Major Research Instrumentation Research Articles

Understanding Curriculum Effectiveness and the Student Experience in a Modular Undergraduate Laboratory Experience Integrating Research and MALDI‐TOF MS

Although undergraduate Organic Chemistry laboratory classes routinely incorporate nuclear magnetic resonance spectroscopy and gas chromatography‐mass spectrometry, hands‐on experiences with Matrix‐Assisted Laser Desorption Ionization‐Time of Flight Mass Spectrometry (MALDI‐TOF MS) are exceedingly rare. This is despite the increased importance of MALDI‐TOF MS in drug discovery, protein identification, biofuels research, and materials analysis. A research‐infused MALDI‐TOF MS experience for undergraduates was created and implemented as the centerpiece of a National Science Foundation Advanced Technological Education grant. Data collected on the student experience with this module indicated both overall satisfaction and future directions for curriculum development.An organic chemistry II class participated in a modular experience centering around MALDI‐TOF MS, which culminated in travel to a mass spectrometry facility to collect data on student‐prepared research samples. Elements incorporated into this experience included active research on biofuels, POGIL activities, videos, and quizzes.A survey instrument assessed the student experience in three areas: satisfaction, quality of the experience, and impact. For each statement presented, students were offered four or five responses that best described their opinion. For example, when asked if the experience were enjoyable, the students were presented with the options “strongly agree”, “agree”, “neutral”, “disagree” or “strongly disagree”. Over a three‐year period, fifty‐two participants completed the survey.The majority of students reported they either strongly agreed or agreed with the statements ‘the purpose was clear’ (90%), as were ‘goals and priorities' (88%); that the experience was educational (94%) and provided an overall high‐quality experience (86%). Items that scored least well were the content was presented “at just the right pace” (63%), included the “right amount of info” (70%) and was a model of effective instruction (76%). With regards to the quality of training, 92% of respondents indicated that content was relevant to learning MALDI TOF MS to either a great extent or a fair amount, and that their active participation was encouraged and valued, while 88% indicated that the sessions provided opportunities to consider applications of what was covered. The lowest scoring item was “adequate opportunities were provided for me to share my experiences and insights” (75%). Additional data were collected on the degree to which individual components of the MALDI TOF MS experience contributed to the success of the enterprise, including an analysis of the perceived effectiveness of the students' presentations to the corporate partners.While significant challenges remain to integrating MALDI‐TOF MS into the laboratory experience of the average undergraduate organic chemistry II course, this systematic analysis of the students' experience and perceptions offers insight into issues with expectations and engagement. Specific elements within the data suggest recurrent themes that could be used to improve a MALDI‐TOF MS experience, or any hands‐on experience with Major Research Instrumentation. Engaging students in real‐world industry experience, and providing hands‐on experience with MALDI TOF MS were two of the most significant aspects of the student experience.Support or Funding InformationThis work was supported by a National Science Foundation Advanced Technological Education Grant 1400885 to CL (PI) and JEG (Co‐PI)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The PhoP/PhoQ two‐component regulatory system influences on Escherichia coli headgroup‐acylated glycerophospholipids

