X-band RF Transmitter Design For Multi-Purpose Small Satellite Communication Operations

This thesis provides a description of the analysis, design, and tests of an X-band RF Transmitter communication system for small satellites. X-band transmitter systems are becoming popular in the upcoming deep space missions. Most of the deep-space ground stations have been using X-band frequencies to receive or transmit signals. The X-band (\u3c10 GHz) can offer lower atmospheric losses and up to a couple of Mbps data rates for multiple satellite operations. Nowadays, many small satellites have been using frequency bands such as VHF, UHF, L, and S-band frequencies for communication. From deep space to the ground station, the low-frequency ranges are inadequate in providing Mbps level data rates and enough bandwidth for deep space missions. The main focus of this thesis was the development of the subsystems such as gain block amplifier, Mixer, Bandpass Filter, and RF power amplifier. The subsystems were designed separately, then they were connected together to perform an end-to-end system test. One of the thesis aims is to design a manageable, power-efficient, and especially cost-effective X-band RF transmitter system. We presented a transmitter system demonstration in this thesis that can also be used in other orbits such as LEO, MEO, or GEO. Additionally, we presented a whole transceiver architecture. However, we focused on specifically designing transmitter subsystems. Initially, the top-level transmitter system objectives were determined. Then, the link budget was calculated. In the next stage, the RF front-end components were determined. Moreover, we simulated a transmitter system to foresee the output power, EVM, LO and IF frequency requirements, harmonics and spurious signals, cascaded gain and noise figure, and phase noise. From the calculated link budget, we were able to close the link by obtaining a 3 dB link margin. At the end of this calculation, we successfully obtained 1.45 Mbps for uplink data rate and 3.05 Kbps downlink rate. We used modulated signal to evaluate EVM. From the simulated transmitter chain, the output EVM was obtained as 1.456% RMS. From the filter board, we obtained an 8.5 dB insertion loss at 8.45 GHz. From the Mixer board, we’ve got 10 dB conversion loss and greater than 20 dB isolation between LO-RF ports. From the gain block amplifier board, we obtained a +9 dB gain at 8.45 GHz. The bandpass filter, mixer, and gain block amplifier boards were designed by using FR-4 dielectric material. We also designed a 5 W RF power amplifier board. From this board, we successfully obtained +37 dBm output at bias current at 200 mA. We reached almost 30% Power-added efficiency (PAE). In the end, we connected all the subsystems together using male-to-male SMA connectors to observe output by using a spectrum analyzer. We obtained transmitter output as +10.67 dBm at 8.45 GHz with a -10.7 dBm input power level. One benefit of this thesis is that its content has inspired other students in the department to develop similar subsystems. The other benefit of this work might be to inspire the way for next-generation X-band communication systems for use in small satellites, such as for deep space missions. This thesis might also be a reference source for institutions with a limited budget to develop a cost-effective satellite communication subsystem and contribute to space exploration for their educational and research objectives

In Vitro Evaluation and Characterization of Newly Designed Alkylamidophospholipid Analogues as Anti-Human Immunodeficiency Virus Type 1 Agents

Our laboratories first reported two novel classes of complex synthetic lipids, including alkylamidophosphocholines (PC lipid; CP-51) and alkylamidophosphate ester-linked lipid-AZT conjugates (lipid-AZT conjugates; CP-92), with selective and potent activity against human immunodeficiency virus type 1 (HIV-1). To extend these observations, we synthesized additional PC lipids and lipid-AZT conjugates (INK and INK-AZT conjugate) to evaluate their structure-activity relationships by testing for selectivity against infectious wild-type (wt) and drug-resistant HIV-1 replication, virus fusogenic activity and toxicity for mouse bone marrow cells. PC lipid compounds with medium chain lengths at positions 1 and 2 gave an improved selective index (SI). INK-3, with 12 and 8 carbons and INK-15, with 10 and 12 carbons were among the most selective when evaluated in CEM-SS cells. INK-14, a lipid-AZT conjugate where AZT replaced the choline in PC lipid INK-3, gave the highest SI of > 1250 against both infectious wt HIV-1 replication in CEM-SS cells and a clinical isolate in peripheral blood leukocytes. Notably, the PC lipid compounds INK-3 and INK-15, but not the lipid-AZT conjugate INK-14, were potent inhibitors of matched pairs of AZT-sensitive and AZT-resistant HIV-1 clinical isolates. INK-3 also inhibited replication of HIV-2 and TIBO-resistant HIV-1, and inhibited HIV-1-mediated fusogenic activity by 78, 41 and 9% in a dose-dependent manner. The TC50 for mouse bone marrow cells was > 100 micrograms/ml for INK-3 compared to 9.15-14.17 micrograms/ml for CP-51 and 0.142-0.259 microgram/ml for AZT. These data suggest that optimum PC lipid compounds are significantly less toxic than AZT and have high potential as novel therapeutic agents for AIDS

