CRISPR/Cas9 system in breast cancer therapy: advancement, limitations and future scope.

Cancer is one of the major causes of mortality worldwide, therefore it is considered a major health concern. Breast cancer is the most frequent type of cancer which affects women on a global scale. Various current treatment strategies have been implicated for breast cancer therapy that includes surgical removal, radiation therapy, hormonal therapy, chemotherapy, and targeted biological therapy. However, constant effort is being made to introduce novel therapies with minimal toxicity. Gene therapy is one of the promising tools, to rectify defective genes and cure various cancers. In recent years, a novel genome engineering technology, namely the clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein-9 (Cas9) has emerged as a gene-editing tool and transformed genome-editing techniques in a wide range of biological domains including human cancer research and gene therapy. This could be attributed to its versatile characteristics such as high specificity, precision, time-saving and cost-effective methodologies with minimal risk. In the present review, we highlight the role of CRISPR/Cas9 as a targeted therapy to tackle drug resistance, improve immunotherapy for breast cancer.

The impact of logging roads on dung beetle assemblages in a tropical rainforest reserve.

The demand for timber products is facilitating the degradation and opening up of large areas of intact habitats rich in biodiversity. Logging creates an extensive network of access roads within the forest, yet these are commonly ignored or excluded when assessing impacts of logging on forest biodiversity. Here we determine the impact of these roads on the overall condition of selectively logged forests in Borneo, Southeast Asia. Focusing on dung beetles along > 40 km logging roads we determine: (i) the magnitude and extent of edge effects alongside logging roads; (ii) whether vegetation characteristics can explain patterns in dung beetle communities, and; (iii) how the inclusion of road edge forest impacts dung beetle assemblages within the overall logged landscape. We found that while vegetation structure was significantly affected up to 34 m from the road edge, impacts on dung beetle communities penetrated much further and were discernible up to 170 m into the forest interior. We found larger species and particularly tunnelling species responded more than other functional groups which were also influenced by micro-habitat variation. We provide important new insights into the long-term ecological impacts of tropical logging. We also support calls for improved logging road design both during and after timber extraction to conserve more effectively biodiversity in production forests, for instance, by considering the minimum volume of timber, per unit length of logging road needed to justify road construction. In particular, we suggest that governments and certification bodies need to highlight more clearly the biodiversity and environmental impacts of logging roads.

Land-sharing versus land-sparing logging: reconciling timber extraction with biodiversity conservation.

Selective logging is a major driver of rainforest degradation across the tropics. Two competing logging strategies are proposed to meet timber demands with the least impact on biodiversity: land sharing, which combines timber extraction with biodiversity protection across the concession; and land sparing, in which higher intensity logging is combined with the protection of intact primary forest reserves. We evaluate these strategies by comparing the abundances and species richness of birds, dung beetles and ants in Borneo, using a protocol that allows us to control for both timber yield and net profit across strategies. Within each taxonomic group, more species had higher abundances with land-sparing than land-sharing logging, and this translated into significantly higher species richness within land-sparing concessions. Our results are similar when focusing only on species found in primary forest and restricted in range to Sundaland, and they are independent of the scale of sampling. For each taxonomic group, land-sparing logging was the most promising strategy for maximizing the biological value of logging operations.

Selective­logging and oil palm: multitaxon impacts, biodiversity indicators, and trade­offs for conservation planning.

