Laser-Synthesized Germanium Nanoparticles as Biodegradable Material for Near-Infrared Photoacoustic Imaging and Cancer Phototherapy.

Biodegradable nanomaterials can significantly improve the safety profile of nanomedicine. Germanium nanoparticles (Ge NPs) with a safe biodegradation pathway are developed as efficient photothermal converters for biomedical applications. Ge NPs synthesized by femtosecond-laser ablation in liquids rapidly dissolve in physiological-like environment through the oxidation mechanism. The biodegradation of Ge nanoparticles is preserved in tumor cells in vitro and in normal tissues in mice with a half-life as short as 3.5 days. Biocompatibility of Ge NPs is confirmed in vivo by hematological, biochemical, and histological analyses. Strong optical absorption of Ge in the near-infrared spectral range enables photothermal treatment of engrafted tumors in vivo, following intravenous injection of Ge NPs. The photothermal therapy results in a 3.9-fold reduction of the EMT6/P adenocarcinoma tumor growth with significant prolongation of the mice survival. Excellent mass-extinction of Ge NPs (7.9 L g-1 cm-1 at 808 nm) enables photoacoustic imaging of bones and tumors, following intravenous and intratumoral administrations of the nanomaterial. As such, strongly absorbing near-infrared-light biodegradable Ge nanomaterial holds promise for advanced theranostics.

Copper Ion-Modified Germanium Phosphorus Nanosheets Integrated with an Electroactive and Biodegradable Hydrogel for Neuro-Vascularized Bone Regeneration.

Severe bone defects accompanied by vascular and peripheral nerve injuries represent a huge orthopedic challenge and are often accompanied by the risk of infection. Thus, biomaterials with antibacterial and neurovascular regeneration properties are highly desirable. Here, a newly designed biohybrid biodegradable hydrogel (GelMA) containing copper ion-modified germanium-phosphorus (GeP) nanosheets, which act as neuro-vascular regeneration and antibacterial agents, is designed. The copper ion modification process serves to improve the stability of the GeP nanosheets and offers a platform for the sustained release of bioactive ions. Study findings show that GelMA/GeP@Cu has effective antibacterial properties. The integrated hydrogel can significantly boost the osteogenic differentiation of bone marrow mesenchymal stem cells, facilitate angiogenesis in human umbilical vein endothelial cells, and up-regulate neural differentiation-related proteins in neural stem cells in vitro. In vivo, in the rat calvarial bone defect mode, the GelMA/GeP@Cu hydrogel is found to enhance angiogenesis and neurogenesis, eventually contributing to bone regeneration. These findings indicate that in the field of bone tissue engineering, GelMA/GeP@Cu can serve as a valuable biomaterial for neuro-vascularized bone regeneration and infection prevention.

Biodegradable germanium nanoparticles as contrast agents for near-infrared-II photoacoustic imaging.

Photoacoustic (PA) imaging using contrast agents with strong near-infrared-II (NIR-II, 1000-1700 nm) absorption enables deep penetration into biological tissue. Besides, biocompatibility and biodegradability are essential for clinical translation. Herein, we developed biocompatible and biodegradable germanium nanoparticles (GeNPs) with high photothermal stability as well as strong and broad absorption for NIR-II PA imaging. We first demonstrate the excellent biocompatibility of the GeNPs through experiments, including the zebrafish embryo survival rates, nude mouse body weight curves, and histological images of the major organs. Then, comprehensive PA imaging demonstrations are presented to showcase the versatile imaging capabilities and excellent biodegradability, including in vitro PA imaging which can bypass blood absorption, in vivo dual-wavelength PA imaging which can clearly distinguish the injected GeNPs from the background blood vessels, in vivo and ex vivo PA imaging with deep penetration, in vivo time-lapse PA imaging of a mouse ear for observing biodegradation, ex vivo time-lapse PA imaging of the major organs of a mouse model for observing the biodistribution after intravenous injection, and notably in vivo dual-modality fluorescence and PA imaging of osteosarcoma tumors. The in vivo biodegradation of GeNPs is observed not only in the normal tissue but also in the tumor, making the GeNPs a promising candidate for clinical NIR-II PA imaging applications.

