Specific Substructure Research Articles

Topological Characterization for Triangular, RegularTriangular Oxides and Silicates Networks

Chemical graph theory can be studied with the aid of mathematical tools called m-polynomials. M-Polynomials offer a potent tool for computing different topological indices associated with vertex degrees and analyzing degree-based structural information in graphs. By counting specific substructure types within them, they are able to encode information about the structure of molecules or networks. In this article, we have developed M-Polynomials with the help of different topological invariants such as first Zagreb (M1(β)), second Zagreb (M2(β)), second modified Zagreb (Mm2(β)), inverse sum (I(β)), harmonic index (H(β)) and Randic index (Rα0(β)) for the molecular structures of Triangular oxide TOX(r), Regular triangular oxide RTOX(r), Triangularsilicate TSL(r) & Regular triangular silicate RTSL(r) networks to introduce new closed formulas to get better understanding the applications of M-Polynomials and topological indices in mathematical chemistry especially in the field of QSAR and QSPR study with the help of some software like MATLAB. We have also discussed the graphical behaviors of the above-mentioned structures.

Investigation of lignin substructures participating in self-assembly for the synthesis of monodisperse lignin spherical particles

The intricate structure of lignin, characterized by a mix of hydrophilic components and hydrophobic structures from its aliphatic and aromatic constituents, poses challenges in creating monodisperse particles. This is due to the need for precise modulation of self-assembly kinetics. Herein, we explore a correlation between the substructure of lignin and its capacity for self-assembly. We have conducted an in-depth investigation into the interactions between hydrophilic groups, such as phenolic and aromatic-OH, and monolignols with interunit linkages that are involved in the formation of lignin particles (LPs). A high degree of hydrophilicity with a condensed structure is crucial for high supersaturation levels, which in turn determines the growth phase and leads to small LPs. An approach based on tailoring the supersaturation level which is contingent on the structural characteristics of extracted organosolv lignin was used to obtain remarkably uniform LPs with mean diameters of approximately 230 and 480 nm. The results of this study have the potential to serve as a foundation for the preparation of monodisperse LPs derived from various lignin sources as well as for the development of methods to extract lignin containing a specific chemical substructure.

Comparison between ammonium formate and ammonium fluoride in the analysis of stratum corneum lipids by reversed phase chromatography coupled with high resolution mass spectrometry

Lipids are key constituents of the barrier function in the human stratum corneum (SC), which is the outermost layer of the epidermis and amenable to non-invasive sampling by tape stripping. The three major lipid classes in the SC, i.e., ceramides, fatty acids, and cholesterol, present equimolar concentration. Liquid chromatography coupled with mass spectrometry (LCMS) is elective in profiling lipids in the SC in both positive and negative ion modes. Nevertheless, the latter one allows for the simultaneous detection of the three major epidermal components of the SC. Determination of ceramides in the SC poses analytical challenges due to their wide range of structures and concentrations especially in the case of limited sample amounts. Ammonium formate is a commonly used modifier added to the mobile phase to assist ionization. However, it introduces uncertainty in the identification of ceramides when operating in negative ion mode, even with high resolution MS. We tested the advantages of using fluoride in the lipid profiling of SC and unambiguous identification of ceramides subclasses. The use of fluoride enhanced the ionization of ceramides, regardless the specific substructure, solved misidentification issues, and was successfully applied to the simultaneous detection of all three lipid classes in the human SC.

Association of Left Ventricular Myocardium Dose Exposure with Heart Failure in Lung Cancer Radiotherapy

