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Germanium has long been considered a therapeutic agent with anticancer, antitumor, antiaging, antiviral and anti-inflammatory effects. Numerous clinical studies have explored the promising therapeutic effects of organic germanium on cancer, arthritis and senile osteoporosis. The immune activation property of organic germanium is considered the foundation of its various therapeutic effects. However, previous human clinical studies investigating immune activation with organic germanium compounds have certain limitations, as some studies did not strictly follow a randomized, double-blind, placebo-controlled design. To build a more clinically substantiated foundation for the mechanism underlying its immunostimulation, we structured by far the most rigorous clinical study to-date with a group of 130 human subjects to examine changes in immune profiles following germanium supplementation. We used Bio-Germanium, an organic germanium compound naturally synthesized via a yeast fermentation process. An 8-week randomized, double-blind, placebo-controlled study was conducted with 130 subjects with leukocyte counts of 4-8 (x10.sup.3 /[mu]L) divided into the Bio-Germanium group and the placebo group. Anthropometric measurements; blood collection; biochemical analysis; urinalysis; and natural killer cell activity, cytokine and immunoglobulin assays were conducted. Results showed the Bio-Germanium group exhibited NK cell activity increases at effector cell:target cell (E:T) ratios of 50:1, 10:1, 5:1 and 2.5:1 (12.60±32.91%, 10.19±23.88%, 9.28±16.49% and 7.27±15.28%, respectively), but the placebo group showed decreases (P<0.01). The difference in the IgG1 change from baseline to follow-up between the Bio-Germanium and placebo groups was significant (P = 0.044). Our results and earlier clinical study of Bio-Germanium confirm that Bio-Germanium acts as an effective immunostimulant by increasing the cytotoxicity of NK cells and activating immunoglobulin, B cells and tumor necrosis factor (TNF)-[alpha] (P<0.05). As we have added newly discovered clinical findings for germanium's immunostimulation mechanism, we believe Bio-Germanium is a highly promising therapeutic agent and should certainly be further explored for potential development opportunities in immunotherapy.

Im Rahmen der Arbeit wurde der Einsatz von Übergangsmetallcarbonylen und Carbonylmetallaten in der Germaniumcluster-Synthese untersucht. Es wurde sowohl die Disproportionierungsreaktion von Germanium(I)-Halogeniden in Gegenwart von Übergangsmetallcarbonylverbindungen, als auch die reduktive Kupplungsreaktion von übergangsmetallsubstituierten Germanium(IV)- und Germanium(II)-Verbindungen zur Clustersynthese genutzt. Es wurden Übergangsmetallcarbonylverbindungen des Chroms, Molybdäns, Wolframs, Mangans, Eisens und Cobalts verwendet. Auf diese Weise ist es gelungen neuartige Germaniumverbindungen mit übergangsmetallbasierten Substituenten zu synthetisieren. Neben einfachen Molekülverbindungen konnten auch Ringverbindungen, sowie polyedrische und binäre Clusterverbindungen erhalten werden. Die Verbindungen wurden mittels gängiger Spektroskopie-Methoden charakterisiert und soweit möglich wurde die Molekülstruktur mittels Röntgenstrukturanalyse aufgeklärt. Um einen Einblick in Bildungsmechanismen und die elektronische Struktur einiger Verbindungen zu erhalten, wurden ebenfalls quantenchemische Rechnungen durchgeführt.

It is conjectured that all perturbative approaches to quantum electrodynamics (QED) break down in the collision of a high-energy electron beam with an intense laser, when the laser fields are boosted to 'supercritical' strengths far greater than the critical field of QED. As field strengths increase toward this regime, cascades of photon emission and electron-positron pair creation are expected, as well as the onset of substantial radiative corrections. Here we identify the important role played by the collision angle in mitigating energy losses to photon emission that would otherwise prevent the electrons reaching the supercritical regime. We show that a collision between an electron beam with energy in the tens of GeV and a laser pulse of intensity 10 24 W cm − 2 at oblique, or even normal, incidence is a viable platform for studying the breakdown of perturbative strong-field QED. Our results have implications for the design of near-term experiments as they predict that certain quantum effects are enhanced at oblique incidence.

AlFe 2 B 2 , a ternary transition metal boride doped with Ag, Ni, Sb, Ga, and Ge, was investigated for the phase constituents, microstructure, and thermoelectric (TE) properties. The parent compound with 20% excess Al (Al 1.2 Fe 2 B 2 ), prepared by vacuum arc melting, contains orthorhombic AlFe 2 B 2 and FeB. Additional phases, such as Ag 5 Al, AlNi 3 , Al 3 Ni 2 , AlSb, and AlB 2 , were formed upon 5% doping (Ag, Ni, Sb, etc.) at the Fe site. The change in lattice parameters (a, b, and c) of the Al 1.2 Fe 2 B 2 phase with Ag, Ni, and Sb-doping is small; however, it increases noticeably in Ga and Ge-doped compounds. The Ga-doped sample shows only FeB as a secondary phase; however, the AlB 2 phase is observed in Ge-doped AlFe 2 B 2 . The microstructure investigated in Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive Spectroscopy (EDS) shows the AlFe 2 B 2 matrix is chemically homogenous in all samples, except the Ga-doped one, with uniformly distributed single or multiple secondary phases. The Differential Scanning Calorimetry (DSC) and thermogravimetry (TG) results show that all the dopants lower the peritectic reaction temperature of the AlFe₂B₂ formation, indicating the structure destabilizes. The measured TE properties show that AlFe₂B₂ is an n-type compound with electrical conductivity in the range of 0.35–0.46 × 10⁶ S/m. Adding Ag, Ni, Ga, and Ge only marginally alters the Seebeck coefficient and electrical conductivity. The noticeable improvement in the Seebeck coefficient, with negligible change in electrical conductivity, resulted in the highest power factor of 0.4mW/mK 2 for the Sb-doped sample. The thermal conductivity of AlFe 2 B 2 , which ranges from 6.4 to 9.1 W/m.K between 300 and 773 K, decreases with Sb doping to 5.2–8.5 W/m·K, resulting in a maximum zT of 0.04 at 773 K.