Headgroup‐acylated glycerophospholipids (GPLs) are a class of low abundance membrane lipids that are thought to play a roll in cell division and membrane integrity in Gram‐negative bacteria, such as Escherichia coli. The PhoP/PhoQ two‐component regulatory system is known to aid in virulence of pathogenic E. coli and responds to low Mg2+ concentrations. Previous research has suggested a protein activated by the PhoP/PhoQ system increases synthesis of acyl phosphatidylglycerol (acyl PG), a type of headgroup‐acylated GPL. Currently, though, the synthase of another headgroup‐acylated GPL, N‐acyl phosphatidylethanolamines (N‐acyl PE), is unknown. In order to determine if the PhoP/PhoQ system affects levels of acyl PGs, as well as N‐acyl PEs, wild‐type MG1655 E. coli with an empty pBAD 33.1 plasmid were grown in N‐minimal media with Mg2+ concentrations of either 8μM or 10mM. To confirm the activation of the PhoP/PhoQ system when cells are grown in 8μM Mg2+ media a reporter strain of E. coli, pNL3, was used. A β‐galactosidase assay of the pNL3 stain confirmed the activation of the PhoP/PhoQ system in low Mg2+ conditions through a 3.8 fold increase of activity in 8μM Mg2+ conditions compared to growths in 10mM Mg2+. In the MG1655 wild‐type strain, three normalized N‐acyl PE and four normalized acyl PG species were measured, utilizing reverse phase column mass spectrometry, and summed in each Mg2+ condition. N‐acyl PE and acyl PG levels in the 8μM Mg2+ growth was double that of the MG1655 grown in 10mM Mg2+. These data suggest that the PhoP/PhoQ system may be implicated in the synthesis of N‐acyl PEs and acyl PGs. Further research is required to verify the correlation between the activated PhoP/PhoQ system in N‐acyl PE and acyl PG synthase, as well as identify the protein specifically responsible for the synthesis of N‐acyl PEs.Support or Funding InformationSupported by National Science Foundation Major Research Instrumentation grant #1039659 and Research at Undergraduate Institution grant #1516805.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Comparative lipidomic profiling of parasite‐infected and non‐infected Northern saw‐whet owls.

Haematozoa are present in avian species around the world. In some cases, parasite infection may be fatal. For example, Plasmodium and Leucocytozoon cause avian malaria and anemia, respectively, which can be detrimental to host species. These parasites are responsible for massive reductions in the populations of birds native to Hawaii, the Galapagos, and other archipelagos. However, the same parasites have seemingly benign effects in other avian species. Here, we use liquid chromatography‐mass spectrometry to analyze lipid profiles and study host‐parasite interactions in a population of Northern saw‐whet owls (Aegolius acadicus) known to be infected with Leucocytozoon (49.5%), Plasmodium (10%), Haemoproteus (5%), and Trypanosoma (2.9%). Fragment ions from MS/MS analyses revealed major classes of glycerophospholipids, including phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidylcholine (PC). Comparison of the total lipid profiles of infected and non‐infected owls revealed distinct features (p < 0.001) between the two groups in the negative‐ (30) and positive‐ion (376) mode. The lower levels (>1.7‐fold difference) of PC in infected individuals suggests haematozoa infections may influence lipid production, which may impact the health of birds. Further investigations can advance our understanding of bird physiology and the role lipid biomarkers may play in the conservation of parasite‐susceptible avian species.Support or Funding InformationSupported by National Science Foundation Major Research Instrumentation Grant #1039659.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Investigating Peptide Assembly in a Membrane Environment

ObjectiveThis study seeks to determine how the properties of a lipid membrane influence protein folding and assembly in model systems using hydrogen‐detuerium exchange mass spectrometry (HDX‐MS).MethodsThe folding and assembly of small model peptides in large unilamellar vesicles (LUVs) have been investigated using HDX‐MS. We currently have results for the 13‐residue, cationic peptide indolicidin in LUVs prepared with 1,2‐Dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) or 1,2‐Dioleoyl‐sn‐glycero‐3‐phosphoglycerl (DOPG).ResultsOur HDX‐MS results indicate that free indolicidin is fully deuterated at all measured time points, including the shortest (30s). Results with LUVs show differences between LUVs made of DOPC (a zwitterionic phospholipid) and DOPG (an anionic phospholipid). Indolicidin mixed with DOPC LUVs has slightly less deuterium incorporation (~3 fewer deuterium), compared to the free peptide in the absence of LUVs. Indolicidin with DOPG LUVs shows additional protection from hydrogen‐deuterium exchange (~5 fewer deuterium), compared to free indolicidin. Preliminary MS/MS experiments suggest that HDX protection occurs at the C‐terminal end of indolicidin.ConclusionsEvidence from several studies shows that MPs fold into their “correct” structures even in certain lipid‐free environments, suggesting that the membrane may not be required for proper MP folding. However, many researchers go to great lengths to mimic the physical and chemical environment of the membrane and claim that characteristics including curvature, fluidity, and symmetry are significant. Overall, we plan to investigate three model peptides known to insert into the membrane and oligomerize to form membrane‐active structures. The model peptides represent different structural classes and their individual structures have already been well‐characterized by traditional biophysical methods.Our results with free indolicidin are consistent with the fact that, in solution, indolicidin remains in a monomeric form and adopts an extended, linear structure. The results with LUVs indicate that the peptide does interact with both types of LUVs. More protection from HDX occurs with the DOPG LUVs, suggesting that the protein may be embedding itself deeper into the DOPG (anionic) LUVs, compared to DOPC (zwitterionic) LUVs. The surface charge of the model membrane may affect the peptide's ability to associate with the membrane. The MS/MS results suggest that the peptide's C‐terminus may be responsible for insertion into both LUV types. We are currently varying the model membranes to examine the effects of fluidity and curvature, as well.Support or Funding InformationThis work was supported by a Major Research Instrumentation grant (MRI1531435) from the National Science Foundation and a grant from the Murdock Charitable Trust.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Quantum interference between heralded single photon state and coherent state**Project supported by the National Special Fund for Major Research Instrument Development of China (Grant No. 11527808), the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11504262), the National Basic Research Program of China (Grant No. 2014CB340103), the Specialized Research Fund for the Doctoral Program of