Strong global demand for tropical timber and agricultural products has driven large-scale logging and subsequent conversion of tropical forests. Given that the majority of tropical landscapes have been or will likely be logged, the protection of biodiversity within tropical forests thus depends on whether species can persist in these economically exploited lands, and if species cannot persist, whether we can protect enough primary forest from logging and conversion. However, our knowledge of the impact of logging and conversion on biodiversity is limited to a few taxa, often sampled in different locations with complex land-use histories, hampering attempts to plan cost-effective conservation strategies and to draw conclusions across taxa. Spanning a land-use gradient of primary forest, once- and twice-logged forests, and oil palm plantations, we used traditional sampling and DNA metabarcoding to compile an extensive data set in Sabah, Malaysian Borneo for nine vertebrate and invertebrate taxa to quantify the biological impacts of logging and oil palm, develop cost-effective methods of protecting biodiversity, and examine whether there is congruence in response among taxa. Logged forests retained high species richness, including, on average, 70% of species found in primary forest. In contrast, conversion to oil palm dramatically reduces species richness, with significantly fewer primary-forest species than found on logged forest transects for seven taxa. Using a systematic conservation planning analysis, we show that efficient protection of primary-forest species is achieved with land portfolios that include a large proportion of logged-forest plots. Protecting logged forests is thus a cost-effective method of protecting an ecologically and taxonomically diverse range of species, particularly when conservation budgets are limited. Six indicator groups (birds, leaf-litter ants, beetles, aerial hymenopterans, flies, and true bugs) proved to be consistently good predictors of the response of the other taxa to logging and oil palm. Our results confidently establish the high conservation value of logged forests and the low value of oil palm. Cross-taxon congruence in responses to disturbance also suggests that the practice of focusing on key indicator taxa yields important information of general biodiversity in studies of logging and oil palm.

Red hot chili pepper. A new Calluella stoliczka, 1872 (Lissamphibia: Anura: Microhylidae) from Sarawak, East Malaysia (Borneo).

A new brightly-coloured (olive and red) species of microhylid frog of the genus Calluella Stoliczka 1872 is described from the upper elevations of Gunung Penrissen and the Matang Range, Sarawak, East Malaysia (Borneo). Calluella capsa, new species, is diagnosable in showing the following combination of characters: SVL up to 36.0 mm; dorsum weakly granular; a faint dermal fold across forehead; toe tips obtuse; webbing on toes basal; lateral fringes on toes present; outer metatarsal tubercle present; and dorsum greyish-olive, with red spots; half of venter bright red, the rest with large white and dark areas. The new species is the eighth species of Calluella to be described, and the fourth known from Borneo. A preliminary phylogeny of Calluella and its relatives is presented, and the new taxon compared with congeners from Malaysia and other parts of south-east Asia. 

Synthesis, antimicrobial activity and application of polymers of praseodymium complexes based on pyridine nitrogen oxide.

The traditional pyridine nitrogen oxide-based antimicrobial agents are often associated with health risks due to heavy metal enrichment. To mitigate this concern, we synthesized two novel complexes, Pr2(mpo)6(H2O)2 and Pr(hpo)(mpo)2(H2O)2, and integrated rare-earth salts, Hhpo (2-hydroxypyridine-N-oxide) and Nampo (2-mercapto-pyridine-N-oxide sodium salt). These complexes were characterized through infrared analysis, elemental analysis, thermogravimetric analysis, and X-ray crystallographic analysis. Our comparative analyses demonstrate that the synthesized rare-earth complexes exhibit stronger antimicrobial activity against Staphylococcus aureus (S. aureus ATCC6538) and Escherichia coli (E. coli ATCC25922) compared to the ligands and rare-earth salts alone. Quantitative results revealed the lowest inhibitory concentrations of the two complexes against S. aureus ATCC6538 and E. coli ATCC25922 at 3.125 µg mL-1, 6.25 µg mL-1, 3.125 µg mL-1 and 6.25 µg mL-1, respectively. Preliminary investigations indicated that the antibacterial mechanism of these complexes involved promoting intracellular substance exudation to achieve antibacterial effects. Incorporation of these complexes into polymeric antimicrobial films resulted in a potent antimicrobial effect, achieving a 100% inhibition rate against S. aureus ATCC6538 and E. coli ATCC25922 at a low addition level of 0.6 wt%. Our results suggest that nitrogen oxide-based praseodymium complexes have potential for various antimicrobial applications.