Spintronics is a promising field beyond complementary metal-oxide semiconductors technology. It presents a unique approach to diminishing the energy consumption of memory and logic devices by utilizing spin. The proposed influential memory and logic device is the spin transistor. However, limited spin injection efficiency from the metallic ferromagnetic electrode into the semiconductor layer has been a major obstacle for the advances of spin transistors. Three key properties are critical for magnetic materials in future spintronic devices to improve the spin injection efficiency, namely high spin polarization, robust room-temperature ferromagnetism, and comparable resistance with the semiconductor. Considering these factors, we will explore four major categories of ferromagnetic materials: Heusler alloys, dilute magnetic semiconductors, Si- or Ge-based intermetallic compounds, and two-dimensional ferromagnets. We present a comprehensive overview of the significant milestones for each type of material in terms of their property improvements, functionality achievements, and fundamental applications for spintronics. Finally, we will briefly address the challenges which need to be tackled for practical application in memory and logic devices.

Currently, a promising direction of study is the use of biologically active coordination compounds in the pharmacopoeia and the creation of effective bactericidal drugs, biomaterials, and enzyme modulators on that basis. The paper considers a coordination germanium compound with 2-amino-3-hydroxybutanoic acid. The prospects for the use of the compound in medicine are outlined. This work is aimed at solving the problems regarding the synthesis of biologically active compounds with a wide spectrum of actions. The structure and composition of the coordination compound have been established through calculation and experimental methods. The biocidal (bactericidal and fungicidal) activity of germanium-containing compounds against a number of bacteria and microscopic fungi has been studied. Using the quantum-chemical method with density functional theory (DFT, B3LYP/6–311++G(2d,2p)), the theoretical IR spectrum of the compound was calculated. The structure of the coordination compound and the structure of the intermediates at all stages of the synthesis process were established by calculation.

To investigate how replacement of H atom with methyl group (CH3) - in tetrahedral compounds of carbon, silicon and germanium - affects electron scattering process, total cross sections (TCS) for electron scattering from C(CH3)4, Si(CH3)4 and Ge(CH3)4 molecules have been compared with data for CH4, SiH4 and GeH4 molecules. All examined data have been obtained with the same experimental setup. The shape of all discussed TCS energy dependences is very similar and is characterized by a dominant maximum peaked below 10 eV. For methylated compounds a gentle structure is also visible on high energy slope of main enhancement, between 10 - 20 eV. A simple formula for TCS evaluation for partially methylated carbon, silicon and germanium compounds is also proposed.

A geometrical and topological analysis has been performed and the self-assembly of crystal structures of the Fe 3 (PFe 3 )P 2 - hP 9, Zr 3 (NiAl 3 )Ni 2 - hP 9, and Y 3 (NiAl 3 )Ge 2 -hP 9 (sp. gr. P 2 m , no. 189), Pr 3 (CoAl 3 )Co 3 (CoPr 3 )Ge- hP 15 (sp. gr. P 2 m , no.189), and Mg(Y 2 Cu 2 Mg 4 )Y 3 (CuMg 3 )Cu 2 - oP 36 (sp. gr.  Pmma , no 51) families has been simulated using computer methods (ToposPro software). The precursor metal clusters of the crystal structures are determined based on the algorithms of structural-graph decomposition in cluster structures. For the topological set of binary, ternary, and quaternary intermetallic compounds Fe 3 (PFe 3 )P 2 - hP 9, Zr 3 (NiAl 3 )Ni 2 - hP 9, and Y 3 (NiAl 3 )Ge 2 -hP 9, which constitute 15, 580, and 64 compounds, a version of their self-assembly from templated precursor clusters Fe 3 (PFe 3 ), Zr 3 (NiAl 3 )Ni 2 , and Y 3 (NiAl 3 )Ge 2 with participation of spacer atoms P, Ni, and Ge is considered. Two chemically different seven-atom precursor clusters are established for quaternary intermetallic compounds of the Pr 3 (CoAl 3 )Co 3 (CoPr 3 )Ge- hP 15 family: K 7 = Pr 3 (CoAl 3 ) and K 7 = Co 3 (CoPr 3 ), as well as Ge spacer atoms. Seven-atom precursor cluster K 7 = 0@Y 3 (CuMg 3 ), new-type nine-atom cluster K 9 = Mg(Y 2 Cu 2 Mg 4 ), and Cu spacer atom are established for the ternary intermetallic compound Mg(Y 2 Cu 2 Mg 4 )Y 3 (CuMg 3 )Cu 2 - oP 36, which has no analogues. The symmetry and topology code of the self-assembly of crystal structures of intermetallic compounds from precursor clusters K 7 and K 9 is reconstructed in the following form: chain → microlayer → microframework .

Germanium is an essential microelement, and its deficiency can result in numerous diseases, particularly oncogenic conditions. Consequently, water-soluble germanium compounds, including inorganic and coordination compounds, have attracted significant attention due to their biological activity. The review analyzes the primary research from the last decade related to the anticancer activity of germanium compounds. Furthermore, the review clarifies their actual toxicity, identifies errors and misconceptions that have contributed to the discrediting of their biological activity, and briefly suggests a putative mechanism of germanium-mediated protection from oxidative stress. Finally, the review provides clarifications on the discovery history of water-soluble organic germanium compounds, which was distorted and suppressed for a long time.