Balanced homodyne detection has been introduced as a reliable technique of reconstructing the quantum state of a single photon Fock state, which is based on coupling the single photon state and a strong coherent local oscillator in a beam splitter and detecting the field quadrature at the output ports separately. The main challenge associated with a tomographic characterization of the single photon state is mode matching between the single photon state and the local oscillator. Utilizing the heralded single photon generated by the spontaneous parametric process, the multi-mode theoretical model of quantum interference between the single photon state and the coherent state in the fiber beam splitter is established. Moreover, the analytical expressions of the temporal-mode matching coefficient and interference visibility and relationship between the two parameters are shown. In the experimental scheme, the interference visibility under various temporal-mode matching coefficients is demonstrated, which is almost accordant with the theoretical value. Our work explores the principle of temporal-mode matching between the single photon state and the coherent photon state, originated from a local oscillator, and could provide guidance for designing the high-performance balanced homodyne detection system.

Etching mask optimization of InAs/GaSb superlattice mid-wavelength infared 640 × 512 focal plane array**Project supported by the National Basic Research Program of China (Grant Nos. 2014CB643903, 2013CB932904, 2012CB932701, and 2011CB922201), the National Special Funds for the Development of Major Research Equipment and Instruments, China (Grant No. 2012YQ140005), the National Natural Science Foundation of China (Grant Nos. 61274013, U1037602, 61306013, and

In this paper we focused on the mask technology of inductively coupled plasma (ICP) etching for the mesa fabrication of infrared focal plane arrays (FPA). By using the SiO2 mask, the mesa has higher graphics transfer accuracy and creates less micro-ripples in sidewalls. Comparing the IV characterization of detectors by using two different masks, the detector using the SiO2 hard mask has the of , while the detector using the photoresist mask has the of in 77 K. After that we focused on the method of removing the remaining SiO2 after mesa etching. The dry ICP etching and chemical buffer oxide etcher (BOE) based on HF and NH4F are used in this part. Detectors using BOE only have closer to that using the combining method, but it leads to gaps on mesas because of the corrosion on AlSb layer by BOE. We finally choose the combining method and fabricated the 640× 512 FPA. The FPA with cutoff wavelength of 4.8 m has the average of and the average detectivity of at 77 K. The FPA has good uniformity with the bad dots rate of 1.21% and the noise equivalent temperature difference (NEDT) of 22.9 mK operating at 77 K.