Synthesis of cerium-based flame retardant containing phosphorus and its impact on the flammability of polylactic acid.

The synthesis and characterization of [Ce2(PPPA)4(OH)2]·4H2O, wherein PPPA denotes 3-(hydroxy(phenyl)phosphoryl)propanoate, were conducted. Its potential as a flame-retardant additive for poly(L-lactic acid) (PLA) in conjunction with ammonium polyphosphate (APP) was investigated. Remarkably, with just incorporation of the 1 % Ce-complex and 4 % APP, the resulting PLA composite (PLA-8) meets the V-0 standard, exhibiting an impressive limiting oxygen index (LOI) of 29.4 %. Moreover, the introduction of the Ce-complex leads to a significant extension of ignition time (TTI), a significant 24.1 % decrease in total heat release (THR) compared to pure PLA, and a notable increase in residual carbon rate from 0.3 % to 3.51 %. Although PLA-8 exhibits a minor decline of 8.7 % in tensile strength and 3.4 % in elongation at break, respectively, compared to pure PLA, there is a substantial improvement of 32.2 % in Young's modulus and 29.9 % in impact resistance. These results emphasise the potential of cerium-based phosphorus-containing flame retardants, with cerium playing a key role in enhancing the flammability characteristics of PLA. This study contributes to the development of sustainable and fire-resistant materials in polymer chemistry.

Reliable, verifiable and efficient monitoring of biodiversity via metabarcoding.

To manage and conserve biodiversity, one must know what is being lost, where, and why, as well as which remedies are likely to be most effective. Metabarcoding technology can characterise the species compositions of mass samples of eukaryotes or of environmental DNA. Here, we validate metabarcoding by testing it against three high-quality standard data sets that were collected in Malaysia (tropical), China (subtropical) and the United Kingdom (temperate) and that comprised 55,813 arthropod and bird specimens identified to species level with the expenditure of 2,505 person-hours of taxonomic expertise. The metabarcode and standard data sets exhibit statistically correlated alpha- and beta-diversities, and the two data sets produce similar policy conclusions for two conservation applications: restoration ecology and systematic conservation planning. Compared with standard biodiversity data sets, metabarcoded samples are taxonomically more comprehensive, many times quicker to produce, less reliant on taxonomic expertise and auditable by third parties, which is essential for dispute resolution.

Therapeutic Effect of Human Adipocyte-derived Stem Cell-derived Exosomes on a Transgenic Mouse Model of Parkinson's Disease.

BACKGROUND/AIM: Stem cell therapy and regenerative medicine are promising for treating Parkinson's disease (PD) not only for the potential for cell replacement but also for the paracrine effect of stem cell secretion, especially proteins and nucleotide-enriched exosomes. This study investigated the neuroprotective effect of exosomes secreted from human adipocyte-derived stem cells (hADSCs) on PD. MATERIALS AND METHODS: hADSCs were isolated from the visceral fat tissue of individuals without PD who underwent bariatric surgery and were validated using surface markers and differentiation ability. Exosomes were isolated from the culture medium of hADSCs through serial ultracentrifugation and validated. Condensed exosomes were administered intravenously to 12-week-old MitoPark mice, transgenic parkinsonism mouse model with conditional knockout of mitochondrial transcription factor A in dopaminergic neurons, monthly for 3 months. Motor function, gait, and memory were assessed monthly, and immunohistochemical analysis of neuronal and inflammatory markers was performed at the end of the experiments. RESULTS: The hADSC-derived exosome-treated mice exhibited better motor function in beam walking and gait analyses than did the untreated mice. In the novel object recognition tests, the exosome-treated mice retained better memory function. Immunohistochemical analysis revealed that although exosome treatment did not prevent the loss of dopaminergic neurons in the substantia nigra of mice, it down-regulated microglial activation and neuroinflammation in the midbrain. CONCLUSION: hADSC-derived exosomes were neuroprotective in this in vivo mouse model of PD, likely because of their anti-inflammatory effect. Use of hADSC-derived exosomes may offer several beneficial effects in stem cell therapy. Since they can also be produced at an industrial level, they are a promising treatment option for PD and other neurodegenerative diseases.