The Renewed Interest on Brunogeierite, GeFe2O4, a Rare Mineral of Germanium: A Review.

GeFe2O4, also known as brunogeierite, is a rare mineral of germanium. It has a normal spinel structure and, as with many other spinels, amazing functional properties thanks to its peculiar structural features. In the past, its spectroscopic, optical, magnetic and electronic properties were determined; then, for many years, this compound was left behind. Only recently, a renewed interest in this oxide has arisen, particularly for its application in the electrochemical field. In this review paper, the crystal structure of GeFe2O4 will be described, as well as the synthesis methods required to obtain single crystals or polycrystalline powders. Its spectroscopic, magnetic, optical and electrical properties will be reported in detail. Then, successful applications known so far will be described: its use as anode in Lithium Ion and Sodium Ion Batteries and as electrocatalyst for urea oxidation reaction.

RADIOACTIVITY ASSESSMENT OF SURFACE SOIL IN THE VICINITY OF A URANIUM MINE IN MALAWI.

The activity concentrations of 238U, 232Th and 40K in the soil of areas surrounding the Kayelekera uranium mine were assessed. This study aims to provide a comprehensive profile of soil radioactivity distribution in the area surrounding the uranium mine to determine radiological hazards associated with mining and processing activities. Soil samples were analysed using gamma-ray spectrometry with a high-purity germanium detector. Mean specific activities of 238U, 232Th and 40K were 58.3 ± 3.7, 40.3 ± 0.3 and 590.9 ± 63.9 Bq kg-1, respectively. Results from this study have indicated changes in radioactivity levels of naturally occurring radioactive materials in the area surrounding the understudied mine, with certain areas close to the mine site showing elevated levels of 238U, highlighting the need for systematic and periodic monitoring.

The asymmetric effect of temperature, exchange rate, metals, and investor sentiments on solar stock price performance in China: evidence from QARDL approach.

The study investigates the asymmetric effect of temperature, exchange rate, metals (rare metals and electrical conductors), and investor sentiments on solar stock price performance in China. The novel econometric techniques, i.e., QARDL (quantile autoregressive distributive lag) approach and Granger causality-in-quantiles to analyze the results. In both short- and long-run estimations, the findings suggest that rare metals (cadmium, germanium, indium, and selenium) and electrical conductors (silver, aluminum, and copper) have significant and positive linkage with solar energy stocks at different quantiles based on bullish, bearish, and normal market conditions. On the other hand, negative effects are found for temperature, RMB exchange rate, and investor sentiments in both the short- and long-run. In the short run, the effect of exchange rate varies across different quantiles but it confines to only lower quantiles (bearish market condition) in the longer run. Solar stocks are more prone to investor sentiments under higher quantiles (bullish market conditions). Lastly, we find that temperature is not merely a behavioral anomaly for the solar energy market as it spreads across middle quantiles (normal market conditions) in the longer run. The findings of Granger causality in quantiles further confirm the results of QARDL.

Understanding aquaporin regulation defining silicon uptake and role in arsenic, antimony and germanium stress in pigeonpea (Cajanus cajan).

Understanding of aquaporins (AQPs) facilitating the transport of water and many other small solutes including metalloids like silicon (Si) and arsenic (As) is important to develop stress tolerant cultivars. In the present study, 40 AQPs were identified in the genome of pigeonpea (Cajanus cajan), a pulse crop widely grown in semi-arid region and areas known to affected with heavy metals like As. Conserved domains, variation at NPA motifs, aromatic/arginine (ar/R) selectivity filters, and pore morphology defined here will be crucial in predicting solute specificity of pigeonpea AQPs. The study identified CcNIP2-1 as an AQP predicted to transporter Si (beneficial element) as well as As (hazardous element). Further Si quantification in different tissues showed about 1.66% Si in leaves which confirmed the predictions. Furthermore, scanning electron microscopy showed a higher level of Si accumulation in trichomes on the leaf surface. A significant alleviation in level of As, Sb and Ge stress was also observed when these heavy metals were supplemented with Si. Estimation of relative water content, H2O2, lipid peroxidation, proline, total chlorophyll content and other physiological parameters suggested Si derived stress tolerance. Extensive transcriptome profiling under different developmental stages from germination to senescence was performed to understand the tissue-specific regulation of different AQPs. For instance, high expression of TIP3s was observed only in reproductive tissues. Co-expression network developed using transcriptome data from 30 different conditions and tissues, showed interdependency of AQPs. Expression profiling of pigeonpea performed using real time PCR showed differential expression of AQPs after Si supplementation. The information generated about the phylogeny, distribution, molecular evolution, solute specificity, and gene expression dynamics in article will be helpful to better understand the AQP transport system in pigeonpea and other legumes.

