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By Vijay Kumar Malesu Feb 14 2024 Reviewed by Lily Ramsey, LLM

In a recent study published in Scientific Reports, a group of researchers evaluated how melanin content and distribution affect ultraviolet (UV)-induced deoxyribonucleic acid (DNA) damage in skin, using reconstructed human epidermis (RHE) models.

Study:  Significance of melanin distribution in the epidermis for the protective effect against UV light . Image Credit: rangizzz/Shutterstock.com Background 

While ultraviolet radiation (UVR) is crucial for vitamin D and endorphins, its overexposure increases the risk of skin cancer through DNA damage.

This damage occurs via UV-B absorption and UV-A-induced radicals, leading to specific DNA lesions. Thanks to melanin, skin pigmentation offers substantial photoprotection, notably reducing cancer rates in darker skin.

Melanin's effectiveness is attributed to its UV-blocking, antioxidant, and radical-neutralizing properties. Nonetheless, the role of melanin is complex, as it may also enhance cell sensitivity to UVR damage.

This contradiction prompts a need for further research to understand melanin's dual effects on photoprotection and photosensitization in skin cancer dynamics. About the study 

In the present study, RHE models developed from primary epidermal keratinocytes and melanocytes of Asian-Caucasian and Afro-American donors were categorized into tanned and light based on their melanin content, established through a newly validated method on ex vivo human skin.

This method involved melanin extraction and spectrometric analysis at 500 nm wavelength, correlating melanin levels with the Individual Typological Angle (ITA°), a measure of skin pigmentation.

Ex vivo human skin samples, sourced from healthy individuals of various ethnic backgrounds undergoing surgery, were used to calibrate the melanin quantification process. These samples allowed researchers to classify the RHE models according to melanin content, facilitating a comparison between light and tanned models. Related StoriesGenetics of estrogen production linked to endometrial cancer risk in postmenopausal womenPlant-based diet linked to less erectile dysfunction, urinary incontinence in prostate cancer patientsTiny device could help improve safety, effectiveness of cell therapy for spinal cord injury patients

The study assessed DNA damage in these models following UV irradiation, employing immunohistochemical staining to quantify damage.

Additionally, the effect of UV exposure on radical formation was examined using Electron Paramagnetic Resonance (EPR) spectroscopy, revealing insights into the oxidative stress induced by UV light in different melanin concentrations.

A critical aspect of the research was investigating melanin distribution within the epidermis, utilizing techniques like Fontana-Masson staining and Two-Photon Excited Fluorescence Lifetime Imaging Microscopy (TPE-FLIM).

These methods provided a detailed view of melanin's localization, contributing to understanding its protective versus potential photosensitizing effects. Study results 

After extracting melanin from human epidermis samples and RHE, researchers quantified the total melanin content spectrometrically by measuring absorbance at 500 nm.

In ex vivo skin samples, melanin content varied significantly, correlating strongly with the skin's ITA°, indicating a methodological validation. This approach was then applied to RHE, revealing distinct melanin levels between tanned and light models.

The correlation between melanin content and ITA° was used to categorize RHE models by skin color, confirming the method's applicability across different epidermal sources.

The study further evaluated DNA damage through immunohistochemical staining, quantifying the extent of damage by the presence of cyclobutane-pyrimidine dimers (CPD) in cells post-UVR exposure.

Results showed significant DNA damage across all RHE models immediately after exposure, with variances in damage levels based on the type of UVR and the model's pigmentation.

Notably, tanned RHE models exhibited more damage than light ones, especially after specific types of UV irradiation. This damage assessment highlighted potential photoprotection discrepancies tied to melanin content and distribution.

Additionally, the research investigated radical formation post-irradiation, finding that tanned RHE models produced more free radicals than light models under certain conditions, suggesting melanin's complex role in the skin's response to UV exposure.

Contrary to in vivo skin, where melanin typically encapsulates keratinocyte nuclei, providing a protective barrier, tanned RHE models displayed a non-homogeneous melanin distribution. This misallocation potentially undermines melanin's protective efficacy against UVR.

The examination extended to the melanin coverage within basal cells, revealing a stark contrast between in vivo conditions and tanned RHE models.

In vivo, melanin distribution was relatively uniform across different skin types, whereas tanned RHE showed minimal melanin presence, diverging significantly from expected patterns. This inconsistency underscores a fundamental difference in melanin's protective mechanism in vitro versus in vivo. Conclusions 

To summarize, melanin plays a dual role in the human body, acting as a skin pigment that protects against solar radiation while also exhibiting photosensitizing properties linked to skin pathologies like melanoma.

