ACM SIGGRAPH Art Papers, SIGGRAPH 2015 | Year: 2015
This paper explores the author's Light Pattern project, a programming language where code is written with photographs rather than text. Light Pattern explores programming languages as the most direct conduit between human thinking and machine logic. It emphasizes the nuance, tone and personal style inherent in all code. It also creates an algorithmic photography structured by the programs one writes, but not ultimately computer-generated. The paper looks at connections to both hobbyist/hacker culture (specifically esolangs) and to art-historical impulses and movements such as Fluxus and Oulipo. © 2015 Daniel Temkin.
Stelwagen K.,SciLactis Ltd. |
Phyn C.V.C.,DairyNZ Ltd. |
Davis S.R.,LIC |
Guinard-Flament J.,Agrocampus Ouest |
And 3 more authors.
Journal of Dairy Science | Year: 2013
Most dairy cows throughout the world are milked twice daily. In intensive dairying systems, however, it is not uncommon to increase milking frequency to between 3 and 6 times daily to increase milk production. Reducing milking frequency is much less common; however, once-daily milking of dairy cows, practiced either strategically during certain parts of the lactation or for the entire lactation, is not uncommon in key dairying countries where less emphasis is placed on milk production per cow. The practice fits well with more extensive dairy production systems, particularly those based on grazed pasture. A feature of once-daily milking is that it reduces milk yield by approximately 22%, depending on stage of lactation, breed, and parity, and it may adversely affect lactation length and persistency. However, it can offer several positive farm management options, especially related to labor requirements and farm working expenses. In addition, it may provide a tool to better manage the metabolism and energy balance of cows during early lactation or during periods of pasture deficit, and it may help to improve reproductive performance and animal health and welfare. Once-daily milking, representing one extreme of the mammary function spectrum, has attracted considerable research interest over the years. Consequently, substantial scientific information is available on its effects on mammary function, at both the physiological and molecular levels. This review focuses instead on the management of the cow milked once daily, covering the production response in relation to breed, stage of lactation, and parity, and its effect on energy status, reproduction, health and welfare, as well as on milk composition and processability. © 2013 American Dairy Science Association.
Journal of Dairy Science | Year: 2014
The objective was to compare reproductive performance of liquid sex-sorted (SS) semen with that of conventional (CON) semen in lactating dairy cows. Between 2011 and 2013, commercial dairy herds (n=101, 203, and 253 for 2011, 2012, and 2013, respectively) with predominantly Holstein-Friesian cows were enrolled in a contract mating program to produce surplus heifers for export using liquid SS semen. During the spring mating period, each herd was allocated with liquid SS semen at 50% of its daily requirement and the remaining daily requirement was allocated with CON liquid semen. Sperm for producing SS semen was sorted by Sexing Technologies NZ Ltd. (Hamilton, New Zealand) and then packaged using the liquid semen technology of LIC (Hamilton, New Zealand) at a dose of 1×106 sperm. Artificial insemination (AI) with liquid SS semen was carried out between 43 and 46h after collection. Conventional semen straws contained 1.25×106, 1.75×106, or 2×106 sperm for semen to be used on d 1, 2, or 3 after collection, respectively. Only CON inseminations on the same days as when SS semen was used were included in the comparison. Herd managers biased usage of SS semen toward cows with a longer postpartum interval before the mating start date (64.0 vs. 62.8 d), cows of higher genetic merit (NZ$107.0 vs. NZ$98.4), younger cows (5.1 vs. 5.2yr), and cows in which they had more confidence of being genuinely in estrus as measured by a lower percentage of short returns between 1 and 17 d (5.3 vs. 7.5%). After adjusting for these factors, the estimated difference in nonreturn rate between AI with SS and CON semen over the 3 seasons was -3.8 percentage points (SS=70.2% vs. CON=74.0%; SS/CON=94.9%). The estimated maximum difference in calving rate per AI between SS and CON semen was -3.1 percentage points for 2011 (SS=51.2% vs. CON=54.3%; SS/CON=94.3%) and -3.0 percentage points for 2012 (SS=49.7% vs. CON=52.6%; SS/CON=94.5%). Calving data for 2013 were not yet available. The percentage of heifer calves born to AI with SS semen was 87.0% for 2011 and 85.8% for 2012, both of which were lower than the expectation of 90% mainly due to misidentification of calf dams in seasonal dairy herds calving on pasture. In summary, results in this report showed that liquid SS semen only required half the dose rate of frozen SS semen to achieve a reproductive performance of over 94% of CON semen in lactating dairy cows. Careful planning and a robust distribution network are required to avoid semen wastage and to maximize the benefit of liquid SS semen. © 2014 American Dairy Science Association.