Methods and Influencing Factors for the Simple and Rapid Identification of Depleted Uranium Weapon Use under Battlefield Conditions.

The purpose of this paper is to explore how to rapidly and easily identify depleted uranium (DU) samples under battlefield conditions and to study the factors that influence their measurement. The air-absorbed dose rate and surface contamination levels for DU samples of 2-330 g were measured using a patrol instrument and portable energy spectrometer. The results were analyzed in accordance with IAEA standards for judging radioactive substances. The energy spectra of 5-g quantities of DU samples were analyzed using a high-purity germanium gamma spectrometer, and the uranium content of 100 mg DU samples was determined with an inductively coupled plasma mass spectrometer to clarify the type and composition of the uranium. The same batches of DU samples were identified using a portable gamma-ray spectrometer. We added 0-5 g environmental soil powders at different proportions. After sealing, the spectra were collected with a detection distance of 1-5 cm for 10 min. The activities of U and U nuclides in the samples were detected with an NaI(TI) scintillation detector. The U and U mass abundances in samples were calculated from measured specific activities. The sample was determined to contain DU if the U to U ratio was below 0.00723. It is found that for detecting DU materials with a low activity, surface contamination level measurements are more effective than calculating the air-absorbed external irradiation dose rate. Hence, for low-activity samples suspected to be radioactive, a radiometer with a high sensitivity for surface contamination is recommended, and the optimal measurement distance is 1-3 cm. Under all detection conditions, U can be identified using a portable gamma spectrometer, whereas U can only be detected under certain conditions. If these nuclides can be detected simultaneously, a U to U ratio of below 0.00723 indicates the presence of DU. The main factors affecting this identification include the sample mass, sample purity, measurement distance, and measurement time. For the rapid identification of DU with a portable gamma-ray spectrometer, the mass of uranium in the sample must be more than 1 g, the measuring distance needs to be less than 1 cm, and the measuring time must be 1-10 min. It is feasible to use a portable gamma-ray spectrometer to rapidly identify the types and composition of nuclides in DU samples. The detection of U activity is a precondition for the identification of DU.

Evaluation of the nuclear reaction cross sections via proton induced reactions on 72Ge and 76Se to produce 72As: A potential entrant for the theranostic pairs.

Theranostic applications of radiopharmaceuticals have revolutionized present era specially, dealing with cancer diseases. Increase in the uses of radionuclides in nuclear medicine has resulted in the demands of optimized new radionuclides to be produced focussing on the economy, simplicity and maximum yield. Two radionuclides of arsenic offer a well agreed theranostic systems namely 77As and 72As. Some arsenic radionuclides are capable of positron-emission, with range of hour to weeks half-lives and have potential to be used for nuclear medicine. Present work will elucidate the production of 72As on Germanium and Selenium via proton induced nuclear reactions. The experimental results obtained by several nuclear reactions were analyzed. The results of nuclear model codes namely ALICE-IPPE, EMPIRE-3.2.3 and TALYS-1.9 are compared with the experimental cross sections to generate recommended cross section data. Recommended excitation functions are used to compute the thick target yields (TTY) of 72As. Assessment of radionuclidic impurities are also studied and comparison of several radionuclidic impurities is done. To produce 72As,72Ge (p, n)72As, 73Ge (p, 2n)72As, 74Ge (p, 3n)72As and 76Se (p, x)72As reactions in different energy ranges are discussed. We have identified 72Ge (p, n)72As reaction; gives pre-eminent yield with least impurities mark it as feasible entrant to be applied in Positron Emission Tomography (PET) and theranostic applications.

