moreover, we demonstrate that the mitochondrial permeability transition pore opening (mPTP) opening and reactive oxygen species (ROS) generation is a critical downstream event of the formation of necrosome in cisplatin-induced necroptosis, which is TNFα independent. Deficiency of cyclophilin-D (CypD) partially reduced cisplatin-induced cell death, indicating CypD mediated-mPTP opening plays an important role during cisplatin-induced necroptosis. Both deletion of CypD and TNFα completely blocked cisplatin-induced cell death, suggesting that cisplatin could induce necroptosis through TNFα dependent and independent pathway. These findings provide new insight into the molecular mechanisms underlying cisplatin-induced necroptosis.

Measurement of contact angles in a simulated microgravity environment generated by a large gradient magnetic field.

The contact angle is an important parameter that is essential for studying interfacial phenomena. The contact angle can be measured using commercially available instruments. However, these well-developed instruments may not function or may be unsuitable for use in some special environments. A simulated microgravity generated by a large gradient magnetic field is such an environment in which the current measurement instruments cannot be installed. To measure the contact angle in this environment, new tools must be designed and manufactured to be compatible with the size and physical environment. In this study, we report the development and construction of a new setup that was specifically designed for use in a strong magnetic field to measure the contact angle between a levitated droplet and a solid surface. The application of the setup in a large gradient magnetic field was tested, and the contact angles were readily measured.

An ignored variable: solution preparation temperature in protein crystallization.

Protein crystallization is affected by many parameters, among which certain parameters have not been well controlled. The temperature at which the protein and precipitant solutions are mixed (i.e., the ambient temperature during mixing) is such a parameter that is typically not well controlled and is often ignored. In this paper, we show that this temperature can influence protein crystallization. The experimental results showed that both higher and lower mixing temperatures can enhance the success of crystallization, which follows a parabolic curve with an increasing ambient temperature. This work illustrates that the crystallization solution preparation temperature is also an important parameter for protein crystallization. Uncontrolled or poorly controlled room temperature may yield poor reproducibility in protein crystallization.

KISS1 methylation and expression as predictors of disease progression in colorectal cancer patients.

AIM: To examine the effect of aberrant methylation of the KISS1 promoter on the development of colorectal cancer (CRC) and to investigate reversing aberrant methylation of the KISS1 promoter as a potential therapeutic target. METHODS: KISS1 promoter methylation, mRNA expression and protein expression were detected by methylation-specific polymerase chain reaction (PCR), real-time quantitative PCR and Western blotting, respectively, in 126 CRC tissues and 142 normal colorectal tissues. Human CRC cells with KISS1 promoter hypermethylation and poor KISS1 expression were treated in vitro with 5-aza-2'-deoxycytidine (5-Aza-CdR). After treatment, KISS1 promoter methylation, KISS1 mRNA and protein expression and cell migration and invasion were evaluated. RESULTS: Hypermethylation of KISS1 occurred frequently in CRC samples (83.1%, 105/126), but was infrequent in normal colorectal tissues (6.34%, 9/142). Moreover, KISS1 methylation was associated with tumor differentiation, the depth of invasion, lymph node metastasis and distant metastasis (P < 0.001). KISS1 methylation was also associated with low KISS1 expression (P < 0.001). Furthermore, we observed re-expression of the KISS1 gene and decreased cell migration after 5-Aza-CdR treatment in a CRC cell line. CONCLUSION: These data suggest that KISS1 is down-regulated in cancer tissues via promoter hypermethylation and therefore may represent a candidate target for treating metastatic CRC.

Promoting protein crystallization using a plate with simple geometry.

Increasing the probability of obtaining protein crystals in crystallization screening is always an important goal for protein crystallography. In this paper, a new method called the cross-diffusion microbatch (CDM) method is presented, which aims to efficiently promote protein crystallization and increase the chance of obtaining protein crystals. In this method, a very simple crystallization plate was designed in which all crystallization droplets are in one sealed space, so that a variety of volatile components from one droplet can diffuse into any other droplet via vapour diffusion. Crystallization screening and reproducibility tests indicate that this method could be a potentially powerful technique in practical protein crystallization screening. It can help to obtain crystals with higher probability and at a lower cost, while using a simple and easy procedure.