No statistical methods were used to predetermine sample size. The experiments were not randomized and the investigators were not blinded to allocation during experiments and outcome assessment. Human HOIP and HOIL-1L cDNA were purchased from Open Biosystems (cloneIDs 4653017 and 3877587, respectively). HOIP RBR (residues 696–1,072), HOIP RING2L (residues 853–1,072) and full-length HOIL-1L were cloned into the pET-NKI-6xHis-3C-LIC vector30 coding for an N-terminal 6×His tag with a 3C protease cleavage site. HOIP UBA–RBR (residues 475–1,072) was cloned into a pET-NKI-6×His-eGFP-3C-LIC vector that codes for a 3C-cleavable His-tagged enhanced green fluorescent protein (eGFP) followed by the HOIP sequence. Human UbcH5B and Cdc34 DNA were a gift from M. Petroski. Coding sequences for UbcH13 and Uev1a were extracted out of a human cDNA library (Agilent Megaman). For crystallization, UbcH5B (residues 2–147) with the mutations S22R (to prevent backside ubiquitin binding31) and C85K (to enable covalent ubiquitin linkage21) was cloned into the pET-NKI-6×His-3C-LIC vector. UbcH5B without S22R and C85K mutations (used for enzymatic assays), Cdc34, UbcH13 and Uev1a were cloned into the same vector. Untagged mono-ubiquitin with native N and C termini, used for crystallization and linear ubiquitination assays, was cloned into the pET29 vector (Novagen) using NdeI/XhoI restriction sites. N-terminally blocked mono-ubiquitin used for thioester assays was cloned in the pET-NKI-6×His-3C-LIC vector. Untagged linear di-ubiquitin was cloned with overlap extension PCR and ligated into the pET29 vector (Novagen) using NdeI/XhoI restriction sites. N- and C-terminally blocked di-ubiquitin with a N-terminal His tag and a C-terminal Ala–Ser sequence was cloned into the pET-NKI-6×His-3C-LIC vector. Human ubiquitin-activating enzyme E1 (Ube1) was cloned into a pET28 vector resulting in an N-terminal His tag. For NF-κB assays full-length HOIP with an N-terminal Flag tag and HOIL-1L with an N-terminal myc tag were cloned into pcDNA3.1(+) (Invitrogen) using EcoRI/NotI restriction sites. Mutations in UbcH5B, ubiquitin and HOIP were introduced using standard site-directed mutagenesis techniques. All proteins were expressed in BL21(DE3) E. coli after induction with 0.5 mM IPTG overnight at 20 °C. For expression of HOIP and HOIL-1L constructs, 0.5 mM ZnCl was added to the cultures before induction. Bacteria were harvested by centrifugation, lysed by addition of lysozyme and sonication in the presence of protease inhibitors (PMSF and leupeptin) and DNase. Lysates were cleared by centrifugation and His-tagged proteins were initially purified using Ni-NTA agarose (Qiagen). For HOIP RBR used for crystallization, and UbcH5B, Cdc34, UbcH13, Uev1a, wild-type ubiquitin to generate K48-linked di-ubiquitin and HOIL-1L His tags were removed by addition of 3C protease overnight at 4 °C. HOIP RBR and HOIL-1L were further purified using Superdex 200 10/300 GL or HiLoad 16/600 Superdex 200 pg size-exclusion chromatography columns (GE Healthcare) equilibrated in protein buffer (10 mM HEPES pH 7.9, 100 mM NaCl). UbcH5B used for biochemical assays was further purified on a Superdex 75 10/300 GL size-exclusion chromatography column (GE Healthcare) equilibrated in protein buffer. HOIP mutants for activity assays, and Cdc34, UbcH13 and Uev1a were desalted into protein buffer directly after Ni-NTA purification using PD MidiTrap G-25 desalting columns (GE Healthcare). Ube1 for biochemical assays was further purified using ion-exchange chromatography (Source Q) in 10 mM HEPES pH 7.9, 10 mM