A near-infrared responsive germanium complex of Ge/GeO2 for targeted tumor phototherapy.

The development of photoactive nanomaterials with high biocompatibility for targeted tumor phototherapy is of great significance for antitumor applications; this study presents a novel phototherapeutic agent, the Ge/GeO2 complex, which shows broad photoabsorption in the near infrared (NIR) region. As a result, it can synchronously produce reactive oxygen species (ROS) and heat under NIR irradiation. After being loaded onto macrophages, Ge/GeO2 could be delivered to tumors in a targeted fashion. Combining the abovementioned merits together, macrophage-loaded Ge/GeO2 realized in vivo synergetic photothermal and photodynamic outcomes to completely remove solid tumors in mice via intravenous administration. In this study, B-ultrasonography was also employed to monitor the tumor evolution after phototherapy, revealing a sequential process of tumor necrosis, liquefaction/softening, and finally disappearance. In addition, Ge/GeO2 proposed in this study shows negligible cytotoxicity and hematotoxicity, especially after being loaded onto macrophages.

Distribution and mode of occurrence of uranium in bottom ash derived from high-germanium coals.

The radioactivity of uranium in radioactive coal bottom ash (CBA) may be a potential danger to the ambient environment and human health. Concerning the limited research on the distribution and mode of occurrence of uranium in CBA, we herein report our investigations into this topic using a number of techniques including a five-step Tessier sequential extraction, hydrogen fluoride (HF) leaching, Siroquant (Rietveld) quantification, magnetic separation, and electron probe microanalysis (EPMA). The Tessier sequential extraction showed that the uranium in the residual and Fe-Mn oxide fractions was dominant (59.1% and 34.9%, respectively). The former was mainly incorporated into aluminosilicates, retained with glass and cristobalite, whereas the latter was especially enriched in the magnetic fraction, of which about 50% was present with magnetite (Fe3O4) and the rest in other iron oxides. In addition, the uranium in the magnetic fraction was 2.6 times that in the non-magnetic fraction. The experimental findings in this work may be important for establishing an effective strategy to reduce radioactivity from CBA for the protection of our local environment.

The study of natural and artificial radionuclides incorporation in teeth and head bones of animals lived nearby Caetité uranium mine, Brazil.

This study aimed at assessing the incorporation of radionuclides in animals in the proximity of the uranium mine in Caetité, Brazil. In 2014, samples of bovine and equine teeth and skull bones were collected and their contents of natural and artificial isotopes were assessed using nuclear spectrometry techniques. Gamma ray emission from 226,228Ra and 40K isotopes was determined using high-purity germanium (HPGe) spectrometry, 90Sr radioactivity was measured with liquid scintillation, and 234,238U, 232,230,228Th, 210Po and 239+240Pu radioactivity was assessed with alpha-spectrometry. Prior to the measurements, sample dissolutions and isotope separations were performed. Our results indicate a high 228Th isotope content in the skull bones and the teeth of animals, up to 179 Bq per kg of ash. The 226Ra and 228Ra concentrations were slightly lower. Activity concentrations of other isotopes were significantly lower or below the detection limit. We could not identify sources of technologically enhanced levels of 228Ra in the area we investigated; therefore we suggest that their origin is natural.

Reactivity of Germylene toward Phosphorus-Containing Compounds: Nucleophilic Addition and Tautomerism.

A series of phosphorus-substituted germanium(II) complexes, L(1)GeR [L(1) = CH{(CMe)(2,6-(i)Pr2C6H3N)}2; 2, R = PPh2; 4, R = OPPh2; 5a, R = OP(O)Ph2; 5b, R = OP(O) (O(n)Bu)2; 6a, R = OP(S)Ph2; 6b, R = OP(S)(OEt)2], were synthesized through the direct activation of various organic phosphorus compounds by N-heterocyclic ylide-like germylene 1. These compounds were characterized by IR and NMR spectroscopy, and 4, 5a, 6a, and 6b were further investigated by X-ray crystallography. Interestingly, the reaction of 1 with Ph2P(O)H produced the tricoordinated phosphorus(III) species L(1)GeOPPh2 (4) rather than the expected isomeric product L(1)GeP(O)Ph2. The reaction of 1 with dialkylthiophosphoric acid and diphenylthiophosphinic acid resulted in the products 6a and 6b containing the P═S double bond rather than the P═O double bond.