Green and economic flame retardant prepared by the one-step method for polylactic acid.

Resolving the flammability of poly(L-lactic acid) (PLA) while ensuring its environmental friendliness and preserving key flame retardancy and mechanical properties represents a critical challenge. We have successfully developed a highly efficient and environmentally friendly flame retardant called Hexamethylenediamine tetramethylene phosphonic acid amine (HDME). The flame retardancy of PLA/HDME composites was significantly improved, as indicated by the LOI value of 29.1 % and UL-94 V-0 rating for PLA/3.5 HDME with only 3.5 % HDME addition. The results show a 23.4 % reduction in the total heat release (THR), a 40.0 % increase in the time to ignition (TTI), and a 21.2 % increase in the flame propagation index (FPI) compared to original PLA. Flame retardant mechanism of HDME involves the gas phase, condensed phase, and interrupted heat exchange effects. The HDME also preserved the original mechanical properties of PLA, with the elongation at break and tensile strength retention of PLA/3.5 HDME reaching 93.05 % and 89.65 %. This work provides a simple and efficient method for flame retardant modification of PLA, which can expand its application scope.

Feasibility and Toxicity of Interval-Compressed Chemotherapy in Asian Children and Young Adults with Sarcoma.

Twelve Asian patients with sarcoma received interval-compressed (ic-) chemotherapy scheduled every 14 days with a regimen of vincristine (2 mg/m2), doxorubicin (75 mg/m2), and cyclophosphamide (1200-2200 mg/m2) (VDC) alternating with a regimen of ifosfamide (9000 mg/m2) and etoposide (500 mg/m2) (IE), with filgrastim (5-10 mcg/kg/day) between cycles. Carboplatin (800 mg/m2) was added for CIC-rearranged sarcoma. The patients were treated with 129 cycles of ic-VDC/IE with a median interval of 19 days (interquartile range [IQR], 15-24 days. Median nadirs (IQR) were neutrophil count, 134 (30-396) × 106/L at day 11 (10-12), recovery by day 15 (14-17) and platelet count, 35 (23-83) × 109/L at day 11 (10-13), recovery by day 17 (14-21). Fever and bacteremia were observed in 36% and 8% of cycles, respectively. The diagnoses were Ewing sarcoma (6), rhabdomyosarcoma (3), myoepithelial carcinoma (1), malignant peripheral nerve sheath tumor (1), and CIC-DUX4 Sarcoma (1). Seven of the nine patients with measurable tumors responded (one CR and six PR). Interval-compressed chemotherapy is feasible in the treatment of Asian children and young adults with sarcomas.

Reduced-impact logging and biodiversity conservation: a case study from Borneo.

A key driver of rain forest degradation is rampant commercial logging. Reduced-impact logging (RIL) techniques dramatically reduce residual damage to vegetation and soils, and they enhance the long-term economic viability of timber operations when compared to conventionally managed logging enterprises. Consequently, the application of RIL is increasing across the tropics, yet our knowledge of the potential for RIL also to reduce the negative impacts of logging on biodiversity is minimal. We compare the impacts of RIL on birds, leaf-litter ants, and dung beetles during a second logging rotation in Sabah, Borneo, with the impacts of conventional logging (CL) as well as with primary (unlogged) forest. Our study took place 1-8 years after the cessation of logging. The species richness and composition of RIL vs. CL forests were very similar for each taxonomic group. Both RIL and CL differed significantly from unlogged forests in terms of bird and ant species composition (although both retained a large number of the species found in unlogged forests), whereas the composition of dung beetle communities did not differ significantly among forest types. Our results show little difference in biodiversity between RIL and CL over the short-term. However, biodiversity benefits from RIL may accrue over longer time periods after the cessation of logging. We highlight a severe lack of studies investigating this possibility. Moreover, if RIL increases the economic value of selectively logged forests (e.g., via REDD+, a United Nations program: Reducing Emissions from Deforestation and Forest Degradation in Developing Countries), it could help prevent them from being converted to agricultural plantations, which results in a tremendous loss of biodiversity.