NaCl and eluted with a gradient from 10–500 mM NaCl. N-terminally His-tagged (di-)ubiquitin was purified using Ni-NTA as described above followed by size-exclusion chromatography using a Superdex 75 10/300 GL column (GE Healthcare) equilibrated in protein buffer or buffer exchange into protein buffer using PD MidiTrap G-25 desalting columns. To purify untagged mono- or di-ubiquitin, 0.5 mM EDTA and 100 mM sodium acetate pH 4.5 were added to the bacterial lysates and lysates were cleared by centrifugation, diluted sevenfold with 50 mM sodium acetate pH 4.5 and applied to a Source S 10/100 ion exchange column (GE Healthcare) equilibrated in 50 mM sodium acetate pH 4.5. Ubiquitin was eluted with a 0–500 mM NaCl gradient and further purified by size-exclusion chromatography on a Superdex 75 10/300 GL column (GE Healthcare) equilibrated in protein buffer. His-eGFP-HOIP was purified using size-exclusion chromatography as described for HOIP RBR, followed by 3C cleavage and removal of His-eGFP via a second round of size-exclusion chromatography. All proteins were generally flash frozen in liquid nitrogen in small aliquots and stored at −80 °C. UbcH5B~ubiquitin linkage was performed based on published methods21. Briefly, Ube1, UbcH5B(S22R/C85K) and ubiquitin were mixed and buffer exchanged into 50 mM Tris pH 10, 150 mM NaCl using PD-10 desalting columns (GE Healthcare). 10 mM MgCl , 5 mM ATP and 1 mM TCEP were added and the protein solution was incubated at 37 °C for 16 h. The completeness of the reaction was monitored using SDS–PAGE and covalently linked UbcH5B~ubiquitin was purified from unreacted proteins and Ube1 using a Superdex 75 10/300 GL size-exclusion chromatography column (GE Healthcare) equilibrated in protein buffer. HOIP RBR was mixed with a 1.3-fold molar excess of UbcH5B~ubiquitin and applied to a Superdex 200 10/300 GL size-exclusion chromatography column equilibrated in protein buffer. Complex formation and purity was confirmed using SDS–PAGE, and complex containing fractions were pooled and concentrated to ~12 mg ml−1 for crystallization. Crystallization was performed using the vapour diffusion technique in sitting drop MRC 96-well plates (Molecular Dimensions). Initial crystals were obtained mixing HOIP/UbcH5B~ubiquitin complex solution with an equimolar amount of free ubiquitin in the Morpheus Screen (Molecular Dimensions). Subsequently, 2 μl of the protein complex were mixed with 0.6 μl reservoir solution (0.1 M Morpheus Buffer 3 pH 8.5 (Tris/Bicine), 0.12 M Morpheus Alcohols Mix (0.02 M each of 1,6-hexanediol; 1-butanol; 1,2-propanediol (racemic); 2-propanol; 1,4-butanediol; 1,3-propanediol), 30% Morpheus P550MME_P20K mix (20% PEG550MME, 10% PEG20K) and 8% glycerol) in MRC 48-well plates (Molecular Dimensions). Crystals appeared after about one week at 12 °C and were cryo-cooled, and evaluated on a rotating anode X-ray generator (Rigaku FR-E superbright). Seeding and dehydration of the crystals was performed to improve crystal diffraction. For successful dehydration, reservoir was slowly added to the protein drop (3 × 0.5 μl within ~2 h) and subsequently equilibrated overnight at 12 °C against a reservoir solution with increased P550MME_P20K concentration by adding 11 μl 60% Morpheus P550MME_P20K stock solution to 50 μl reservoir solution. The new reservoir solution was then slowly added to the protein drop (3 × 0.5 μl, followed by 2 × 1 μl with removal of 1 μl each in the last steps). After further overnight equilibration, crystals were harvested from the drop and directly cryo-cooled in a cryogenic nitrogen stream at 