Metabolic Modulation of Cell Surface Sialoform of Macrophages

Macrophages and their precursors, monocytes, mediate the innate immune system through the initiation and regulation of inflammation and contribute to the adaptive immunity via variety mechanisms. Macrophage cell surface expresses a dense layer of glycans often terminated with sialic acids (SAs). SAs are a family of 9-carbon containing acidic monosaccharides and terminate cell surface glycans of either glycoproteins or glycolipids. The C-5-amino derivative represents the well-known neuraminic acid, and its amino functional group can be either acetylated (N-acetylneuraminic acid, Neu5Ac) or glycolylated (N-glycolylneuraminic acid, Neu5Gc). The most abundant SA is Neu5Ac. Notably, humans make Neu5Ac but are incapable of synthesizing Neu5Gc. The NeuGc deficiency in humans is attributed to a truncation in the gene encoding cytidine monophosphate sialic acid hydroxylase (CMAH). In this study, we investigated Neu5Gc incorporation of both THP-1 monocytes and THP-1 macrophages and to see its impact on macrophage functions. In addition, we designed a Neu5Gly as a Neu5Gc analog and investigated its metabolic inhibition of Neu5Gc incorporation into THP-1 monocytes and THP-1 macrophages. As a result, there is no inhibition of the Neu5Gc incorporation found when cells were treated with both Neu5Gc and Neu5Gly for both THP-1 monocytes and THP-1 macrophages, while Neu5Gly incorporation were found for both THP-1 monocytes and THP-1 macrophages. The ability to alter cell surface sialic acid structures will provide insights into structure-function relationships and the importance of individual structures in glycan-mediated processes. Further, the ability to remodel cell surface glycan architectures is expected to offer a novel approach to manipulate cellular physiology and phenotypic outcomes. Support or Funding InformationThis work was supported by Faculty Research Development Fund and the research fund from the Center for Gene Regulation in Health and Disease (GRHD) at Cleveland State University supported by Ohio Department of Development (ODOD). The authors acknowledge the National Science Foundation Major Research Instrumentation Grants for supporting NMR and QTrap 5500 mass spectrometer instrument requisition at Cleveland State University Figure 1Open in figure viewerPowerPoint Cell surface sialosides Figure 2Open in figure viewerPowerPoint Metabolic modulation of cell-surface sialic acids of monocytes and macrophages Scheme 1Open in figure viewerPowerPoint Synthesis of Zwitterionic Sialic Acid - Neu5Gly

What could chemistry do with more expensive instruments?

Chemistry and physics differ not only in the scales of the systems they study but also in the scales of the instruments they use for research. Physicists and astronomers work on some large projects involving multiple facilities and big instruments. For example, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected gravitational waves for the first time at two multi-kilometer-long facilities in the U.S. Meanwhile, much of chemistry research still happens with instruments that sit in individual researchers’ labs. The National Science Foundation underwrites much of the research infrastructure in the U.S. at both the small and large scales. NSF’s Major Research Instrumentation Program will pay for instruments up to $4 million. That’s the program scientists apply to if they’re looking for instruments for individual labs or departments. In contrast, NSF’s Major Research Equipment and Facilities Construction funds much larger projects. It funded LIGO to the tune of about $1.1 billion. NSF

Very long wavelength infrared focal plane arrays with 50% cutoff wavelength based on type-II InAs/GaSb superlattice**Project supported by the National Basic Research Program of China (Grant Nos. 2013CB932904 and 2011CB922201), the National Special Funds for the Development of Major Research Equipment and Instruments, China (Grant No. 2012YQ140005), and the National Natural Science Foundation of China (Grant Nos. 61274013, 61290303, and

A very long wavelength infrared(VLWIR) focal plane array based on InAs/GaSb type-II super-lattices is demonstrated on a GaSb substrate. A hetero-structure photodiode was grown with a 50% cut-off wavelength of 15.2 m, at 77 K. A 320×256 VLWIR focal plane array with this design was fabricated and characterized. The peak quantum efficiency without an antireflective coating was 25.74% at the reverse bias voltage of −20 mV, yielding a peak specific detectivity of cm·Hz ·W−1. The operability and the uniformity of response were 89% and 83.17%. The noise-equivalent temperature difference at 65 K exhibited a minimum at 21.4 mK, corresponding to an average value of 56.3 mK.