Preservation versus division of ilioinguinal nerve on open mesh repair of inguinal hernia: a meta-analysis of randomized controlled trials.

BACKGROUND: Chronic groin pain after inguinal hernia repair, a serious problem, is caused by entrapment of the ilioinguinal nerve either by mesh or development of fibrosis. Division of the ilioinguinal nerve during hernioplasty has been found to reduce the incidence of chronic groin pain. However, the traditional approach favors preservation of the ilioinguinal nerve during open hernia repair. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials that compared the outcomes of preservation versus division of the ilioinguinal nerve during open mesh repair of inguinal hernia. The primary outcome was the incidence of groin pain; secondary outcomes were numbness and sensory loss. RESULTS: We reviewed six trials with 1,286 patients. We found no difference between the groups for the incidence of groin pain or numbness at 1, 6, and 12 months after open mesh inguinal repair. The incidence of sensory loss or change was significantly higher in the division group than in the preservation group at 6 months [risk ratio (RR) 1.25; 95 % confidence interval (CI) 1.02-1.53] and at 12 months (RR 1.55; 95 % CI 1.01-2.37) postoperatively. No significant differences between the groups were noted at any other points in time. CONCLUSIONS: Preservation of the ilioinguinal nerve during open mesh repair of inguinal hernia is associated with a decreased incidence of sensory loss at 6 and 12 months postoperatively compared with that of the division technique. No significant differences were found between the groups for chronic groin pain or numbness.

Degraded lands worth protecting: the biological importance of Southeast Asia's repeatedly logged forests.

Southeast Asia is a hotspot of imperiled biodiversity, owing to extensive logging and forest conversion to oil palm agriculture. The degraded forests that remain after multiple rounds of intensive logging are often assumed to be of little conservation value; consequently, there has been no concerted effort to prevent them from being converted to oil palm. However, no study has quantified the biodiversity of repeatedly logged forests. We compare the species richness and composition of birds and dung beetles within unlogged (primary), once-logged and twice-logged forests in Sabah, Borneo. Logging had little effect on the overall richness of birds. Dung beetle richness declined following once-logging but did not decline further after twice-logging. The species composition of bird and dung beetle communities was altered, particularly after the second logging rotation, but globally imperiled bird species (IUCN Red List) did not decline further after twice-logging. Remarkably, over 75 per cent of bird and dung beetle species found in unlogged forest persisted within twice-logged forest. Although twice-logged forests have less biological value than primary and once-logged forests, they clearly provide important habitat for numerous bird and dung beetle species. Preventing these degraded forests from being converted to oil palm should be a priority of policy-makers and conservationists.

A Novel Signature of CCNF-Associated E3 Ligases Collaborate and Counter Each Other in Breast Cancer.