100 K. Crystals diffracted in-house to 4–6 Å. Complete diffraction data were measured at 100 K at beamline 23ID-D of the General Medical Sciences and Cancer Institutes Structural Biology Facility at the Advanced Photon Source (GM/CA @ APS), Argonne National Laboratory. Despite their size (common dimensions of ~200 × 140 × 100 μm3) crystals exhibited substantial inhomogeneity resulting in split and smeared diffraction spots. Using raster scans32, a suitable region for data collection could be identified at the edge of the crystal. Using a small (20 μm diameter) beam, split spots could be separated to allow reliable indexing and integration. Utilization of a small beam necessitated higher flux to retain reliable diffraction. To mitigate the radiation damage, the total dose was distributed over a 100-μm stretch of the crystal by using the ‘helical’ mode of ‘vector’ data collection as implemented in JBluIce33. Data were measured at 1.282 Å wavelength with a Pilatus3 6M pixel array detector with a 1-mm-thick sensor (Dectris). Data were collected from a single crystal and indexed, integrated and scaled in XDS/XSCALE34. Data were further processed using AIMLESS35 from the CCP4 suite36 with a resolution cut-off of 3.48 Å, resulting in an and CC1/2 = 0.648 in the highest resolution shell. Phasing was carried out in Phaser37 using an MR-SAD protocol as implemented in PHENIX38. For this, independent molecular replacement searches were initially performed for the RING2L domain of HOIP (from PDB: 4LJP (ref. 14)), UbcH5B (from PDB: 3A33 (ref. 39)), and ubiquitin (from PDB: 4LJP (ref. 14)) with the four C-terminal residues deleted. Various ambiguous solutions were identified that could not be separated, and Zn2+ sites could not be identified using MR-SAD due to incompleteness of resultant models. However, manual inspection revealed that some MR solutions contained ubiquitin oriented near identically to the symmetry-related donor ubiquitin observed in the HOIP RING2L/ubiquitin-ubiquitin transfer complex (PDB: 4LJP (ref. 14)). Based on this observation, a trimmed search model was created that contained a complex of the core of HOIP RING2L (with residues 906–924 and 949–999 removed) and C-terminally truncated ubiquitin. An MR search using this model found a single solution for two copies of the complex. After successful iterative searches for two UbcH5B molecules and two further ubiquitin molecules, MR-SAD using Phaser identified 15 distinct Zn2+ sites including the known Zn2+ sites in the RING2L domain of HOIP. Further molecular replacement in Phaser using a single unit of the initial HOIP RING2L/UbcH5B~ubiquitin complex (without the additional second ubiquitin), and the NMR structure of HOIP IBR (zinc atoms removed, deposited in Protein Data Bank40 under PDB accession number 2CT7, unpublished) correctly placed a single HOIP IBR domain, which was then manually copied to the other NCS-related HOIP in the asymmetric unit. For molecular replacement of the HOIP RING1, Sculptor41 was used to generate a search model based on the structure of the RING1 domain of HHARI (PDB: 4KBL (ref. 11)). However, Phaser was not able to correctly place this domain, probably owing to the low sequence conservation of only 27% identity. However, since mutational analysis of HOIP suggested that the RING/E2 interaction is preserved between RING-type E3 ligases and RBR-type E3 ligases5, we overlaid the E2 of the published RNF4–RING/UbcH5A~ubiquitin structure (PDB: 4AP4 (ref. 21)) with the E2 in our structure and then used this overlay to add the RING1 model generated by