No abstract

The appropriate supply of dNTPs is critical for cell growth and genome integrity. Here, we investigated the interrelationship between dUTP pyrophosphatase (dUTPase) and ribonucleotide reductase (RNR) in the regulation of genome stability. Our results demonstrate that reducing the expression of dUTPase increases genome stress in cancer. Analysis of clinical samples reveals a significant correlation between the combination of low dUTPase and high R2, a subunit of RNR, and a poor prognosis in colorectal and breast cancer patients. Furthermore, overexpression of R2 in non-tumorigenic cells progressively increases genome stress, promoting transformation. These cells display alterations in replication fork progression, elevated genomic uracil, and breaks at AT-rich common fragile sites. Consistently, overexpression of dUTPase abolishes R2-induced genome instability. Thus, the expression level of dUTPase determines the role of high R2 in driving genome instability in cancer cells.

Sn whiskers are observed by scanning electron microscope on the Cu surface in Cu(top)-Sn(bottom) bilayer system upon room temperature aging. Only Cu6Sn5 phase appears in the X-ray diffraction patterns and no Sn element is detected in the Cu sublayer by scanning transmission electron microscopy. Based on the interfacial thermodynamics, the intermetallic Cu6Sn5 compound phase may form directly at the Sn grain boundary. Driven by the stress gradient during the formation of Cu6Sn5 compound at Sn grain boundaries, Sn atoms segregate onto the Cu surface and accumulate to form Sn whisker.

The color of stainless steel surface is mainly determined by its own material or substance attached to the outer face of stainless steel. It can be roughly classified as follows: 1. Color of stainless steel itself or the unique outer surface color after physical processing such as polishing, frosting, drawing and sand blasting. 2. Attach a thin layer of other metals or alloys to the surface of stainless steel object with different chemical electrolysis principles to make stainless steel show specific color and promote the enhancement for corrosion resistance of stainless steel. 3. The outer surface of stainless steel is exposed to the natural environment, the metal (steel component) in contact with the air or natural environment (temperature, air, time, surface roughness, etc.), thus a layer of oxide will be oxidized on its surface, which tends to gradually become the same color. The characteristics of stainless steel include durability, little maintenance required, long service life, and scientific and modern appearance. The curtain wall of Science and Technology Museum of Start of Optics Valley is made of stainless steel, which also avoids light pollution caused by stainless steel surface to the surrounding environment. The architect performed physical sandblasting on exterior to form diffuse reflection on the surface. On the outer surface with countless tiny concave potholes of stainless steel after sandblasting, the change in stainless steel color of building exterior was caused by the change in angle and light of plates. In this regard, the changes in surface color of stainless steel were tried to improve by consulting relevant experts in stainless steel materials and performing a lot of related tests. This article includes detailed records and analyses of the process. Readers may therefore be inspired to avoid or solve similar problems in similar curtain wall with stainless steel surface.

The Sn whisker growth in Cu(top)-Sn(bottom) bilayer system upon room temperature aging was investigated by scanning electron microscope and X-ray diffraction techniques. The experimental observations indicate that the Sn whisker growth on the Cu surface in Cu-Sn bilayer system is different from that on the Sn surface in Sn-Cu bilayer system. When the Sn sublayer thickness is less than 0.5μm, the Sn whisker growth can take place in Cu-Sn system but not in Sn-Cu system. An explanation for Sn whisker growth in Cu-Sn bilayer system is given.