Perceptions of higher education quality at three universities in Vietnam

Purpose Vietnam is experiencing rapid expansion in the provision of higher education that requires quality assurance appropriate for the Vietnamese-centralised Confucian cultural context. This paper aims to examine the concept of quality from the perspectives of academic leaders, quality assurance members and academics at three higher education institutions in Vietnam. Design/methodology/approach Based on an interpretative study, semi-structured interviews were used as a major research instrument augmented with document analysis across three case studies. Interviews were conducted with 35 participants from three groups of stakeholders. Findings The concept of quality was found to be under-conceptualised in this Vietnamese context. Quality was conceptualised as meeting societal needs across the case studies underpinned by the belief that the purpose of higher education is to prepare graduates for employment. Research limitations/implications The study was conducted in similar disciplines at three state-owned universities in Vietnam in 2011. This provides insight within this context and timeframe that may not be generalised. It is suggested to extend this research to other disciplines, the private sector and other groups of stakeholders. Practical implications The paper discusses the necessity of revisiting the philosophy of higher education and re-conceptualising quality in Vietnam that informs quality assurance processes that are relevant to the cultural context. Originality/value This paper provides a centralised Confucian perspective to the literature on quality assurance in higher education. How quality is perceived by academic leaders, quality assurance members and, in particular, academic staff can be used to inform policy. In a centralised country such as Vietnam, academic leaders and quality assurance members may indicate their “obedient” attitudes to policies, leading to the same view with what is centrally enacted, while the academic staff have a different perception of quality.

SU‐F‐T‐127: Charged Particle Transport in Condensed Media

Purpose:Provide quality interaction cross sections for charged particle Monte Carlo (MC) track structure codes and evaluate low energy electron transport in condensed media.Methods:MC methods and codes are often used to model or simulate charged particle radiation transport in matter. Detailed (or event‐by‐event) track structure simulations are of special interest for the modeling of the physical and chemical stages of radiation action with matter and the initial radiation damage to biological systems. They require reliable interaction cross sections of all radiation qualities considered (e.g., electrons, protons, alpha particles, light and heavy ions) with the target material under consideration, mainly in the condensed phase, including liquids and solids. Interaction cross sections are calculated using the dielectric formalism, a mixture of first principles, theoretical modeling and experimental information for bulk and surface transport and implemented into MC track structure codes. Secondary electron emission yields from amorphous solid water (ASW) and thin metal foils (copper and gold) after fast proton impact are simulated and measured experimentally.Results:After considering different transport models for bulk and surface transport and a careful modeling of the experimental geometry, simulated secondary electron emission yields follow the trends of experimental data well. Furthermore, yields for electron emissions below 50 eV are sensitive to differential elastic scattering cross sections.Conclusion:Low‐energy electron transport in condensed media is still a challenge for detailed track structure simulation codes. Interaction cross‐sections, transport models, and target geometry need to be considered adequately.The research was funded in part by NSF Major Research Instrumentation Program 2009, Award Number: 0923270 and by NIH/NCI R01 CA93351.

Functional Analysis of DUF1 in Saccharomyces cerevesiae

The yeast DUF1 gene encodes a highly‐conserved, WD40‐repeat protein that interacts with and activates deubiquitinases (DUBs). DUBs carry out the process of deubiquitination, the removal of ubiquitin from tagged proteins. Animal homologues of DUF1 have been shown to form complexes with DUBs that have a variety of important functions. Human WDR48 activates DUBs that deubiquitinate key subunits in the Fanconi anemia DNA repair pathway. Caenorhabditis elegans WDR48 interacts with Usp46 and stabilizes Glutamate receptors (GLR‐1) to promote changes in locomotion behavior. Previous research has shown that in Saccharomyces cerevisiae, Duf1 interacts with Ubp9 and Ubp13, DUBs involved in the biosynthesis of mitochondrial subunits necessary for respiration. When a DUF1 mutant strain was grown at a higher temperature on a non‐fermentable carbon source, increased petite colony formation was observed. Thus, we hypothesize that Duf1 enhances the yeast's ability to cope with stress. Our interest lies in determining which cellular stress pathways require Duf1 in order to gain insight about its function. By exposing a DUF1 knockout mutant strain to different stress conditions and comparing its growth to the wild type parent strain, phenotypes may be revealed to provide a better understanding of the cellular activities of Duf1. Cell growth experiments were performed in 96‐well plates using a Spectramax i3 plate reader and cell number was plotted against time. Growth rate and maximum cell number were computed in R and differences between the knockout mutant and the wild type parent strain were determined using a pairwise Mann‐Whitney U test. When grown in minimal media, the knockout mutant strain grew faster than the wild type parent strain. The knockout mutant was also able to reach a larger maximum cell number than that of the wild type parent strain in minimal media containing high levels of glucose, a stressful growth situation. Conversely, the wild type parent strain grew better when minimal media was supplemented with high amounts of ethanol. This implies that the action of Duf1 as either a positive or negative regulator is dependent upon the type of stress experienced and that DUF1 may play a role in multiple cellular stress response pathways.Support or Funding InformationThis project is supported by an NSF Major Research Instrumentation grant and Salisbury University's Henson Undergraduate Research Fund.

