Multi-scale X-ray Tomography of Solder Interconnects in Microelectronics

Advanced packaging, including 3D IC integration, is one of the main drivers in packaging and system integration to meet the requirements for miniaturized smart systems with high functionality and high performance. For 3D stacking of wafers or dies, interconnections like micro solder bumps and Cu pillars are used. Figure 1 (left) shows a stack with a TSV interposer structure [1]. 3D-stacked products and advanced packaging challenge materials and process characterization. The control of the micro-bump quality is a particular issue. Special tasks are the characterization of the geometry of the solder bumps to estimate the stress enhancement risks, the nondestructive imaging of micron-size pores and of intermetallic phases as well as the visualization of cracks. Several NDE techniques for metrology and failure analysis are currently under discussion. In this paper, the potential and the limits of micro XCT and nano XCT for NDE of solder interconnects are described. Strategies for nondestructive evaluation of geometry, materials and defects are discussed. It is shown that multi-scale imaging with several resolution ranges is one potential approach. Micro XCT (resolution about 1 m) and nano XCT (resolution about 50 nm) are very useful lab-based techniques with a promising prospect for the future. We demonstrate the capabilities for nondestructive imaging of multi-die stacks with TSVs and micro solder bumps. Figure 1 (middle and right) right demonstrates a micro XCT overview and a nano XCT ROI study of such a multi-die stack with solder interconnects. An analysis of individual solder bumps reveals mismatches in relative positioning, variability in the shape, micron-size pores, and the distribution of intermetallic phases. This information is important to evaluate the respective process steps (process control) and the product reliability (quality control). Since deviations from the targeted geometry and defects are difficult to locate precisely from a two-dimensional image, X-ray computed tomography has to be applied

Defective antifungal immunity in patients with COVID-19

The COVID-19 pandemic has placed a huge strain on global healthcare and been a significant cause of increased morbidity and mortality, particularly in atrisk populations. This disease attacks the respiratory systems and causes significant immune dysregulation in affected patients creating a perfect opportunity for the development of invasive fungal disease (IFD). COVID-19 infection can instill a significant, poorly regulated pro-inflammatory response. Clinically induced immunosuppression or pro-inflammatory damage to mucosa facilitate the development of IFD and Aspergillus, Mucorales, and Candida infections have been regularly reported throughout the COVID-19 pandemic. Corticosteroids and immune modulators are used in the treatment of COVID-19. Corticosteroid use is also a risk factor for IFD, but not the only reason for IFD in COVID -19 patients. Specific dysregulation of the immune system through functional exhaustion of Natural killer (NK) cells and T cells has been observed in COVID-19 through the expression of the exhaustion markers NK-G2A and PD-1. Reduced fungicidal activity of neutrophils from COVID-19 patients indicates that immune dysfunction/imbalance are important risk factors for IFD. The COVID-19 pandemic has significantly increased the at risk population for IFD. Even if the incidence of IFD is relatively low, the size of this new at-risk population will result in a substantial increase in the overall, annual number of IFD cases. It is important to understand how and why certain patients with COVID-19 developed increased susceptibility to IFD, as this will improve our understanding of risk of IFD in the face of future pandemics but also in a clinical era of increased clinical immuno-suppression/modulation

Small interfering RNA targeting HIF-1α reduces hypoxia-dependent transcription and radiosensitizes hypoxic HT 1080 human fibrosarcoma cells in vitro

Background: : Hypoxia inducible factor-1 has been identified as a potential target to overcome hypoxia-induced radioresistance The aim of the present study was to investigate whether selective HIF-1 inhibition via small interfering RNA (siRNA) targeting hypoxia-inducible factor 1α (HIF-1α) affects hypoxia-induced radioresistance in HT 1080 human fibrosarcoma cells. Material and Methods: : HIF-1α expression in HT 1080 human fibrosarcoma cells in vitro was silenced using HIF-1α siRNA sequence primers. Quantitative real-time polymerase chain reaction assay was performed to quantify the mRNA expression of HIF-1α. HIF-1α protein levels were studied by Western blotting at 20% (air) or after 12 hours at 0.1% O2 (hypoxia). Cells were assayed for clonogenic survival after irradiation with 2, 5, or 10 Gy, under normoxic or hypoxic conditions in the presence of HIF-1α-targeted or control siRNA sequences. A modified oxygen enhancement ratio (OER´) was calculated as the ratio of the doses to achieve the same survival at 0.1% O2 as at ambient oxygen tensions. OER´ was obtained at cell survival levels of 50%, 37%, and 10%. Results: : HIF-1α-targeted siRNA enhanced radiation treatment efficacy under severely hypoxic conditions compared to tumor cells treated with scrambled control siRNA. OER was reduced on all survival levels after treatment with HIF-1α-targeted siRNA, suggesting that inhibition of HIF-1 activation by using HIF-1α-targeted siRNA increases radiosensitivity of hypoxic tumor cells in vitro. Conclusion: : Inhibition of HIF-1 activation by using HIF-1α-targeted siRNA clearly acts synergistically with radiotherapy and increase radiosensitivity of hypoxic cells in vitr

Multiplex PCR based strategy for detection of fungal pathogen DNA in patients with suspected invasive fungal infections