Germanium in ginseng is low and causes no sodium and water retention or renal toxicity in the diuretic-resistant rats.

Ginseng preparations contain high concentrations of germanium (Ge), which was reported to contribute to diuretic resistance or renal failure. However, Ge content in ginseng and the influence on renal functions remain unclear. Forty rats were randomly divided into control group, low, moderate, and high Ge ginseng-treated group and observed for 25 days. Daily urine, renal functions, and serum and urine electrolytics were measured. Ge retention in the organs and renal histological changes were also evaluated. Ge content ranged from 0.007 to 0.450 µg/g in various ginseng samples. Four groups showed no difference in the daily urine output, glomerular filtration rate, urinary electrolytes excretions, 24 h-urine protein, as well as plasma and urine urea nitrogen, creatinine, osmotic pressure, and pH values. Ge did not cause any renal pathological effects in this study. No Na and water retention was detected in the ginseng-treated groups. Ge retention in various organs was found highest in spleen, followed by the kidney, liver, lung, stomach, heart, and pancreas. The total Ge contents in various ginsengs were low, and ginseng treatment did not affect renal functions or cause renal histological changes.

Effects of germanium biotite supplement on immune responses of vaccinated mini-pigs to foot-and-mouth disease virus challenge.

Since the outbreaks of foot-and-mouth disease (FMD) in South Korea in 2010-2011, a trivalent vaccine has been used as a routine vaccination. Despite the high efficacy of the trivalent vaccine, low antibody formation was reported in the pig industry and there is considerable concern about the ability of the vaccine to protect against the Andong strain responsible for recent outbreaks in South Korea. To overcome these problems, immunostimulators have been widely used to improve vaccine efficacy in South Korea, although without any scientific evidence. Based on the current situation, the aim of this study was to investigate the effects of germanium biotite, a feed supplement used to enhance the immune system, on the immune responses to FMD vaccination through the Andong strain challenge experiment in trivalent vaccinated pigs. Following the challenge, the germanium biotite-fed pigs showed high levels of IL-8 in serum, and increased cellular immune responses to stimulation with the Andong strain antigen compared to nonsupplemented pigs. In addition, higher FMD virus (FMDV) neutralizing antibody titers were detected in the germanium biotite-fed group than in the nonsupplemented group before the challenge. The findings of this study indicate that germanium biotite supplement might enhance immune responses to the FMD vaccine in pigs.

Mode-coupling mechanisms of resonant transmission filters.

We study theoretically modal properties and parametric dependence of guided-mode resonance bandpass filters operating in the mid- and near-infrared spectral domains. We investigate three different device architectures consisting of single, double, and triple layers based on all-transparent dielectric and semiconductor thin films. The three device classes show high-performance bandpass filter profiles with broad, flat low-transmission sidebands accommodating sharp transmission peaks with their efficiencies approaching 100% with appropriate blending of multiple guided modes. We present three modal coupling configurations forming complex mixtures of two or three distinct leaky modes coupling at different evanescent diffraction orders. These modal compositions produce various widths of sidebands ranging from ~30 nm to ~2100 nm and transmission peak-linewidths ranging from ~1 pm to ~10 nm. Our modal analysis demonstrates key attributes of subwavelength periodic thin-film structures in multiple-modal blending to achieve desired transmission spectra. The design principle is applicable to various optical elements such as high-power optical filters, low-noise label-free biochemical sensor templates, and high-density display pixels.

Ag-nanoparticle-decorated Ge nanocap arrays protruding from porous anodic aluminum oxide as sensitive and reproducible surface-enhanced Raman scattering substrates.