Child-Pugh classification dependent alterations in serum leptin levels among cirrhotic patients: a case controlled study

BACKGROUND: As anorexia and hypermetabolism are common in cirrhosis, leptin levels may be increased in this disease. In this study, we investigated the relation between the severity of disease and serum leptin levels in post-hepatitis cirrhosis and the role of body composition, gender and viral aetiology of cirrhosis in this association. METHODS: Thirty-five cases with post-hepatitis cirrhosis and 15 healthy controls were enrolled in this study. Body composition including body mass index, body fat percentage and body fat mass were determined. Serum leptin levels were assayed. RESULTS: Leptin levels were significantly higher among cirrhotic patients independent of sex compared to controls (p = 0.001). Female patients in both groups have had higher leptin levels than males (in cirrhotics p = 0.029, in controls p = 0.02). Cirrhotic patients in each of A, B and C subgroups according to the Child- Pugh classification revealed significantly different levels compared to controls (p = 0.046, p = 0.004, p = 0.0001, respectively). Male cirrhotics in Child-Pugh Class B and C subgroups had significantly higher leptin levels compared to male controls (p = 0.006, p = 0.008). On the other hand, female patients only in Child Pugh class C subgroup have had higher levels of serum leptin compared to controls (p = 0.022). Child-Pugh classification has been found to be the sole discriminator in determination of leptin levels in cirrhotics by linear regression (beta: 0.435 p = 0.015). CONCLUSION: Serum leptin levels increase in advanced liver disease independently of gender, body composition in posthepatitic cirrhosis. The increase is more abundant among patients that belong to C subgroup according to the Child- Pugh classification

Biosimilar filgrastim vs filgrastim: a multicenter nationwide observational bioequivalence study in patients with chemotherapy-induced neutropenia

Background: We studied the comparative effectiveness of biosimilar filgrastim vs original filgrastim in patients with chemotherapy-induced neutropenia.Patients and methods: This multicenter, observational study was conducted at 14 centers. The study included 337 patients experiencing neutropenia under chemotherapy. Patients were given either filgrastim 30 MIU or 48 MIU (Neupogen (R)) or biosimilar filgrastim 30 MIU (Leucostim (R)). Data regarding age, chemotherapeutic agents used, number of chemotherapy courses, previous diagnosis of neutropenia, neutrophil count of patients after treatment, medications used for the treatment of neutropenia, and duration of neutropenia were collected. Time to absolute neutrophil count (ANC) recovery was the primary efficacy measure.Results: Ambulatory and hospitalized patients comprised 11.3% and 45.1% of the enrolled patients, respectively, and a previous diagnosis of neutropenia was reported in 49.3% of the patients, as well. Neutropenia occurred in 13.7% (n=41), 45.5% (n=136), 27.4% (n=82), 11.4% (n=34), and 2.0% (n=6) of the patients during the first, second, third, fourth, and fifth cycles of chemotherapy, respectively. While the mean neutrophil count was 0.53 +/- 0.48 before treatment, a significant increase to 2.44 +/- 0.66 was observed after treatment (p=0.0001). While 90.3% of patients had a neutrophil count,1.49 before treatment, all patients had a neutrophil count >= 1.50 after treatment. Neutropenia resolved within <= 4 days of filgrastim therapy in 60.1%, 56.7%, and 52.6% of the patients receiving biosimilar filgrastim 30 MIU, original filgrastim 30 MIU, and original filgrastim 48 MIU, respectively. However, there was no significant difference between the three arms (p=0.468). Similarly, time to ANC recovery was comparable between the treatment arms (p=0.332).Conclusion: The results indicate that original filgrastim and biosimilar filgrastim have comparable efficacy in treating neutropenia. Biosimilar filgrastim provides a valuable alternative; however, there is need for further studies comparing the two products in different patient subpopulations