This complex molecule's protective and harmful effects on the skin are still not fully understood.

Research using reconstructed RHE of tanned and light skin types has sought to delve deeper into melanin's multifaceted roles, examining how melanin content and distribution influence UV-induced DNA damage and the generation of reactive oxygen species (ROS).

These studies have shown that despite higher melanin levels in tanned models suggesting greater protection, all models exhibited significant DNA damage following UV exposure, challenging the notion of melanin's protective efficacy.

The distribution of melanin, particularly its concentration in certain cells and absence in others, may contribute to its photosensitizing effects, leading to increased free radical production and DNA damage.  Journal reference:

Zamudio Díaz, D.F., Busch, L., Kröger, M. et al. (2024) Significance of melanin distribution in the epidermis for the protective effect against UV light. Sci Rep. doi: https://doi.org/10.1038/s41598-024-53941-0. https://www.nature.com/articles/s41598-024-53941-0 

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Technology

Musk says Tesla is expanding Austin robotaxi service, adding Grok to cars

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Musk says Tesla is expanding Austin robotaxi service, adding Grok to cars

Tesla CEO Elon Musk attends an opening ceremony for Tesla China-made Model Y program in Shanghai, China, on Jan. 7, 2020.

Aly Song | Reuters

Tesla CEO Elon Musk said the company is expanding its robotaxi service area and bringing xAI’s Grok to vehicles as it rolled out a new iteration of the artificial intelligence chatbot.

Shares gained about 3%.

Musk said on X that Grok, his AI chatbot that praised Adolf Hitler and posted a barrage of antisemitic comments recently, will be available in Tesla vehicles “next week at the latest.”

xAI officially launched the Grok 4 update overnight as the company continued to face backlash for the vitriol written by the chatbot.

In response to a user post on his social media platform X, Musk said the company is expanding its Austin, Texas robotaxi service area this weekend. He also said Tesla is awaiting regulatory approval for a launch in the Bay Area “probably in a month or two.”

Read more CNBC tech news

The expansion of robotaxi and Grok integration comes at a fraught time for Musk and his empire.

Tesla set its annual shareholder meeting for Nov. 6, a Thursday filing showed. A group of investors recently called on the electric vehicle company to schedule the meeting.

Its last shareholder meeting was in June 2024, as Musk established himself as a major backer of President Donald Trump‘s reelection campaign. Musk later led the Trump administration’s Department of Government Efficiency, known as DOGE.

After stepping down from DOGE at the end of May, Musk has openly feuded with Trump on social media over the major tax bill, with the president suggesting the government look at cutting contracts for Musk’s companies.

Shares have tanked from their post-election high over investor concerns that the public fight could hamper Tesla. Slowing sales and rising competition also stifled some investor appetite.

Tesla shares fell Monday, with the company losing $68 billion in value after Musk continued to blast Trump’s “Big Beautiful Bill” and said he was establishing his own political party, the “America Party.”

The world’s richest man suffered another blow Wednesday when Linda Yaccarino stepped down as CEO of his social media platform X, leaving the role after a turbulent two years for the company.

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Environment

The Hyundai IONIQ 6 N is here and it’s even better than expected

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The Hyundai IONIQ 6 N is here and it's even better than expected

The Hyundai IONIQ 6 N is finally here, and it delivers. Hyundai’s electric sports car is loaded with fun new features, a sleek design (including a massive rear wing), 641 horsepower, and much more.

Meet the Hyundai IONIQ 6 N

After teasing the new model for the first time last month, Hyundai created quite a buzz. Now, we are finally getting our first look at the upgraded high-performance EV.

Hyundai unveiled the new IONIQ 6 N at the famed Goodwood Festival of Speed on Thursday in West Sussex, England. The upgraded model follows Hyundai’s first high-performance EV, the IONIQ 5 N.

At the event, the company boasted that its new electric sports car marks “a pivotal milestone in Hyundai N’s electrification journey,” adding “Hyundai N is once again redefining the boundaries of high-performance electrification with the debut of the IONIQ 6 N.”

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The IONIQ 6 N delivers an impressive 641 horsepower (478 kW) and 77 Nm of torque, enabling a 0 to 100 km/h (0 to 62 mph) sprint in just 3.2 seconds. Its top speed is about 160 mph (257 km/h).