Investigation of a field-widened Mach–Zehnder receiver to extend Fe Doppler lidar wind measurements from the thermosphere to the ground

A receiver employing a field-widened Mach-Zehnder interferometer (MZI) is investigated for extending the wind measurement range of a narrow-band Fe Doppler lidar operating at 372 nm from its existing measurement range in the mesosphere and lower thermosphere (MLT) down to near the ground. This design uses the multiple transmitted frequencies available from the base Fe Doppler lidar in combination with a novel MZI receiver to make a measurement of the Doppler shift that rejects the influence of atmospheric parameters such as the aerosol backscatter ratio, temperature, and pressure of the lidar volume and receiver parameters such as the geometric overlap, the chopper function, and any other factor affecting the proportion of the signal in both channels of the MZI equally. A ratio is constructed from the three frequencies and two channels of the interferometer that exhibits a measurement performance of 1.75 times the Cramer-Rao lower bound, which is comparable to the dual MZI (DMZ) while preserving the insensitivity to backscatter spectrum of the quad MZI (QMZ). In addition, we show how the use of multiple transmitted frequencies can yield a wind measurement wherein the accuracy is insensitive to the optical imperfection and misalignment of the MZI or any other factor that affects the contrast, though the precision is still impacted by the fringe contrast. Simply adding a second surface mirror of a particular thickness to the basic tilted MZI can allow the field of the MZI to be widened sufficiently for most resonance Doppler lidar receivers in operation today. Provided that the detection sensitivity in each channel is known, the original resonance fluorescence and Rayleigh scattering signals can be recovered by simply scaling and adding the contributions from both channels. Consequently, the wind and temperature from the MLT region and the temperature from the Rayleigh region can be derived alongside the Rayleigh Doppler wind measurement without compromising the measurement precision. Using actual data obtained recently from a Major Research Instrumentation Fe Doppler lidar, we show the expected measurement performance and some potential scientific avenues for this embodiment of a "whole-atmosphere" lidar system.