A new and easy polymerase chain reaction (PCR) multiplex strategy, for the identification of the most common fungal species involved in invasive fungal infections (IFI) was developed in this work. Two panels with species-specific markers were designed, the Candida Panel for the identification of Candida species, and the Filamentous Fungi Panel for the identification of Aspergillus species and Rhizopusarrhizus. The method allowed the correct identification of all targeted pathogens using extracted DNA or by colony PCR, showed no cross-reactivity with nontargeted species and allowed identification of different species in mixed infections. Sensitivity reached 10 to 1 pg of DNA and was suitable for clinical samples from sterile sites, with a sensitivity of 89% and specificity of 100%. Overall, the study showed that the new method is suitable for the identification of the ten most important fungal species involved in IFI, not only from positive blood cultures but also from clinical samples from sterile sites. The method provides a unique characteristic, of seeing the peak in the specific region of the panel with the correct fluorescence dye, that aids the ruling out of unspecific amplifications. Furthermore, the panels can be further customized, selecting markers for different species and/or resistance genes.This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145- FEDER-007569) funded by national funds through the FCT I.P., by the ERDF through the COMPETE2020, by the strategic programme UID/BIA/04050/2019 funded by national funds through the FCT I.P., and co-founded by FEDER through Programa Operacional Regional do Norte, in the scope of the project U. Norte Inova. Joana Carvalho-Pereira was funded by FCT/Ministério da Educação e Ciência, grant number SFRH/BD/113384/2015. The authors confirm independence from the sponsors; the content of the article has not been influenced by the sponsors

Treatment with etanercept and low monocyte concentration contribute to the risk of invasive aspergillosis in patients post allogeneic stem cell transplantation

Invasive aspergillosis (IA) is a life-threatening complication among allogeneic hematopoietic stem cell transplant (alloSCT) recipients. Despite well known risk factors and different available assays, diagnosis of invasive aspergillosis remains challenging. 103 clinical variables from patients with hematological malignancies and subsequent alloSCT were collected. Associations between collected variables and patients with (n = 36) and without IA (n = 36) were investigated by applying univariate and multivariable logistic regression. The predictive power of the final model was tested in an independent patient cohort (23 IA cases and 25 control patients). Findings were investigated further by in vitro studies, which analysed the effect of etanercept on A. fumigatus-stimulated macrophages at the gene expression and cytokine secretion. Additionally, the release of C-X-C motif chemokine ligand 10 (CXCL10) in patient sera was studied. Low monocyte concentration (p = 4.8 × 10−06), severe GvHD of the gut (grade 2–4) (p = 1.08 × 10−02) and etanercept treatment of GvHD (p = 3.5 × 10−03) were significantly associated with IA. Our studies showed that etanercept lowers CXCL10 concentrations in vitro and ex vivo and downregulates genes involved in immune responses and TNF-alpha signaling. Our study offers clinicians new information regarding risk factors for IA including low monocyte counts and administration of etanercept. After necessary validation, such information may be used for decision making regarding antifungal prophylaxis or closely monitoring patients at risk

Diagnosis of aspergillosis by PCR: clinical considerations and technical tips

Standardization of Aspergillus polymerase chain reaction (PCR) protocols has progressed, and analytical validity of blood-based assays has been formally established. It remains necessary to consider how the tests can be used in practice to maximize clinical utility. To determine the optimal diagnostic strategies and influence on patient management, several factors require consideration, including the patient population, incidence of invasive aspergillosis (and other fungal disease), and the local antifungal prescribing policy. Technical issues such as specimen type, ease of sampling, frequency of testing, access to testing centers, and time to reporting will also influence the use of PCR in clinical practice. Interpretation of all diagnostic tests is dependent on the clinical context and molecular assays are no exception, but with the proposal to incorporate Aspergillus PCR into the second revision of the consensus guidelines for defining invasive fungal disease the acceptance and understanding of molecular tests should improve

CcpA- and Shm2-pulsed myeloid dendritic cells induce T-cell activation and enhance the neutrophilic oxidative burst response to aspergillus fumigatus

Aspergillus fumigatus causes life-threatening opportunistic infections in immunocompromised patients. As therapeutic outcomes of invasive aspergillosis (IA) are often unsatisfactory, the development of targeted immunotherapy remains an important goal. Linking the innate and adaptive immune system, dendritic cells are pivotal in anti-Aspergillus defense and have generated interest as a potential immunotherapeutic approach in IA. While monocyte-derived dendritic cells (moDCs) require ex vivo differentiation, antigen-pulsed primary myeloid dendritic cells (mDCs) may present a more immediate platform for immunotherapy. To that end, we compared the response patterns and cellular interactions of human primary mDCs and moDCs pulsed with an A. fumigatus lysate and two A. fumigatus proteins (CcpA and Shm2) in a serum-free, GMP-compliant medium. CcpA and Shm2 triggered significant upregulation of maturation markers in mDCs and, to a lesser extent, moDCs. Furthermore, both A. fumigatus proteins elicited the release of an array of key pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, IL-8, and CCL3 from both DC populations. Compared to moDCs, CcpA- and Shm2-pulsed mDCs exhibited greater expression of MHC class II antigens and stimulated stronger proliferation and IFN-γ secretion from autologous CD4+ and CD8+ T-cells. Moreover, supernatants of CcpA- and Shm2-pulsed mDCs significantly enhanced the oxidative burst in allogeneic neutrophils co-cultured with A. fumigatus germ tubes. Taken together, our in vitro data suggest that ex vivo CcpA- and Shm2-pulsed primary mDCs have the potential to be developed into an immunotherapeutic approach to tackle IA

Comparison of nonculture blood-based tests for diagnosing invasive Aspergillosis in an animal model

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