Sensitivity of lysozyme crystallization to minute variations in concentration.

It is well known that the crystallization of proteins is strongly dependent on the crystallization conditions, which are sometimes very sensitive to environmental disturbances. Parameters such as the concentration of precipitants or protein, pH, temperature and many others are known to affect the probability of crystallization, and the task of crystallizing a new protein often involves a trial-and-error test using numerous combinations of crystallization conditions. These crystallization parameters, such as the concentration of either the protein or the precipitant, are important because they directly affect the driving force of crystallization: the supersaturation of the solution. Although it is common sense that the concentration can affect the crystallization process, the sensitivity of the crystallization process to variations in the concentration has seldom been addressed. Owing to the difficulty of directly preparing solutions with very small concentration variations, it is hard to carry out an investigation of their effect on the crystallization process. In this paper, a simple but novel method for studying the effect of minute concentration variations on the success rate of protein crystallization is presented. By evaporating the crystallization droplet, a fine concentration gradient could be created. With this fine-tuned concentration gradient, it was possible to observe the effects of minute variations in the concentration or supersaturation on the crystallization. A very minor change in concentration (as low as 0.13% of the initial concentration, i.e. 0.026 mg ml(-1) for lysozyme and 0.052 mg ml(-1) for NaCl in the current study) or a very minor change in supersaturation (as small as 0.018) could cause a clear difference in the crystallization success rate, indicating that the crystallization of proteins is very sensitive to the concentration level. Such sensitive behaviour may be one reason for the poor reproducibility of protein crystallization.

[Critical illness polyneuropathy in a patient with Parkinson disease: a case report and review of the literature].

OBJECTIVE: To report a case of critical illness polyneuropathy (CIP) with Parkinson disease and discuss the development, clinical features and early diagnosis of this condition. METHODS: The clinical data of a patient with CIP and Parkinson's disease and the relevant literature were reviewed. RESULTS: This case showed no typical disease course of sepsis, and the condition exacerbated rapidly. The patient presented initially with abnormal homeostasis, followed by rapid onset of respiratory muscle weakness to require mechanical ventilation, but no limb weaknesses were detected. Intravenous antibiotics and aggressive treatment of sepsis did not produce any positive responses to wean from mechanical ventilation. Examinations of creatine kinase and cerebrospinal fluid showed no abnormalities. Electromyography and nerve conduction studies demonstrated declined nerve conduction velocity and decreased sensory and motor muscle action potentials, suggesting the possibility of CIP. CONCLUSION: In patients with Parkinson disease, the occurrence of sepsis with prolonged mechanical ventilation and limb weakness indicates the necessity of neurophysiological examination, muscle biopsies and laboratory tests, which may help detect CIP in the early phase. Proper interventions of sepsis may reduce the likeliness of CIP. Elimination of the risk factors and aggressive management of sepsis can be effective measures for preventing CIP.

[The heat shock protein 70-2 gene +1267(A/G) polymorphism and susceptibility to ankylosing spondylitis in Chinese Han population].

OBJECTIVE: To investigate the association between the heat shock protein 70-2 gene polymorphism and ankylosing spondylitis (AS). METHODS: The polymorphisms of HSP70-2 gene Pst I 1267 site were analysed in 176 Chinese Han AS patients and 127 healthy controls by PCR and restriction fragment length polymorphisms(RFLP) methods. RESULTS: In AS patients HSP70-2 genotypes AA, AG and GG were 46.6%, 46.0% and 7.4% respectively, frequencies of A and G were 69.6%(A) and 30.4%(G). In healthy controls HSP70-2 genotypes AA, AG and GG were 44.1%, 48.8% and 6.9% respectively, frequencies of A and G were 68.5%(A)and 31.5%(G). No significant differences were found in the distribution of HSP70-2 genotypes and allele frequencies between AS patients and controls. CONCLUSION: Our results indicate that the there may be no association of the HSP70-2 gene polymorphism with AS in Chinese Han population.