Sculptor. This overlay placed the HOIP RING1 Zn2+-coordinating residues near the last remaining free Zn2+ ions found earlier by Phaser MR-SAD, indicating correct placement of the RING1 domain. In the final round of molecular replacement, the two additional ubiquitin (Ub ) molecules were reinstated at the RING1–IBR interface. At this stage, Refmac42 was used for refinement using settings optimized for low-resolution refinement43 including ‘jelly body refinement’ and Babinet scaling. ProSMART44 was used to generate external restraints against high-resolution structures (PDB: 4LJO (ref. 14) for HOIP RING2L and ubiquitin, and PDB: 2ESK (ref. 45) for UbcH5B). After this, clear extra electron density became visible for the unmodelled helical linker regions of the RING1–IBR and IBR–RING2L transitions and for other regions omitted in the initial search models. Further model building and refinement was manually performed in Coot46 and Refmac. During refinement additional clear positive difference map electron density became visible and Phaser was used to place one additional UbcH5B molecule (UbcH5B ) into this density. TLS restraints were generated using the TLSMD server47 and NCS restraints were used throughout refinement. One overall B-factor was refined in Refmac. In later rounds of refinement the PDB_REDO server48 was used for refinement optimization and MolProbity49 was used for structure validation. Data processing and refinement statistics are summarized in Extended Data Fig. 2b. Ramachandran statistics were calculated using MolProbity and 94.8% of all residues are in favoured regions, 4.9% in allowed regions and 0.3% are outliers. The final structure has a MolProbity score of 1.75 (100th percentile). In the final structure the two HOIP RBR molecules (see also Extended Data Fig. 3) are defined by electron density from residues 699 to 707, 711 to 948, 969 to 991, and 996 to 1,011 (chain A) and 699 to 754, 760 to 957, 967 to 1,015, 1,019 to 1,035 and 1,054 to 1,066 (chain B). The catalytic UbcH5B~ubiquitin conjugates are defined from UbcH5B residues 3 to 147 and ubiquitin residues 1 to 76 (chains C and E), and UbcH5B residues 2 to 147 and ubiquitin residues 1 to 76 (chains D and F). The allosteric ubiquitin chains (chains G and H) are defined from residues 1 to 76 and the additional UbcH5B (chain I) is defined from residues 2 to 146. PHENIX was used to calculate simulated annealing (SA) composite omit maps and feature enhanced maps (FEM). All molecular figures were prepared in PyMOL (Schrödinger, LLC). K48-linked and K63-linked ubiquitin chains were formed through a linkage-specific enzymatic reaction using Cdc34 and UbcH13/Uev1a E2 ubiquitin-conjugating enzymes, respectively, as described in the literature50. Ubiquitin chains were separated using ion-exchange chromatography as described above for purification of mono-ubiquitin. Purified K48-linked di-ubiquitin was directly desalted into protein buffer using PD-10 desalting columns, whereas K63-linked di-ubiquitin was further purified on a Superdex 75 10/300 GL size-exclusion chromatography column equilibrated in protein buffer. Native ubiquitin without additional residues was used to generate di-ubiquitin chains for ITC experiments, whereas N-terminally blocked ubiquitin was used to form K48-linked di-ubiquitin for testing allosteric activation of HOIP RBR. Linear ubiquitin formation assays were performed in 50 mM HEPES pH 7.9, 100 mM NaCl, 10 mM MgCl and 0.6 mM DTT using 200 nM E1, 1 μM UbcH5B, 1 μM HOIP RBR or HOIP RING2L and 40 μM untagged ubiquitin. Reactions were started by addition