Breast cancer (BRCA) malignancy causes major fatalities amongst women worldwide. SCF (Skp1-cullin-F-box proteins) E3 ubiquitin ligases are the most well-known members of the ubiquitination-proteasome system (UPS), which promotes cancer initiation and progression. Recently, we demonstrated that FBXL8, a novel F-box protein (SCFF-boxes) of SCF E3 ligase, accelerates BRCA advancement and metastasis. Since SCFF-boxes is a key component of E3 ligases, we hypothesized that other SCFF-boxes besides FBXL8 probably collaborate in regulating breast carcinogenesis. In this study, we retrospectively profiled the transcriptome of BRCA tissues and found a notable upregulation of four SCFF-box E3 ligases (FBXL8, FBXO43, FBXO15, and CCNF) in the carcinoma tissues. Similar to FBXL8, the knockdown of FBXO43 reduced cancer cell viability and proliferation, suggesting its pro-tumorigenic role. The overexpression of CCNF inhibited cancer cell progression, indicating its anti-tumorigenic role. Unexpectedly, CCNF protein was markedly downregulated in BRCA tissues, although its mRNA level was high. We showed that both E3 ligases, FBXL8 and FZR1, pulled down CCNF. Double knockdown of FBXL8 and FZR1 caused CCNF accumulation. On the other hand, CCNF itself pulled down a tumorigenic factor, RRM2, and CCNF overexpression reduced RRM2. Altogether, we propose a signature network of E3 ligases that collaboratively modulates CCNF anti-cancer activity. There is potential to target BRCA through modulation of the partnership axes of (i) CCNF-FBXL8, (ii) CCNF-FZR1, and (iii) CCNF-RRM2, particularly, via CCNF overexpression and activation and FBXL8/FZR1 suppression.

4,4'-[Oxalylbis(azanediyl)]dipyridinium bis(perchlorate).

In the title molecular salt, C(12)H(12)N(4)O(2) (2+)·2ClO(4) (-), the complete cation is generated by crystallographic inversion symmetry. In the crystal, the cations and anions are linked via N-H⋯O and N-H⋯(O,O) hydrogen bonds, forming a three-dimensional framework.

Human FBXL8 Is a Novel E3 Ligase Which Promotes BRCA Metastasis by Stimulating Pro-Tumorigenic Cytokines and Inhibiting Tumor Suppressors.

The initiation and progression of breast cancer (BRCA) is associated with inflammation and immune-overactivation, which is critically modulated by the E3 ubiquitin ligase. However, the underlying mechanisms and key factors involved in BRCA formation and disease advancement remains under-explored. By retrospective studies of BRCA patient tissues; and gene knockdown and gain/loss-of-function studies, we uncovered a novel E3 ligase, FBXL8, in BRCA. A signature expression profile of F-box factors that specifically target and degrade proteins involved in cell death/survival, was identified. FBXL8 emerged as a prominent member of the F-box factors. Ex vivo analysis of 1349 matched BRCA tissues indicated that FBXL8 promotes cell survival and tumorigenesis, and its level escalates with BRCA progression. Knockdown of FBXL8 caused: (i) intrinsic apoptosis, (ii) inhibition of cell migration and invasion, (iii) accumulation of two tumor-suppressors, CCND2 and IRF5, and (iv) downregulation of cancer-promoting cytokines/chemokines; all of which curtailed the tumor microenvironment and displayed potential to suppress cancer progression. Co-IP study suggests that two tumor-suppressors, CCND2 and IRF5 are part of the immune-complex of FBXL8. The protein levels of CCND2 and IRF5 inversely correlated with FBXL8 expression, implying that FBXL8 E3 ligase was associated with the degradation of CCND2 and IRF5. Altogether, we propose the exploitation of the ubiquitin signaling axis of FBXL8-CCND2-IRF5 for anti-cancer strategies and potential therapeutics.

Surgical outcomes of robotic transanal minimally invasive surgery for selected rectal neoplasms: A single-hospital experience.

