Brittle Fracture Behavior of Sn-Ag-Cu Solder Joints with Ni-Less Surface Finish via Laser-Assisted Bonding.

In this study, we investigated the brittle fracture behavior of Sn-3.0Ag-0.5Cu (SAC305) solder joints with a Direct Electroless Gold (DEG) surface finish, formed using laser-assisted bonding (LAB) and mass reflow (MR) techniques. Commercial SAC305 solder balls were used to ensure consistency. LAB increases void fractions and coarsens the primary ß-Sn phase with higher laser power, resulting in a larger eutectic network area fraction. In contrast, MR produces solder joints with minimal voids and a thicker intermetallic compound (IMC) layer. LAB-formed joints exhibit higher high-speed shear strength and lower brittle fracture rates compared to MR. The key factor in the reduced brittle fracture in LAB joints is the thinner IMC layer at the joint interface. This study highlights the potential of LAB in enhancing the mechanical reliability of solder joints in advanced electronic packaging applications.

Association between Decreased ITGA7 Levels and Increased Muscle α-Synuclein in an MPTP-Induced Mouse Model of Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra (SN), reducing dopaminergic levels in the striatum and affecting motor control. Herein, we investigated the potential relationship between integrin α7 (ITGA7) and α-synuclein (α-syn) in the muscle of methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP)-induced mice and C2C12 cells. To characterize the pathology of PD, we examined the expression of tyrosine hydroxylase (TH) in the SN of the midbrain. Compared with the control group, MPTP-treated mice showed a significant decrease in TH expression in the SN, accompanied by a significant decrease in muscle ITGA7 expression. Compared with the control group, α-syn expression was increased in the MPTP group. Furthermore, the pattern of α-syn expression in the MPTP group was similar to the ITGA7 expression pattern in the control group (linear forms). To determine the relationship between ITGA7 and PD, we examined the expression of ITGA7 and α-syn after ITGA7 knockdown using siRNA in C2C12 cells. ITGA7 expression significantly decreased while α-syn expression significantly increased in siRNA-treated C2C12 cells. These results suggest that decreased ITGA7 muscle expression could increase α-syn expression. Moreover, α-syn accumulation, induced by decreased muscle ITGA7, might contribute to PD pathology.

Multiplex SNP Genotyping Using SWITCH: Sequence-Specific Nanoparticle with Interpretative Toehold-Mediated Sequence Decoding in Hydrogel.

Single nucleotide polymorphisms (SNPs) that can alter phenotypes of individuals play a pivotal role in disease development and, more importantly, responses to therapy. However, SNP genotyping has been challenging due to the similarity of SNP alleles and their low concentration in biological samples. Sequence-specific nanoparticle with interpretative toehold-mediated sequence decoding in hydrogel (SWITCH) for multiplex SNP genotyping is presented. The encoding with gold nanoparticle probes transduces each SNP target to ≈1000 invaders with prominently different sequences between wild and mutant types, featuring polymerase chain reaction (PCR)-free amplification. Subsequently, the toehold-mediated DNA replacement in hydrogel microparticles decodes the invaders via SNP-specific fluorescence signals. The 4-plex detection of the warfarin-associated SNP targets spiked in commercially validated human serum (S1-100ML, Merck) is successfully demonstrated with excellent specificity. This work is the first technology development presenting PCR-free, multiplex SNP genotyping with a single reporting fluorophore, to the best of knowledge.

Decrease in ITGA7 Levels Is Associated with an Increase in α-Synuclein Levels in an MPTP-Induced Parkinson's Disease Mouse Model and SH-SY5Y Cells.

We investigated the potential association between integrin α7 (ITGA7) and alpha-synuclein (α-syn) in a methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model. Tyrosine hydroxylase (TH), ITGA7, and α-syn expression in the substantia nigra (SN) of the brain were observed to examine the pathological characteristics of PD. To determine the relationship between ITGA7 and PD, the expression of TH and α-syn was investigated after ITGA7 siRNA knockdown in SH-SY5Y cells. The ITGA7 microarray signal was decreased in the SN of the MPTP group, indicating reduced ITGA7 expression compared to that in the control. The expression patterns of ITGA7 in the control group and those of α-syn in the MPTP group were similar on immunohistochemical staining. Reduction in ITGA7 expression by ITGA7 siRNA administration induced a decrease in TH expression and an increase in α-syn expression in SH-SY5Y cells. The decreased expression of ITGA7 significantly decreased the expression of bcl2 and increased the bax/bcl2 ratio in SH-SY5Y cells. These results suggest that reduced ITGA7 expression may be related to increased α-syn expression and apoptosis of dopaminergic cells in an MPTP-induced PD mouse model. To the best of our knowledge, this is the first study to show an association between ITGA7 and PD.