The volume of left anterior descending (LAD) coronary artery dose receiving 15 Gy (LAD V15 Gy) has been associated with major adverse cardiac events (MACE; a composite endpoint of unstable angina, heart failure hospitalization/urgent visit, myocardial infarction, coronary revascularization, and cardiac death) and mortality in patients with locally advanced non-small cell lung cancer (LA-NSCLC) following radiotherapy (RT). With growing evidence supporting specific cardiac substructure dose exposure with distinct pathophysiologic cardiac endpoints, our objective was to assess whether RT dose to the left ventricular myocardium (LVM) was associated with the specific cardiac endpoints of heart failure (HF) vs. overall MACE. Retrospective analysis of 701 patients with LA-NSCLC treated with RT between 2003 and 2014. LAD was segmented manually, while LVM (excluding blood pool) was segmented using an open-source deep learning-based automated algorithm (TotalSegmentator; Wasserthal et al, 2022) and dosimetric parameters (mean, max, and VX Gy in 5 Gy increments) collected. HF was defined as any grade ≥3 Common Terminology Criteria for Adverse Event (CTCAE) HF or cardiomyopathy. Receiver operating curve and cut-point analyses estimating HF were performed. Fine and Gray and Cox regressions, adjusting for preexisting cardiovascular (CV) risk factors and other prognostic factors, were calculated. Of 701 patients, the median age was 65 years (interquartile range [IQR], 57-73), 51% were men. At a median follow up of 20 months (IQR, 8-45) following RT, there were 64 HF events. The median time to HF was 20 months (IQR, 9-43), with a 2-year cumulative incidence of 5.2%. The optimal cut-point for the LVM dose variable with the highest C-index predicting HF was LVM V10 Gy ≥10% (.58). By LVM V10 Gy cut point ≥10% vs <10%, the 2-year HF cumulative incidence was 7.2% vs 4.0% (p = .005). Adjusting for baseline CV risk, there was an increased risk of HF with LVM V10 Gy ≥10% (vs. <10%) (subdistribution hazard ratio [SHR] 2.81; 95% confidence interval [CI], 1.02-7.70; p = .045), but not LAD V15 Gy ≥10% (p>.3). Conversely, adjusting for baseline CV risk, there was an increased risk of MACE with LAD V15 Gy ≥10% (SHR = 19.70; 95% CI = 2.57-151.35; p = 0.004), but not LVM V10 Gy ≥10% (p>0.3). On all-cause mortality analysis, adjusting for CV and other prognostic factors, LAD V15 Gy ≥10% (HR = 1.4; 95% CI = 1.02-1.80; p = 0.036), but not LVM ≥10% (p>0.5), remained significantly associated with mortality. Left ventricular myocardium V10 ≥10%, is associated with the specific endpoint of HF, but not overall MACE, while LAD V15 ≥10% remained strongly associated with MACE and all-cause mortality, but not HF. These findings underscore the need to study the interaction between RT dose to specific substructures (i.e., myocardium) and pathophysiologically relevant cardiac endpoints (i.e., HF).

Explicating the role of amygdala substructure alterations in the link between hypoleptinemia and rumination in anorexia nervosa.

The amygdaloid complex plays a pivotal role in emotion processing and has been associated with rumination transdiagnostically. In anorexia nervosa (AN), we previously observed differential reductions of amygdala nuclei volumes (rostral-medial cluster substantially affected) and, in another study, elevated food-/weight-related rumination. Both amygdala volumes and rumination frequency correlated with characteristically suppressed leptin levels in AN. Thus, we hypothesized that amygdala nuclei alterations might be associated with AN-related rumination and potentially mediate the leptin-rumination relationship in AN. Rumination (food-/weight-related) was assessed using ecological momentary assessment for a 14-day period. We employed frequentist and Bayesian linear mixed effects models in females with AN (n = 51, 12-29 years, majority admitted to inpatient treatment) and age-matched healthy females (n = 51) to investigate associations between rostral-medial amygdala nuclei volume alterations (accessory basal, cortical, medial nuclei, corticoamygdaloid transitions) and rumination. We analyzed mediation effects using multi-level structural equation models. Reduced right accessory basal and cortical nuclei volumes predicted more frequent weight-related rumination in AN; both nuclei fully mediated the effect of leptin on weight-related rumination. In contrast, we found robust evidence for the absence of amygdala nuclei volume effects on rumination in healthy females. This study provides first evidence for the relevance of specific amygdala substructure reductions regarding cognitive symptom severity in AN and points toward novel mechanistic insight into the relationship between hypoleptinemia and rumination, which might involve the amygdaloid complex. Our findings in AN may have important clinical value with respect to understanding the beneficial neuropsychiatric effects of leptin (treatment) in AN and potentially other psychiatric conditions such as depression.