Promoting chondroinduction with naturally derived hydrogel pastes

Event Abstract Back to Event Promoting chondroinduction with naturally derived hydrogel pastes Emily Beck1, Marilyn Barragan2, Madeleine H. Tadros3, Stevin H. Gehrke1, 4, Sarah L. Kieweg1, 5, Cory J. Berkland1, 4, 6 and Michael S. Detamore1, 4 1 University of Kansas, Bioengineering Program, United States 2 University of Kansas, Department of Molecular Biosciences, United States 3 Rice University, Department of Chemical and Biomolecular Engineering, United States 4 University of Kansas, Department of Chemical and Petroleum Engineering, United States 5 University of Kansas, Department of Mechanical Engineering, United States 6 University of Kansas, Department of Pharmaceutical Chemistry, United States Introduction: ECM-based materials are gaining wide attention in the tissue engineering field due to their ability to support cellular attachment, growth, and differentiation[1]. Although ECM materials have been incorporated into hydrogels and show great promise, hydrogels also have one major drawback because their precursors are liquid solutions that are prone to leaking after surgical placement[2]. Therefore, in this work, we mixed porcine devitalized cartilage (DVC) particles into methacrylated, solubilized, devitalized, porcine cartilage (MeSDVC) to achieve a hydrogel precursor that was not only paste-like to overcome the drawbacks of traditional hydrogels, but additionally to achieve a hydrogel that would induce chondrogensis and could be further crosslinked and analyzed. Methods: Porcine cartilage that was devitalized and cryoground into a fine powder was mixed with devitalized cartilage that was solubilized and then methacrylated, and the precursors were analyzed rheologically for yield stress. Formulations tested rheologically were 5% DVC, 10% DVC, 10% MeSDVC, 10% MeSDVC 10% DVC, and 10% MeSDVC 10% DVC + TGF-β3. The formulations containing MeSDVC were then mixed with rat bone marrow stem cells and UV crosslinked to further characterize them as solids. The gels were cultured in vitro for 6 weeks, where chondrogenic gene expression, the compressive modulus, swelling, and histology were also analyzed. Results and Discussion: All formulations tested exhibited a yield stress, where the yield stress of 10% MeSDVC and 10% DVC were 725 ± 55 and 57.9 ± 0.3, respectively. When 10% MeSDVC and 10% DVC were mixed, the yield stress increased by a factor of 2.6 compared to 10% MeSDVC alone (p<0.05). Because the yield stress is not additive, it suggests that there is some physiological or chemical interaction between MeSDVC and DVC that is creating the synergistic yield stress effect. After crosslinking, the only gels that were noted to not have contraction throughout culture were the gels containing DVC particles. At the 2 week and 3 week time points, Sox-9 and aggrecan expression were significantly higher in the DVC groups (p<0.05) and by 6 weeks, the relative collagen II expressions of the 10% MeSDVC 10% DVC and the 10% MeSDVC 10% DVC + TGF-β3 groups were 78 and 40 fold higher than 10% MeSDVC alone, respectively (p<0.05). The compressive moduli of all but one group ranged between 70 and 160 kPa, although the 20% MeSDVC acellular group had a modulus of 680 ± 130 kPa, which is much closer to that of native cartilage. Finally, aggrecan immunohistological staining showed increased staining around the cells at 6 weeks in the growth factor supplemented and the 10% MeSDVC group. Conclusion: Given that the mixtures of MeSDVC and DVC combined yielded hydrogel precursors that exhibited a yield stress and crosslinked to form hydrogels that did not contract over time, stimulated chondroinductive gene expression, as well as had a compressive moduli on the same order of magnitude as native cartilage, these MeSDVC and DVC mixtures may be promising materials for translational cartilage tissue engineering applications. NIH S10 RR024664; NSF Graduate Research Fellowship (E.B.); NSF Major Research Instrumentation Grant (0320648); Kansas Bioscience Authority Rising Star Award (M.D.); NIH R01 DE022472 (C.B.)

2-μm single longitudinal mode GaSb-based laterally coupled distributed feedback laser with regrowth-free shallow-etched gratings by interference lithography**Project supported by the National Key Basic Research Program of China (Grant Nos. 2014CB643903 and 2013CB932904), the National Special Funds for the Development of Major Research Equipment and Instruments, China (Grant No. 2012YQ140005), the National Natural Science Foundation of China (Grant Nos. 61435012, 61274013,

We report a type-I GaSb-based laterally coupled distributed-feedback (LC-DFB) laser with shallow-etched gratings operating a continuous wave at room temperature without re-growth process. Second-order Bragg gratings are fabricated alongside the ridge waveguide by interference lithography. Index-coupled LC-DFB laser with a cavity of 1500 μm achieves single longitudinal mode continuous-wave operation at 20 °C with side mode suppression ratio (SMSR) as high as 24 dB. The maximum single mode continuous-wave output power is about 10 mW at room temperature (uncoated facet). A low threshold current density of 230 A/cm2 is achieved with differential quantum efficiency estimated to be 93 mW/A. The laser shows a good wavelength stability against drive current and working temperature.

Wet Chemical Etching of Antimonide-Based Infrared Materials**Supported by the National Basic Research Program of China under Grant Nos 2014CB643903, 2013CB932904, 2012CB932701 and 2011CB922201, the National Special Funds for the Development of Major Research Equipment and Instruments under Grant No 2012YQ140005, the National Natural Science Foundation of China under Grant Nos 61274013, U1037602 and 61290303, and the Strategic Priority Research Program

The roughness and the crystallographic orientation selectivity of etched antimonide-based infrared materials are examined and are used to optimize the chemical mesa etching process of the InAs/GaSb superlattice photodiode with the goal of reducing the dark current. The etchant used is based on phosphoric acid (H3PO4), citric acid (C6H8O7) and hydrogen peroxide (H2O2). The roughness of the mesa sidewalls and etching rates are compared and used to find an optimized etchant, with which we obtain optimized mid-wavelength infrared photodiodes possessing an R0A value of 466 ω·cm2 and a detectivity of 1.43 × 1011 cm·Hz1/2 W−1. Crystallographic orientation selectivity is seen in InAs etching, and also is seen in the InAs/GaSb superlattice wet chemical etching process.