BACKGROUND: Rectal neoplasm is one of the most common malignancies worldwide. Screening programs for rectal neoplasm result in early diagnosis and a decrease in disease-related mortality and morbidity. In selected patients, early rectal cancer may be treated with local excision. Owing to poor exposure during conventional transanal excision, transanal minimally invasive surgery (TAMIS) was developed, and TAMIS is feasible for the local excision of selected rectal neoplasms. However, the limited range of motion is a major disadvantage of this operation. Therefore, robotic TAMIS was developed to resolve this issue. This paper describes the surgical outcomes of robotic TAMIS for selected rectal tumors. METHODS: The eligibility criteria for robotic TAMIS were as follows: benign neoplasms, early malignancy, complete remission after concurrent chemoradiotherapy, lesions located in the middle or lower rectum, and a lesion size of less than 5 cm. To gain access to the anal canal, a transanal access platform was used, and the da Vinci robotic system was mounted for surgery. Patient characteristics and surgical outcomes were recoded. RESULTS: A total of 23 patients were included, and the median tumor size was 2.5 cm (range: 1.1-4.5 cm) on average. The median tumor location was 5 cm (range: 2-8 cm) from the anal verge. The median length of hospital stay was 3 days (range: 1-10 days). No intraoperative complications were reported, and no patient readmission occurred. The median follow-up period was 9.6 months. No recurrent lesion was found in the follow-up period. CONCLUSION: Based on the short-term results, robotic TAMIS is a feasible and safe technique for the local excision of selected rectal neoplasms.

Luminescence properties and optimized structural conformations of the S0, S1 and T1 states of a tetranuclear formamidinate complex based on AuI and AgI metal ions.

N,N'-Bis(pyridin-4-yl)formamidine (4-pyfH) was reacted with AuI and AgI metal salts to form a novel tetranuclear complex, tetrakis[µ-N,N'-bis(pyridin-4-yl)formamidinato]digold(I)disilver(I), [Ag2Au2(C11H9N4)2] or [AuxAg4-x(4-pyf)4] (x = 0-4), 1, which is supported by its metallophilicity. Due to the potential permutation of the coordinated metal ions, six different canonical structures of 1 can be obtained. Complex 1 shows an emission at 501 nm upon excitation at 375 nm in the solid state and an emission at 438 nm upon excitation at 304 nm when dispersed in methanol. Time-dependent density functional theory (TD-DFT) calculations confirmed that these emissions can be ascribed to metal-to-ligand charge transfer (MLCT) processes. Moreover, the calculations of the optimized structural conformations of the S0 ground state, and the S1 and T1 excited states are discussed and suggest a distorted planar conformation for the tetranuclear Au2Ag2 complex.

The Role of Active Engagement of Peer Observation in the Acquisition of Surgical Skills in Virtual Reality Tasks for Novices.

OBJECTIVE: Peer-assisted learning has been regarded as an adjunct to teaching modalities. It remains inconclusive regarding the benefits of peer observation in skills learning. Hence, we investigated whether the active engagement (AE) of peer observation in addition to expert demonstration would facilitate the performance in the virtual reality (VR) tasks. SETTING/DESIGN: The programs involved 4 VR tasks including basic (camera targeting), intermediate (energy dissection and energy switching), and advanced (suture sponge) tasks in the da Vinci Skills Simulators, which were set up in the operating room at Taipei Medical University Hospital. Fifty medical students participated in the study. The AE of the participants was defined as the total number of peer observations in addition to expert observation before their performance. We assessed the correlations between AE and surgical task performance using Pearson correlation and the concept of learning analytics. PARTICIPANTS: Medical students (sixth-year students in Taiwan, equivalent to fourth-year students in the US system) from Taipei Medical University were recruited. RESULTS: AE was correlated with the energy dissection task (r = 0.329, p = 0.02) and marginally associated with the energy switching task (r = 0.271, p = 0.057). However, AE was not correlated with either task scores for camera targeting (r = 0.096, p = 0.509) or task scores for suture sponge (r = -0.091, p = 0.529). CONCLUSIONS: Our findings suggest that AE of peer observation may facilitate learning energy dissection task, which is an intermediate-level task, but not in other basic or advanced tasks in a VR context. The study highlights the potential effect of AE of peer observation on surgical learning based on a distinct level of tasks. Tasks that fit the learners' level are recommended. Nevertheless, the effectiveness of peer observation on surgical training still has to be explored to ensure favorable results and optimal learning outcomes.