C. elegans Hemidesmosomes Sense Collagen Damage to Trigger Innate Immune Response in the Epidermis.

The collagens are an enormous family of extracellular matrix proteins that play dominant roles in cell adhesion, migration and tissue remodeling under many physiological and pathological conditions. However, their function mechanisms in regulating innate immunity remain largely undiscovered. Here we use C. elegans epidermis as the model to address this question. The C. elegans epidermis is covered with a collagen-rich cuticle exoskeleton and can produce antimicrobial peptides (AMPs) against invading pathogens or physical injury. Through an RNAi screen against collagen-encoding genes, we found that except the previously reported six DPY collagens and the BLI-1 collagen, the majority of collagens tested appear unable to trigger epidermal immune defense when damaged. Further investigation suggests that the six DPY collagens form a specific substructure, which regulates the interaction between BLI-1 and the hemidesmosome receptor MUP-4. The separation of BLI-1 with MUP-4 caused by collagen damage leads to the detachment of the STAT transcription factor-like protein STA-2 from hemidesmosomes and the induction of AMPs. Our findings uncover the mechanism how collagens are organized into a damage sensor and how the epidermis senses collagen damage to mount an immune defense.

Improved passivation ability via tuning dislocation cell substructures for FeCoCrNiMn high-entropy alloy fabricated by laser powder bed fusion

Elemental-decorated dislocation cell is a specific substructure in additively manufactured metals and alloys due to the intrinsic layer-by-layer rapid melting and solidification process, and the novel cellular structures would have significant influences on the service performances of the printed components. In this work, sub-micro Mn-decorated dislocation cells are verified in FeCoCrNiMn high-entropy alloys (HEAs) fabricated via laser powder bed fusion (L-PBF), and the related passivation capabilities are comparably investigated with the as-casted and heat-treated L-PBF counterparts (HEA-800, 800 °C for 2 h). The passive current density of L-PBF HEA-800 is the lowest in borate buffer solutions, while the as-casted HEAs show the highest corrosion rate therein. The high-density dislocation and the alleviation of Mn segregation at the cellular boundaries are conducive to the superior protectiveness (stable and thick passive film) for L-PBF HEA-800 and the underlying mechanisms for different passivation behaviors are discussed.

하이브리드 모델링 기법과 베이지안 최적화를 통한 엔진 마운트 응답개선

This paper presents a method for predicting and improving the response of the engine mount using hybrid modeling technique and Bayesian optimization. The hybrid modeling technique based on the FRF based substructuring (FBS) theory can improve the accuracy of results and reduce the required time and cost compared to full-FE analysis using both experimental and finite element results. Using FBS theory, a transfer function of complex system can be changed to transfer function of several simple substructures. At this time, the hybrid modeling technique replaces the transfer function of a specific substructure with the result of FE analysis. Using this method, it is possible to predict the effect of the design change in the entire system by changing the CAD model design for the substructure applied to FE analysis. Furthermore, an optimal design is proposed by applying the Bayesian optimization technique.

Evaluation of the InnoTyper21® system for the applications into trace and degraded DNA in the Korean population.

The InnoTyper 21® Human Identification kit consists of amelogenin and 20 bi-allelic Alus, retrotransposon markers existing abundantly in human genome. The InnoTyper 21® kit produces shorter amplicons (60-125 bp) than conventional short tandem repeat (STR) genotyping kit, then it is effective on the analysis of challengeable forensic samples including insufficient or highly degraded DNAs. Also, as the genotyping with InnoTyper21® kit is compatible with PCR and capillary electrophoresis, it is easy to incorporate into the workflow in forensic laboratories. In the internal validation of InnoTyper21® kit on sensitivity, degradation, and mixture studies for the evaluation in this study, we acquired full profiles on analyzing small concentration DNA (as low as 25 pg) and highly degraded DNA (up to 105 degradation index value). Through the Korean population study, forensic statistical parameters were investigated and a specific variant of T insertion in NBC51 was confirmed in six samples. Comparison of Korean population with five populations or 1000 Genomes Project data show Korean specific substructure. It is expected that the InnoTyper 21® kit will be used into the actual forensic cases, utilizing the population study investigated through this research.

Analysis of cardiac motion without respiratory motion for cardiac stereotactic body radiation therapy.