A Study of the Laser-Induced Breakdown Spectroscopy of Carbon in the Ultraviolet Wavelength Range Under Vacuum Conditions**supported by the National Special Fund for the Development of Major Research Equipment and Instruments of China (No. 2014YQ120351)

The influence of a vacuum on the laser-induced breakdown spectroscopy (LIBS) of carbon in the ultraviolet wavelength range is studied. Experiments are performed with graphite using a LIBS system, which consists of a 1064 nm Nd:YAG laser, a vacuum pump, a spectrometer and a vacuum chamber. The vacuum varies from 10 Pa to 1 atm. Atomic lines as well as singly and doubly charged ions are confirmed under the vacuums. A temporal evolution analysis of intensity is performed for the atomic lines of C I 193.09 nm and C I 247.86 nm under different vacuum conditions. Both time-integrated and time-resolved intensity evolutions under vacuums are achieved. The lifetimes of the two atomic lines have similar trends, which supports the point of view of a ‘soft spot’. Variations of plasma temperature and electron density under different vacuums are measured. This study is helpful for research on carbon detection using LIBS under vacuum conditions.

High power laser diodes of 2 μm AlGaAsSb/InGaSb type I quantum-wells**Project supported by the National Basic Research Program of China (Nos. 2014CB643903, 2013CB932904, 2011CB922201), the National Special Funds for the Development of Major Research Equipment and Instruments, China (No. 2012YQ140005), the National Natural Science Foundation of China (Nos. 61274013, U1037602, 61290303), and the Strategic Priority Research Program (B) of the

2 μm AlGaAsSb/InGaSb type-I quantum-well high-power laser diodes (LDs) are grown using molecular beam epitaxy. Stripe-type waveguide single LD (single emitter) and array LD (four emitters) devices without facet coatings are fabricated. For the single LDs (single emitter) device, the maximum output power under continuous wave (CW) operation is 0.5 W at 10 °C with a threshold current density of 150 A/cm2 and a slope efficiency of 0.17 W/A, the output powers under the pulse mode in the 5% duty cycles are much higher, up to 0.98 W. For the array LD devices, the maximum output powers are 1.02 W under the CW mode and 3.03 W under the pulse mode at room temperature.

Development of Smart Electric Power System (SEPS) Laboratory for Advanced Research and Undergraduate Education

In this work, the author discusses development of the Smart Electric Power System (SEPS) Laboratory at The College of New Jersey (TCNJ). The fully reconfigurable six-bus, three-phase power system hardware operates with ratings of 208 VLL (at 60 Hz) and 0.2 kW. It is composed of various synchronous generators with associated prime movers, induction motors with associated dynamometers, transformers, transmission lines, contactors, constant-impedance loads, renewable generation-emulator modules, battery storage devices, and appropriate power electronic converters. The SEPS lab significantly expands the ability of faculty and students at TCNJ to study energy problems, providing a sound foundation for the institution's small but growing power engineering program. The National Science Foundation Major Research Instrumentation Program provided external funding for the hardware.

Determinants of Students’ Observance of Library Regulations in Federal Polytechnic Nekede, Owerri, Imo State, Nigeria

This paper studied the determinants of students’ observance of library regulations in Federal Polytechnic Nekede, Owerri. The survey design was used. The population of the study consisted of all the 400 registered users of the library from which a sample of 196 was drawn. The questionnaire structured using the 4-point scale was the major research instrument. The data collected were analyzed using the mean rating scale and 2.50 was the cut-off point. The findings showed that 5 out of the 6 determinants stated by the researchers, namely, user education, availability of information resources, staff attitude, disciplinary measures and security measures have influence on students’ observance of library regulations while operating hours as a determinant does not have influence on students’ observance of library regulations. Based on the findings, the study recommended that the determinants that encourage observance of library regulations should be continued and improved with electronic monitor added to the other security measures.