Detection by tissue printing hybridization of Pome fruit viroids in the mediterranean basin

Available data on the incidence and biodiversity of pome fruit viroids in the Mediterranean basin are limited. Before starting a research survey to fill this gap, a tissue-printing hydridization (TPH) method to detect Apple scar skin viroid (ASSVd), Pear blister canker viroid (PBCVd) and Apple dimple fruit viroid (ADFVd) has been developed and validated. Afterward, TPH was used in large-scale indexing of pome fruit viroids in Bosnia and Herzegovina, Malta, Lebanon and Turkey. A total of about 1,000 trees was randomly collected and tested. Positive results obtained by TPH were confirmed by at least one additional detection method (RT-PCR and/or Northern-blot hybridization) and viroids were finally identified by sequencing full-length cDNA clones. PBCVd was detected in 13%, 12.4% and 5.4% of the tested pear trees in Bosnia and Herzegovina, Malta and Turkey, respectively, showing a wider diffusion of this viroid than expected. In contrast, ASSVd was never detected and ADFVd was only found in symptomatic trees (cv. Starking Delicious) in Lebanon, confirming a restricted presence of these viroids in the Mediterranean basin. Altogether, these data support the use of TPH as an easy and valuable tool for exploring pome fruit viroid spread. Keywords: Viroid disease, viroid spread, pome fruit trees, detection methods, molecular hybridizatio

A parametric integer programming algorithm for bilevel mixed integer programs

We consider discrete bilevel optimization problems where the follower solves an integer program with a fixed number of variables. Using recent results in parametric integer programming, we present polynomial time algorithms for pure and mixed integer bilevel problems. For the mixed integer case where the leader's variables are continuous, our algorithm also detects whether the infimum cost fails to be attained, a difficulty that has been identified but not directly addressed in the literature. In this case it yields a ``better than fully polynomial time'' approximation scheme with running time polynomial in the logarithm of the relative precision. For the pure integer case where the leader's variables are integer, and hence optimal solutions are guaranteed to exist, we present two algorithms which run in polynomial time when the total number of variables is fixed.Comment: 11 page

Searching for Lee-Wick Gauge Bosons at the LHC

In an extension of the Standard Model(SM) based on the ideas of Lee and Wick, Grinstein, O'Connell and Wise have found an interesting way to remove the usual quadratically divergent contributions to the Higgs mass induced by radiative corrections. Phenomenologically, the model predicts the existence of Terascale, negative-norm copies of the usual SM fields with rather unique properties: ghost-like propagators and negative decay widths, but with otherwise SM-like couplings. The model is both unitary and causal on macroscopic scales. In this paper we examine whether or not such states with these unusual properties can be uniquely identified as such at the LHC. We find that in the extended strong and electroweak gauge boson sector of the model, which is the simplest one to analyze, such an identification can be rather difficult. Observation of heavy gluon-like resonances in the dijet channel offers the best hope for this identification.Comment: 17 pages, 4 figs; discussion adde

Functional brain activity constrained by structural connectivity reveals cohort-specific features for serum neurofilament light chain