Purpose/objective(s)To study the heart motion using cardiac gated computed tomographies (CGCT) to provide guidance on treatment planning margins during cardiac stereotactic body radiation therapy (SBRT).Materials/methodsTen patients were selected for this study, who received CGCT scans that were acquired with intravenous contrast under a voluntary breath‐hold using a dual source CT scanner. For each patient, CGCT images were reconstructed in multiple phases (10%–90%) of the cardiac cycle and the left ventricle (LV), right ventricle (RV), ascending aorta (AAo), ostia of the right coronary artery (O‐RCA), left coronary artery (O‐LCA), and left anterior descending artery (LAD) were contoured at each phase. For these contours, the centroid displacements from their corresponding average positions were measured at each phase in the superior–inferior (SI), medial–lateral (ML), and anterior–posterior (AP). The average volumes as well as the maximum to minimum ratios were analyzed for the LV and RV.ResultsFor the six contoured substructures, more than 90% of the measured displacements were <5 mm. For these patients, the average volumes ranged from 191.25 to 429.51 cc for LV and from 91.76 to 286.88 cc for RV. For each patient, the ratios of maximum to minimum volumes within a cardiac cycle ranged from 1.15 to 1.54 for LV and from 1.34 to 1.84 for RV.ConclusionBased on this study, cardiac motion is variable depending on the specific substructure of the heart but is mostly within 5 mm. Depending on the location (central or peripheral) of the treatment target and treatment purposes, the treatment planning margins for targets and risk volumes should be adjusted accordingly. In the future, we will further assess heart motion and its dosimetric impact.

Intratumoral Distribution and pH-Dependent Drug Release of High Molecular Weight HPMA Copolymer Drug Conjugates Strongly Depend on Specific Tumor Substructure and Microenvironment.

Stimulus-sensitive polymer drug conjugates based on high molecular weight N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers carrying doxorubicin via a pH-dependent cleavable bond (pHPMA-Dox) were previously shown to be able to overcome multi-drug resistance. Nevertheless, a tumor type dependent differential response was observed. Although an improved and more selective tumor accumulation of pHPMA-Dox is generally achieved due to the enhanced permeability and retention (EPR) effect, little is known about the fate of these conjugates upon entering the tumor tissue, which could explain the different responses. In this study, we compared in vitro and in vivo accumulation and Dox-activation of pHPMA-Dox in three cancer cell line models (1411HP, A2780cis, HT29) and derived xenograft tumors using a near-infrared fluorescence-labeled pHPMA-Dox conjugate. Firstly, cytotoxicity assays using different pH conditions proved a stepwise, pH-dependent increase in cytotoxic activity and revealed comparable sensitivity among the cell lines. Using multispectral fluorescence microscopy, we were able to track the distribution of drug and polymeric carrier simultaneously on cellular and histological levels. Microscopic analyses of cell monolayers confirmed the assumed mechanism of cell internalization of the whole conjugate followed by intracellular cleavage and nuclear accumulation of Dox in all three cell lines. In contrast, intratumoral distribution and drug release in xenograft tumors were completely different and were associated with different tissue substructures and microenvironments analyzed by Azan- and Hypoxisense®-staining. In 1411HP tumors, large vessels and less hypoxic/acidic microenvironments were associated with a pattern resulting from consistent tissue distribution and cellular uptake as whole conjugate followed by intracellular drug release. In A2780cis tumors, an inconsistent pattern of distribution partly resulting from premature drug release was associated with a more hypoxic/acidic microenvironment, compacted tumor tissue with compressed vessels and specific pre-damaged tissue structures. A completely different distribution pattern was observed in HT29 tumors, resulting from high accumulation of polymer in abundant fibrotic structures, with small embedded vessels featuring this tumor type together with pronounced premature drug release due to the strongly hypoxic/acidic microenvironment. In conclusion, the pattern of intratumoral distribution and drug release strongly depends on the tumor substructure and microenvironment and may result in different degrees of therapeutic efficacy. This reflects the pronounced heterogeneity observed in the clinical application of nanomedicines and can be exploited for the future design of such conjugates.

A straightforward estimation of cardiac substructure exposure for clinical practice: example of breast rotational intensity modulated radiation therapy

Introduction. Mean heart dose (MHD) is the most widely used dosimetric parameter for cardiac sparing during treatment planning. Specific cardiac substructure exposure could be more clinically important, but MHD cannot provide the radiation oncologist with precise insight at the substructural level. Materials. We propose a straightforward method for estimating cardiac substructure exposure based on linear regressions between mean dose delivered to cardiac substructures and MHD. We focused on breast irradiation with intensity modulated radiation therapy as an application example. Correlations between mean dose to cardiac substructures and MHD were statistically significant and usually moderate (r > 0.5) or strong (r > 0.7), allowing the use of such linear regression models to estimate cardiac substructure exposure from MHD for clinical practice. Conclusion. This method can be extrapolated to other clinical situations for daily practice, albeit with some restrictions.