We report on the fabrication of Ag nanoparticle (Ag NP) decorated germanium (Ge) nanocap (Ag-NPs@Ge-nanocap) arrays protruding from highly ordered porous anodic aluminum oxide (AAO) template as highly sensitive and uniform surface-enhanced Raman scattering (SERS) substrates. The hybrid SERS substrates are fabricated via a combinatorial process of AAO template-assisted growth of Ge nanotubes with each tube having a hemispherical nanocap on the AAO pore bottom, wet chemical etching of the remaining aluminum and the AAO barrier layer to expose the Ge nanocaps, and sputtering Ag NPs on the Ge nanocap arrays. Because sufficient SERS "hot spots" are created from the electromagnetic coupling among the Ag NPs on the Ge nanocap and the highly ordered Ge nanocap arrays also have semiconducting chemical supporting enhancement, the hybrid SERS substrates have high SERS sensitivity and good signal reproducibility. Using the hybrid SERS substrates, Rhodamine 6G with a concentration down to 10(-11) M is identified, and one congener of highly toxic polychlorinated biphenyls with a concentration as low as 10(-6) M is also recognized, showing great potential for SERS-based rapid detection of organic pollutants in the environment.

Supplementation of dietary germanium biotite enhances induction of the immune responses by foot-and-mouth disease vaccine in cattle.

BACKGROUND: After the recent outbreak of foot-and-mouth disease (FMD) in Korea, a vaccination policy has been applied to control the disease. In addition, several non-specific immune stimulators have been used without any scientific evidence that they would enhance the immune response after FMD vaccination and/or protect against FMD. Based on the current situation, the aim of this study was to evaluate the effect of the non-specific immune stimulator germanium biotite on FMD vaccination and immune responses in cattle. To achieve our goal, immune responses to FMD vaccination, such as levels of IgG and IgA, antibody duration, and virus-neutralizing titers were investigated after germanium biotite feeding. The PBMC typing and proliferative response after stimulation with mitogens, the cytokines expression level of PBMC, and the lysozyme activity in the serum were measured to evaluate the immune enhancing effects of germanium biotite following its administration. RESULTS: Following the first vaccination, high level of IgG (at 4 weeks) and IgA (at 2 and 31 weeks) titers in serum and saliva were observed in the germanium biotite-feeding group (p < 0.05). The germanium biotite group also showed high and longstanding inhibition percentage value in ELISA assay at 31 weeks (p < 0.05). Generally, higher virus-neutralizing antibody titers were observed in the feeding group at 20 and 31 weeks after vaccination. Following the feeding germanium biotite, the germanium biotite group showed increased subpopulation of CD4+ lymphocytes and MHC I+II+ cells in PBMCs at 23 week, responding to stimulation of ConA. The levels of IFN-γ (at 3 and 8 weeks), IL-1α (at 3, 11, and 23 weeks), IL-1ß (at 3, 8, and 11 weeks), and IL-4 (at 8 and 11 weeks) gene expression were also significantly increased in the feeding group (p < 0.01 and p < 0.05). Feeding with germanium biotite increased the lymphocytes' proliferative response to the stimulation of ConA and LPS at 23 weeks and lysozyme activity at 9 weeks after feeding. CONCLUSIONS: These results suggest that germanium biotite feeding could increase the protection against FMD virus infection via the induction of higher humoral and cellular immune responses in cattle.

Composition-tunable Cu2(Ge(1-x),Sn(x))(S(3-y),Se(y)) colloidal nanocrystals: synthesis and characterization.

A facile colloidal approach was developed to prepare cubic Cu2(Ge1-x,Snx)(S3-y,Sey) nanocrystals (NCs) (0 ≤ x ≤ 1, 0 ≤ y ≤ 3). The band gaps of the NCs can be tuned in the range of 1.35-2.45 eV by varying the chemical compositions, and the NCs display promising applications in solar energy utilization.

Physiological parameters of Macaca fascicularis immunized with anti-rubella vaccine with germanium-based adjuvants.

Clinical status, hematological and biochemical parameters, and allergenic activity of organogermanium compounds used as adjuvants in complex with preparation from Orlov rubella virus vaccine strain and reference commercial anti-rubella vaccine based on Wistar RA 27/3 strain were studied on Macaca fascilcularis of both genders. Physiological parameters of monkeys immunized with the Russian and foreign rubella virus vaccine strains with and without adjuvants did not differ. The adjuvants were inessential for the safety of vaccines (absence of toxicity, reactogenic activity, or allergenic activity) in preclinical studies on lower primates.