Background: Neuro-axonal brain damage releases neurofilament light chain (NfL) proteins, which enter the blood. Serum NfL has recently emerged as a promising biomarker for grading axonal damage, monitoring treatment responses, and prognosis in neurological diseases. Importantly, serum NfL levels also increase with aging, and the interpretation of serum NfL levels in neurological diseases is incomplete due to lack of a reliable model for age-related variation in serum NfL levels in healthy subjects. Methods: Graph signal processing (GSP) provides analytical tools, such as graph Fourier transform (GFT), to produce measures from functional dynamics of brain activity constrained by white matter anatomy. Here, we leveraged a set of features using GFT that quantified the coupling between blood oxygen level dependent signals and structural connectome to investigate their associations with serum NfL levels collected from healthy subjects and former athletes with history of concussions. Results: Here we show that GSP feature from isthmus cingulate in the right hemisphere (r-iCg) is strongly linked with serum NfL in healthy controls. In contrast, GSP features from temporal lobe and lingual areas in the left hemisphere and posterior cingulate in the right hemisphere are the most associated with serum NfL in former athletes. Additional analysis reveals that the GSP feature from r-iCg is associated with behavioral and structural measures that predict aggressive behavior in healthy controls and former athletes. Conclusions: Our results suggest that GSP-derived brain features may be included in models of baseline variance when evaluating NfL as a biomarker of neurological diseases and studying their impact on personality traits

Charge neutralized poly(β-amino ester) polyplex nanoparticles for delivery of self-amplifying RNA

Therapeutic self-amplifying RNA (saRNA) is a promising approach for disease treatment, as it can be administered in lower doses than messenger RNA (mRNA) to achieve comparable protein production levels. However, saRNA requires an appropriate delivery vehicle to protect it during transit and facilitate its transfection. A widely-adopted approach has been to use polycations to condense these large anionic macromolecules into polyplex nanoparticles, however their high charge density often elicits cytotoxic effects. In this study we postulated that we could improve the potency and tolerability of such delivery vehicles by co-formulating poly(β-amino ester)s saRNA polyplexes with a non-toxic anionic polymer, γ-polyglutamic acid (γ-PGA) to neutralize partially this positive charge. Accordingly, we prepared a poly(β-amino ester) from 1,6-hexanedioldiacrylate (HDDA) and 4-aminobutanol (ABOL) and initially evaluated the physicochemical properties of the binary polyplexes (i.e. formed from polymer and saRNA only). Optimised binary polyplex formulations were then taken forward for preparation of ternary complexes containing pHDDA–ABOL, saRNA and γ-PGA. Our findings demonstrate that γ-PGA integration into polyplexes significantly enhanced transfection efficacy in HEK293T and A431 cells without affecting polyplex size. Notably, γ-PGA incorporation leads to a pronounced reduction in zeta potential, which reduced the toxicity of the ternary complexes in moDC, NIH3T3, and A431 cells. Furthermore, the presence of γ-PGA contributed to colloidal stability, reducing aggregation of the ternary complexes, as evidenced by insignificant changes in polydispersity index (PDI) after freeze–thaw cycles. Overall, these results suggest that incorporating the appropriate ratio of a polyanion such as γ-PGA with polycations in RNA delivery formulations is a promising way to improve the in vitro delivery of saRNA

First report of the recently introduced, destructive powdery mildew Erysiphe corylacearum on hazelnut in Turkey

Hazelnut (Corylus avellana) is Turkey’s most valuable agricultural export, and an essential source of income for many families in the Black Sea Region. In spring 2013, hazelnut leaves, fruit clusters and shoots showing powdery mildew infection symptoms different from those observed previously were discovered in Giresun, Ordu and Trabzon provinces of Turkey. The disease has become epidemic throughout all hazelnut production areas spreading from east to west of the Black Sea Region over the subsequent years. Erysiphe corylacearum was identified as the causal agent of this new and highly destructive powdery mildew based on its morphological characteristics and analyses of DNA sequences of the internal transcribed spacer (ITS) and 28S regions of the ribosomal DNA. Pathogenicity of this species was examined in an infection test and proven for the first time. To our knowledge, this is the first report of E. corylacearum on Corylus avellana worldwide