of 10 mM ATP and were incubated at 30 °C for 2 h. Samples were taken at the indicated time points and treated with 50 mM sodium acetate pH 4.5 as described previously6, mixed with SDS sample buffer and analysed by SDS–PAGE using 12% Bolt Bis-Tris gels (Life Technologies). Proteins were visualized with Coomassie Brilliant blue dye. To test the activating effect of linear di-ubiquitin on auto-inhibited HOIP UBA–RBR, 5 μM HOIP UBA–RBR was pre-incubated with N- and C-terminally blocked linear di-ubiquitin or HOIL-1L at the indicated concentrations before addition of the remaining assay components. Samples were taken after 60 min and subsequently treated as described above. To monitor HOIP~ubiquitin thioester ubiquitin transfer from UbcH5B to HOIP, Ube1 (100 nM), UbcH5B (4 μM) and N-terminally blocked ubiquitin (32 μM) were mixed in 50 mM HEPES pH 7.9, 100 mM NaCl, 10 mM MgCl and 5 mM ATP and incubated at 25 °C for 5 min when 2 μM HOIP RBR was added. Samples were taken 10 s after HOIP addition, quenched by addition of pre-heated SDS protein-loading buffer without DTT, and run on a 12% SDS–PAGE gel (Life Technologies). The 10-s time point used was empirically determined with a time-course experiment (Extended Data Fig. 9g). Gels were stained with Coomassie Brilliant blue dye and scanned on a Li-COR Odyssey scanner using the 700 nm (red) channel. For the thioester transfer assay shown in Fig. 3d, 200 nM Ube1, 2 μM UbcH5B, 8 μM HOIP RBR, 8 μM N-terminally blocked ubiquitin and 10 mM ATP were used and samples taken after 30 s. Furthermore, proteins were transferred to a PVDF membrane and ubiquitin was visualized on a LI-COR Odyssey scanner at 800 nm using an anti-ubiquitin antibody (P4D1, Santa Cruz, 1:200 dilution in TBST (50 mM Tris pH 7.4, 150 mM NaCl, 0.05% Tween-20)) followed by an IRDye 800CW secondary antibody (LI-COR, 1:10,000 dilution in TBST). All quantitative experiments shown in graphs were performed in triplicates and band intensities were quantified using the ImageStudio software (LI-COR). HOIP thioester transfer activity was calculated as the fraction of HOIP~ubiquitin to total HOIP for each mutant and normalized against thioester transfer activity of wild-type HOIP. Data were analysed in GraphPad Prism using two-tailed unpaired Student’s t-test or one-way ANOVA followed by Tukey’s post hoc test. To test the allosteric activation of HOIP RBR by linear di-ubiquitin, a modified ubiquitin transfer assay was performed. HOIP RBR was pre-incubated with N- and C-terminally blocked linear di-ubiquitin at the indicated final concentrations for 5 min at 25 °C. At the same time, Ube1, UbcH5B, ubiquitin and ATP were premixed and incubated for 5 min at 25 °C, resulting in fully loaded UbcH5B~ubiquitin. Both mixtures were subsequently mixed together, resulting in final concentrations of 100 nM Ube1, 2 μM UbcH5B, 8 μM N-terminally blocked ubiquitin and 2 μM HOIP RBR in the final buffer described for the standard ubiquitin transfer assay. Samples were taken after 30 s and further treated as described for the standard transfer assay. A 30-s time point was determined to give the best results in this assay, in which lower E2 and mono-ubiquitin concentrations were used, resulting in an overall slower reaction rate. The experiments comparing the effects of linear versus K48-linked di-ubiquitin (Extended Data Fig. 9e) were performed similarly, with the difference that all samples were incubated with apyrase (Sigma) for 5 min to deplete ATP before addition of HOIP/di-ubiquitin and prevent E2-loading of K48-linked di-ubiquitin, which features a