Analysis of Cardiac Motion without Respiratory Motion for Cardiac Stereotactic Body Radiation Therapy

PURPOSE/OBJECTIVE(S) To study the heart motion using cardiac gated computed tomographies (CGCT) to provide guidance on treatment planning margins during cardiac stereotactic body radiation therapy (SBRT). MATERIALS/METHODS Ten patients were selected for this study, who received CGCT scans that were acquired with intravenous contrast under a voluntary breath-hold using a dual source CT scanner. For each patient, CGCT images were reconstructed in multiple phases (10%-90%) of the cardiac cycle and the left ventricle (LV), right ventricle (RV), ascending aorta (AAo), ostia of the right coronary artery (O-RCA), left coronary artery (O-LCA), and left anterior descending artery (LAD) were contoured at each phase. For these contours, the centroid displacements from their corresponding average positions were measured at each phase in the superior-inferior (SI), medial-lateral (ML), and anterior-posterior (AP). The average volumes as well as the maximum to minimum ratios were analyzed for the LV and RV. RESULTS For the six contoured substructures, more than 90% of the measured displacements were <5 mm. For these patients, the average volumes ranged from 191.25 to 429.51 cc for LV and from 91.76 to 286.88 cc for RV. For each patient, the ratios of maximum to minimum volumes within a cardiac cycle ranged from 1.15 to 1.54 for LV and from 1.34 to 1.84 for RV. CONCLUSION Based on this study, cardiac motion is variable depending on the specific substructure of the heart but is mostly within 5 mm. Depending on the location (central or peripheral) of the treatment target and treatment purposes, the treatment planning margins for targets and risk volumes should be adjusted accordingly. In the future, we will further assess heart motion and its dosimetric impact.

Structure-based design of allosteric calpain-1 inhibitors populating a novel bioactivity space

Dimeric calpains constitute a promising therapeutic target for many diseases such as cardiovascular, neurodegenerative and ischaemic disease. The discovery of selective calpain inhibitors, however, has been extremely challenging. Previously, allosteric inhibitors of calpains, such as PD150606, which included a specific α-mercaptoacrylic acid sub-structure, were reported to bind to the penta-EF hand calcium binding domain, PEF(S) of calpain. Although these are selective to calpains over other cysteine proteases, their mode of action has remained elusive due to their ability to inhibit the active site domain with and without the presence of PEF(S), with similar potency. These findings have led to the question of whether the inhibitory response can be attributed to an allosteric mode of action or alternatively to inhibition at the active site. In order to address this problem, we report a structure-based virtual screening protocol as a novel approach for the discovery of PEF(S) binders that populate a novel chemical space. We have identified compound 1, Vidupiprant, which is shown to bind to the PEF(S) domain by the TNS displacement method, and it exhibited specificity in its allosteric mode of inhibition. Compound 1 inhibited the full-length calpain-1 complex with a higher potency (IC50 = 7.5 μM) than the selective, cell-permeable non-peptide calpain inhibitor, PD150606 (IC50 = 19.3 μM), where the latter also inhibited the active site domain in the absence of PEF(S) (IC50 = 17.8 μM). Hence the method presented here has identified known compounds with a novel allosteric mechanism for the inhibition of calpain-1. We show for the first time that the inhibition of enzyme activity can be attributed to an allosteric mode of action, which may offer improved selectivity and a reduced side-effects profile.

Modal properties of cyclically symmetric systems with central components vibrating as three-dimensional rigid bodies

This study investigates the vibration mode structure of general cyclically symmetric systems with central components vibrating as three-dimensional rigid bodies. This work does not rely on the assumptions of the system matrix symmetries; asymmetric inertia matrix, damping, gyroscopic, and circulatory terms can be present. In the equation of motion of a general cyclically symmetric system, the matrix operators are proved to have properties related to the cyclic symmetry. These symmetry-related properties are used to prove the modal properties of general cyclically symmetric systems. Only three types of modes can exist: substructure modes, translational-tilting modes, and rotational-axial modes. Each mode type is characterized by specific central component modal deflections and substructure phase relations. Instead of solving the full eigenvalue problem, all vibration modes and natural frequencies can be obtained by solving smaller eigenvalue problems associated with each type. This computational advantage is dramatic for systems with many substructures or many degrees of freedom per substructure.