Hyundai-IONIQ-6-N-EV
Hyundai IONIQ 6 N (Source: Hyundai)

That’s when using Hyundai’s Launch Control, one of the many performance features the new EV offers. Like its other N models, the IONIQ 6 is based on three pillars: Corner Rascal, Racetrack Capability, and, of course, an Everyday Sportscar.

Powered by two electric motors, a 223 hp (166 kW) at the front and another 378 hp (282 kW) motor at the rear, for a combined 600 hp (448 kW).

Hyundai-IONIQ-6-N-EV
Hyundai IONIQ 6 N (Source: Hyundai)

Redefining the EV driving experience

The upgraded IONIQ 6 “redefines the EV driving experience,” according to Hyundai, thanks to its advanced in-house vehicle control software.

Central to this is Hyundai’s N Active Sound + system, which mimics the feel and sound of a traditional engine. An added N e-Shift simulates shifting gears.

Hyundai-IONIQ-6-N-EV
Hyundai IONIQ 6 N interior (Source: Hyundai)

And that’s just the start. Other performance features, such as N Drift Optimizer, N Grin Boost, and N Torque Distribution, give you even more control over the vehicle while delivering increased power.

The IONIQ 6 N is powered by an 84 kWh battery, providing a WLTP range of up to 291 miles (469 km). However, EPA figures will be revealed closer to launch. Given the IONIQ 5 N has an EPA-estimated range of up to 221 miles, you can expect it to be slightly higher when it arrives.

With a 350 kW DC fast charger, Hyundai’s new performance EV can recharge from 10% to 80% in about 18 minutes.

With a length of 4,935 mm, a width of 1,940 mm, and a height of 1,495 mm, the IONIQ 6 N is about the size of the Porsche Taycan.

Hyundai will showcase the new high-performance EV during the hillclimb event alongside other models like the IONIQ 5 N, IONIQ 6 N Drift Spec, and IONIQ 6 N with N Performance parts. Hyundai promises each vehicle brings unique capabilities to the event, “guaranteeing a dynamic and thrilling on-track experience for all attendees.” Check back soon for more info.

What do you think of Hyundai’s new electric sports car? Would you buy one over the Porsche Taycan? Let us know in the comments.

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Environment

Elon Musk says Grok is coming to Tesla vehicles just after it went full Hitler

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Elon Musk says Grok is coming to Tesla vehicles just after it went full Hitler

Elon Musk said that Tesla owners will “soon” have access to Grok, a large language developed by Musk’s xAI startup, days after the AI started calling itself ‘MechaHitler’.

Yesterday, xAI launched Grok 4, the latest version of its large language model.

The new model is benchmarking very well, but that’s generally the case with the latest model to come out. It edges the latest models from Google and OpenAI on intelligence by a few points, but it falls behind on speed:

At the launch event, Musk announced that Grok will “soon” be integrated into Tesla vehicles.

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This is something that the CEO has been discussing since founding xAI, which has been controversial because Musk has also positioned Tesla to compete in the AI space. He even stepped down from his role at OpenAI due to a “conflict of interest with Tesla.”

The announcement of the imminent integration of Grok into Tesla vehicles comes just days after the language model went haywire on X and started praising Hitler, referring to itself as ‘MechaHitler’, and made several antisemitic comments.

xAI acknowledge the issue and put Grok on timeout while they fixed it:

We are aware of recent posts made by Grok and are actively working to remove the inappropriate posts. Since being made aware of the content, xAI has taken action to ban hate speech before Grok posts on X. xAI is training only truth-seeking and thanks to the millions of users on X, we are able to quickly identify and update the model where training could be improved.

The “bug” came just a few weeks after Musk stated that he was displeased with Grok supporting left-wing narratives, even though it didn’t say anything inncurate, and that he would update Grok to “fix” it.

Now, the large language model (LLM) is expected to power the new voice assistant inside Tesla vehicles.

LLMs are becoming quite common in cars, especially premium vehicles. Ford, Mercedes-Benz, Stellantis, and a few others have all integrated Chat-GPT in some models.

Many Chinese automakers have also developed their own and deployed them in cars, even entry-level ones.

Tesla is playing catch up on that front.

Electrek’s Take

As I have previously stated, I think Musk is setting up Tesla to invest or even merge with xAI at a ridiculous valuation – making Tesla shareholders virtually pay twice for Twitter, which is now part of xAI.

This is how he will be able to gain wider control over the company’s share.

Of course, it will be widely challenged in court. In fact, shareholders have already filed a lawsuit alleging that Musk was in breach of fiduciary duties to Tesla shareholders when he started xAI.

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