free C terminus on one of the ubiquitin units. Sedimentation equilibrium experiments were performed in a ProteomeLab XL-I (Beckman Coulter) analytical ultracentrifuge. HOIP RBR/UbcH5B~ubiquitin as used for crystallization was loaded into a 6-channel equilibrium cell at 5.0, 2.5 and 1.25 μM concentration and centrifuged at 10,000 r.p.m., 20 °C in an An-50 Ti 8-place rotor until equilibrium was achieved. Data were analysed using HeteroAnalysis software (J. L. Cole and J. W. Lary, University of Connecticut; http://www.biotech.uconn.edu/auf/). ITC experiments were performed on an ITC200 calorimeter (Microcal). Aliquots (2 μl each) of 500–650 μM UbcH5B~ubiquitin or di-ubiquitin solution were injected into the cell containing 40–50 μM HOIP RBR or HOIP RBR/di-ubiquitin complexes. The experiments were performed at 23 °C in buffer containing 10 mM HEPES pH 7.9, 100 mM NaCl. For titrations of UbcH5B~ubiquitin into HOIP RBR/di-ubiquitin complexes, HOIP RBR was pre-incubated with an equimolar amount of di-ubiquitin before the ITC experiments. Data were analysed using the Origin software (Microcal). Human embryonic kidney (HEK) 293T cells (ATCC) were co-transfected with NF-κB-luc reporter plasmid that contains an NF-κB response element upstream of the promoter driving the luciferase reporter gene, pGL4.74[hRluc/TK] control vector (Promega) and epitope tagged Flag-HOIP or myc-HOIL-1L pcDNA3.1(+) plasmids in 6-well plates in triplicates using Lipofectamine 2000 transfection reagent. Since this assay could be carried out in a variety of cellular contexts, HEK293T cells were used because they are easy to transfect and suitable for the assay. The cells tested negative for mycoplasma contamination. Empty pcDNA3.1(+) vector was used as control. After 36 h, cells were lysed and 20 μl cell lysates were used to measure firefly luciferase and Renilla luciferase (transfection control) signals using the dual luciferase reporter assay system according to the manufacturer’s protocol (Promega). Data were analysed in GraphPad Prism and one-way ANOVA followed by Tukey’s post hoc tests were used for statistical analysis. Immunoblotting was performed with anti-Flag (clone M2, Sigma-Aldrich) and anti-myc (clone 9E10, Sigma-Aldrich) antibodies, to confirm equivalent wild-type and mutant protein expression levels.
Lithium-ion capacitors (LICs) are hybrid energy storage devices that have the potential to bridge the gap between conventional high-energy lithium-ion batteries and high-power capacitors by combining their complementary features. The challenge for LICs has been to improve the energy storage at high charge−discharge rates by circumventing the discrepancy in kinetics between the intercalation anode and capacitive cathode. In this article, the rational design of new nanostructured LIC electrodes that both exhibit a dominating capacitive mechanism (both double layer and pseudocapacitive) with a diminished intercalation process, is reported. Specifically, the electrodes are a 3D interconnected TiC nanoparticle chain anode, synthesized by carbothermal conversion of graphene/TiO hybrid aerogels, and a pyridine-derived hierarchical porous nitrogen-doped carbon (PHPNC) cathode. Electrochemical properties of both electrodes are thoroughly characterized which demonstrate their outstanding high-rate capabilities. The fully assembled PHPNC//TiC LIC device delivers an energy density of 101.5 Wh kg−1 and a power density of 67.5 kW kg−1 (achieved at 23.4 Wh kg−1), and a reasonably good cycle stability (≈82% retention after 5000 cycles) within the voltage range of 0.0−4.5 V.