Intelligent interpretation of mass spectra of natural products

Tandem mass spectrometry (MS/MS) plays an important role in the screening and structural characterization of natural products. In addition to general fragmentations, chemicals sharing a same particular structure often produce a common characteristic fragmentation pattern under MS/MS experiments which represent a specific characteristic substructure. Therefore, the class of unknown natural products can be predicted by the diagnostic fragment ions based on MS/MS. The peripheral groups of the chemicals within a class could be inferred by general fragmentation pattern. Based on above mentioned concepts, SmartMass, a software program was developed and implemented for intelligent interpretation of natural products.

Adaptive multicomponent nanocomposite coatings in surface engineering

This paper reviews experimental research on nanocomposite protective coatings of various chemical compositions and structure. For adaptive multielement and multilayer systems with specific phase composition, structure, substructure, stress state, and high functional properties, formation conditions are considered; the behavior of such systems under extreme operating conditions and in tribological applications is examined; the structural, phase, and chemical composition are discussed as well as the hardness, friction and wear at elevated temperatures; and the adhesive strength of hierarchical protective coatings is analyzed. Finally, the adaptive behavior under different tribological test conditions of multifunctional, multilayer coatings as a function of their properties and structure is examined.

Fault diagnosis of sensor networked structures with multiple faults using a virtual beam based approach

This paper presents a virtual beam based approach suitable for conducting diagnosis of multiple faults in complex structures with limited prior knowledge of the faults involved. The “virtual beam”, a recently-proposed concept for fault detection in complex structures, is applied, which consists of a chain of sensors representing a vibration energy transmission path embedded in the complex structure. Statistical tests and adaptive threshold are particularly adopted for fault detection due to limited prior knowledge of normal operational conditions and fault conditions. To isolate the multiple faults within a specific structure or substructure of a more complex one, a ‘biased running’ strategy is developed and embedded within the bacterial-based optimization method to construct effective virtual beams and thus to improve the accuracy of localization. The proposed method is easy and efficient to implement for multiple fault localization with limited prior knowledge of normal conditions and faults. With extensive experimental results, it is validated that the proposed method can localize both single fault and multiple faults more effectively than the classical trust index subtract on negative add on positive (TI-SNAP) method.

Sensing and Decision Making in Cyber-Physical Systems: The Case of Structural Event Monitoring

Wireless sensor networks (WSNs) are being suggested at an increasing rate for structural health monitoring (SHM). The objective is to monitor complex events (e.g., damage) in structures (e.g., an industrial machine and a high-rise building) that are usually carried out with wired-based SHM systems. However, monitoring events with a WSN deployed over large structures is challenging due to WSN constraints (high-resolution data transmission and energy) and the quality of monitoring. In this paper, we attempt to design a cyber-physical system (CPS) of structural event monitoring with WSNs and propose a novel model-based in-network decision making in the CPS named MODEM. We think of the idea of generic event detection (like target/object) schemes, and enable each sensor to sense and make a simplified local decision (0/1) on the complex events. We then think of the formation of engineering structures and find that a large physical structure consists of a number of substructures. We enable deployed sensors to be organized into groups in such a way that a groupwise final decision (e.g., 0/1) can be provided for each substructure independently so that the existence of an event (if there is any) in a specific substructure can be identified by WSNs. MODEM is fully distributed in nature, promises to have the monitoring quality similar to the original wired-based schemes, and consumes much less energy for transmissions and computations than existing schemes do. The effectiveness of MODEM is shown via both simulations and real experiments.

The Centrosome, a Multitalented Renaissance Organelle.

The centrosome acts as a microtubule-organizing center (MTOC) from the G1 to G2 phases of the cell cycle; it can mature into a spindle pole during mitosis and/or transition into a cilium by elongating microtubules (MTs) from the basal body on cell differentiation or cell cycle arrest. New studies hint that the centrosome functions in more than MT organization. For instance, it has recently been shown that a specific substructure of the centrosome-the mother centriole appendages-are required for the recycling of endosomes back to the plasma membrane. This alone could have important implications for a renaissance in our understanding of the development of primary cilia, endosome recycling, and the immune response. Here, we review newly identified roles for the centrosome in directing membrane traffic, the immunological synapse, and the stress response.