Emergent Anisotropic Non-Fermi Liquid at a Topological Phase Transition in Three Dimensions.

Understanding correlation effects in topological phases and their transitions is a cutting-edge area of research in recent condensed matter physics. We study topological quantum phase transitions (TQPTs) between double-Weyl semimetals (DWSMs) and insulators, and argue that a novel class of quantum criticality appears at the TQPT characterized by emergent anisotropic non-Fermi-liquid behaviors, in which the interplay between the Coulomb interaction and electronic critical modes induces not only anisotropic renormalization of the Coulomb interaction but also strongly correlated electronic excitation in three spatial dimensions. Using the standard renormalization group methods, large N_{f} theory, and the ε=4-d method with a fermion flavor number N_{f} and spatial dimension d, we obtain the anomalous dimensions of electrons (η_{f}=0.366/N_{f}) in large N_{f} theory and the associated anisotropic scaling relations of various physical observables. Our results may be observed in candidate materials for DWSMs such as HgCr_{2}Se_{4} or SrSi_{2} when the system undergoes a TQPT.

Incidentally Discovered Solitary Gastrointestinal Polyp with Pathological Significance in Children: Four Case Reports.

Most solitary gastrointestinal (GI) polyps in children are either inflammatory or hamartomatous. Solitary hyperplastic polyp, sentinel polyp and solitary adenomatous polyp have been occasionally diagnosed in adults, but very rarely reported in Korean children. We recently came across a case with adenomatous polyp in the colon, a case with hyperplastic polyp beneath the gastroesophageal junction, a case with hyperplastic polyp in the prepyloric area, and a case with sentinel polyp in the distal esophagus, which are unusual pathologic types in children. These mucosal lesions were diagnosed incidentally during elective endoscopic examinations for GI symptoms. Most polyps do not cause significant symptoms, so the diagnosis might be delayed, especially in children, in whom GI endoscopy is not commonly performed for screening purpose as in the adults.

Draft Genome Sequence of Fusobacterium nucleatum subsp. animalis ChDC F324, Isolated from a Human Subgingival Plaque in the Republic of Korea.

Five subspecies of Fusobacterium nucleatum have been classified: animalis, nucleatum, polymorphum, vincentii, and fusiforme. F. nucleatum subsp. animalis ChDC F324 (KCOM 1325) was isolated from a human subgingival plaque in the Republic of Korea. Here, we report the draft genome sequence of the strain.

Ethylene responsive element binding protein 1 (StEREBP1) from Solanum tuberosum increases tolerance to abiotic stress in transgenic potato plants.

To identify components of the plant stress signal transduction cascade and response mechanisms, we screened plant genes using reverse Northern blot analysis, and chose the ethylene responsive element binding protein 1 (StEREBP1) for further characterization. To investigate its biological function in the potato, we performed Northern blot analysis and observed enhanced levels of transcription in response to several environmental stresses including low temperature. In vivo targeting experiments using a green fluorescent protein (GFP) reporter indicated that StEREBP1 localized to the nucleus of onion epidermal cells. StEREBP1 was found to bind to GCC and DRE/CRT cis-elements and both microarray and RT-PCR analyses indicated that overexpression of StEREBP1 induced expression of several GCC box-containing stress response genes. In addition, overexpression of StEREBP1 enhanced tolerance to cold and salt stress in transgenic potato plants. The results of this study suggest that StEREBP1 is a functional transcription factor that may be involved in abiotic stress responses in plants.

Cloning and characterization of a gene encoding trehalose phosphorylase (TP) from Pleurotus sajor-caju.

Complementary DNA for a gene encoding trehalose phosphorylase (TP) that reversibly catalyzes trehalose synthesis and degradation from alpha-glucose-1-phosphate (alpha-Glc-1-P) and glucose was cloned from Pleurotus sajor-caju. The cDNA of P. sajor-caju TP (designated PsTP, GenBank Accession No. AF149777) encodes a polypeptide of 751 amino acids with a deduced molecular mass of 83.7 kDa. The PsTP gene is expressed in mycelia, pilei, and stipes of fruiting bodies. Trehalose phosphorylase PsTP was purified from PsTP-transformed Escherichia coli. The enzyme catalyzes both the phosphorolysis of trehalose to produce alpha-Glc-1-P and glucose, and the synthesis of trehalose. The apparent K(m) values for trehalose and Pi in phosphorolytic reaction at pH 7.0 were 74.8 and 5.4 mM, respectively. The PsTP gene complemented Saccharomyces cerevisiae Deltatps1, Deltatps2 double-mutant cells, allowing their growth on glucose medium. Furthermore, yeast transformed with PsTP produced 2-2.5-fold more trehalose than non-transformants or cells transformed with empty vector only.